Wella ULTIMATE REPAIR Night Hair Serum

DESCRIPTION

What It Does: Exfoliates dead skin cells by disrupting desmosomal adhesion bonds, brightens skin tone, stimulates collagen production, and improves product active penetration through the exfoliated sc.

Why It's Used: Aha exfoliation is the most evidence-backed chemical exfoliation mechanism with 30+ years of clinical use data; different acid sizes allow formulators to select penetration depth and intensity for specific skin types.

How It Works: Aha carboxylic groups donate h⁺ disrupting ca²⁺ coordination of desmoglein desmosomal proteins at formulation ph 3–4, weakening corneocyte cohesion. smaller ahas (glycolic, mw 76) penetrate fastest; larger (mandelic, mw 152) penetrate slower for gentler exfoliation.

Typically Found In: Exfoliating toners,aha serums,anti-aging

TECHNICAL DETAILS

Primary Category: Active ingredient – alpha hydroxy acid (aha)

Secondary Functions: Brightening,collagen stimulation

Application Areas:

Facial Skincare

Body Care

Hair Care

Beard Care

Color Cosmetics (Makeup)

Dietary/Oral Supplements

Typical Concentration Range: 1%–15%

SOURCING & ETHICS

Vegan Status: Yes

Halal Status: Yes

Source Notes: Fermentation-derived or synthetic. ph must be ≤4.0 for aha activity.

SKIN COMPATIBILITY

Irritancy Rating: 2/5 – low to moderate

Comedogenicity Rating: 0/5 – non-comedogenic

Sensitivity Concerns: Photosensitizing – mandatory spf use. start at low frequency.

Safe for Sensitive Skin: Use with caution – spf required

SAFETY & COMPATIBILITY

Safety Profile: Safe at otc concentrations. eu: ≤10% leave-on at ph ≥3.5. mandatory spf advisory.

Works Well With: Niacinamide,ceramides,hyaluronic acid,spf

Avoid Combining With: Retinol in same step; multiple exfoliants simultaneously

SCIENTIFIC NOTE

Glycolic acid is the most clinically studied aha; mandelic and lactic are preferred for sensitive or darker skin types from their larger molecular weight and slower penetration kinetics.

Last Verified: Cosing database,aha aha exfoliant review

Primary Sources: 2026-03-12

DESCRIPTION

What It Does: Delivers targeted skin-conditioning or bioactive benefits through a specific mechanism of action suited to the formulation's intended purpose.

Why It's Used: Specialty actives address specific skin concerns through targeted molecular mechanisms, providing efficacy beyond what base formulation ingredients alone can achieve.

How It Works: The bioactive compound interacts with specific molecular targets in skin cells or the extracellular matrix — enzymes, receptors, structural proteins, or signaling molecules — triggering beneficial biological responses.

Typically Found In: Serums,treatments,moisturizers,specialty products

TECHNICAL DETAILS

Primary Category: Specialty actives

Secondary Functions: Skin-conditioning,anti-aging

Application Areas:

Facial Skincare

Body Care

Hair Care

Beard Care

Color Cosmetics (Makeup)

Dietary/Oral Supplements

Typical Concentration Range: 0.01–5%

SOURCING & ETHICS

Vegan Status: Yes

Halal Status: Yes

Source Notes: Specialty active ingredient; check individual sourcing for vegan status.

SKIN COMPATIBILITY

Irritancy Rating: 1

Comedogenicity Rating: 0

Sensitivity Concerns: Low sensitization potential at recommended use concentrations.

Safe for Sensitive Skin: Yes

SAFETY & COMPATIBILITY

Safety Profile: Well-characterized cosmetic ingredient with established safety profile. generally non-irritating at typical use concentrations. suitable for leave-on and rinse-off cosmetics.

Works Well With: Niacinamide,hyaluronic acid,vitamin c,peptides

Avoid Combining With: Incompatible with oxidizing agents; check ph stability

SCIENTIFIC NOTE

Specialty actives typically work through enzyme inhibition (e.g., tyrosinase inhibition for brightening, mmp inhibition for anti-aging), receptor activation (e.g., retinoid receptors, ppar-γ for barrier genes), or transcription factor modulation (e.g., nrf2 for antioxidant gene upregulation). structure-activity relationships determine potency and selectivity.

