Paula's Choice Skin Perfecting 25% AHA + 2% Bha Exfoliant Peel

DESCRIPTION

What It Does: Soothes irritation, accelerates wound healing, promotes skin cell renewal, and provides mild keratolytic exfoliation.

Why It's Used: Gold standard multi-function soothing active – one of the most widely used cosmetic ingredients across all product types for its exceptional tolerability and clinically proven multi-action skin conditioning.

How It Works: Promotes keratinocyte proliferation and fibroblast migration for wound healing. mild keratolytic activity by disrupting corneocyte binding. anti-irritant via direct protein binding and anti-inflammatory cytokine reduction. humectant activity via hydroxyl groups.

Typically Found In: Post-procedure products,sensitive skin formulas,wound care,anti-acne treatments,baby products

TECHNICAL DETAILS

Primary Category: Active ingredient – soothing / anti-inflammatory

Secondary Functions: Wound healing,keratolytic,anti-irritant

Application Areas:

Facial Skincare

Body Care

Hair Care

Beard Care

Color Cosmetics (Makeup)

Dietary/Oral Supplements

Typical Concentration Range: 0.1%–2%

SOURCING & ETHICS

Vegan Status: Yes – synthetic or comfrey-derived

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: Exceptionally well-tolerated; suitable for all skin types including baby and compromised skin.

Safe for Sensitive Skin: Yes – particularly recommended for sensitive skin

SAFETY & COMPATIBILITY

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

Works Well With: Ceramides,panthenol,allantoin,hyaluronic acid,centella asiatica

Avoid Combining With: No significant incompatibilities

SCIENTIFIC NOTE

Allantoin's keratinocyte proliferation stimulation occurs via receptor-mediated signaling (possibly machr activation) rather than non-specific irritation-driven proliferation, making it a true wound-healing stimulant rather than a pro-inflammatory proliferative signal.

Last Verified: Cosing database,cir safety assessment,araújo et al. allantoin review

Primary Sources: 2026-03-12

DESCRIPTION

What It Does: Reduces skin inflammation, soothes irritation, promotes wound healing, and enhances penetration of co-formulated actives.

Why It's Used: Premium natural soothing active with combined anti-inflammatory, wound healing, and penetration-enhancing activity – clinically validated across sensitive, reactive, and irritated skin types.

How It Works: Inhibits nf-kb pathway reducing pro-inflammatory cytokines il-1β, il-6, tnf-α. enhances stratum corneum lipid fluidity increasing penetration of co-delivered actives. antimicrobial against s. aureus and c. albicans. promotes keratinocyte migration for wound healing.

Typically Found In: Sensitive skin products,post-procedure formulations,anti-irritant formulas,wound healing

TECHNICAL DETAILS

Primary Category: Active ingredient – soothing / anti-inflammatory

Secondary Functions: Anti-inflammatory,penetration enhancement,antimicrobial

Application Areas:

Facial Skincare

Body Care

Hair Care

Beard Care

Color Cosmetics (Makeup)

Dietary/Oral Supplements

Typical Concentration Range: 0.1%–1%

SOURCING & ETHICS

Vegan Status: Yes – from candeia tree (vanillosmopsis erythropappa) or synthetic

Halal Status: Yes

Source Notes: Natural (-)-alpha-bisabolol from brazilian candeia tree is more sustainable and potent than chamomile-derived bisabolol. synthetic (±)-bisabolol is racemic with slightly lower anti-inflammatory potency.

SKIN COMPATIBILITY

Irritancy Rating: 1/5 – very low

Comedogenicity Rating: 0/5 – non-comedogenic

Sensitivity Concerns: Non-irritating; ideal for reactive and sensitive skin.

Safe for Sensitive Skin: Yes – particularly recommended for sensitive skin

SAFETY & COMPATIBILITY

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

Works Well With: Ceramides,panthenol,allantoin,hyaluronic acid,centella asiatica

Avoid Combining With: No significant incompatibilities

SCIENTIFIC NOTE

Bisabolol's dual function as both an anti-inflammatory and a penetration enhancer is synergistic – by reducing the inflammatory response that increases barrier tightness while simultaneously fluidizing stratum corneum lipids, it provides enhanced delivery of co-formulated actives in the very conditions where delivery is most needed.

