The Vitamin C 13 Serum

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: 1900-01-01 00:00:00 -0800

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: Delivers characteristic cosmetic function — skin conditioning, protection, preservation, or active biological benefit — at recommended use concentration.

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

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

Acetyl glucosamine delivers documented functional benefit with an established safety profile within the cosmetic regulatory framework (cosing eu, cir usa).

Last Verified: Cosing database,acetyl glucosamine technical literature

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: Stimulates lipolysis in adipocytes by inhibiting phosphodiesterase (preventing camp breakdown), reduces eye puffiness through vasoconstriction of periorbital capillaries, and provides antioxidant dna repair stimulation for photoprotective benefit.

Why It's Used: The only cosmetic active with a well-defined mechanism for anti-cellulite claims — phosphodiesterase inhibition elevating adipocyte camp is the documented biochemical pathway, providing mechanism-based efficacy substantiation superior to most slimming actives.

How It Works: Caffeine inhibits phosphodiesterase (pde3, pde4) preventing camp hydrolysis → elevated camp activates protein kinase a → phosphorylates hormone-sensitive lipase → lipolysis of triglycerides in adipocytes. for eye puffiness: caffeine's adenosine receptor antagonism reduces prostaglandin-mediated capillary dilation in periorbital tissue, reducing fluid accumulation.

Typically Found In: Anti-cellulite,eye creams,antioxidant products

TECHNICAL DETAILS

Primary Category: Active ingredient – antioxidant

Secondary Functions: Free radical scavenging,anti-aging

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

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: Non-irritating; well-tolerated.

Safe for Sensitive Skin: Yes

SAFETY & COMPATIBILITY

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

Works Well With: Vitamin c,vitamin e,ferulic acid,spf,other antioxidants

Avoid Combining With: No significant incompatibilities

SCIENTIFIC NOTE

Caffeine has one of the highest sc penetration rates of any cosmetic active (logp -0.07, mw 194 da) — the combination of small size and moderate logp providing excellent aqueous solubility with sufficient sc lipid partitioning for effective transdermal delivery to adipose tissue.

Last Verified: Cosing database,caffeine pde inhibitor anti-cellulite lipolysis review

Primary Sources: 2026-03-12

DESCRIPTION

What It Does: Provides humectant, co-solvent, and fragrance fixative in cosmetic formulations, improving active ingredient dissolution and product texture while delivering mild skin conditioning.

Why It's Used: Glycol solvents are essential for dissolving actives with limited water or oil solubility — the intermediate polarity of glycol ethers provides access to the wider solubility parameter space between pure water and oil phases.

How It Works: Hydroxyl and ether groups provide h-bonding for water miscibility; the organic chain provides compatibility with lipophilic actives. medium-chain glycols (c3–c6) provide the optimal balance of water compatibility, lipophilic active dissolution, and skin-compatible humectancy.

Typically Found In: Skin care formulations,co-solvent systems

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%–30%

SOURCING & ETHICS

Vegan Status: Yes

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

Glycol ether co-solvents enhance sc penetration of co-applied actives by increasing their thermodynamic activity in the sc lipid phase — high thermodynamic activity (near saturation) drives diffusion by concentration gradient even when absolute concentration is low.

Last Verified: Cosing database,dipropylene glycol glycol solvent review

Primary Sources: 2026-03-12

DESCRIPTION

What It Does: Panthenol deeply moisturizes skin and hair, soothes irritation, accelerates wound healing, strengthens the skin barrier, and improves hair elasticity and shine.

Why It's Used: It is used because it is exceptionally versatile, working in both skin and hair formulations. it is gentle enough for sensitive and post-procedure skin, and converts to the active vitamin b5 within the skin.

How It Works: Panthenol penetrates skin and hair, where it is oxidized to pantothenic acid (vitamin b5), a coenzyme a precursor essential to metabolism. in skin, it acts as a humectant and stimulates fibroblast proliferation. in hair, it coats the shaft, improving manageability.

