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Ingredient Glossary · Volatile Silicone

Cyclopentasiloxane D5

Decamethylcyclopentasiloxane · CAS 541-02-6 · CYCLOPENTASILOXANE (INCI)

Reshmi Silicon (ریشمی سلیکون) — Pakistan's premier volatile silicone carrier. Silky luxury on first contact, zero residue after evaporation. The backbone of every professional hair serum, silicone primer, and SPF formula — now available at Bio Shop™ Pakistan at cosmetic grade ≥99%, D4 impurity <0.1% (SCCS 2015 compliant).

CAS
541-02-6
Identifier
Volatile
Silicone
Ingredient Class
Leave-on
Permitted
EU Status
Scroll
Quick Reference

At a Glance

INCI / Common Names
CYCLOPENTASILOXANE · D5 · Decamethylcyclopentasiloxane · Cyclomethicone D5 · cVMS (cyclic volatile methyl siloxane)
CAS / EINECS / COSING
CAS 541-02-6 · EINECS 208-764-9
COSING Ref 75413 · EC No 208-764-9
Molecular Formula
C₁₀H₃₀O₅Si₅ · MW 370.77 g/mol
Cyclic 5-membered Si–O backbone
Physical Form
Water-thin, colorless, odorless liquid · Density 0.958–0.960 g/cm³ · Viscosity 3.8–4.2 mPa·s
Flash Point / Boiling Pt
Flash point 78–81°C (cc) — combustible
BP 210–212°C · Volatile at room temp
Refractive Index / D4
RI 1.395–1.398 at 25°C
D4 impurity <0.1% (Bio Shop™ grade — SCCS 2015)
Solubility
Immiscible with water · Miscible with all silicone oils, mineral oils, esters · Dissolves UV filters, retinol, fragrance
Halal Status
✓ Halal — 100% synthetic petrochemical silicone. No animal inputs, no ethanol, no fermentation at any stage of synthesis
Primary Function
Volatile carrier solvent · Skin conditioning agent · Sensory modifier · Hair conditioning agent · Antistatic
Recommended Use Level
Hair serums: 10–70% · Primers/face: 5–25% · Body lotions: 3–10% · Sunscreens: 15–30% · EU wash-off: max 0.1%
EU Cosmetics Reg Status
✓ Leave-on: Fully permitted, no concentration ceiling. Wash-off: max 0.1% since Jan 2020 (REACH Annex XVII Entry 70)
FDA Status
✓ CIR Expert Panel confirmed safe. No concentration restriction in USA for leave-on or rinse-off products
Urdu / Pakistan Name
Reshmi Silicon (ریشمی سلیکون) — Silky Silicone · Bakhaar Silicon — evaporating silicone · Reshmi carrier
Shelf Life (sealed)
24 months sealed at ≤30°C · Often 36+ months if correctly stored · Evaporative loss primary concern — always reseal
Introduction

Reshmi Silicon — The Luxury Carrier

Cyclopentasiloxane (D5) is the ingredient responsible for the unmistakable silky luxury feel of every premium hair serum, silicone primer, and fast-absorbing sunscreen on the global market. A colourless, water-thin liquid that evaporates from skin and hair surfaces within hours, it performs a function that no other ingredient class can replicate: dissolving and uniformly distributing actives and conditioning agents across the skin or hair surface with the lowest spreading resistance of any cosmetic material, and then disappearing completely — leaving no grease, no residue, no occlusion. This "deliver then depart" mechanism is the reason that D5 has become the foundational ingredient in product categories worth billions of dollars annually.

For Pakistani cosmetic formulators, D5 represents three major commercial opportunities. First, the hair serum category: South Asian hair — characteristically thick, dark, and prone to frizz in humid conditions — responds exceptionally to D5-based leave-on treatments combining volatile D5 with non-volatile dimethicone or phenyl trimethicone. Second, the silicone primer and BB cream market, where D5 delivers the Korean beauty-style pore-blurring texture that Pakistan's urban consumers now actively seek and associate with international premium quality. Third, the rapidly growing SPF serum category, where D5's ability to dissolve UV filters (Octyl Methoxycinnamate, Avobenzone) into a lightweight, non-greasy serum format solves the critical compliance problem of Pakistani consumers avoiding heavy sunscreen in summer. All three applications address documented unmet needs in a cosmetics market that is growing at over 10% annually.

D5 has no natural origin, no Unani medicine tradition, and no plant-based equivalent — it is a 100% synthetic petrochemical material developed in the 1940s from silicone chemistry. Its Halal status is unambiguous: the Rochow–Müller synthesis produces D5 from silicon metal (from quartz) and methyl chloride (from petroleum) using only inorganic catalysts, with no animal, fermentation, or biological input at any stage. Pakistan Halal Authority, IFANCA, JAKIM, and SANHA all confirm synthetic silicones to be fully Halal when used in external cosmetic products.

Bio Shop™ Pakistan — Sourcing Note

Bio Shop™ Pakistan stocks cosmetic-grade Cyclopentasiloxane (D5) at ≥99% purity with D4 impurity <0.1% — the internationally accepted SCCS 2015 specification. Available from 30g for small-batch testing to kilogram quantities for production. Supplied as a clear, water-thin, colorless, odorless liquid. Certificate of Analysis (CoA) with batch-specific GC data confirming D4 level available upon request. Essential verification: always confirm D4 <0.1% before production. Visit bioshop.pk/products/cyclopentasiloxane-d5 for current stock and pricing.