Last Verified: Cosing database,piazza et al. bisabolol anti-inflammatory study,cir safety assessment

Primary Sources: 2026-03-12

DESCRIPTION

What It Does: Glycerin pulls water from the environment and deeper skin layers into the outer skin layer (epidermis), boosting moisture levels and keeping skin soft, smooth, and plump.

Why It's Used: It is used in virtually every moisturizer, serum, and cleanser because it is highly effective at hydrating skin, is well-tolerated by all skin types, and enhances the texture and spreadability of formulations.

How It Works: As a humectant, glycerin forms hydrogen bonds with water molecules, trapping them in the skin. it also reinforces the skin barrier by integrating into lipid structures between skin cells.

Typically Found In: Moisturizers,serums,cleansers,toners,sheet masks,sunscreens,body lotions,shampoos,conditioners

TECHNICAL DETAILS

Primary Category: Humectant

Secondary Functions: Skin barrier support,emollient,solvent

Application Areas:

Facial Skincare

Body Care

Hair Care

Beard Care

Color Cosmetics (Makeup)

Dietary/Oral Supplements

Typical Concentration Range: 1%–30% (typical: 3–10%)

SOURCING & ETHICS

Vegan Status: Yes – plant-derived (coconut, soy, palm) or synthetic

Halal Status: Yes – when plant-derived or synthetic; verify source with supplier

Source Notes: Derived from plant oils via hydrolysis or saponification; synthetic versions also available. palm-derived glycerin carries sustainability concerns.

SKIN COMPATIBILITY

Irritancy Rating: 1/5 – very low; non-irritating at all standard concentrations

Comedogenicity Rating: 0/5 – non-comedogenic

Sensitivity Concerns: Extremely rare allergic reactions; generally safe for all skin types including sensitive and baby skin

Safe for Sensitive Skin: Yes

SAFETY & COMPATIBILITY

Safety Profile: Widely recognized as safe. ewg hazard score: 1. no significant concerns for irritation, sensitization, or toxicity at typical concentrations (up to 50%).

Works Well With: Hyaluronic acid,ceramides,niacinamide,panthenol,urea,peptides,retinol,ahas/bhas

Avoid Combining With: No known incompatibilities at standard concentrations

SCIENTIFIC NOTE

Glycerin is an endogenous skin component found naturally in the stratum corneum. aquaporin-3 channels in keratinocytes facilitate glycerin transport, making it integral to natural skin hydration pathways.

Last Verified: Cosing database,cir safety assessment,ewg skin deep,inci decoder

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 shimmer and pearlescence from flat-platelet mica crystal light reflection.

Why It's Used: Universal cosmetic shimmer ingredient – mica's flat-platelet morphology provides the directional light reflection responsible for the dimensional shimmer effect in all pearlescent cosmetics.

How It Works: Flat platelets (1-200μm) reflect and refract light specularly producing shimmer. when coated with tio2 or iron oxides, provides colour-shifting pearlescence via thin-film optical interference. natural slip from platelet layering reduces application friction.

Typically Found In: Foundation,eyeshadow,highlighter,blush – virtually all colour cosmetics

TECHNICAL DETAILS

Primary Category: Colorant – mineral shimmer pigment

Secondary Functions: Skin conditioning

Application Areas:

Facial Skincare

Body Care

Hair Care

Beard Care

Color Cosmetics (Makeup)

Dietary/Oral Supplements

Typical Concentration Range: 0.01%–50%

SOURCING & ETHICS

Vegan Status: Yes – natural mineral

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

Mica-based pearlescent pigments (mica coated with tio2 or iron oxides) produce colour-shifting optical effects via thin-film light interference – the same phenomenon as oil on water or butterfly wings. as tio2 coating thickness increases, the interference wavelength shifts from silver → gold → red → violet → blue → green, creating the entire pearlescent colour palette from a single mineral substrate by controlling coating thickness.

Last Verified: Cosing database,eu cosmetics regulation annex iv,cir safety assessment

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 humectant and solvent functionality from sustainable corn-based fermentation.

