L'Oreal Paris Hyaluron Moisture Hair Serum

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 the complete fragrance profile contributing to product sensory experience and consumer appeal.

Why It's Used: Fragrance is a major consumer purchase driver — up to 70% of consumers make purchasing decisions partially based on product scent.

How It Works: Fragrance blends interact with olfactory receptors providing the sensory profile — complex mixtures activate multiple receptor types for rich, multidimensional scent experiences.

Typically Found In: All fragrance products

TECHNICAL DETAILS

Primary Category: Active ingredient – cosmetic active

Secondary Functions: Skin conditioning

Application Areas:

Facial Skincare

Body Care

Hair Care

Beard Care

Color Cosmetics (Makeup)

Dietary/Oral Supplements

Typical Concentration Range: Standard use levels

SOURCING & ETHICS

Vegan Status: Conditional

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

Ifra guidelines set usage limits for fragrance ingredients based on skin sensitisation and phototoxicity assessment for each application category.

Last Verified: Eu regulation 1223/2009 annex iii,ifra standards,fragrance allergen declaration requirements

Primary Sources: 2026-03-12

DESCRIPTION

What It Does: Hyaluronic acid draws and locks moisture into the skin at multiple depths (surface and deeper layers depending on molecular weight), creating a plumping, smoothing, and hydrating effect.

Why It's Used: It is used because it is endogenous to human skin, making it exceptionally biocompatible and non-irritating. its unparalleled moisture-binding capacity makes it the most effective hydrating ingredient available.

How It Works: Ha binds water molecules through its many hydroxyl and carboxyl groups, creating a gel-like matrix. high molecular weight ha (>500 kda) hydrates the skin surface; low molecular weight ha (<50 kda) penetrates deeper to provide interior hydration.

Typically Found In: Serums,moisturizers,sheet masks,toners,eye creams,lip treatments,dermal fillers (injectable)

TECHNICAL DETAILS

Primary Category: Active ingredient – humectant/hydrator

Secondary Functions: Barrier repair,plumping,anti-aging

Application Areas:

Facial Skincare

Body Care

Hair Care

Beard Care

Color Cosmetics (Makeup)

Dietary/Oral Supplements

Typical Concentration Range: 0.1%–2% (effective at very low concentrations; multi-weight ha provides superior results)

SOURCING & ETHICS

Vegan Status: Yes – biotechnology-derived (microbial fermentation of streptococcus equi or b. subtilis); vegan-certified versions widely available

Halal Status: Yes

Source Notes: Originally extracted from rooster combs; now predominantly produced via biotechnology (bacterial fermentation), which is vegan and more sustainable.

SKIN COMPATIBILITY

Irritancy Rating: 1/5 – very low; one of the gentlest skincare ingredients known

Comedogenicity Rating: 0/5 – non-comedogenic

Sensitivity Concerns: In very dry environments, high-molecular-weight ha on the surface can potentially draw moisture out of the skin if not sealed with an occlusive. apply to damp skin and seal with moisturizer.

Safe for Sensitive Skin: Yes – ideal for all skin types including rosacea, eczema, and post-procedure skin

SAFETY & COMPATIBILITY

Safety Profile: Exceptional safety profile. endogenous molecule – no toxicity concerns. ewg hazard score: 1. safe during pregnancy.

Works Well With: Virtually all ingredients; especially ceramides,glycerin,peptides,retinol (reduces irritation),niacinamide,vitamin c

Avoid Combining With: No significant incompatibilities; high concentrations of alcohol in a formula may reduce its efficacy

SCIENTIFIC NOTE

Hyaluronic acid naturally degrades in skin (half-life ~1–2 days). the skin produces it endogenously, but production decreases with age. multi-molecular-weight ha formulas provide hydration at both surface and deeper skin levels.

Last Verified: Cosing database,cir safety assessment,papakonstantinou et al. (2012) dermato-endocrinology

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: Exfoliates dead skin cells, attracts and retains moisture, brightens skin tone, and improves texture.

Why It's Used: Dual exfoliant and humectant – uniquely hydrating vs other ahas. gentler and suitable for normal-to-sensitive skin.

