Acetyl Cysteine
INCI: aceytlcysteine
Reviewed by Kate · Last updated 18 Aug 2026
Also known as: aceytlcysteine, n-acetylcysteine, NAC, Glutathione, L-Cysteine
Derivative of the amino acid l-cysteine Precursor to the body's master antioxidant, glutathione
Best For Skin Types
All skin types
Usage Frequency
As directed on product packaging
EWG Safety Score
Acetyl Cysteine products at Skintique
View all →What Is Acetyl Cysteine?
Acetyl cysteine, known also as aceytlcysteine, n-acetylcysteine and NAC, is an ingredient used for years in clinical settings to treat acetaminophen overdose. It is a derivative of the amino acid l-cysteine and is a precursor of the body’s master antioxidant, glutathione.
In recent years, scientists have discovered new properties and uses for acetyl cysteine, one of which is its value as an anti-ageing ingredient in skin care. As a precursor to glutathione, it also has antioxidant properties and with it, free-radical scavenging abilities that fight premature signs of ageing.
Acetyl cysteine also showed skin-calming effects and in some studies improved skin hydration via decrease of trans-epidermal water loss.
The independent Cosmetic Ingredient Review Expert Panel has ruled acetyl cysteine safe in its current usage and practice in cosmetics. Use levels of acetyl cysteine in cosmetics range from 0.0005-0.1%.
Benefits for Your Skin
Clinical Evidence & References
- Journal of Clinical and Aesthetic Dermatology, May 2019, pages 20-26
- Indian Journal of Dermatology, Venereology and Nephrology, November-December 2018, pages 652-659
- International Journal of Toxicology, May-June 2017, pages 17S-56S
- Journal of Dermatological Science, May 2017, pages 4-19
- Cell Journal, December 2016, pages 11-17
- Annals of Dermatology, July 2015, pages 450-451
- Journal of Investigative Dermatology, May 2003, pages 835-841
Published Research
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N-acetylcysteine: Antioxidant and skin applications Biomed Pharmacother, 2017
From the Clinic
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Acetyl Carnitine HCL
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Acetyl Methionine
An amino acid, which are fundamental building blocks of all proteins in the body
Achillea Millefolium Flower Extract
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