Tincture of benzoin is often recommended to protect sensitive skins and treat minor wounds. Its sticky consistency creates a thin protective layer that prevents moisture loss, while its main chemical constituent, called benzoic acid, fights infections thanks to its antimicrobial properties.
Benzoin is a natural resin that can be collected from two types of styrax trees: Styrax benzoin, native to Sumatra, and Styrax tonkinensis, which grows in Southeast Asia.
Although often referred to as gums, resins are slightly different, as they contain many more essential oils and are not soluble in water. Resin flows off tree trunks when they're injured. It's liquid but hardens with air exposure, like a bandage that protects the tree from disease. Once collected, it can be ground into a powder, refined with solvents to make a scented extract or soaked in alcohol to obtain a tincture.
The tincture has been traditionally used to protect the skin. It is, for example, the main ingredient of Friar's balsam (a soothing balm) and of a 19th-century beauty tonic called ‘virgin’s milk’. It also gives shine and condition to the hair and its strong antimicrobial properties can help preserve products’ formulae.
Lush purchase this ingredient from a UK based company, specialising in botanical extracts. They prepare the tincture from Sumatran benzoin, using ethanol as the solvent.