Nioxin Scalp + Hair Thickening System 2 Leave-On Treatment

DESCRIPTION

What It Does: Absorbs or reflects uv radiation, preventing uv-induced dna damage, photo-oxidative stress, and premature skin aging.

Why It's Used: Uv filters are the active ingredients in sun protection — without them, formulations cannot make spf claims or prevent solar-induced skin damage.

How It Works: The uv-absorbing chromophore undergoes photoexcitation by uv photons, then dissipates the absorbed energy through thermal relaxation (chemical filters) or photon scattering/reflection (physical filters), preventing photon penetration to skin cells.

Typically Found In: Sunscreens,moisturizers with spf,foundations with spf

TECHNICAL DETAILS

Primary Category: Uv filters

Secondary Functions: Skin-protecting

Application Areas:

Facial Skincare

Body Care

Hair Care

Beard Care

Color Cosmetics (Makeup)

Dietary/Oral Supplements

Typical Concentration Range: 0.5–25% (within regulatory limits)

SOURCING & ETHICS

Vegan Status: Yes

Halal Status: Yes

Source Notes: Synthetic uv filter; no animal components.

SKIN COMPATIBILITY

Irritancy Rating: 1

Comedogenicity Rating: 0

Sensitivity Concerns: Contact allergy to uv filters occurs in approximately 1–3% of the general population; patch testing recommended for those with known photosensitivity.

Safe for Sensitive Skin: Yes

SAFETY & COMPATIBILITY

Safety Profile: Regulatory approval required per market (eu annex vi, fda otc monograph, etc.). generally non-irritating at approved concentrations.

Works Well With: Other uv filters,antioxidants,emollients

Avoid Combining With: Incompatible filter combinations (photodegradation); check regulatory approvals per region

SCIENTIFIC NOTE

Uv filters operate through two mechanisms: organic/chemical filters absorb uv photons through electronic excitation (π→π* transitions in conjugated systems), then dissipate energy via thermal relaxation; inorganic/physical filters (tio2, zno) scatter and reflect photons through mie scattering (particle size 50–300 nm) and band gap absorption. spf is measured in vivo (iso 24444) as the ratio of minimal erythema doses with and without sunscreen.

Last Verified: Cosing eu database; pcpc cosmetic ingredient safety reviews; eu cosmetics regulation annex vi; iso 24444 (in vivo spf testing)

Primary Sources: 2025-01-15

DESCRIPTION

What It Does: Supports keratin production for stronger hair and nails.

Why It's Used: Hair and nail keratin infrastructure support; widely marketed despite evidence being primarily oral supplementation-based.

How It Works: Coenzyme for carboxylase enzymes essential for fatty acid synthesis and amino acid metabolism relevant to hair follicle function.

Typically Found In: Hair growth shampoos,nail treatments,multivitamin products

TECHNICAL DETAILS

Primary Category: Active ingredient – vitamin b7

Secondary Functions: Hair growth support,nail strengthening

Application Areas:

Facial Skincare

Body Care

Hair Care

Beard Care

Color Cosmetics (Makeup)

Dietary/Oral Supplements

Typical Concentration Range: 0.01%–0.5%

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. ewg score: 1.

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

Avoid Combining With: No significant incompatibilities

SCIENTIFIC NOTE

Evidence for topical biotin efficacy in hair growth is limited – most clinical evidence comes from oral supplementation in biotin-deficient individuals.

Last Verified: Cosing database,cir safety assessment,patel et al. (2017) skin appendage disorders

Primary Sources: 2026-03-12

DESCRIPTION

What It Does: Supports keratin production for stronger hair and nails.

Why It's Used: Hair and nail keratin infrastructure support; widely marketed despite evidence being primarily oral supplementation-based.

How It Works: Coenzyme for carboxylase enzymes essential for fatty acid synthesis and amino acid metabolism relevant to hair follicle function.