Last Verified: Cosing eu database; pcpc cosmetic ingredient safety reviews; ingredient-specific safety and efficacy literature

Primary Sources: 2025-01-15

DESCRIPTION

What It Does: Provides soft, lasting rose-floral fragrance note.

Why It's Used: Essential rose fragrance monoterpene for lasting smooth floral notes in high-quality perfumery and cosmetic fragrances.

How It Works: Allylic alcohol monoterpene provides fixative property in fragrance blends. good skin substantivity for lasting scent. softer, rounder rose note vs geraniol's fresher character. natural in rose otto at 18-34%.

Typically Found In: Rose perfumes,floral fragrances,luxury skincare

TECHNICAL DETAILS

Primary Category: Fragrance component – monoterpene alcohol

Secondary Functions: Skin conditioning

Application Areas:

Facial Skincare

Body Care

Hair Care

Beard Care

Color Cosmetics (Makeup)

Dietary/Oral Supplements

Typical Concentration Range: 0.001%–1%

SOURCING & ETHICS

Vegan Status: Yes – from rose, geranium, citronella oils

Halal Status: Yes

Source Notes: Commercially produced for cosmetic use. verify vegan/halal status with supplier.

SKIN COMPATIBILITY

Irritancy Rating: 1/5 – very low

Comedogenicity Rating: 0/5 – non-comedogenic

Sensitivity Concerns: Well-tolerated by most skin types.

Safe for Sensitive Skin: Yes

SAFETY & COMPATIBILITY

Safety Profile: Eu cosmetics regulation: declared fragrance allergen. ifra guidelines apply.

Works Well With: Standard skincare actives

Avoid Combining With: No known significant incompatibilities

SCIENTIFIC NOTE

Citronellol's r-enantiomer (natural) vs s-enantiomer (synthetic) provide meaningfully different scent character – a remarkable demonstration of chiral scent discrimination by olfactory receptors. the (r) form provides the characteristic rose note while the (s) form has a distinctly different, less pleasant character. this enantiomeric scent difference means that the biological handedness of naturally-sourced vs racemic synthetic citronellol produces perceptibly different fragrance quality.

Last Verified: Cosing database,ifra standards

Primary Sources: 2026-03-12

DESCRIPTION

What It Does: Provides silicone-characteristic silky feel and skin protection with adjustable viscosity.

Why It's Used: The benchmark cosmetic silicone – sets the gold standard for silky application feel, spreadability, and skin protection in virtually all skin care categories.

How It Works: Polydimethylsiloxane chain flexibility provides extremely low surface tension and high spreadability. inert si-o backbone provides chemical stability and excellent skin tolerance. occlusive film formation reduces tewl. higher viscosity grades provide more intense conditioning.

Typically Found In: Moisturizers,foundations,primers,sunscreens – nearly universal

TECHNICAL DETAILS

Primary Category: Functional ingredient – polydimethylsiloxane

Secondary Functions: Barrier sealing,softening

Application Areas:

Facial Skincare

Body Care

Hair Care

Beard Care

Color Cosmetics (Makeup)

Dietary/Oral Supplements

Typical Concentration Range: 0.1%–30%

SOURCING & ETHICS

Vegan Status: Yes – synthetic

Halal Status: Yes

Source Notes: Plant-derived, synthetic or animal-derived. verify source.

SKIN COMPATIBILITY

Irritancy Rating: 1/5 – very low

Comedogenicity Rating: 1/5 – low; formulation-dependent

Sensitivity Concerns: Non-irritating.

Safe for Sensitive Skin: Yes

SAFETY & COMPATIBILITY

Safety Profile: Excellent safety profile. ewg score: 1.

Works Well With: Humectants,ceramides,actives as carrier

Avoid Combining With: No significant incompatibilities

SCIENTIFIC NOTE

Dimethicone's exceptional silky feel arises from its very low intermolecular attractive forces (weak van der waals forces due to non-polar methyl groups) that allow silicone chains to slide freely over skin. the coefficient of kinetic friction for pdms against skin (~0.04) is among the lowest of any cosmetic material – explaining why even small amounts transform product feel.

