Chlorella Vulgaris Extract

Chlorella Vulgaris Extract is primarily used as an antioxidant/skin-conditioning botanical, typically at low concentrations, and is generally well tolerated in routine cosmetic use. However, as a complex algae-derived mixture (proteins, polysaccharides, pigments), it has a non-trivial risk of irritation or allergy in highly reactive or eczematous patients compared with inert humectants, especially with leave-on exposure and cumulative use alongside other actives. Given this sensitization potential seen with some botanical extracts in patch testing populations, I score it as mild rather than “gentle.” Safety Notes: In mass-market leave-on products (creams/lotions/serums), Chlorella Vulgaris Extract is often used at very low levels (around 0.0005–0.05%) as part of multi-botanical blends or pre-preserved glycerin/water extracts where the listed INCI represents a dilute extract. More performance-positioned anti-aging/firming leave-on products commonly use ~0.1–2% depending on extract potency and solvent system, while a small number of consumer-available “single-algae/high-load” ampoules, masks, and concentrates push the active extract phase to the upper end around 3–5% (typically for hydroglycolic extracts rather than dry powder). Rinse-off products generally sit in the lower half of the range due to brief contact time, though high-load wash-off masks can reach the upper end when marketed around algae content.