Rosmarinus Officinalis Leaf Extract

Rosmarinus officinalis (rosemary) leaf extract is typically used as an antioxidant/soothing or odor-masking botanical at low percentages, but it contains terpene and phenolic constituents that can be irritating and can trigger allergic contact dermatitis in a meaningful minority of sensitive or eczematous patients. Patch-test literature and clinical experience show botanicals/fragrance-adjacent extracts are not reliably “gentle,” and risk increases with leave-on use and cumulative exposure in multi-product routines. Given the potential for both immediate irritation and delayed sensitization in compromised skin, a moderate irritancy score is the safest clinically-aligned assessment. Safety Notes: In mass-market leave-on skincare (creams/serums/toners) Rosmarinus Officinalis (Rosemary) Leaf Extract is often used at very low “label-support/antioxidant blend” levels around 0.001–0.05%, with rinse-off cleansers and shampoos commonly in a similar low range due to cost, odor, and sensitization considerations. Higher-strength consumer products marketed as botanical/“natural” actives—especially scalp tonics, hair oils, and concentrated antioxidant/botanical serums—can reach ~1–5% extract (typically as a glycerin/propylene glycol/water extract or similar), with >5% uncommon in OTC due to stability, color/odor impact, and increased irritation risk.