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DESCRIPTION

What It Does: Provides maximum aha efficacy from the smallest most penetrating alpha-hydroxy acid.

Why It's Used: The most potent aha — glycolic acid's smallest molecular size provides the deepest penetration and highest efficacy of any alpha-hydroxy acid for exfoliation and anti-aging.

How It Works: Smallest aha (mw 76) provides deepest stratum corneum penetration. disrupts corneodesmosomes reducing cohesion. stimulates fibroblast collagen i and iii synthesis. efficacy is ph-dependent — free acid fraction determines activity.

Typically Found In: Chemical peels,body lotions,anti-aging serums,exfoliating toners

TECHNICAL DETAILS

Primary Category: Active ingredient – primary 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%–10% cosmetic; higher professional

SOURCING & ETHICS

Vegan Status: Yes – synthetic or fermentation-derived

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: Eu cosmetics: max 10% leave-on, ph ≥3.5, mandatory sun protection advisory. professional peel concentrations regulated separately.

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

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

SCIENTIFIC NOTE

Glycolic acid's ph-dependent efficacy is critical: at ph 3.0 ~100% is in the free acid (membrane-permeable) form; at ph 3.5 ~70%; at ph 4.0 ~50%. the eu ph ≥3.5 requirement reduces free acid proportion, lowering efficacy but also reducing irritation — why professional peel concentrations at lower ph are far more active than equivalent cosmetic concentrations.

Last Verified: Cosing database,eu aha guidelines,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: 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