Aldehydes consist of an oxygen atom double-bonded to a carbon atom at the end of the carbon chain. Their effectiveness is most beneficial when used in a lower concentration, such as 1% or less. Known for their citrus-like and sometimes aphrodisiac fragrance, aldehydes are generally calming, anti-inflammatory and hypotensive. Aldehydes can also be strongly antifungal, antiviral, and antiseptic, but may cause skin irritation.
