A type of lichen. Lichens consist of fungi and algae growing together symbiotically; xanthoparmelia is a specific type of lichen commonly found on the United States’ mid-eastern coast.

Because it is a vasodilator (a substance that promotes blood flow by expanding blood vessels), xanthoparmelia is included in some sexual health supplements. Manufacturers often claim that this ingredient improves sensation or enhances arousal. It has also been promoted as a treatment for erectile dysfunction. However, there is limited clinical evidence supporting these uses.

Xanthoparmelia seems safe in small amounts, but it may be dangerous in large amounts. It is not safe for pregnant or breastfeeding women.