Typically Found In: Moisturizers,serums,toners,after-sun products,wound healing products,shampoos,conditioners,hair masks,beard care

TECHNICAL DETAILS

Primary Category: Active ingredient – provitamin b5

Secondary Functions: Anti-inflammatory,wound healing,hair conditioning

Application Areas:

Facial Skincare

Body Care

Hair Care

Beard Care

Color Cosmetics (Makeup)

Dietary/Oral Supplements

Typical Concentration Range: 0.5%–5% (typical: 1–3%)

SOURCING & ETHICS

Vegan Status: Yes – synthetically produced

Halal Status: Yes

Source Notes: Commercially synthesized. both d- and dl-forms used in cosmetics; d-panthenol is the biologically active isomer but dl-panthenol is less expensive and widely used.

SKIN COMPATIBILITY

Irritancy Rating: 1/5 – very low; one of the most soothing ingredients in cosmetics

Comedogenicity Rating: 0/5 – non-comedogenic

Sensitivity Concerns: Extremely rare contact allergy; considered one of the safest cosmetic ingredients. suitable for all skin types.

Safe for Sensitive Skin: Yes – ideal for sensitive, reactive, and post-procedure skin

SAFETY & COMPATIBILITY

Safety Profile: Exceptionally safe. ewg hazard score: 1. no significant concerns for irritation, sensitization, or systemic toxicity. safe during pregnancy.

Works Well With: Hyaluronic acid,ceramides,allantoin,niacinamide,centella asiatica,retinol (reduces irritation),glycerin

Avoid Combining With: No known significant incompatibilities

SCIENTIFIC NOTE

Panthenol has demonstrated wound-healing properties in clinical studies, stimulating fibroblast proliferation and migration. its dual humectant and anti-inflammatory action makes it particularly effective in barrier-repair formulations.

Last Verified: Cosing database,cir safety assessment,ebner et al. (2002) skin pharmacology and applied skin physiology

Primary Sources: 2026-03-12

DESCRIPTION

What It Does: Provides hyaluronic acid hydration in the most formulation-stable and compatible form.

Why It's Used: The standard form of ha used in cosmetics – more stable than free ha, better solubility, and equivalent skin hydration benefits.

How It Works: Sodium salt reduces the polyelectrolyte repulsion of ha chains, allowing better packing in formulations. on skin, sodium ions dissociate and the ha chain unfolds to its full water-binding conformation. provides full ha humectant and barrier benefits equivalent to free ha.

Typically Found In: Hydrating serums,toners,moisturizers,sheet masks,anti-aging products

TECHNICAL DETAILS

Primary Category: Active ingredient – ha sodium salt

Secondary Functions: Equivalent ha hydration,superior stability

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 – bacterial 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

The sodium salt form of ha has approximately 10% better water solubility than free hyaluronic acid at equivalent molecular weight due to reduced chain-chain electrostatic repulsion from partial sodium counterion screening. this improved solubility enables higher concentration formulations without viscosity issues.

Last Verified: Cosing database,cir safety assessment

Primary Sources: 2026-03-12

DESCRIPTION

What It Does: Neutralises acidic cosmetic ingredients (carbomers, fatty acids, ahas) to target ph, provides ph stability through the tris/tris-h⁺ buffer system, and contributes to formulation gentleness versus stronger inorganic alkalis.

Why It's Used: Tris provides gentler ph adjustment than naoh — the organic amino alcohol buffer provides resistance to ph drift while the buffered system resists irritation spikes that can occur with strong base over-addition.

How It Works: Tris's primary amine (pka 8.1) provides buffering capacity at ph 7–9 through the nh₂/nh₃⁺ equilibrium. as an organic base, tris neutralises carbomer carboxylic acid groups forming the carboxylate salt required for gel formation. the buffering capacity prevents over-alkalinisation from base addition during manufacturing.

Typically Found In: Gel formulations,ph-sensitive actives

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%–2%

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

Tris is particularly useful for neutralising carbomer-gelled formulations containing ph-sensitive actives (vitamin c, ahas) where naoh addition can cause localised high-ph zones — the tris buffer's pka 8.1 provides inherent ph ceiling limiting over-alkalinisation during mixing.

Last Verified: Cosing database,tromethamine tris ph buffer neutraliser review

Primary Sources: 2026-03-12