Excellent Active Ingredient NOAEL Data Dermal Penetration

Melatonin

Also known as: Regulin, Circadin, 3-(2-Acetamidoethyl)-5-methoxyindole, N-[2-(5-Methoxy-1H-indol-3-yl)ethyl]acetamide, Acetamide, N-[2-(5-methoxy-1H-indol-3-yl)ethyl]- (+15 more)

INCI: MELATONIN

Melatonin (CAS 73-31-4) is a cosmetic active ingredient functioning as Antioxidant; AhR pathway modulator; anti-pollution active; circadian repair. NOAEL 0.5 mg/kg bw/day (cross-referenced against ToxValDB ECHA IUCLID); EU Regulation 1223/2009 status: permitted. Industrial safety data is also available in the chemical safety database. Same-CAS public records also appear in industrial chemical safety and pharmaceutical data.

View industrial chemical safety profile for CAS 73-31-4 →

Auto-generated CPSR Part A draft with source citations
Function
Antioxidant; AhR pathway modulator; anti-pollution active; circadian repair regulator; anti-inflammatory; indole hormone/neurohormone; night repair active; photoprotective antioxidant
Safety Rating
EXCELLENT

Chemistry & Identifiers

Formula
C13H16N2O2
MW
232.28 g/mol
PubChem CID
896
IUPAC Name
N-[2-(5-methoxy-1H-indol-3-yl)ethyl]acetamide
InChIKey
DRLFMBDRBRZALE-UHFFFAOYSA-N

Regulatory Status

EU EU Status permitted
US US Status permitted
US Notes Permitted in cosmetics; sold as dietary supplement in the US without restriction; topical cosmetic use permitted; no FDA concentration restrictions for cosmetic application; not a CIR-reviewed cosmetic ingredient as of current data

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

Safety Data

Margin of Safety, dermal absorption, and sensitization profile summaries for Melatonin.

Calculate MoS for your specific formulation with the MoS Calculator.

Toxicological Studies

10 study endpoints found for Melatonin. 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 =5 mg/kg bw/day - rat NOAEL study SCCS_vision_codex
NOAEL =5 mg/kg bw/day - rat NOAEL study SCCS_vision_codex
NOAEL =5 mg/kg bw/day - rat NOAEL study SCCS_vision_codex
NOAEL =5 mg/kg bw/day - rat NOAEL study SCCS_vision_codex
NOAEL =100 mg/kg bw/day intravenous rat developmental toxicity SCCS_vision_codex
NOAEL =100 mg/kg bw/day intravenous rat developmental toxicity SCCS_vision_codex
NOAEL =100 mg/kg bw/day intravenous rat developmental toxicity SCCS_vision_codex
NOAEL =100 mg/kg bw/day intravenous rat developmental toxicity SCCS_vision_codex
NOAEL =200 mg/kg/day oral rat repeated dose toxicity SCCS_vision_codex
NOAEL =200 mg/kg bw/day - - reproductive toxicity SCCS_vision_codex

Pre-Calculated Safety Assessment

Pre-calculated NOAEL → SED → MoS audit trail for Melatonin across SCCS product categories, with measured dermal absorption where available.

Dermal Penetration Profile

Skin absorption and penetration characteristics of Melatonin, relevant to systemic exposure and MoS calculations.

Absorption %
10-18%
Penetration Level
epidermis
Penetration Depth
epidermis
Molecular Weight
232.3 Da
Log P
1.2
Systemic Absorption
minimal
Topical Bioavailability
6-14%
Safety Margin Factor
moderate
Vehicle Dependent
Yes — absorption varies by formulation

Source: J Pineal Res 2013

Expanded Dermal Absorption Data

Cross-database dermal penetration: EPA Dryad physics-based, Roberts Mendeley permeation, and SCCS-aggregated measured values.

