L’Oréal Paris Hyaluron Pure 72H Purifying Shampoo, For Oily Scalp & Dry Hair With Salicylic And Hyaluronic Acid

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 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: Salicylic acid exfoliates the skin surface and inside pores, dissolves the 'glue' holding dead skin cells together, reduces sebum production, and combats acne-causing bacteria.

Why It's Used: Its oil solubility makes it uniquely effective at penetrating pores and dissolving sebum plugs – a function that water-soluble ahas cannot perform. it is the preferred exfoliant for oily, acne-prone, and congested skin.

How It Works: Salicylic acid disrupts desmosomal bonds between corneocytes, promoting exfoliation. its oil solubility allows it to penetrate the sebaceous follicle, dissolving sebum and dead cells. it also has anti-inflammatory properties by inhibiting prostaglandin synthesis.

Typically Found In: Cleansers,toners,serums,spot treatments,masks,chemical peels,anti-dandruff shampoos,acne treatments

TECHNICAL DETAILS

Primary Category: Active ingredient – beta hydroxy acid (bha)

Secondary Functions: Anti-acne,anti-dandruff,keratolytic

Application Areas:

Facial Skincare

Body Care

Hair Care

Beard Care

Color Cosmetics (Makeup)

Dietary/Oral Supplements

Typical Concentration Range: 0.5%–2% (otc acne treatment in us); up to 30% in professional chemical peels

SOURCING & ETHICS

Vegan Status: Yes – synthetic or willow bark derived

Halal Status: Yes

Source Notes: Naturally occurring in willow bark (salix alba) and wintergreen oil. commercially produced synthetically via kolbe-schmitt reaction for cosmetic use.

SKIN COMPATIBILITY

Irritancy Rating: 3/5 – moderate; can cause dryness, peeling, and irritation, especially at higher concentrations

Comedogenicity Rating: 0/5 – non-comedogenic; actually anti-comedogenic

Sensitivity Concerns: Can cause irritation, dryness, and sun sensitivity. avoid contact with eyes. not recommended during pregnancy at high concentrations. can be drying – follow with moisturizer.

Safe for Sensitive Skin: Use with caution – start with lower concentrations and frequency; may not be suitable for reactive or rosacea-prone skin

SAFETY & COMPATIBILITY

Safety Profile: Safe at otc concentrations (0.5–2%). regulated as a drug in some countries (us: fda category i acne treatment). avoid in pregnancy at high concentrations.

Works Well With: Niacinamide,zinc,tea tree oil,benzoyl peroxide (at different times),hyaluronic acid (to counteract dryness)

Avoid Combining With: High concentrations of retinol (cumulative irritation),multiple exfoliating acids simultaneously,benzoyl peroxide in same step (can increase irritation)

SCIENTIFIC NOTE

Salicylic acid is a member of the salicylate family and shares structural similarity with aspirin. its anti-inflammatory mechanism mirrors aspirin's cox inhibition pathway, making it uniquely effective for inflammatory acne.

Last Verified: Cosing database,cir safety assessment,us fda acne monograph,journal of the american academy of dermatology

Primary Sources: 2026-03-12