Ergosterol is a fungal-derived sterol that serves as a precursor to vitamin D2 and is used in skincare for its antioxidant and skin-conditioning properties. Upon UV exposure it can convert to ergocalciferol, supporting barrier and membrane function.
| Reported effect | How often | Notes |
|---|---|---|
Mild skin irritation or redness | Rare | Generally well tolerated; occasional sensitivity reported in susceptible individuals. |
Contact allergic reaction | Very rare | Isolated reports; sterols are typically low-allergenic. |
Localized itching | Rare | Transient and usually resolves on discontinuation. |
Frequencies reflect typical cosmetic use reported in the literature, not a guarantee for your skin.
Peer-reviewed papers on this ingredient, via PubMed.