COSRX The Retinol 0.3 Cream

DESCRIPTION

What It Does: Delivers characteristic cosmetic function at recommended use concentration.

Why It's Used: Selected for functional contribution and formulation compatibility supported by cosmetic science and regulatory safety data.

How It Works: Works through the mechanism of its molecular class — physicochemical or biological interaction with skin proteins, lipids, or receptors as documented in peer-reviewed cosmetic literature.

Typically Found In: Skin care formulations

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: 0.1%–10%

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

1-2-hexanediol has an established safety and efficacy profile within the cosmetic regulatory framework at standard use concentrations.

Last Verified: Cosing database,1-2-hexanediol technical literature

Primary Sources: 2026-03-12

DESCRIPTION

What It Does: Loosens corneocyte adhesion in the stratum corneum, accelerating cell turnover, refining skin texture, and improving radiance.

Why It's Used: Organic acids at cosmetic ph values provide controlled keratolytic exfoliation that improves skin texture, pore appearance, and radiance without mechanical irritation.

How It Works: At appropriate ph, the acid's undissociated form penetrates the stratum corneum and dissolves the ionic bonds between corneocyte desmosomes (calcium chelation mechanism), facilitating controlled desquamation and cell renewal.

Typically Found In: Toners,exfoliants,serums,peels,cleansers

TECHNICAL DETAILS

Primary Category: Exfoliants

Secondary Functions: Brightening,keratolytic

Application Areas:

Facial Skincare

Body Care

Hair Care

Beard Care

Color Cosmetics (Makeup)

Dietary/Oral Supplements

Typical Concentration Range: 0.5–20%

SOURCING & ETHICS

Vegan Status: Yes

Halal Status: Yes

Source Notes: Synthetic or plant-derived acid; no animal components.

SKIN COMPATIBILITY

Irritancy Rating: 2

Comedogenicity Rating: 0

Sensitivity Concerns: May cause irritation or stinging in sensitive or barrier-compromised skin at high concentrations; patch test recommended.

Safe for Sensitive Skin: Conditional

SAFETY & COMPATIBILITY

Safety Profile: Safe within recommended ph and concentration ranges. sensitization risk increases above 10% aha. patch test recommended for sensitive skin. mildly irritating to some individuals at typical cosmetic use concentrations.

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

Avoid Combining With: High concentrations on sensitive/broken skin; avoid with physical exfoliants

SCIENTIFIC NOTE

Cosmetic acids function at the pka boundary: only the undissociated acid (rcooh) penetrates the stratum corneum lipid barrier, while the ionized carboxylate (rcoo⁻) does not. the henderson-hasselbalch equation governs the fraction of active species at formulation ph; typically 0.5–3.0% undissociated acid provides efficacy while minimizing irritation.

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: Reduces fine lines, stimulates collagen, firms skin, and reduces inflammation.

Why It's Used: Fda-recognized anti-wrinkle active with multi-action collagen stimulation + wrinkle reduction + anti-inflammatory efficacy.

How It Works: Activates adenosine a2a receptors on fibroblasts stimulating collagen type i. also activates pka pathway promoting atp production and reducing inflammatory cytokines.

Typically Found In: Anti-aging serums,wrinkle treatments,korean skincare

TECHNICAL DETAILS

Primary Category: Active ingredient – purine nucleoside / anti-aging

Secondary Functions: Collagen stimulation,anti-inflammatory,cell energy

Application Areas:

Facial Skincare

Body Care

Hair Care

Beard Care

Color Cosmetics (Makeup)

Dietary/Oral Supplements

Typical Concentration Range: 0.04%–0.1%

SOURCING & ETHICS

Vegan Status: Yes – synthetically produced

Halal Status: Yes

Source Notes: Synthetically produced for cosmetic use.

SKIN COMPATIBILITY

Irritancy Rating: 1/5 – very low

Comedogenicity Rating: 0/5 – non-comedogenic

Sensitivity Concerns: Non-irritating; excellent tolerability.

Safe for Sensitive Skin: Yes

SAFETY & COMPATIBILITY

Safety Profile: Excellent safety profile. fda-recognized as safe and effective anti-wrinkle ingredient. ewg score: 1.

Works Well With: Other b vitamins,niacinamide,antioxidant complexes

Avoid Combining With: No significant incompatibilities

SCIENTIFIC NOTE

A 2002 clinical study demonstrated 0.04% adenosine cream significantly reduced wrinkle depth and increased skin elasticity after 4 weeks. fda recognition requires controlled clinical trial evidence.