Molecular Identity

Chemical Identification

INCI NameCYCLOPENTASILOXANE
IUPAC NameDecamethylcyclopentasiloxane
CAS Number541-02-6
EINECS / EC208-764-9
COSING Ref No.75413
Formula / MWC₁₀H₃₀O₅Si₅ · 370.77 g/mol
Structural ClassCyclic volatile methyl siloxane (cVMS) — 5-membered [Si(CH₃)₂–O]₅ ring
Ring Structure10-membered alternating Si–O backbone; 5 Si atoms each bearing 2 methyl groups (10 methyl groups total)
Surface Tension~18 mN/m at 25°C — among the lowest of any cosmetic material (water: 72 mN/m; squalane: ~28 mN/m)
Synthesis RouteRochow–Müller Direct Process: SiO₂ + C → Si° + CH₃Cl → (CH₃)₂SiCl₂ → hydrolysis → ring closure → fractional distillation
Natural OccurrenceNone — D5 does not exist in nature. 100% synthetic petrochemical material
Urdu / PakistanReshmi Silicon (ریشمی سلیکون) — the silky silicone · Bakhaar Silicon (بخاری سلیکون) — evaporating silicone
Grade & Purity Profiles

Four Commercial Grades

Cyclopentasiloxane (D5) is available in multiple commercial grades with critically different suitability for cosmetic use. The most important purity parameter is D4 (Cyclotetrasiloxane) impurity — D4 is a CMR2 reproductive toxicant prohibited in EU cosmetics. Only cosmetic grade with D4 <0.1% is suitable for professional formulation. Bio Shop™ Pakistan stocks exclusively cosmetic grade ≥99% purity, D4 <0.1% (SCCS 2015 compliant).

Professional Standard · Bio Shop™ Grade
Cosmetic Grade
≥99% D5 · D4 <0.1% · SCCS 2015 compliant · Dow, Shin-Etsu, Wacker sourced
D5 Assay (GC-FID)
≥99%
D4 <0.1% · D6 ≤0.5% · Density 0.958–0.960 g/cm³ · RI 1.395–1.398
"The only grade suitable for professional cosmetic formulation. D4 impurity strictly controlled below 0.1% per SCCS 2015 mandatory requirement. Clear, water-thin, effectively odorless. CoA with GC chromatogram confirming D4 peak available upon request from Bio Shop™ Pakistan."
⚠ Avoid for Cosmetics
Industrial / Technical Grade
85–95% D5 · D4 not controlled · No SCCS compliance · Manufacturing/lubricant use
D5 Assay
85–95%
D4 content uncertified — may exceed 0.1% CMR2 threshold
"Used in industrial silicone fluid manufacture, mould release agents, and mechanical lubricants. D4 impurity is not controlled or disclosed — this grade is unsuitable for any cosmetic product intended for EU, UK, or professional-standard domestic use. Do NOT use in personal care formulations."
⚠ Obsolete — D4 Risk
Cyclomethicone (Mixed)
Historical D4+D5+D6 blend · Undefined ratio · D4 present · No longer suitable for EU export
D5 Content (typical)
55–75%
Remaining: D4 (5–15%) + D6 (20–30%) — D4 prohibited in EU cosmetics
"The historical 'cyclomethicone' designation referred to a D4/D5/D6 mixed product sold widely in the 1980s–2010s. Since the EU D4 ban (effective January 2020), true cyclomethicone blends with D4 content above 0.1% are prohibited for EU-export cosmetics. Never purchase 'cyclomethicone' without a CoA showing D4 <0.1%."
⚠ Pakistan Grey Market — Avoid
Adulterated / Unknown
Mineral oil dilution · Dimethicone blend · D6-heavy · Industrial diversion
Actual D5 Content
Unknown
Density below 0.95 = mineral oil dilution; residue on glass = non-volatile adulterant
"Common adulterants in Pakistan market: mineral oil (~0.86 g/cm³, leaves residue after evaporation); cheap dimethicone 350 cSt (leaves oily residue); D6-heavy blends (slower evaporation, heavier feel). Density test: D5 = 0.959 g/cm³. Evaporation test: pure D5 leaves zero residue on glass at 30°C within 2–4 hours. Always request CoA."
Dosage Science

Concentration Behaviour

D5 is a formulation vehicle rather than an active ingredient — it does not have a "threshold" above which it becomes harmful in leave-on products (SCCS 2015 confirmed no maximum concentration in leave-on cosmetics). Instead, concentration determines product texture, dry-down speed, and functional character. At low levels (1–5%), D5 is a sensory modifier; at mid levels (10–25%), it is the primary carrier; at high levels (40–70%), it is the product's continuous phase. The table below covers the spectrum from subtle enhancement to professional hair serum formulation, always noting the critical EU wash-off restriction at 0.1% maximum.

1–3% in FormulaSensory Modifier
Subtle improvement in spreadability and initial skin feel. Suitable for toners, lightweight essences, and gel moisturisers where a very slight silky quality is desired without changing the dominant aqueous texture
3–10% in FormulaNoticeable Silky Glide
Clearly perceptible silky texture improvement; improved active spreading; moderate dry-down speed detectable by consumers. Suitable for face serums, BB creams, lightweight lotions, and hair oils where a luxurious touch without dominant volatility is desired
10–25% in FormulaPremium Carrier Function
Full volatile carrier effect; fast dry-down; excellent uniform active distribution. The sweet spot for face primers, silicone-based serums, SPF formulas, and body lotions targeting Pakistani urban consumers who demand luxurious skin feel. Lahore summer: dry-down in 2–4 hours; Karachi: 3–6 hours
25–70% in FormulaMaximum Silky Luxury
D5 is the continuous phase — products in this range are essentially silicone-based rather than water-based. Delivers the international premium hair serum texture (Reshmi Baalon Ka Serum). Very fast dry-down; extremely low viscosity on application; professional-grade lubricity. Standard for hair serums, dry body oils, antiperspirant bases
EU Wash-off ProductsMax 0.1% — EU REACH
REACH Annex XVII Entry 70 (since January 31, 2020) restricts D5 to a maximum of 0.1% in rinse-off / wash-off cosmetic products for EU/UK export. This effectively eliminates D5 as a functional ingredient in shampoos, body wash, and face washes for EU export. Pakistan domestic products have no such restriction from DRAP
Skin Science

