What it is
Mastic gum is the aromatic resin exuded by the bark of the mastic tree (Pistacia lentiscus) and dries into hard, translucent tears that are processed for cosmetic use. In sunscreens and color cosmetics it helps form a cohesive surface film, which can support an even, matte finish and improved wear of the product. It also lends a subtle resinous character and acts as a conditioning component.
Safety & warnings
Mastic is a fragrant tree resin, and resinous botanical materials can occasionally provoke contact sensitization in predisposed individuals. People with known sensitivities to natural resins or fragrance constituents may wish to patch test products containing it.
Origin & sourcing
Natural; a tree resin tapped from Pistacia lentiscus, most famously the mastic variety cultivated on the Greek island of Chios.
History
Mastic gum has been harvested around the Mediterranean for thousands of years and was historically chewed and used as an aromatic and varnish material long before its modern cosmetic applications.
Questions everyone asks
What is mastic gum?
It is the natural resin tapped from the mastic tree, Pistacia lentiscus, traditionally associated with the Greek island of Chios.
Why is it used in sunscreen?
It acts mainly as a film former and conditioning agent that can help the product wear evenly and feel more uniform on skin.