Aggregated DA Values (1 records across 5 sources)
Type DA % Method Skin Model SCCS Ref
measured 100.0% - - SCCS/0022

Additional Ingredient Properties

7 property records from structured ingredient metadata.

anti_aging
{"anti_aging_claim": "antioxidant-protection, anti-wrinkle", "mechanism_of_action": "Cofactor for enzymatic reactions, antioxidant activity", "target_skin_layer": "epidermis", "collagen_stimulation": "Mild", "elastin_protection": "Mild", "wrinkle_reduction_pct": "8-15", "clinical_study_duration_weeks": "12", "sample_size": "30", "double_blind": "Yes", "placebo_controlled": "Yes", "published_journa…
anti_pollution
{"cas_number": "73-31-4", "ingredient_class": "digital_aging_defense/antioxidant_pollution_shield", "primary_mechanism": "free_radical_scavenging", "pollution_types_targeted": "PM2_5/UV_A/blue_light_HEV/oxidative_stress", "IR_A_protection": "no", "visible_light_protection": "no", "digital_screen_protection_claim": "no", "PAH_neutralization": "no", "ozone_protection": "no", "lipid_peroxidation_inhi…
antioxidant
{"cas_number": "73-31-4", "antioxidant_class": "vitamin", "chemical_subclass": "indole hormone", "molecular_weight_daltons": "232.28", "orac_value_umol_te_per_g": "1640", "dpph_radical_scavenging_ic50_ug_per_ml": "18-32", "abts_trolox_equivalent": "not available", "singlet_oxygen_quenching": "not available", "superoxide_dismutase_mimetic": "not available", "hydroxyl_radical_scavenging": "not avail…
dermal_absorption
{"molecular_weight_da": "232.3", "log_p_value": "1.2", "skin_penetration_level": "epidermis", "penetration_depth": "epidermis", "absorption_pct": "10-18", "systemic_absorption": "minimal", "penetration_enhancer": "no", "occlusion_effect": "no", "vehicle_dependent": "yes", "skin_barrier_effect": "strengthens", "bioavailability_topical_pct": "6-14", "safety_margin_factor": "moderate", "source": "J P…
ph_stability
{"optimal_ph_min": "5.0", "optimal_ph_max": "7.0", "stable_ph_min": "4.5", "stable_ph_max": "7.5", "degrades_above_ph": "8.0", "degrades_below_ph": "4.0", "ph_dependent_function": "Antioxidant; circadian rhythm support", "formulation_note": "Sensitive to light and pH extremes", "source": "Formulation literature"}
skin_brightening
{"cas_number": "73-31-4", "mechanism_of_action": "Tyrosinase inhibition; circadian rhythm regulation", "melanogenesis_pathway_target": "Tyrosinase; melanocyte circadian control", "tyrosinase_inhibition_ic50_um": "~100-200", "tyrosinase_inhibition_vs_kojic_acid": "~1-3x weaker", "melanosome_transfer_inhibitor": "No", "melanin_oxidation_reducer": "Yes", "endothelin_pathway_blocker": "No", "alpha_msh…
skin_suitability
{"oily_skin": "acceptable", "dry_skin": "acceptable", "sensitive_skin": "acceptable", "combination_skin": "acceptable", "normal_skin": "acceptable", "acne_prone": "acceptable", "rosacea": "acceptable", "eczema": "acceptable", "hyperpigmentation": "acceptable", "aging_mature": "recommended", "dehydrated": "acceptable", "skin_benefit_primary": "antioxidant", "skin_benefit_secondary": "protective", "…

PubChem Annotations

Safety and regulatory annotations from PubChem (NCBI) aggregated sources.

Safety (1)
Carcinogen Classification
No indication of carcinogenicity to humans (not listed by IARC).
Source: Toxin and Toxin Target Database (T3DB)

Function Categories & List Membership

Cosmetic/Chemical Function Categories
Antioxidant

Expert Verdict

Expert safety assessment and concern-level summary for Melatonin.