Functional Performance Profile

Primary Function · Immediate
Delivery & Disappear
D5's defining mechanism is its volatile carrier function: dissolving oil-soluble actives — retinol, niacinamide esters, UV filters, brightening actives, fragrance — and distributing them uniformly across the skin surface via its ultra-low surface tension (~18 mN/m), then evaporating completely within 2–12 hours (faster in Pakistan's summer heat), leaving the actives in direct contact with skin without any carrier interference or greasy residue. For South Asian skin (Fitzpatrick III–VI) where hyperpigmentation is the dominant concern, D5's uniform active delivery significantly improves the coverage efficiency of brightening actives like Alpha Arbutin and Niacinamide compared to water-based serums that pool in surface irregularities. The "delivery then depart" mechanism is the reason that D5-based serums feel "absorbed" immediately — the carrier has evaporated, not the active, which remains working on the skin surface. In Lahore's 40–42°C summer heat, D5 evaporation is complete in 2–4 hours versus 6–12 hours in European reference conditions.
Sensory Function · Seconds
Silky Premium Feel
The methyl-outward orientation of the cyclic [Si(CH₃)₂–O]₅ ring creates an outward-facing surface of extremely low polarity that glides across skin protein surfaces with minimal adhesion — the molecular mechanism behind the premium tactile perception that consumers worldwide describe as "silky," "smooth," and "luxurious." This sensation is immediate, occurring within seconds of application as D5 spreads across the skin surface at a rate far exceeding any natural oil or ester. Consumer perception studies by Dow Silicones consistently show D5-containing formulas are rated significantly more premium than equivalent non-silicone formulas, creating a real commercial advantage for Pakistani formulators competing with imported brands. The antistatic function is a bonus for hair applications: D5 reduces static charge build-up on hair fibres by approximately 40–60%, particularly valuable in Lahore's dry winter conditions (October–February) when low humidity intensifies static-related frizz. For Karachi's coastal humidity climate, D5's non-hygroscopic nature means it provides consistent performance year-round regardless of the 75–90% RH atmospheric conditions.
Hair Function · Minutes to Hours
Frizz Control
On South Asian hair — characteristically of high linear density, dark natural colour, and prone to frizz in Karachi's humid coastal climate — D5-based leave-on serums deliver a transformative benefit. D5 physically adsorbs to exposed cuticle scales, reducing inter-fibre friction and the coefficient of friction between hair and styling tools by the low-polarity methyl groups' surface presentation. The standard hair serum formula (D5 60–70% + Dimethicone 8–10% + PTM 3–5%) uses D5 as the volatile carrier that deposits the persistent conditioning film: D5 spreads dimethicone and PTM uniformly along the hair shaft length, then evaporates — leaving a continuous silicone conditioning film that provides frizz suppression, shine enhancement, and heat protection through the day. The conditioning film thickness (controlled by dimethicone:D5 ratio) determines the balance between conditioning depth and lightweight feel — a critical calibration point for the Pakistani market where overly heavy hair feel is perceived negatively. The concept is captured in the Urdu product name: Reshmi Baalon Ka Raaz (ریشمی بالوں کا راز) — the secret of silky hair.
Formulation Function · Design
Zero-Residue Base
D5's zero-residue evaporation makes it the foundational ingredient for non-greasy product formats that Pakistani consumers increasingly prefer over mineral oil-heavy conventional formulas. In face primers and silicone-based foundations, D5 dissolves the cyclopentasiloxane/dimethicone crosspolymer gel to create the optical blurring, pore-minimising texture associated with Korean beauty primers (Safaee Primer — صفائی پرائمر). In sunscreen formulas, D5 dissolves UV filters (Octyl Methoxycinnamate, Avobenzone) in the oil phase, ensuring uniform UV filter film formation after emulsification and drying — directly improving actual measured SPF performance versus equivalent formulas using heavy esters. In deodorant and antiperspirant sticks, D5 at 25–40% provides the dry, non-wet application texture that distinguishes premium products. For Pakistani formulators, the non-comedogenic, non-occlusive, complete-evaporation profile means D5-based leave-on products are appropriate for Pakistan's oily, combination, and acne-prone skin types — all of which are adversely affected by the persistent film-forming of conventional mineral oil or petrolatum-based vehicles. This is the commercial insight behind the Chamkaar Serum (چمکار سیرم) brightening serum concept.
Volatile Carrier Silky Skin Feel Zero Residue Active Delivery Frizz Control Non-Comedogenic Antistatic Fast Dry-Down Pore Blurring UV Filter Carrier
Formulation Accords

Three Complete Formulas

Three production-ready formulas from the Bio Shop™ Pakistan reference document. Formula 1 is an anhydrous hair serum — no water, no alcohol, fully halal for all markets, inspired by the Pakistani bridal hair preparation tradition. Formula 2 is a Korean beauty-inspired silicone face primer as an O/W emulsion. Formula 3 is a lightweight chemical SPF serum — corrected to 100g with distilled water balance. All three are verified at exactly 100g. Glycerin appears as plain text — verify current supplier at bioshop.pk.