Last Verified: Cosing database,cir safety assessment

Primary Sources: 2026-03-12

DESCRIPTION

What It Does: Provides fresh rose-geranium floral scent with antimicrobial activity.

Why It's Used: The rose fragrance terpene – geraniol defines the fresh, sweet rose-geranium note found in more than 60 essential oils and is essential for recreating natural floral fragrance profiles.

How It Works: Monoterpene alcohol inhibits bacterial membrane integrity for antimicrobial activity. activates trpv1 for anti-nociception. inhibits nf-kb for anti-inflammatory activity. antioxidant via allylic radical scavenging.

Typically Found In: Rose-scented products,floral fragrances,natural cosmetics

TECHNICAL DETAILS

Primary Category: Fragrance component – acyclic monoterpene alcohol

Secondary Functions: Skin conditioning

Application Areas:

Facial Skincare

Body Care

Hair Care

Beard Care

Color Cosmetics (Makeup)

Dietary/Oral Supplements

Typical Concentration Range: 0.001%–1%

SOURCING & ETHICS

Vegan Status: Yes – from rose, geranium, palmarosa oils

Halal Status: Yes

Source Notes: Commercially produced for cosmetic use. verify vegan/halal status with supplier.

SKIN COMPATIBILITY

Irritancy Rating: 1/5 – very low

Comedogenicity Rating: 0/5 – non-comedogenic

Sensitivity Concerns: Well-tolerated by most skin types.

Safe for Sensitive Skin: Yes

SAFETY & COMPATIBILITY

Safety Profile: Eu cosmetics regulation: declared fragrance allergen. ifra guidelines apply.

Works Well With: Standard skincare actives

Avoid Combining With: No known significant incompatibilities

SCIENTIFIC NOTE

Geraniol's isomers (geraniol, nerol, citronellol) provide subtly different scent characters despite identical molecular formulae (c10h18o): geraniol provides the sweet, fresh rose note while its z-isomer nerol has a more delicate, neroli-like character. these isomeric scent differences arise from different spatial presentation of the hydroxyl and double bond groups to the olfactory receptor – demonstrating the extraordinary structural sensitivity of olfactory perception.

Last Verified: Cosing database,ifra standards

Primary Sources: 2026-03-12

DESCRIPTION

What It Does: Provides nmf conditioning with copper-chelating antioxidant and uv-absorbing activity from imidazole ring.

Why It's Used: Antioxidant nmf amino acid — histidine's imidazole ring provides unique copper-chelating antioxidant activity alongside nmf hydration and uv absorption not available from other nmf amino acids.

How It Works: Imidazole ring chelates cu²⁺ and fe²⁺ for antioxidant metal chelation (inhibiting fenton reaction). uv absorption at 211nm provides partial photoprotection. precursor for carnosine (with beta-alanine) for anti-glycation. nmf component via imidazole + carboxylate water binding.

Typically Found In: Antioxidant skincare,anti-aging products,nmf moisturisers

TECHNICAL DETAILS

Primary Category: Active ingredient – imidazole amino acid

Secondary Functions: Skin conditioning

Application Areas:

Facial Skincare

Body Care

Hair Care

Beard Care

Color Cosmetics (Makeup)

Dietary/Oral Supplements

Typical Concentration Range: 0.5%–5%

SOURCING & ETHICS

Vegan Status: Yes – fermentation

Halal Status: Yes

Source Notes: Commercially produced for cosmetic use. verify vegan/halal status with supplier.

SKIN COMPATIBILITY

Irritancy Rating: 1/5 – very low

Comedogenicity Rating: 0/5 – non-comedogenic

Sensitivity Concerns: Well-tolerated by most skin types.

Safe for Sensitive Skin: Yes

SAFETY & COMPATIBILITY

Safety Profile: Good safety profile at recommended concentrations. ewg score: 1–2.

Works Well With: Standard skincare actives

Avoid Combining With: No known significant incompatibilities

SCIENTIFIC NOTE

Histidine's imidazole ring's copper chelation provides the same chemical mechanism as the pharmaceutical cuprimine (d-penicillamine) used for copper chelation therapy in wilson's disease — just with significantly lower affinity. the imidazole copper chelation prevents fenton-type radical generation from free copper ions that would otherwise catalyse hydroxyl radical production from hydrogen peroxide.

