Excellent Active Ingredient NOAEL Data GHS Classified

Niacinamide

INCI: NIACINAMIDE

CAS Number
98-92-0
Function
Melanosome transfer inhibitor; vitamin B3 amide; inhibits transfer of melanosomes from melanocytes to keratinocytes (35–68% inhibition in coculture); also reduces keratinocyte PGE2 production and AGE formation, both of which stimulate melanosome transfer; does not affect tyrosinase catalytic activity
Safety Rating
EXCELLENT

Regulatory Status

🇪🇺 EU Status permitted
🇺🇸 US Status permitted
US Notes No FDA concentration restriction. Used at 2–10% in OTC brightening and barrier products without drug classification concerns. Not listed in OTC skin-bleaching monograph (21 CFR 310.545). Generally recognised as safe in dietary context; topical cosmetic use unrestricted.

For full compliance data across 55 jurisdictions, use the Substance Compliance tool.

Safety Data

Margin of Safety (MoS)
adequate
Dermal Absorption
moderate
Sensitization
none

Calculate MoS for your specific formulation with the MoS Calculator.

Toxicological Studies

9 study endpoints found for Niacinamide. NOAEL (No Observed Adverse Effect Level) values are used to calculate the Margin of Safety per SCCS methodology.

Endpoint Value Route Species Study Type Source
NOAEL 1000 mg/kg bw/day oral rat Short Term Toxicity COSMOS_DB
NOAEL 1000 mg/kg bw/day oral rat Short Term Toxicity COSMOS_DB
NOAEL 600 mg/kg bw/day oral rabbit Short Term Toxicity COSMOS_DB
NOAEL 800 mg/kg bw/day oral guinea pig Short Term Toxicity COSMOS_DB
NOAEL 400 mg/kg bw/day oral rat Short Term Toxicity COSMOS_DB
dose_tested 600 mg/kg bw/day oral rabbit Short Term Toxicity COSMOS_DB
dose_tested 800 mg/kg bw/day oral guinea pig Short Term Toxicity COSMOS_DB
NOAEL 215 mg/kg bw/day oral rat oral REACH
NOAEL 12.5 mg/kg bw/day oral - oral REACH

GHS Hazard Classification

Globally Harmonized System classification per ECHA C&L inventory and ILO/WHO International Chemical Safety Cards.

Signal Word
WARNING
Hazard Statements
Causes eye irritation
Short-term Exposure Effects
The substance is irritating to the eyes.

Expert Verdict

Workhorse brightening active with best-in-class safety and mechanistically unique position: inhibits melanosome transfer (not tyrosinase), making it complementary to every tyrosinase inhibitor and enabling additive combination formulas. 35–68% reduction in melanosome transfer in coculture models. Additionally reduces PGE2 and AGE formation that drive melanosome transfer. Japan quasi-drug since 2007. No EU or US restrictions at any cosmetic concentration. 2025 clinical data (Nature Sci Rep RCT): TXA 5% + niacinamide 4% combination outperformed 4% HQ for melasma with significantly fewer adverse reactions. Essential ingredient in any brightening formulation.

⚠️
Concern Level: None

Regulatory Flags

brightening melanosome-transfer-inhibitor vitamin-b3 35-68pct-transfer-inhibition pge2-reduction age-formation-reduction not-tyrosinase-direct synergistic-txa synergistic-tyrosinase-inhibitors quasi-drug-japan-2007 no-restrictions-any-market melasma pih combination-backbone eu-allowed us-allowed fda_food_additive

Frequently Asked Questions

Is Niacinamide safe in cosmetics?

Workhorse brightening active with best-in-class safety and mechanistically unique position: inhibits melanosome transfer (not tyrosinase), making it complementary to every tyrosinase inhibitor and enabling additive combination formulas. 35–68% reduction in melanosome transfer in coculture models. Additionally reduces PGE2 and AGE formation that drive melanosome transfer. Japan quasi-drug since 2007. No EU or US restrictions at any cosmetic concentration. 2025 clinical data (Nature Sci Rep RCT): TXA 5% + niacinamide 4% combination outperformed 4% HQ for melasma with significantly fewer adverse reactions. Essential ingredient in any brightening formulation. The EU classifies Niacinamide as "permitted". Safety rating: EXCELLENT. 9 toxicological study endpoint(s) are available in our database.

Is Niacinamide allowed in the EU?

Niacinamide EU regulatory status: permitted. This is based on EU Regulation 1223/2009 and its amendments.

What does Niacinamide do in cosmetics?

Niacinamide functions as: Melanosome transfer inhibitor; vitamin B3 amide; inhibits transfer of melanosomes from melanocytes to keratinocytes (35–68% inhibition in coculture); also reduces keratinocyte PGE2 production and AGE formation, both of which stimulate melanosome transfer; does not affect tyrosinase catalytic activity. It is classified as a Active Ingredient in our database. CAS number: 98-92-0.

What is the Margin of Safety for Niacinamide?

adequate The Margin of Safety (MoS) is calculated using SCCS methodology. A MoS above 100 is generally considered safe. Use the MoS Calculator tool to calculate MoS for your specific formulation and product category.

What is the NOAEL for Niacinamide?

The NOAEL (No Observed Adverse Effect Level) for Niacinamide is 1000 mg/kg bw/day based on a Short Term Toxicity study via oral route in rat. A total of 9 study endpoints are available. Source: COSMOS_DB.

Is Niacinamide classified as hazardous under GHS?

Niacinamide carries a GHS signal word of "WARNING". Hazard statements: Causes eye irritation. This classification is based on the ILO/WHO International Chemical Safety Card and ECHA C&L inventory data. Note: GHS classification applies to the pure substance — at cosmetic use concentrations, hazard thresholds may not be met.

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