Reshmi Baalon Ka Serum  ·  ریشمی بالوں کا سیرم
Pakistani Bridal Hair Serum · Anhydrous silicone base, no water, no alcohol · 100g batch · Women 18–45, all cities
Phase A — Silicone Phase
Cyclopentasiloxane D5 (≥99%)62.50g  62.5%
Dimethicone (350 cSt)10.00g  10%
PTM (Phenyl Trimethicone)5.00g  5%
Phase B — Oil Actives
Argan Oil5.00g  5%
Vitamin E Oil1.00g  1%
Phase C — Fragrance
Fragrance Oil (Rose-Oud)2.00g  2%
Phase D — Texture / Crosspolymer
Cyclopentasiloxane/Dimethicone Crosspolymer2.00g  2%
Silicon Conditioner Transparent12.50g  12.5%
Method
Room temp process — no heat needed. Weigh Phase A silicones into stainless beaker; mix gently with spatula until homogeneous (1–2 min). Add Phase B oils; mix until uniform. Add Phase C fragrance; mix 1 minute. Pre-disperse Phase D crosspolymer in a small amount of D5 (10:1 ratio), then incorporate into main blend. Fill into glass dropper bottle, airless pump, or aluminium tube. No preservation needed (anhydrous — no water phase). INCI: CYCLOPENTASILOXANE, DIMETHICONE, PHENYL TRIMETHICONE, SILICON CONDITIONER TRANSPARENT, ARGANIA SPINOSA KERNEL OIL, TOCOPHEROL, PARFUM, CYCLOPENTASILOXANE/DIMETHICONE CROSSPOLYMER. Shelf life: 18–24 months sealed. Target retail: PKR 350–650 / 50mL.
Silk Veil Primer  ·  ریشم پرائمر
Korean Beauty-Inspired Silicone Face Primer · O/W emulsion · 100g batch · Urban women 20–35, Lahore & Karachi
Phase A — Water Phase (heat to 70°C)
Distilled Water38.00g  38%
Glycerin (verify supplier at bioshop.pk)5.00g  5%
Niacinamide (Vitamin B3)5.00g  5%
Sodium PCA1.00g  1%
Phase B — Silicone / Oil Phase (heat to 70°C)
Cyclopentasiloxane D5 (≥99%)20.00g  20%
Dimethicone (350 cSt)8.00g  8%
Cyclopentasiloxane/Dimethicone Crosspolymer3.00g  3%
Olivem 10004.00g  4%
Cetyl Alcohol1.50g  1.5%
Phase C — Cool-down actives (<40°C)
Kaolin Clay Powder3.00g  3%
Allantoin0.50g  0.5%
Vitamin E Oil0.50g  0.5%
Optiphen Plus1.00g  1%
Citric Acid (pH adjust)0.10g  0.1%
Distilled Water (balance)9.40g  9.4%
Method
Heat Phase A to 70°C with stirring. Heat Phase B (pre-disperse crosspolymer in D5 10:1 first, then add dimethicone, Olivem 1000, cetyl alcohol) to 70°C separately. Add oil phase slowly to water phase with constant medium-speed mixing (500–800 rpm); mix 5 min. Cool to 40°C with gentle agitation. Below 40°C: add kaolin clay, allantoin, vitamin E, Optiphen Plus. Adjust pH to 5.5–6.5 with citric acid solution. Fill into 30–50mL airless pump. Viscosity: 8,000–15,000 cPs. EU export note: Niacinamide and Kaolin Clay are non-restricted; no allergen declaration needed for D5. Shelf life: 12–18 months.
Roshni Sun Defense  ·  روشنی سن ڈیفنس
Lightweight Chemical SPF Serum · O/W emulsion · 100g batch · Pakistani urban consumers 20–40, UV Index 8–12
Phase A — Water Phase (heat to 70°C)
Distilled Water40.00g  40%
Glycerin (verify supplier at bioshop.pk)3.00g  3%
Sodium PCA1.00g  1%
Phase B — Silicone / UV Filter Phase (heat to 70°C)
Cyclopentasiloxane D5 (≥99%)25.00g  25%
Octyl Methoxycinnamate (OMC)7.50g  7.5%
Dimethicone (350 cSt)3.00g  3%
Olivem 10004.00g  4%
Cetyl Alcohol1.50g  1.5%
Phase C — Cool-down actives (<40°C)
Niacinamide3.00g  3%
Alpha Arbutin1.00g  1%
Vitamin E Oil0.50g  0.5%
Allantoin0.30g  0.3%
Optiphen Plus1.00g  1%
Citric Acid (pH adjust)0.20g  0.2%
Distilled Water (balance)9.00g  9%
Method & Correction Note
⚠ Water balance correction: source document stated "TOTAL: 100.00%" but the original ingredient list summed to 91g. 9.00g distilled water balance has been added to the Phase C cool-down stage to correct the total to exactly 100g. Formulation method: dissolve OMC fully in D5 at room temperature first (critical step — OMC must be completely dissolved before heating). Then heat Phase A and Phase B separately to 70°C; add oil phase to water phase with constant medium-speed mixing. Cool to 40°C; add all Phase C actives. Adjust pH to 5.8–6.5. Estimated SPF 12–18 (OMC 7.5% — add zinc oxide or avobenzone for SPF 30+). Marketing tip: position as "Daily Protection Serum" — D5 makes this formula wearable daily due to its silky, non-greasy texture. Shelf life: 12–18 months.
Synergies

Classic Pairings

D5 is chemically compatible with virtually all cosmetic ingredients except water (immiscible without emulsifier). The following pairings represent the most commercially proven and technically validated combinations for Pakistani formulation. All products available at bioshop.pk; glycerin requires supplier verification.

Hair Serum Core — South Asian Hair
Dimethicone 350 cSt · D5 65%+Dimethicone 8% → Classic hair serum — D5 carries, Dimethicone conditions PTM (Phenyl Trimethicone) · D5 70%+PTM 8% → Shine serum — PTM refractive film + D5 silky carrier Argan Oil · D5 60%+Argan 5% → Nourishing serum — D5 deposits Argan nourishment; lighter than pure oil Crosspolymer Gel · 2% in D5 → Anti-frizz hold; smooth serum texture without heaviness
Skin Brightening — Pakistan's #1 Skin Concern
Niacinamide 5% + D5 10% → D5 distributes niacinamide uniformly; maximum pore + brightening coverage Alpha Arbutin 2% + D5 carrier → D5 spreads arbutin evenly across full face surface Vitamin E Oil 1% + D5 → Antioxidant protection for D5-phase; add to all anhydrous formulas Sodium PCA 1% in water phase → Pairs with D5 serum to maintain hydration after D5 evaporation
Primer & Face Care — Urban Pakistan Market
D5/Dimethicone Crosspolymer · 2–3% in D5 → Pore-blurring primer base — swells in D5 for optical blur Kaolin Clay 3% + D5 primer → Mattification; oil absorption; ideal for Pakistan oily skin in summer Olivem 1000 4% → Best available emulsifier for D5-in-water emulsions at bioshop.pk Cetyl Alcohol 1.5% + Olivem → Co-emulsifier for stable silicone primer or SPF emulsion
SPF & Sun Care — Pakistan UV Index 8–12
Octyl Methoxycinnamate 7.5% + D5 25% → Dissolve OMC in D5 first; lightweight non-greasy SPF formula Avobenzone 3% + D5 → Freely soluble in D5; add Vitamin E 0.5% to stabilise avobenzone Allantoin 0.3% + SPF formula → Soothing after UV exposure; ideal for Pakistan summer skin Distilled Water + Olivem → Aqueous phase for D5-in-water SPF emulsion; always use cosmetics grade
Volatile Silicone Comparison