Typically Found In: Hair growth shampoos,nail treatments,multivitamin products

TECHNICAL DETAILS

Primary Category: Active ingredient – vitamin b7

Secondary Functions: Hair growth support,nail strengthening

Application Areas:

Facial Skincare

Body Care

Hair Care

Beard Care

Color Cosmetics (Makeup)

Dietary/Oral Supplements

Typical Concentration Range: 0.01%–0.5%

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. ewg score: 1.

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

Avoid Combining With: No significant incompatibilities

SCIENTIFIC NOTE

Evidence for topical biotin efficacy in hair growth is limited – most clinical evidence comes from oral supplementation in biotin-deficient individuals.

Last Verified: Cosing database,cir safety assessment,patel et al. (2017) skin appendage disorders

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: 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 natural phospholipid emulsification with barrier-compatible delivery and liposome-forming properties.

Why It's Used: The most biologically authentic emulsifier – identical to cell membrane composition providing barrier-compatible delivery and liposome formation unavailable from synthetic emulsifiers.

How It Works: Phosphatidylcholine (pc), phosphatidylethanolamine (pe), phosphatidylinositol (pi) mixture provides hlb 7-12 for o/w emulsification. forms liposomal bilayers for active encapsulation. pc/pe/pi composition mirrors cell membrane for barrier-compatible delivery.

Typically Found In: Natural cosmetics,liposomal products,barrier repair,penetration-enhanced formulas

TECHNICAL DETAILS

Primary Category: Functional ingredient – natural phospholipid emulsifier

Secondary Functions: Skin conditioning

Application Areas:

Facial Skincare

Body Care

Hair Care

Beard Care

Color Cosmetics (Makeup)

Dietary/Oral Supplements

Typical Concentration Range: 0.5%–10%

SOURCING & ETHICS

Vegan Status: Conditional – soy lecithin (vegan); egg lecithin (not vegan)

Halal Status: Conditional – soy (halal); egg (verify)

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

Lecithin's phospholipid composition mirrors the composition of the stratum corneum's own lamellar bodies that deliver barrier lipids to the skin surface. this structural mimicry allows lecithin-based delivery systems to integrate seamlessly with the barrier lipid structure, exploiting the same transport pathway the skin uses for its own lipid secretion.

Last Verified: Cosing database,cir safety assessment

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: Niacinamide strengthens the skin barrier, reduces visible pore size, regulates sebum production, fades dark spots, and improves skin texture and tone.

Why It's Used: It is used because it addresses multiple skin concerns at once without irritation, making it suitable for all skin types. it is stable in formulations and pairs well with most other actives.

How It Works: Niacinamide inhibits the transfer of melanosomes (pigment packets) to skin cells, reducing hyperpigmentation. it also stimulates ceramide synthesis to strengthen the skin barrier and reduces inflammation by modulating cytokine activity.

Typically Found In: Serums,moisturizers,toners,cleansers,eye creams,sunscreens,primers

TECHNICAL DETAILS

Primary Category: Active ingredient – vitamin

Secondary Functions: Barrier repair,brightening,anti-inflammatory

Application Areas:

Facial Skincare

Body Care

Hair Care

Beard Care

Color Cosmetics (Makeup)

Dietary/Oral Supplements

Typical Concentration Range: 2%–10% (typical: 5%; higher concentrations may cause flushing in some individuals)

SOURCING & ETHICS

Vegan Status: Yes – synthetically produced

Halal Status: Yes – synthetic origin

Source Notes: Commercially produced via synthesis from nicotinic acid or 3-cyanopyridine. no animal-derived sources used in cosmetic-grade niacinamide.

SKIN COMPATIBILITY

Irritancy Rating: 1/5 – very low; concentrations above 10% may cause temporary flushing in sensitive individuals

Comedogenicity Rating: 0/5 – non-comedogenic

Sensitivity Concerns: At concentrations >10%, some users experience niacin flush (transient redness/tingling). generally very well-tolerated.