Why It's Used: Bio-based propylene glycol alternative from renewable corn — propanediol provides equivalent functionality to propylene glycol with sustainable renewable feedstock and superior skin feel.

How It Works: Two oh groups provide humectant water binding. excellent solvent for fragrances, actives, and preservatives. mild antimicrobial from diol structure for preservative system boosting. renew corn fermentation origin (dupont zemea process). better skin feel than propylene glycol — less sticky.

Typically Found In: Virtually all cosmetic categories as pg alternative

TECHNICAL DETAILS

Primary Category: Functional ingredient – humectant

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: 1%–20%

SOURCING & ETHICS

Vegan Status: Yes – from corn sugar fermentation

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

Propanediol's dupont tate & lyle bio products 'zemea' process ferments corn sugar to 1,3-propanediol using engineered e. coli — one of the first commercially viable bio-fermentation routes to a cosmetic diol previously made only from petroleum. the renewable route produces chemically identical 1,3-propanediol while reducing carbon footprint by approximately 40% vs petrochemical synthesis.

Last Verified: Cosing database,dupont tate & lyle zemea technical data,cir safety assessment

Primary Sources: 2026-03-12

DESCRIPTION

What It Does: Tocopherol neutralizes free radicals that damage skin cells, protects cell membranes from lipid peroxidation, moisturizes, and helps maintain a healthy skin barrier.

Why It's Used: It is used as both a skin-active antioxidant and a formulation stabilizer (preventing oxidation of other ingredients). it has decades of safety and efficacy evidence and works synergistically with vitamin c.

How It Works: As a chain-breaking antioxidant, tocopherol donates hydrogen atoms to interrupt lipid peroxidation chain reactions. it is regenerated by vitamin c (ascorbic acid) in the vitamins c+e antioxidant cycle, creating a more durable antioxidant defense.

Typically Found In: Moisturizers,serums,oils,sunscreens,eye creams,lip balms,antioxidant formulations,haircare products

TECHNICAL DETAILS

Primary Category: Active ingredient – antioxidant/vitamin e

Secondary Functions: Emollient,formulation stabilizer,barrier support

Application Areas:

Facial Skincare

Body Care

Hair Care

Beard Care

Color Cosmetics (Makeup)

Dietary/Oral Supplements

Typical Concentration Range: 0.1%–1% (typical: 0.1–0.5% as active; higher as formulation antioxidant)

SOURCING & ETHICS

Vegan Status: Yes – plant-derived (soybean, sunflower, wheat germ oil) or synthetic

Halal Status: Yes – plant-derived or synthetic

Source Notes: Natural d-alpha-tocopherol is derived from plant oils and is more bioactive. synthetic dl-alpha-tocopherol is less expensive. tocopherol acetate (tocopheryl acetate) is the more stable ester form.

SKIN COMPATIBILITY

Irritancy Rating: 1/5 – very low; rare contact sensitivity reported

Comedogenicity Rating: 2/5 – mildly comedogenic at higher concentrations; formulation-dependent

Sensitivity Concerns: A small percentage of people report contact sensitization to tocopherol, particularly with leave-on products. comedogenicity risk is higher in oil-heavy formulations.

Safe for Sensitive Skin: Generally yes; perform patch test if history of vitamin e sensitivity

SAFETY & COMPATIBILITY

Safety Profile: Very safe; widely used. ewg hazard score: 2–3 (depending on concentration). no significant systemic concerns from topical use.

Works Well With: Ascorbic acid (vitamin c) – synergistic antioxidant pair,ferulic acid – stabilizes and boosts both c and e,ceramides,spf,retinol

Avoid Combining With: Very high concentrations of benzoyl peroxide may oxidize tocopherol; potential comedogenicity concerns in acne-prone skin when in heavy oil bases

SCIENTIFIC NOTE

The combination of vitamin c, vitamin e, and ferulic acid (the 'ce ferulic' formulation) provides fourfold photoprotection against uv-induced free radical damage – a synergy documented in landmark research by pinnell et al.

Last Verified: Cosing database,cir safety assessment,pinnell et al. (2005) journal of investigative dermatology,efsa panel on food additives

Primary Sources: 2026-03-12