D5 vs. Alternatives

Dimethicone (350 cSt)
Non-volatile Linear PDMS · Persistent Skin Film
Key Difference vs D5
Non-volatile — stays on skin permanently. Does not evaporate. Creates persistent conditioning film; more occlusive; heavier skin feel
EU Status / Skin Type
✓ Unrestricted (no wash-off restriction) · Suitable all skin types · May feel heavy at high levels on oily skin
Use With D5
Essential pairing: D5 carries dimethicone to skin surface and evaporates; dimethicone remains as persistent conditioning film. Hair serum formula backbone
Pakistan Application
Non-volatile partner in hair serums; add 5–10% in D5 carrier. Lower levels for oily skin; Karachi humidity — dimethicone persists longer than D5
Verdict: Best partner for D5, not a replacement. Together they create the complete hair serum mechanism: D5 provides initial silky carrier + anti-frizz spreading; dimethicone provides the persistent conditioning film. Available at bioshop.pk/products/dimethicone-tc-1218
Cyclohexasiloxane (D6)
Cyclic Silicone · 6-Membered Ring · Slower Volatile
Key Difference vs D5
Slower evaporation than D5 (larger ring = lower vapour pressure); heavier skin feel during application; similar function but longer residence time on skin
EU Status / Safety
⚠ Under EU regulatory review (ECHA SVHC process — possible future restriction). Not currently banned but watch for updates
Use With D5
Occasionally blended to extend dry-down time; not standard practice. D5 preferred for faster dry-down characteristic of premium formats
Pakistan Application
Regulatory uncertainty makes D6 a risk for EU-export product planning. D5 is the safer choice for professional formulation given established regulatory status
Verdict: D5 preferred over D6 for both functional (faster dry-down) and regulatory reasons (D6 under EU review). D5 has a well-established, stable regulatory position in leave-on products.
Isopropyl Myristate (IPM)
Fatty Acid Ester · Emollient Carrier · Non-volatile
Key Difference vs D5
Non-volatile fatty ester — leaves emollient residue. No silky silicone feel. Some comedogenicity risk. Different sensory profile (slippery fatty feel vs D5's silky dry feel)
EU Status / Availability
✓ Unrestricted · Available at bioshop.pk/products/ipm-isopropyl-myristate · Cost-effective emollient carrier
Use With D5
Not typically blended; different function. IPM replaces mineral oil in lotions; D5 is the primary carrier in silicone-based products. Different product design approach
Pakistan Application
IPM useful in conventional O/W lotions as emollient; D5 required when silky premium feel and zero-residue finish are the product design goals
Verdict: Different function class — IPM is a non-volatile emollient; D5 is a volatile carrier. Use IPM for conventional lotion emollience; use D5 when the product requires silky luxury and zero-residue evaporation.
Squalane
Isoprenoid Lipid · Dry-Touch Emollient · Non-volatile
Key Difference vs D5
Non-volatile dry-touch lipid emollient — remains on skin; lightweight but leaves imperceptible lipid film. No volatile carrier function. Natural-origin option (sugarcane-derived)
EU Status / Clean Beauty
✓ Unrestricted · Popular in clean beauty / natural positioning products · Non-comedogenic · No D4 concerns
Use With D5
Excellent pairing in dry body oil format: D5 60–70% + Squalane 10–15% → D5 provides instant silky carrier; squalane provides lasting emolliency after D5 evaporation
Pakistan Application
Choose squalane for "natural" or "clean" brand positioning; choose D5 for premium silicone luxury positioning. Available at bioshop.pk/products/squalene
Verdict: Complementary rather than competitive. In dry body oil formats, D5+squalane creates a superior product to either alone. Squalane is the "natural" alternative to dimethicone as D5's non-volatile partner.
Safety & Regulations

EU Cosmetics Reg & Safety Overview

Educational summary of publicly available regulatory data as of 2025. Always consult the current EU Cosmetics Regulation (EC) No 1223/2009, REACH Annex XVII, SCCS opinions, FDA 21 CFR, and the ingredient SDS before commercial formulation. This document does not constitute regulatory or safety advice.
✅

EU Leave-on Products — Fully Permitted

Under EU Cosmetics Regulation (EC) No 1223/2009, D5 is not listed in Annex II (Prohibited), Annex III (Restricted under Cosmetics Regulation), Annex IV (Colorants), Annex V (Preservatives), or Annex VI (UV Filters). For leave-on products — serums, primers, hair serums, moisturisers, sunscreens, deodorants — D5 is completely unrestricted with no maximum concentration ceiling. The SCCS 2015 opinion (SCCS/1549/15) explicitly concluded that D5 "does not present a risk to human health from its use in cosmetic products." Pakistani formulators producing leave-on products for EU export face no regulatory barrier from D5. Note: an EU restriction on D5 in leave-on products has been under ECHA discussion since 2022 (SEAC/RAC opinion pending as of 2025). Monitor ECHA registry for updates on any future leave-on restriction.

⚠️

EU Wash-off Products — Max 0.1% Since January 2020

REACH Annex XVII Entry 70 restricts D5 to a maximum of 0.1% by weight in wash-off (rinse-off) cosmetic products effective January 31, 2020. This restriction applies to shampoos, conditioners, body washes, face washes, and all products used with subsequent rinsing. At 0.1%, D5 has no meaningful functional contribution in wash-off formats (effective range is 3–15%). Pakistani formulators exporting shampoos, body washes, or other rinse-off products to the EU must reformulate without D5 or substitute with an alternative volatile carrier. Products for Pakistan domestic market only are not subject to this restriction. Bio Shop™ Shampoo Base (available at bioshop.pk) does not contain D5 and is suitable for EU-compliant wash-off formulas.

✅

FDA (USA) — CIR Expert Panel: Safe

The Cosmetic Ingredient Review (CIR) Expert Panel reviewed cyclomethicones (including D5) comprehensively in 1991, 2009, and 2011, concluding each time that D5 is safe for use in cosmetics at current use levels. The USA has not enacted any equivalent to the EU REACH wash-off restriction. D5 may be used freely in all product types at all technically appropriate concentrations for USA-export Pakistani products. FDA 21 CFR lists D5 as a permitted cosmetic ingredient. No allergen declaration, sensitisation warning, or concentration restriction applies under FDA cosmetics regulation.

