What it is
Rosmarinus Officinalis Leaf Extract is an extract obtained from the leaves of rosemary, an evergreen shrub in the mint family (Lamiaceae). The leaves contain flavonoids, phenolic acids and diterpenes, with rosmarinic acid and carnosic acid among the better-characterized antioxidant constituents. In formulations it is valued chiefly for its antioxidant and skin-conditioning behavior, and the small fraction of essential oil naturally present (roughly 1-2% of the leaf) also contributes aroma. It is a common supporting botanical rather than an active sunscreen filter.
Safety & warnings
Rosemary extract carries a small amount of naturally occurring essential oil, so people who are sensitive or allergic to fragrance components may prefer to avoid it or patch test first. Reactions in leave-on cosmetics are uncommon for most users, but the aromatic fraction is the main consideration for reactive or fragrance-intolerant skin.
Origin & sourcing
The extract is plant-derived, made from the leaves of rosemary (Rosmarinus officinalis, reclassified as Salvia rosmarinus in 2017), a Mediterranean evergreen shrub native to the Mediterranean region as well as Portugal and northwestern Spain. The leaves are processed to yield an extract containing the plant's phenolic and diterpene constituents.
History
Rosemary has a long history of cultivation: it was naturalized in China by 220 CE during the Han dynasty, reached England through Roman contact, and became established in Britain around 1338 when cuttings were sent to Queen Philippa. One of its signature antioxidant constituents, rosmarinic acid, was first isolated and identified from rosemary by the Italian chemists Scarpati and Oriente in 1958.
Questions everyone asks
What does rosemary leaf extract do in sunscreen?
It mainly acts as an antioxidant and skin-conditioning botanical, supporting the formula rather than providing UV protection itself, which comes from the dedicated filters.
Is rosemary extract a sunscreen filter?
No. It is a plant extract used for antioxidant and conditioning effects; the sun protection in a product comes from its UV filters, not from rosemary.
Can fragrance-sensitive skin use it?
Rosemary leaf contains a little natural essential oil, so those allergic to fragrance may want to avoid it or patch test first.