Acetyl cysteine (N-acetylcysteine) is a thiol-containing antioxidant and glutathione precursor used topically for its free-radical scavenging and skin-conditioning properties. It is studied for conditions such as melasma, acne, and barrier support.
| Reported effect | How often | Notes |
|---|---|---|
Skin irritation or stinging | Uncommon | Mild transient burning or redness at the application site, more likely at higher concentrations. |
Contact dermatitis | Rare | Allergic or irritant reaction in sensitized individuals. |
Unpleasant sulfurous odor | Common | Cosmetic complaint rather than a health effect, due to the thiol group. |
Dryness or peeling | Uncommon | Occasional with frequent use or in combination with other actives. |
Frequencies reflect typical cosmetic use reported in the literature, not a guarantee for your skin.