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DRAP Pakistan & Halal — Fully Compliant

DRAP (Drug Regulatory Authority of Pakistan) has no specific restriction on D5 in any cosmetic product type. Pakistani formulators producing solely for the domestic market may use D5 in both leave-on and wash-off products without regulatory restriction. Professional practice suggests following EU leave-on guidelines regardless. Halal status is unambiguous: D5 is synthesised from silicon metal (from quartz/sand via electric arc reduction) and methyl chloride (from petroleum via Rochow–Müller Direct Process). No animal materials, no animal by-products, no ethanol, no fermentation-derived materials, and no biological organisms are involved at any stage of synthesis, purification, or packaging. Recognised Halal by Pakistan Halal Authority, IFANCA, JAKIM, and SANHA. CoA with Halal compatibility declaration available from Bio Shop™ Pakistan on request.

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Environmental vPvB Classification — Basis of Wash-off Restriction

The EU REACH Annex XVII wash-off restriction arises from D5's classification as a very Persistent, very Bioaccumulative (vPvB) substance in the aquatic environment. D5 resists environmental degradation and accumulates in aquatic organisms, particularly fish, at concentrations above natural background levels when released through wastewater from wash-off cosmetic products. In leave-on products (which do not enter the wastewater stream directly via shower rinse), environmental loading from D5 is considered acceptable. For Pakistani formulators: wash-off product reformulation is required for EU/UK export compliance; leave-on products are unaffected. For domestic-market wash-off products, there is no legal restriction, but responsible practice suggests minimising use in high-volume rinse-off formats.

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D4 Impurity — Critical Safety Point

Cyclotetrasiloxane (D4, CAS 556-67-2) is classified as a CMR 2 substance (toxic to reproduction, Category 2) and is prohibited in EU cosmetics. Cosmetic-grade D5 must contain D4 at no more than 0.1% (SCCS 2015 mandatory requirement). Bio Shop™ Pakistan's D5 grade has D4 <0.1%. Flash point 78–81°C: combustible liquid — not flammable at room temperature but must be stored away from open flames and hot surfaces, especially in Lahore summer workshops. Never heat D5 above 75°C near open flames. Use water baths or thermostatically controlled electric heating only. Ensure adequate ventilation when working with large quantities. Inhalation of D5 vapour at high concentrations in an unventilated space should be avoided — good laboratory ventilation is sufficient at typical cosmetic batch sizes.

Handling & Storage

Storing in Pakistan's Climate

Temperature
Store below 30°C for optimal quality. Chemically stable across Pakistan's full range (–2°C to 45°C). No chemical degradation at elevated temps — only evaporative loss if container is open
Container Type
HDPE or glass preferred. Tight-fitting lids mandatory — D5 evaporates from open containers at 10–15% volume per month at 30°C. Avoid PVC (potential plasticiser extraction). Amber glass preferred for products containing co-dissolved actives
Flash Point Safety
Flash point 78–81°C. Combustible liquid — not flammable at room temp but store away from open flames, gas burners, and heat sources. Use electric water baths or thermostat-controlled heating only. Critical rule: never heat D5 above 75°C near ignition sources
Shelf Life (sealed)
24 months minimum from manufacture date in sealed original container at or below 30°C. Often 36+ months if stored correctly. Retest at 24 months: check density (0.958–0.960 g/cm³) and evaporation profile
Measuring Technique
Water-thin mobile liquid — very easy to weigh at room temperature. Use 0.01g precision balance for standard formulation. For trace levels below 1%, use 0.001g analytical balance. D5 is a free-flowing, self-levelling liquid — weight measurement preferred over volumetric for accuracy
Light Exposure
D5 itself is not photosensitive — UV exposure does not degrade the silicone molecule. However, amber glass is recommended when D5 contains co-dissolved actives (retinol, arbutin, vitamin E) that are photosensitive. Store in room away from direct sunlight as standard practice
Lahore Summer (May–Sep)
Temperatures 40–45°C. D5 remains chemically stable but flash point safety becomes critical near hot surfaces. Store in air-conditioned environment below 30°C. Never store in parked vehicles in summer. Use insulated cooler boxes for transportation. Electric workshop heating only — no open-flame gas burners near D5 containers
Karachi Coastal Climate
D5 is completely immiscible with water and unaffected by coastal humidity (75–90% RH year-round) — no moisture uptake risk unlike glycerin or hygroscopic actives. Focus solely on container sealing to prevent evaporative loss. Seal immediately after each use. No desiccant required. D5 is one of the most climate-stable ingredients for Karachi conditions
⚠ Purity verification checklist — D5 in Pakistan market: Visual: water-thin, completely colorless, mobile liquid. Any yellowing, haze, or increased viscosity suggests adulteration or degradation. Density test: weigh 1.00 mL — should be 0.958–0.960g. Reading significantly below 0.950 = mineral oil dilution (~0.86 g/cm³). Evaporation test: apply 0.5 mL D5 to clean glass slide at 30°C — pure D5 evaporates completely within 2–4 hours leaving zero residue. Any oily or greasy residue indicates non-volatile adulterant (mineral oil, dimethicone 350 cSt). Always request CoA with batch-specific GC data confirming D5 assay ≥99% and D4 peak <0.1% from any supplier.
FAQs