Regulatory Flags

anti-pollution ahr-modulator ahr-96pct-reduction circadian-repair night-cream-active antioxidant anti-inflammatory carnosine-synergy blue-light-repair endogenous

NOAEL Studies Summary

View details ->

Public NOAEL study rows linked to Melatonin by CAS number or substance name.

Studies
16
Lowest NOAEL
5
Highest NOAEL
200

Units vary across source rows: mg/kg/day, mg/kg bw/day

SCCS_vision_codex

Dermal Absorption

View details ->
Absorption % Method Vehicle
100.0% - -

Known Synonyms

Regulin Circadin 3-(2-Acetamidoethyl)-5-methoxyindole N-[2-(5-Methoxy-1H-indol-3-yl)ethyl]acetamide Acetamide, N-[2-(5-methoxy-1H-indol-3-yl)ethyl]- Acetamide, N-(2-(5-methoxyindol-3-yl)ethyl)- N-(2-(5-methoxyindol-3-yl)ethyl)acetamide 5-22-12-00042 BRN 0205542 EINECS 200-797-7 UNII-JL5DK93RCL MT6 Melatonin (synth.) standard-grade Melatonin (synth.) ultra-pure N-(2-(5-Methoxy-1H-indol-3-yl)ethyl)acetamide N-(2-(5-Methoxyindol-3-yl)ethyl)-Acetamide N-Acetyl-5-methoxy-tryptamine N-Acetyl-5-methoxy-tryptamine Melatonine N-[2-(5-Methoxy-1H-indol-3-yl)ethyl)acetamide N-[2-(5-Methoxy-1H-indol-3-yl)ethyl]-Acetamide

Chemical Function

Antioxidant

Regulatory Lists

Canada; consumer_product; Substances in Products - Canada (4/2014) active_ingredient; Australia Canada; Personal care; Substances in PCP - Canada (4/2014) pharmaceutical pharmaceutical active_ingredient; animal_products; Europe; pharmaceutical; residue Europe; pharmaceutical Canada; pharmaceutical Canada; pharmaceutical

Cross-Vertical Safety Context

Same-CAS public records found in pharmaceutical data.

SOURCE ChEMBL / DrugCentral / FAERS DB_PHARMA CAS match

Pharmaceutical Data

Same-CAS rows from the pharmaceutical spoke database.

Compound
MELATONIN
ChEMBL ID
CHEMBL45
Max Phase
4
Adverse Event Associations
4879
View full pharmaceutical profile →

Frequently Asked Questions

Is Melatonin safe in cosmetics?

Melatonin has a safety rating of "EXCELLENT" in our database. EU status: permitted. US status: permitted. 10 toxicological study endpoint(s) are available in our database.

Is Melatonin allowed in the EU?

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

What does Melatonin do in cosmetics?

Melatonin functions as: Antioxidant; AhR pathway modulator; anti-pollution active; circadian repair regulator; anti-inflammatory; indole hormone/neurohormone; night repair active; photoprotective antioxidant. It is classified as a Active Ingredient in our database. CAS number: 73-31-4.

What is the NOAEL for Melatonin?

The NOAEL (No Observed Adverse Effect Level) for Melatonin is =5 mg/kg bw/day based on a NOAEL study study via oral route in rat. A total of 10 study endpoints are available. Source: SCCS_vision_codex.

Is Melatonin used outside cosmetics?

Melatonin also appears in industrial chemical safety and pharmaceutical data. The cross-vertical cards on this page render same-CAS public rows from the matched databases.

Is Melatonin in Your Products?

Scan any product label with Piro — our free ingredient scanner. Point your camera at the ingredients list and get instant safety scores for every ingredient.

Try Piro Free →

Analyze Your Full Ingredient List

Paste any INCI list into the Decoder for instant safety analysis, or calculate the Margin of Safety for Melatonin in your formulation.