How It Works: Disrupts desmosomes to promote exfoliation at low ph. acts as humectant. also stimulates ceramide synthesis at lower concentrations for barrier support.

Typically Found In: Chemical exfoliants,toners,serums,professional peels

TECHNICAL DETAILS

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

Secondary Functions: Humectant,brightening,barrier support,ceramide synthesis

Application Areas:

Facial Skincare

Body Care

Hair Care

Beard Care

Color Cosmetics (Makeup)

Dietary/Oral Supplements

Typical Concentration Range: 2%–10% (daily); 20%–90% (professional); active at ph ≤3.9

SOURCING & ETHICS

Vegan Status: Yes – synthetic or fermentation-derived

Halal Status: Yes

Source Notes: Fermentation-derived from carbohydrates or synthetically produced. both l-form and dl-form used.

SKIN COMPATIBILITY

Irritancy Rating: 2/5 – low to moderate

Comedogenicity Rating: 0/5 – non-comedogenic

Sensitivity Concerns: Photosensitizing – spf required. better tolerated than glycolic acid for most skin types.

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

Lactic acid's role as a natural moisturizing factor (nmf) component makes it uniquely hydrating among ahas. ceramide synthesis stimulation at 2% provides barrier benefits complementing exfoliating activity.

Last Verified: Cosing database,stiller et al. lactic acid review,sccs aha opinion

Primary Sources: 2026-03-12

DESCRIPTION

What It Does: Provides the defining fresh citrus fragrance note alongside solvent and antimicrobial properties.

Why It's Used: The citrus industry's primary fragrance compound and the most abundant terpene in essential oils – limonene provides the clean, universally appealing fresh citrus scent character.

How It Works: D-limonene activates trpv1 mildly at high concentrations. antimicrobial via membrane disruption. solvent for oils and lipophilic compounds. cleaning via emulsification of lipid soils.

Typically Found In: Citrus-scented products,cleaning products,fragrance compounds

TECHNICAL DETAILS

Primary Category: Fragrance component – cyclic monoterpene

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 citrus peel essential 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. oxidises to sensitising compounds (limonene hydroperoxides) on air exposure – use with antioxidant stabilisers. ifra guidelines apply.

Works Well With: Standard skincare actives

Avoid Combining With: No known significant incompatibilities

SCIENTIFIC NOTE

Limonene's sensitisation risk arises not from limonene itself but from its autooxidation products (limonene-1,2-epoxide and limonene hydroperoxides) formed on air exposure. fresh limonene has low sensitisation potential, but air-oxidised limonene's hydroperoxide products are potent skin sensitisers. this explains why oxidation-stabilised formulations (with bht or other antioxidants) are required to manage limonene safety.

Last Verified: Cosing database,ifra standards,bråred christensson et al. limonene oxidation study

Primary Sources: 2026-03-12

DESCRIPTION

What It Does: Stabilises o/w emulsions by reducing interfacial tension, solubilises oils and fragrances in aqueous systems, and wets oil-phase components for improved formulation homogeneity.

Why It's Used: Peg emulsifiers are selected for their precise hlb, broad ph stability (unlike soap emulsifiers that lose function at acidic ph), and compatibility with both anionic and cationic co-ingredients in the formulation system.

How It Works: Peg chain length determines hlb: longer peg = higher hlb = more hydrophilic = better o/w emulsification. at the o/w interface, the peg chain extends into the water phase forming a hydrated steric barrier that prevents droplet coalescence. nonionic character provides ph-independent function across the full cosmetic ph range.

Typically Found In: Emulsions,fragrance solubilisation

TECHNICAL DETAILS

Primary Category: Active ingredient – cosmetic active

Secondary Functions: Skin conditioning

Application Areas:

Facial Skincare

Body Care

Hair Care

Beard Care

Color Cosmetics (Makeup)

Dietary/Oral Supplements

Typical Concentration Range: 1%–10%

SOURCING & ETHICS

Vegan Status: Yes

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

Mixed peg emulsifier systems (e.g., peg-100 stearate + glyceryl stearate) form more cohesive interfacial films than single emulsifiers — the geometric complementarity of the co-emulsifier pair providing better mechanical emulsion stability than either component alone.

