Macrocystis Pyrifera Extract

Macrocystis Pyrifera (giant kelp) extract is typically used at low concentrations as a humectant/skin-conditioning and antioxidant component, and is generally well-tolerated in routine patch-testing experience. However, as a marine botanical mixture (polysaccharides, proteins, trace minerals/iodine), it has a non-zero risk of irritant reactions or occasional sensitization in highly reactive or eczematous skin, especially when skin barrier is compromised. Given this predictable but low-level risk, it fits best as a gentle (not inert) ingredient. Safety Notes: In mass-market leave-on lotions/serums and rinse-off cleansers, Macrocystis pyrifera (kelp) extract is commonly used as a secondary botanical at very low levels (often ~0.01–0.1%) to support a marketing story and provide minor conditioning without impacting odor/color or stability. Higher-strength, consumer-available “seaweed/kelp” masks, body gels, and concentrated anti-cellulite/firming products can push total kelp extract to the low single digits, with the upper observed OTC end around ~5% when the extract is a major featured active (typically in leave-on gels/creams; rinse-off products rarely sustain the highest levels due to cost and sensorial constraints).