beauty
cleaning
food
industrial

N-Acetyl-L-cysteine

CAS 7696-05-1 · 40/100 · High conf.

Also registered as 2 other CAS numbers

1261105-20-7 · 616-91-1

Concern score

40/100Moderate concern based on regulatory listings.

High confidence

N-Acetyl-L-cysteine in plain language

What it is: On cosmetic ingredient lists it appears as “Acetyl cysteine”.
Also known as Acetyl cysteine · Acetylcysteine · (2R)-2-acetamido-3-sulfanylpropanoic acid · N-acetyi-l-cysteine · Nac · (2R)-2Acetamido-3-sulfanylpropanoic acid
Show all 36 names
(r)-n-acetylcysteine · Acetadote · Acetilcisteina · Acetylcysteinum · Asist · Broncholysin · Broncholysin (mucolytic) · Brunac · Cetylev · Cysteine, N-acetyl-, L- · Cysteplus · Fluimicil · Fluimucetin · L-Acetylcysteine · L-Cysteine, N-acetyl- · Mercapturic acid · Mucomyst · Mucosil · Mucolyticum · Mucolyticum-Lappe · N-acetyl cysteine · N-acetyl-(r)-cysteine · N-ACETYL-3-MERCAPTOALANINE · N-acetylcysteine · Neo-fluimucil · Oristar nalc · Respaire · RK-0202 · Syntemucol · Tixair
What it does: Used in cosmetics as an antioxidant and a skin-conditioning agent.
Antioxidant
Skin conditioning
Conditioner
Is it a concern?: Moderate concern: no hazard classifications on record. It is listed for cosmetic use in the EU.

Why it's flagged

EPA CPDat observed this chemical in 22 composition records across product categories including Laboratory supplies, Food and drug, Personal care.

The score describes this ingredient's chemical identity — its hazard profile from published classifications and regulatory status — not the safety of any product it appears in.

Regulation

No restrictions found. N-Acetyl-L-cysteine appears in these published regulatory listings.

In marketed US drugs

Recorded in these product areas

Found in consumer products
Beauty
Cleaning
Pharma
Food
Industrial

EUCosIngActiveListed in CosIng inventory for cosmetic use.
- Listed in CosIng inventory for cosmetic use.Source →
EUEFSAEFSA opinionOpinion of the Scientific Panel on Food Additives, Flavourings, Processing Aids and Materials in Contact with Food (AFC) on a request from the Commission related to N-Acetyl-L-cysteine for use in foods for particular nutritional uses and in foods for special medical purposes (EFSA AFC)
- Opinion of the Scientific Panel on Food Additives, Flavourings, Processing Aids and Materials in Contact with Food (AFC) on a request from the Commission related to N-Acetyl-L-cysteine for use in foods for particular nutritional uses and in foods for special medical purposes (EFSA AFC)Source →
USEPAcommercial use observedEPA CPDat observed this chemical in 22 composition records across product categories including Laboratory supplies, Food and drug, Personal care. EPA CPDat classifies this chemical for functional uses including Antioxidant, Softener and conditioner.
- EPA CPDat observed this chemical in 22 composition records across product categories including Laboratory supplies, Food and drug, Personal care. EPA CPDat classifies this chemical for functional uses including Antioxidant, Softener and conditioner.Source →
USFDAmarketed drug occurrenceFDA NDC lists this ingredient in 36 active drug products and 36 total products.
- FDA NDC lists this ingredient in 36 active drug products and 36 total products.Source →
USFDAlisted in openFDA substanceopenFDA substance registry classifies this ingredient as chemical.
- openFDA substance registry classifies this ingredient as chemical.Source →

Expert safety opinions

Independent scientific assessments cited by the records we hold, with the year and link where the record gives one.

SCCS
EU Scientific Committee on Consumer Safety
No SCCS opinion on file.
CIR
Cosmetic Ingredient Review (US expert panel)
No CIR safety assessment on file.
EFSA
European Food Safety Authority
- Opinion of the Scientific Panel on Food Additives, Flavourings, Processing Aids and Materials in Contact with Food (AFC) on a request from the Commission related to N-Acetyl-L-cysteine for use in foods for particular nutritional uses and in foods for special medical purposes (EFSA AFC)
  2004 · EU EFSA listing · Read the source →

Evidence & sources

No graded research studies for N-Acetyl-L-cysteine yet. This record is compiled from the published data sources below — registries and regulatory listings, not study findings.

8 data sources

Where this comes from

CosIng
regulatory · updated 2026-09-23
Open →
EFSA OpenFoodTox
regulatory · updated 2026-10-04
Open →
EPA Chemical and Products Database
exposure · updated June 2013
Open →
EPA DSSTox Identifiers
chemistry · updated 2025-12-29
Open →
FDA National Drug Code Directory
regulatory · updated 2027-12-31
Open →
FDA GSRS UNII
registry · updated 2026-02-26
Open →
openFDA Substance
registry · updated 2026-05-24
Open →
PubChem Live Enrichment
chemistry · updated 2026-05-17
Open →

Reference links (3)

Openfda substance

ncit.nci.nih.gov

Read →

Openfda substance

clinicalkey.com

Read →

Openfda substance

en.wikipedia.org

Read →

Suitability

Context-specific fit derived from published classifications and the current ingredient evidence profile.

Food use

Food-use source coverage is present in the current record.

Good fit

The ingredient appears in food-oriented source coverage or allowed-use references, which makes food use easier to support than a context with no domain signal at all.

Fragrance avoidance

No fragrance-linked caution surfaced in the current profile.

Good fit

This ingredient does not currently read as a fragrance-linked driver in the published evidence and hazard profile.

Where it has been recorded

How often FDA National Drug Code directory has listed N-Acetyl-L-cysteine in a product composition. These are source records, not Greenveil catalog products.

Source records

Typical roles

AntioxidantSkin conditioningConditioner

See products using N-Acetyl-L-cysteine →

Catalog

Found in these products

Their ingredient lists include N-Acetyl-L-cysteine; each product's own rating depends on its whole formula, so it is shown on the product page, not here.

See all 27 →Find products without it →