3-Butanediol (1,3-butylene glycol) is a small diol commonly used in cosmetics as a humectant, solvent, and mild antimicrobial agent that helps retain moisture and stabilize formulations. It is generally considered safe and well tolerated at typical use concentrations.
| Reported effect | How often | Notes |
|---|---|---|
Mild skin irritation | Uncommon | Transient redness or stinging, more likely at higher concentrations or on compromised skin. |
Allergic contact dermatitis | Rare | Sensitization reported in isolated patch-test cases. |
Eye irritation | Rare | On direct contact with concentrated material. |
Frequencies reflect typical cosmetic use reported in the literature, not a guarantee for your skin.