Last Verified: Cosing database,cir safety assessment

Primary Sources: 2026-03-12

DESCRIPTION

What It Does: Provides non-ionic thickening compatible with anionic surfactants and electrolyte-containing formulations.

Why It's Used: Non-ionic cellulose thickener for surfactant systems where anionic/cationic thickener incompatibility is a concern.

How It Works: Hydroxyethyl substitution disrupts cellulose crystallinity enabling water solubility. non-ionic nature provides compatibility with anionic, cationic, and amphoteric surfactants. pseudoplastic rheology provides shear-thinning for dispensing. film formation from cellulose backbone.

Typically Found In: Shampoos,body washes,clear gels,surfactant systems

TECHNICAL DETAILS

Primary Category: Functional ingredient – cellulose thickener

Secondary Functions: Tewl reduction,skin plumping

Application Areas:

Facial Skincare

Body Care

Hair Care

Beard Care

Color Cosmetics (Makeup)

Dietary/Oral Supplements

Typical Concentration Range: 0.1%–3%

SOURCING & ETHICS

Vegan Status: Yes – from cellulose (plant)

Halal Status: Yes

Source Notes: Synthetic or naturally derived. excellent aqueous solubility.

SKIN COMPATIBILITY

Irritancy Rating: 1/5 – very low

Comedogenicity Rating: 0/5 – non-comedogenic

Sensitivity Concerns: Non-irritating; suitable for all skin types.

Safe for Sensitive Skin: Yes

SAFETY & COMPATIBILITY

Safety Profile: Excellent safety profile. ewg score: 1.

Works Well With: Ceramides,emollients,occlusives,glycerin,hyaluronic acid

Avoid Combining With: No significant incompatibilities

SCIENTIFIC NOTE

Hydroxyethylcellulose's non-ionic character is its primary differentiator from anionic carboxymethylcellulose – the absence of ionizable groups means hec maintains stable viscosity across ph 2-12 and at high electrolyte concentrations where carboxymethylcellulose destabilizes. this ionic independence makes hec the preferred cellulose thickener for acidic and salt-containing formulations.

Last Verified: Cosing database,ashland hec technical data,cir safety assessment

Primary Sources: 2026-03-12

DESCRIPTION

What It Does: Provides natural phospholipid emulsification with barrier-compatible delivery and liposome-forming properties.

Why It's Used: The most biologically authentic emulsifier – identical to cell membrane composition providing barrier-compatible delivery and liposome formation unavailable from synthetic emulsifiers.

How It Works: Phosphatidylcholine (pc), phosphatidylethanolamine (pe), phosphatidylinositol (pi) mixture provides hlb 7-12 for o/w emulsification. forms liposomal bilayers for active encapsulation. pc/pe/pi composition mirrors cell membrane for barrier-compatible delivery.

Typically Found In: Natural cosmetics,liposomal products,barrier repair,penetration-enhanced formulas

TECHNICAL DETAILS

Primary Category: Functional ingredient – natural phospholipid emulsifier

Secondary Functions: Skin conditioning

Application Areas:

Facial Skincare

Body Care

Hair Care

Beard Care

Color Cosmetics (Makeup)

Dietary/Oral Supplements

Typical Concentration Range: 0.5%–10%

SOURCING & ETHICS

Vegan Status: Conditional – soy lecithin (vegan); egg lecithin (not vegan)

Halal Status: Conditional – soy (halal); egg (verify)

Source Notes: Commercially produced for cosmetic use. verify vegan/halal status with supplier.

SKIN COMPATIBILITY

Irritancy Rating: 1/5 – very low

Comedogenicity Rating: 0/5 – non-comedogenic

Sensitivity Concerns: Well-tolerated by most skin types.

Safe for Sensitive Skin: Yes

SAFETY & COMPATIBILITY

Safety Profile: Good safety profile at recommended concentrations. ewg score: 1–2.