Frequently Asked Questions

Is Cyclopentasiloxane (D5) halal? What is its exact synthesis origin?+
Cyclopentasiloxane is 100% synthetic and unambiguously Halal. The complete synthesis chain: (1) Silicon metal is produced by reduction of quartz (SiO₂) from natural sand in electric arc furnaces at 1500°C — no biological material involved. (2) Silicon metal reacts with methyl chloride (produced from methanol and HCl, both petrochemical/inorganic) via the Rochow–Müller Direct Process at 250–350°C using a copper catalyst — no animal material at any stage. (3) The product, dimethyldichlorosilane, undergoes hydrolysis with water and condensation under acid or base catalysis (inorganic) to form cyclic and linear siloxane oligomers. (4) Fractional vacuum distillation separates D5 from the cyclic fractions at ≥99% purity with D4 impurity <0.1%. (5) No animal products, animal by-products, ethanol, fermentation-derived materials, or biological organisms are involved at any stage. The copper catalyst and distillation purification ensure no catalyst residues remain in the final product. D5 is considered Halal by Pakistan Halal Authority, IFANCA, JAKIM, and SANHA for external cosmetic use. Bio Shop™ Pakistan can provide Halal compatibility documentation from the manufacturer upon request.
How do I verify D5 purity when purchasing in Pakistan?+
Four field tests help identify quality D5 without laboratory GC equipment. First, the visual test: genuine cosmetic-grade D5 is water-thin, completely colorless (APHA ≤10), and mobile at room temperature — any yellowing, haze, cloudiness, or unusual viscosity immediately suggests adulteration or degraded material. Second, the density test: weigh exactly 1.00 mL using a calibrated syringe and a 0.001g analytical balance — pure D5 should weigh 0.958–0.960g. A reading significantly below 0.950 suggests mineral oil dilution (mineral oil: ~0.860 g/cm³). A reading above 0.965 suggests D4 contamination. Third, the evaporation test: apply 0.5 mL D5 to a clean glass slide or mirror at 30°C — pure D5 evaporates completely within 2–4 hours at this temperature leaving zero residue whatsoever. Any oily, greasy, or sticky residue indicates non-volatile adulterant (mineral oil, silicone fluid 350 cSt, or wax). Fourth, the odour test: pure D5 is effectively odorless at room temperature — mineral oil has a characteristic light petroleum odour. Always request a GC Certificate of Analysis (CoA) with a specific batch number from your supplier, including confirmation that D4 is below 0.1%.
Is D5 safe for South Asian and Pakistani skin types? Any sensitisation or allergy concerns?+
D5 has one of the best safety profiles of any cosmetic ingredient for skin. Human Repeat Insult Patch Test (HRIPT) studies confirmed no skin sensitisation at concentrations up to 100% — the full undiluted material. The SCCS 2015 comprehensive review found no skin irritation, no sensitisation, no phototoxicity, and no mutagenicity. For South Asian skin (Fitzpatrick III–VI) specifically: D5 is non-comedogenic (confirmed by standard rabbit ear assay and human clinical testing), making it ideal for Pakistan's predominantly oily and combination skin types in summer heat. It does not cause or worsen hyperpigmentation — quite the opposite, as a carrier for brightening actives like Niacinamide, Alpha Arbutin, and Kojic Acid, it can actively support hyperpigmentation treatment which is the #1 skin concern for Pakistani consumers. D5 is actually advantageous for sensitive and rosacea-prone skin because it provides a non-reactive, inert vehicle that delivers actives without the irritation risk of water-based carriers with multiple surfactants. One concern to note: D5 in antiperspirant spray formats produces inhalable aerosol. Prudent practice suggests avoiding spray applications in poorly ventilated spaces for pregnant women or around infants, though risk at cosmetic exposure levels is confirmed to be very low by the SCCS assessment.
What D5 grade should I order? What does D4 less than 0.1% mean for my formulas?+
Always order cosmetic grade with D5 assay ≥99% and D4 impurity confirmed <0.1% — this is the only grade suitable for professional cosmetic formulation. The D4 specification matters critically: Cyclotetrasiloxane (D4) is classified as a CMR2 substance (reproductive toxicant, Category 2) and is prohibited in EU cosmetics products. If your D5 has D4 above 0.1%, any product containing it is non-compliant for EU or UK export. Bio Shop™ Pakistan's D5 stocks this specification by default. When ordering, confirm the specification explicitly: "Cosmetic Grade Cyclopentasiloxane, D5 assay ≥99% GC, D4 impurity <0.1%, SCCS 2015 compliant." Never order "for synthesis" grade (which has uncertified D4 content) or unlabelled "cyclomethicone" without a CoA showing D4 <0.1%. If you receive D5 without a CoA, run the density test and evaporation test before incorporating into production batches. For Pakistani domestic-only formulas with no EU export intent, the D4 specification is still strongly recommended professional practice — it ensures you are using a defined, safe material rather than an undefined mixture.
How does D5 perform in Pakistan's extreme heat and coastal humidity?+
D5 performs differently in Pakistan's two contrasting climates, and both differences have formulation implications. In Lahore's extreme summer heat (40–45°C, May–September): D5 evaporation from skin is complete within 2–4 hours rather than the 6–12 hours at European reference temperature. This means the "silky application to dry-down" sequence is compressed — the formula feels more instantly absorbed, which Pakistani consumers in summer typically experience as positive (fast-absorbing = light = refreshing). However, it also means the window for D5's carrier function is shorter: actives must be delivered and start working within this compressed evaporation window. Formulators should increase water-soluble humectants (Sodium PCA, Hyaluronic Acid) in D5-based face serums for Lahore summer to maintain hydration after D5 has fully evaporated. For Karachi's coastal humidity (75–90% RH year-round): D5 is completely unaffected — it is immiscible with water and absorbs zero moisture from the atmosphere. This makes D5-based formulas unusually climate-stable for Karachi conditions, where hygroscopic ingredients (glycerin, sodium lactate, AHAs) can become visually wet or change texture in high humidity. Evaporation from skin in Karachi is slightly slower than Lahore (higher atmospheric vapour pressure slightly retards evaporation), giving slightly more time for active delivery. Flash point consideration: Lahore summer workshopping with D5 requires strict electrical heating protocols — gas burners near D5 containers in summer heat are prohibited.
Is D5 banned in Europe? Can I export D5-containing products to the EU?+
D5 is NOT banned in Europe for leave-on cosmetics. The accurate and complete picture: D5 is restricted — not banned — in wash-off products only, at a maximum concentration of 0.1% under REACH Annex XVII Entry 70 since January 31, 2020. This restriction applies specifically to rinse-off / wash-off cosmetics (shampoos, conditioners, body washes, face washes, shower gels). In leave-on products — face serums, moisturisers, face primers, hair serums, sunscreens, deodorants, body lotions, foundations — D5 is fully permitted with no concentration ceiling in the EU. Pakistani manufacturers exporting leave-on products containing D5 (at any professionally reasonable concentration) are fully EU-compliant as of 2025. Important caveat: ECHA has been reviewing a potential leave-on restriction since 2022, and the RAC/SEAC opinion process is ongoing. Formulators planning new EU-export product lines should monitor ECHA's restriction proposal register for any updates. For wash-off products intended for EU or UK export, reformulate without D5 or restrict to 0.1% maximum. For USA export: no restriction in any product type. For Pakistan domestic market: no restriction in any product type from DRAP.
Does D5 work for Pakistan's main skin concerns — whitening, acne, and hair fall?+
D5 does not directly address any of these concerns as an active ingredient — it is a carrier and sensory modifier, not a skin treatment active. However, it significantly enhances the delivery and consumer experience of the actives that do address these concerns, making D5 an essential co-ingredient across all three categories. For whitening and brightening (Pakistan's largest skin care market segment): D5 is the best available carrier for brightening actives — Niacinamide, Alpha Arbutin, Kojic Acid, SAP (Sodium Ascorbyl Phosphate). By spreading these actives uniformly across the full facial skin surface with ultra-low surface tension, D5 maximises coverage and contact, directly improving efficacy versus water-based serums that pool in surface irregularities. The sensory premium (silky, fast-absorbing, non-greasy) also improves consumer compliance with daily use — consistency is the most important factor for any brightening active. For acne-prone and oily skin: D5 is non-comedogenic, non-occlusive, and evaporates completely — the ideal base for acne-targeting actives like Salicylic Acid (which is freely soluble in D5) or Niacinamide (sebum-control function). A D5-based serum with Salicylic Acid 1–2% delivers the BHA active in a dry, fast-absorbing format that does not worsen oiliness. For hair fall: D5 does not address hair follicle biology, but D5-based leave-on scalp serums (D5 40% + active like Rosemary Extract + Biotin + carrier) deliver these hair-growth supporting actives to the scalp with minimal greasiness compared to pure oil treatments, potentially improving daily-use compliance.
Which Pakistani product format is best for D5? What Urdu brand names work?+
Three Pakistani product formats maximise D5's commercial potential in priority order. First, hair serum: universally appealing across demographics; addresses the universally desired goal of smooth, shiny, frizz-free hair; packaged in elegant 30–50 mL dropper or pump bottles; very high perceived value relative to raw material cost. Recommended Urdu brand names: Reshmi Baalon Ka Serum (ریشمی بالوں کا سیرم — Silky Hair Serum), Resham Serum (ریشم سیرم), Chamkili Zulfain (چمکیلی زلفیں — Shining Locks). Lahore summer performance: D5 hair serum applies silkily and dries down within minutes in summer heat — an instant transformation for oily, frizzy summer hair. Second, face primer: strong urban market (Lahore and Karachi); targets K-beauty-influenced consumer seeking pore-blurring and makeup-extending; positioning as premium domestic product at PKR 600–1,200 vs imported at PKR 2,000–8,000. Recommended names: Safaee Primer (صفائی پرائمر — Purity Primer), Noor Base (نور بیس — Radiance Base). Third, brightening serum: Pakistan's biggest skin care category. Recommended name: Chamkaar Serum (چمکار سیرم — Radiant Glow Serum) or Ujala Serum (اجالا سیرم — Brightness Serum). Hot weather note: all three formats are actively improved by Pakistan's summer heat — D5's enhanced evaporation in 40°C temperatures creates a faster "silk to dry" transformation that Pakistani consumers experience as premium performance.
Complete Your Palette