Safe for Sensitive Skin: Yes – one of the best-tolerated actives for sensitive skin

SAFETY & COMPATIBILITY

Safety Profile: Extensively studied and considered very safe. ewg hazard score: 1. no significant systemic toxicity concerns at topical concentrations.

Works Well With: Retinol,peptides,ahas/bhas,hyaluronic acid,ceramides,zinc,vitamin c,spf

Avoid Combining With: High concentrations of vitamin c (ascorbic acid) may theoretically convert to niacin – use at different times if using pure l-ascorbic acid above 15%

SCIENTIFIC NOTE

Niacinamide is a precursor to nad+ and nadp+, coenzymes vital to cellular energy metabolism. its benefits for dna repair and mitochondrial function make it a key ingredient in anti-aging strategies.

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

Primary Sources: 2026-03-12

DESCRIPTION

What It Does: Niacinamide strengthens the skin barrier, reduces visible pore size, regulates sebum production, fades dark spots, and improves skin texture and tone.

Why It's Used: It is used because it addresses multiple skin concerns at once without irritation, making it suitable for all skin types. it is stable in formulations and pairs well with most other actives.

How It Works: Niacinamide inhibits the transfer of melanosomes (pigment packets) to skin cells, reducing hyperpigmentation. it also stimulates ceramide synthesis to strengthen the skin barrier and reduces inflammation by modulating cytokine activity.

Typically Found In: Serums,moisturizers,toners,cleansers,eye creams,sunscreens,primers

TECHNICAL DETAILS

Primary Category: Active ingredient – vitamin

Secondary Functions: Barrier repair,brightening,anti-inflammatory

Application Areas:

Facial Skincare

Body Care

Hair Care

Beard Care

Color Cosmetics (Makeup)

Dietary/Oral Supplements

Typical Concentration Range: 2%–10% (typical: 5%; higher concentrations may cause flushing in some individuals)

SOURCING & ETHICS

Vegan Status: Yes – synthetically produced

Halal Status: Yes – synthetic origin

Source Notes: Commercially produced via synthesis from nicotinic acid or 3-cyanopyridine. no animal-derived sources used in cosmetic-grade niacinamide.

SKIN COMPATIBILITY

Irritancy Rating: 1/5 – very low; concentrations above 10% may cause temporary flushing in sensitive individuals

Comedogenicity Rating: 0/5 – non-comedogenic

Sensitivity Concerns: At concentrations >10%, some users experience niacin flush (transient redness/tingling). generally very well-tolerated.

Safe for Sensitive Skin: Yes – one of the best-tolerated actives for sensitive skin

SAFETY & COMPATIBILITY

Safety Profile: Extensively studied and considered very safe. ewg hazard score: 1. no significant systemic toxicity concerns at topical concentrations.

Works Well With: Retinol,peptides,ahas/bhas,hyaluronic acid,ceramides,zinc,vitamin c,spf

Avoid Combining With: High concentrations of vitamin c (ascorbic acid) may theoretically convert to niacin – use at different times if using pure l-ascorbic acid above 15%

SCIENTIFIC NOTE

Niacinamide is a precursor to nad+ and nadp+, coenzymes vital to cellular energy metabolism. its benefits for dna repair and mitochondrial function make it a key ingredient in anti-aging strategies.

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

Primary Sources: 2026-03-12

DESCRIPTION

What It Does: Provides documented cosmetic activity from peg-23m.

Why It's Used: Peg-23m delivers formulation value through its specific biological activity and established safety and efficacy.

How It Works: Source: peg-23m. mechanism: documented in cosmetic literature. safety: cosing-reviewed. standard cosmetic use concentrations.

Typically Found In: Skin care formulations,active 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%–5%

SOURCING & ETHICS

Vegan Status: Conditional

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

Peg-23m provides cosmetic activity through its characteristic mechanism. at standard concentrations it delivers documented biological activity with an established safety profile from cosmetic science literature and regulatory review.

Last Verified: Cosing database,peg-23m technical literature

Primary Sources: 2026-03-12