Last Verified: Cosing database,adenosine anti-aging clinical data,fda otc anti-wrinkle monograph

Primary Sources: 2026-03-12

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: 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: Ascorbic acid neutralizes free radicals, stimulates collagen production, inhibits melanin synthesis for a brighter complexion, and supports skin repair.

Why It's Used: It is used because it offers comprehensive antioxidant and brightening benefits supported by extensive clinical evidence. it is the most bioavailable form of vitamin c for topical application.

How It Works: As an antioxidant, it donates electrons to neutralize reactive oxygen species. it is an essential cofactor for the hydroxylation of proline and lysine in collagen synthesis. it inhibits tyrosinase, the enzyme responsible for melanin production, reducing hyperpigmentation.

Typically Found In: Vitamin c serums,brightening moisturizers,antioxidant formulations,spf products,eye creams

TECHNICAL DETAILS

Primary Category: Active ingredient – vitamin c

Secondary Functions: Collagen booster,tyrosinase inhibitor,ph adjuster

Application Areas:

Facial Skincare

Body Care

Hair Care

Beard Care

Color Cosmetics (Makeup)

Dietary/Oral Supplements

Typical Concentration Range: 5%–20% (effective range: 10–20%; ph must be below 3.5 for activity)

SOURCING & ETHICS

Vegan Status: Yes – synthetically produced or corn/plant-derived

Halal Status: Yes

Source Notes: Commercially produced by reichstein synthesis or guangxi fermentation process from glucose. some plant-derived versions exist.

SKIN COMPATIBILITY

Irritancy Rating: 2/5 – low to moderate; low ph formulations can cause initial tingling or stinging, especially at concentrations above 15%

Comedogenicity Rating: 0/5 – non-comedogenic

Sensitivity Concerns: Acidic ph can irritate sensitive or compromised skin barriers. highly unstable – oxidizes rapidly when exposed to air, light, and heat (turns orange/brown). use in the morning under spf.

Safe for Sensitive Skin: Use with caution – start at lower concentrations (5–10%). stabilized derivative forms (vitamin c derivatives) may be better tolerated.

SAFETY & COMPATIBILITY

Safety Profile: Very safe; well-studied. key concern is formulation stability, not safety. ewg hazard score: 1.

Works Well With: Vitamin e (tocopherol) – synergistic antioxidant effect,ferulic acid – stabilizing and boosting,spf,hyaluronic acid,niacinamide (use at different times if concentrations are high)

Avoid Combining With: Retinol (use at separate times – ph incompatibility),benzoyl peroxide (oxidizes vitamin c),ahas/bhas (cumulative irritation risk)

SCIENTIFIC NOTE

L-ascorbic acid is the only form of vitamin c that is proven bioactive in skin at the molecular level. its instability (rapid oxidation) has driven development of numerous stable derivatives including ascorbyl glucoside, magnesium ascorbyl phosphate, and ascorbyl tetraisopalmitate.

Last Verified: Cosing database,cir safety assessment,pinnell et al. studies,journal of the american academy of dermatology

Primary Sources: 2026-03-12

DESCRIPTION

What It Does: Neutralizes free radicals, provides photoprotection support, conditions skin, and imparts healthy skin tone.

Why It's Used: Natural antioxidant, skin conditioning, and natural colorant with additional provitamin a activity.

How It Works: Quenches singlet oxygen and free radicals. enzymatic cleavage yields retinal. accumulates in stratum corneum for photoprotective antioxidant defense.

Typically Found In: Self-tanners,sunscreens,natural colorants,anti-aging formulations

TECHNICAL DETAILS

Primary Category: Active ingredient – vitamin a derivative

Secondary Functions: Uv protection support,natural colorant,vitamin a precursor

Application Areas:

Facial Skincare

Body Care

Hair Care

Beard Care

Color Cosmetics (Makeup)

Dietary/Oral Supplements

Typical Concentration Range: 0.01%–1%

SOURCING & ETHICS

Vegan Status: Yes – plant-derived or fermentation

Halal Status: Yes

Source Notes: Derived from dunaliella salina algae, carrot oil, or synthesized. algae-derived most sustainable.

SKIN COMPATIBILITY

Irritancy Rating: 1/5 – very low

Comedogenicity Rating: 0/5 – non-comedogenic

Sensitivity Concerns: Very well-tolerated; high concentrations may impart orange tint.

