What it is
Hydroxydecyl Ubiquinone is a structurally modified analog of coenzyme Q10, with a shortened hydroxylated side chain that alters its solubility and stability compared with native ubiquinone. It is used in skincare primarily for its antioxidant character, helping to support the skin against free-radical and oxidative stress. In sunscreens it acts as a supporting antioxidant rather than as a UV filter.
Safety & warnings
Hydroxydecyl Ubiquinone is generally well tolerated, though some users can experience irritation or sensitization, and it has been associated with allergic contact dermatitis in a minority of individuals; a patch test is reasonable for sensitive skin. It is colored and can lend a tint to formulas.
Origin & sourcing
Synthetic. It is a laboratory-produced analog of the naturally occurring coenzyme Q10 (ubiquinone), modified to change its side-chain structure.
History
This molecule is widely known by the name idebenone, which was originally developed and studied in a pharmaceutical context before being adopted as a cosmetic antioxidant.
Questions everyone asks
Is Hydroxydecyl Ubiquinone the same as coenzyme Q10?
It is a close synthetic relative. It is an analog of coenzyme Q10 with a modified side chain, and it is commonly known as idebenone.
What does it do in a sunscreen?
It works as an antioxidant that helps support the skin against oxidative stress. It is not a UV filter and does not provide SPF by itself.