Last Verified: Cosing database,peg-40 hydrogenated castor oil peg emulsifier review

Primary Sources: 2026-03-12

DESCRIPTION

What It Does: Prevents microbial contamination and spoilage in cosmetic formulations.

Why It's Used: The benchmark cosmetic preservative – eu-permitted up to 1%, effective against virtually all cosmetically relevant microorganisms, and excellent tolerability.

How It Works: Phenol ring provides broad antimicrobial activity via disruption of bacterial and fungal cell membranes and inhibition of enzymatic activity. effective against gram-positive and gram-negative bacteria, yeasts (candida), and molds (aspergillus). activity ph range: 3-9.

Typically Found In: All cosmetic formulations as primary preservative

TECHNICAL DETAILS

Primary Category: Functional ingredient – broad-spectrum preservative

Secondary Functions: Skin conditioning

Application Areas:

Facial Skincare

Body Care

Hair Care

Beard Care

Color Cosmetics (Makeup)

Dietary/Oral Supplements

Typical Concentration Range: 0.1%–1% (eu max 1%)

SOURCING & ETHICS

Vegan Status: Yes – synthetic

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 max 1%. sccs assessed as safe at ≤1%. avoid use around eyes in baby products per some country regulations. ewg score: 4.

Works Well With: Standard skincare actives

Avoid Combining With: No known significant incompatibilities

SCIENTIFIC NOTE

Phenoxyethanol's widespread adoption as the primary cosmetic preservative followed the phaseout of parabens from many formulations in the 2000s-2010s. despite having a comparable or better safety profile to parabens, it is often cited in 'free-from' formulations – a consumer perception issue rather than a scientific safety concern.

Last Verified: Cosing database,sccs opinion on phenoxyethanol,cir safety assessment

Primary Sources: 2026-03-12

DESCRIPTION

What It Does: Provides the universal solvent and vehicle for water-soluble actives and the continuous phase of all o/w emulsions.

Why It's Used: The most essential cosmetic ingredient — aqua (water) is listed first on virtually all water-containing cosmetic inci labels as the highest-concentration ingredient, serving as the foundation of the global cosmetics industry.

How It Works: Acts as solvent for all water-soluble ingredients (glycols, amino acids, water-soluble actives). forms the continuous external phase of o/w emulsions (lotions, creams, serums). provides aqueous environment for enzymatic and chemical reactions between actives. ph adjustment medium.

Typically Found In: Virtually all cosmetic products — the most universal cosmetic ingredient globally

TECHNICAL DETAILS

Primary Category: Functional ingredient – water

Secondary Functions: Skin conditioning

Application Areas:

Facial Skincare

Body Care

Hair Care

Beard Care

Color Cosmetics (Makeup)

Dietary/Oral Supplements

Typical Concentration Range: Varies widely — up to 95% in some toners and serums

SOURCING & ETHICS

Vegan Status: Yes – water (deionised/purified)

Halal Status: Yes

Source Notes: Cosmetic-grade water is purified (deionised, distilled, or ro filtered) to prevent mineral content interference with formulation stability. european pharmacopoeial water (aqua purificata ph. eur.) is the quality standard for pharmaceutical and high-end cosmetic formulations.

SKIN COMPATIBILITY

Irritancy Rating: 1/5 – non-irritant

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

Water's position as the first inci ingredient on most cosmetic labels reflects the regulatory requirement to list ingredients in descending concentration order — meaning water is the most abundant ingredient in the majority of cosmetic products. the fundamental role of water as the universal cosmetic solvent and vehicle makes it simultaneously the most important cosmetic ingredient and the one that requires the most sophisticated formulation chemistry to control — every emulsifier, thickener, preservative, and ph adjuster exists primarily to manage water's interaction with other ingredients in formulation.

Last Verified: Cosing database,eu cosmetics regulation 1223/2009 inci requirements,ph. eur. aqua purificata monograph

Primary Sources: 2026-03-12