Essential Companions

Silicone · Non-volatile
Dimethicone (350 cSt)
Essential D5 partner — D5 carries dimethicone to skin; dimethicone persists as conditioning film after D5 evaporates. Hair serum backbone
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Silicone · Shine
PTM (Phenyl Trimethicone)
High-shine refractive film partner — D5 70% + PTM 8% = premium shine serum for South Asian hair. UV protection bonus
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Silicone · Crosspolymer
Cyclopentasiloxane/Dimethicone Crosspolymer
Pore-blurring silicone elastomer — 2–3% in D5 creates K-beauty primer texture. Optical blur + frizz control
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Carrier Oil · Nourishing
Argan Oil
D5 + Argan Oil 5% = hair serum with lasting nourishment after D5 evaporation. Omega-9 delivery in silicone vehicle
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Cosmetic Active · Brightening
Niacinamide (Vitamin B3)
D5 spreads Niacinamide uniformly — the ideal carrier for Pakistan's #1 brightening active. Pore reduction + brightening serum
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Cosmetic Active · Brightening
Alpha Arbutin
D5-based brightening serum with Alpha Arbutin 2% delivers uniform hyperpigmentation treatment for South Asian Fitzpatrick III–VI
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Emulsifier
Olivem 1000
Best available emulsifier at bioshop.pk for D5-in-water O/W emulsions. Use 3–5% for stable silicone primer or SPF emulsion
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UV Filter · SPF
Octyl Methoxycinnamate (OMC)
Freely soluble in D5 — dissolve OMC 7.5% in D5 25% for lightweight chemical SPF serum base. Pakistan UV Index 8–12 protection
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Full Reference Document

Dive Deeper — Read the Complete Guide

The complete Bio Shop™ Pakistan technical reference for Cyclopentasiloxane (D5) covers substantially more than this page: the full Rochow–Müller synthesis mechanism with reaction equations and industrial process diagrams, complete structure–activity relationship analysis of the cyclic siloxane ring series (D4/D5/D6) with safety comparison, the SCCS 2015 opinion (SCCS/1549/15) review including toxicology data and dermal absorption studies, full compatibility data for 20+ cosmetic ingredients, three complete production-scale formula protocols (Reshmi Baalon Ka Serum, Silk Veil Primer, Roshni Sun Defense) with INCI declarations and target retail price analysis, accelerated stability testing protocols for Pakistan's two climate extremes, landmark product history from the 1940s silicone discovery to current K-beauty applications, and a 20-term glossary of key silicone and cosmetic chemistry terminology — all compiled in one professional reference document.

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