Works Well With: Standard skincare actives

Avoid Combining With: No known significant incompatibilities

SCIENTIFIC NOTE

Lecithin's phospholipid composition mirrors the composition of the stratum corneum's own lamellar bodies that deliver barrier lipids to the skin surface. this structural mimicry allows lecithin-based delivery systems to integrate seamlessly with the barrier lipid structure, exploiting the same transport pathway the skin uses for its own lipid secretion.

Last Verified: Cosing database,cir safety assessment

Primary Sources: 2026-03-12

DESCRIPTION

What It Does: Provides the most common natural floral-citrus fragrance note with additional anti-inflammatory properties.

Why It's Used: The most abundant fragrance terpene in nature – linalool forms the primary scent character of lavender, responsible for lavender's documented aromatherapy calming effects.

How It Works: Monoterpene alcohol activates gaba-a receptors for anti-anxiety activity (same receptor as benzodiazepines). inhibits glutamate-induced excitotoxicity. antimicrobial via membrane disruption. anti-inflammatory via nf-kb inhibition.

Typically Found In: Virtually all fragranced cosmetics

TECHNICAL DETAILS

Primary Category: Fragrance component – tertiary terpene alcohol

Secondary Functions: Skin conditioning

Application Areas:

Facial Skincare

Body Care

Hair Care

Beard Care

Color Cosmetics (Makeup)

Dietary/Oral Supplements

Typical Concentration Range: 0.001%–3%

SOURCING & ETHICS

Vegan Status: Yes – from lavender, coriander, bergamot

Halal Status: Yes

Source Notes: Commercially produced for cosmetic use. verify vegan/halal status with supplier.

SKIN COMPATIBILITY

Irritancy Rating: 1/5 – very low

Comedogenicity Rating: 0/5 – non-comedogenic

Sensitivity Concerns: Well-tolerated by most skin types.

Safe for Sensitive Skin: Yes

SAFETY & COMPATIBILITY

Safety Profile: Eu cosmetics regulation: declared fragrance allergen on label when >0.001% (leave-on) or >0.01% (rinse-off). ifra guidelines apply.

Works Well With: Standard skincare actives

Avoid Combining With: No known significant incompatibilities

SCIENTIFIC NOTE

Linalool's gaba-a receptor activation provides a pharmacological basis for lavender aromatherapy's documented anxiolytic effects. the same receptor modulation used by benzodiazepine drugs (such as diazepam) is activated by inhaled linalool vapor, providing receptor-mediated calming without the tolerance and dependence associated with pharmaceutical gaba-a modulators.

Last Verified: Cosing database,ifra standards,elisabetsky et al. linalool gaba study

Primary Sources: 2026-03-12

DESCRIPTION

What It Does: Provides documented cosmetic activity from peg-2m.

Why It's Used: Peg-2m delivers formulation value through its specific biological activity and established safety and efficacy.

How It Works: Source: peg-2m. mechanism: documented in cosmetic literature. safety: cosing-reviewed. standard cosmetic use concentrations.

Typically Found In: Skin care formulations,active products

TECHNICAL DETAILS

Primary Category: Active ingredient – antioxidant

Secondary Functions: Free radical scavenging,anti-aging

Application Areas:

Facial Skincare

Body Care

Hair Care

Beard Care

Color Cosmetics (Makeup)

Dietary/Oral Supplements

Typical Concentration Range: 0.1%–5%

SOURCING & ETHICS

Vegan Status: Conditional

Halal Status: Yes

Source Notes: Plant-derived extract or synthetic.

SKIN COMPATIBILITY

Irritancy Rating: 1/5 – very low

Comedogenicity Rating: 0/5 – non-comedogenic

Sensitivity Concerns: Non-irritating; well-tolerated.

Safe for Sensitive Skin: Yes

SAFETY & COMPATIBILITY

Safety Profile: Excellent safety profile. ewg score: 1.

Works Well With: Vitamin c,vitamin e,ferulic acid,spf,other antioxidants

Avoid Combining With: No significant incompatibilities

SCIENTIFIC NOTE

Peg-2m provides cosmetic activity through its characteristic mechanism. at standard concentrations it delivers documented biological activity with an established safety profile from cosmetic science literature and regulatory review.

Last Verified: Cosing database,peg-2m technical literature

Primary Sources: 2026-03-12