Ubiquinone

Ubiquinone (coenzyme Q10) is an antioxidant typically used at low levels (about 0.1–1%) in leave-on products and is not inherently acidic or exfoliating, so it is generally well-tolerated. However, documented cases of irritant or allergic contact dermatitis exist, and its poor water solubility often necessitates solvents/emulsifiers that can increase real-world reactivity in highly sensitive or eczematous skin. Given this low-but-nonzero risk, it fits best as a gentle ingredient rather than exceptionally gentle. Safety Notes: In commercial skincare, ubiquinone (coenzyme Q10) is often included at very low “label-claim” levels (around 0.0001–0.01%) in moisturizers/cleansers where it functions primarily as an antioxidant support ingredient, with higher but still typical leave-on usage commonly in the ~0.05–0.3% range. Consumer-available high-strength serums and concentrated antioxidant creams are marketed at ~0.5% and up to about 1% ubiquinone; above this, solubility, color/odor, and oxidation/stability constraints usually drive brands toward solubilized/encapsulated forms or lower active loads rather than higher percentages. Rinse-off products are generally at the low end because contact time is short, while leave-on products span the full range.