Safe for Sensitive Skin: Yes

SAFETY & COMPATIBILITY

Safety Profile: Safe at cosmetic concentrations. use spf. avoid during pregnancy. ewg score: 2.

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

Avoid Combining With: No significant incompatibilities

SCIENTIFIC NOTE

Beta-carotene accumulates in the stratum corneum and provides measurable photoprotection against uv-induced oxidative stress when applied topically. not a replacement for uv filters.

Last Verified: Cosing database,cir safety assessment,stahl & sies carotenoid review

Primary Sources: 2026-03-12

DESCRIPTION

What It Does: Provides humectant hydration and active ingredient solubilization with excellent skin feel.

Why It's Used: Preferred glycol humectant in premium and k-beauty formulations for superior skin feel vs propylene glycol with equivalent functionality.

How It Works: Two hydroxyl groups at 1,3-positions provide water binding and solvent activity. better tolerated than propylene glycol with minimal sensitization risk. 4-carbon backbone provides slightly greater hydrophobic character enabling dissolution of less polar actives vs pg.

Typically Found In: Toners,essences,serums,k-beauty formulas

TECHNICAL DETAILS

Primary Category: Functional ingredient – glycol 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%–10%

SOURCING & ETHICS

Vegan Status: Yes – synthetic

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

K-beauty's preference for butylene glycol over propylene glycol is driven by two factors: bg's superior skin feel (less tacky than pg's higher viscosity) and its lower sensitization potential (1,3-bg has better spatial distribution of hydroxyl groups that reduces protein interaction vs pg's 1,2-position oh groups).

Last Verified: Cosing database,cir safety assessment

Primary Sources: 2026-03-12

DESCRIPTION

What It Does: Lightweight, stable emollient that solubilizes oil-soluble actives for excellent delivery without greasy feel.

Why It's Used: Universal lightweight emollient base and solubilizer for oil-soluble actives in serums and low-viscosity formulations where mineral oil or petrolatum would be too heavy.

How It Works: Medium-chain length provides ideal balance of spreading coefficient, penetration rate, and barrier-sealing properties. excellent solubilizer for vitamin e, retinoids, and other lipophilic actives.

Typically Found In: Serums,facial oils,sunscreens,anti-aging products,hair products

TECHNICAL DETAILS

Primary Category: Active ingredient – medium-chain triglyceride emollient

Secondary Functions: Active solubilizer,spreading agent

Application Areas:

Facial Skincare

Body Care

Hair Care

Beard Care

Color Cosmetics (Makeup)

Dietary/Oral Supplements

Typical Concentration Range: 1%–50%

SOURCING & ETHICS

Vegan Status: Yes – from coconut/palm kernel oil

Halal Status: Yes

Source Notes: Fractionated by hydrolysis and re-esterification of coconut oil. only c8 and c10 fatty acids retained.

SKIN COMPATIBILITY

Irritancy Rating: 1/5 – very low

Comedogenicity Rating: 1/5 – very low; medium-chain length generally non-comedogenic

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

Mct oil's medium-chain length (c8/c10) provides superior oxidative stability vs longer polyunsaturated chains and better skin aesthetics (lighter, less greasy) vs longer chain emollients (c16/c18). excellent solubilizer for retinoic acid, tocopheryl esters, and other lipophilic actives.

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

Primary Sources: 2026-03-12

DESCRIPTION

What It Does: Provides transparent gel textures and thickening at very low concentrations via ph-responsive swelling.

Why It's Used: The most widely used gel thickener – provides crystal-clear, stable gels at concentrations as low as 0.1-0.5% with ph-controlled viscosity.

How It Works: Highly crosslinked polyacrylic acid remains tightly coiled at acidic ph. neutralization with naoh or triethanolamine ionizes carboxylic groups causing electrostatic repulsion that unfolds and swells the polymer coils, dramatically increasing viscosity. concentration-dependent thickening.

Typically Found In: Gels,serums,emulsions,sunscreens

TECHNICAL DETAILS

Primary Category: Functional ingredient – polyacrylic acid thickener

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%–2%

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: 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

Carbomer's ph-responsive swelling mechanism provides an elegant formulation control tool: a neutralized gel can be liquefied by ph reduction (adding acid) and re-thickened by reneutralization. this reversible rheology control allows two-phase products that mix on application without the need for mechanical emulsification.

Last Verified: Cosing database,cir safety assessment

Primary Sources: 2026-03-12