Dihydroxyacetone

Dihydroxyacetone is a self-tanning active typically used around 3–10% in leave-on formulas, where it can cause stinging, dryness, and irritant contact dermatitis, especially on eczematous or barrier-compromised skin. Patch testing and post-marketing reports show it is not universally “gentle,” with higher risk when applied repeatedly over large areas or combined with other irritants (acids, retinoids, strong cleansers). Given its leave-on use at active concentrations and predictable barrier-drying/irritant potential in sensitive populations, a moderate irritancy score is warranted. Safety Notes: In consumer self-tanning products, DHA is used at very low levels (~0.2–1%) in gradual tanners and tone-correcting/“tan-extender” moisturizers, while standard self-tanning lotions/foams commonly sit around 3–8%. High-strength OTC formulations marketed for deeper/rapid color (including some bronzing drops and at-home spray-tan solutions) reach ~10–15% DHA; above this is uncommon due to odor, irritation, and stability/packaging constraints. DHA is primarily used in leave-on products (lotions, foams, drops), while rinse-off bronzing washes typically use much lower effective levels or rely more on immediate colorants.