Mahonia Aquifolium Root Extract

Mahonia aquifolium (Oregon grape) root extract is used for anti-inflammatory/antimicrobial and sebum-modulating benefits, typically at low percentages in leave-on products, but it contains isoquinoline alkaloids (e.g., berberine) that can be irritating on compromised skin. Human data and clinical experience suggest most users tolerate it, yet reactive or eczematous patients can experience stinging or contact dermatitis, especially when layered with other actives. Given the nontrivial sensitization/irritation potential of botanical extracts in highly sensitive populations, it warrants a mild-risk score. Safety Notes: In commercial leave-on skincare (calming/blemish, redness, and psoriasis-prone positioning), Mahonia aquifolium root extract is frequently used as a minor botanical active or supporting extract at ~0.01–0.2%, often within multi-extract blends and at the low end primarily for label/marketing and gentle skin-feel impact. Higher-strength OTC specialty products (not prescription/pro-only)—especially targeted serums/creams drawing on berberine/alkaloid activity—are seen around ~1–3%, with the upper end approaching ~5% when the extract is a primary featured active, constrained by color/odor, solubility, and potential irritation. Rinse-off products generally sit toward the lower portion of the range due to short contact time, while the highest levels are overwhelmingly in leave-on formats.