Camphor

Camphor is a counterirritant/fragrance-like terpene used in topical analgesics and “cooling” products (often ~0.1–3% in cosmetics; higher in OTC rubs), and it commonly causes stinging/burning on compromised skin. Clinical experience and patch testing literature support irritant contact dermatitis risk, with occasional allergic reactions, and it can significantly flare eczema due to sensory nerve activation. Given its high likelihood of irritation in sensitive or barrier-impaired users and frequent inclusion in multi-ingredient rubs, it warrants a high irritancy score. Safety Notes: In mainstream cosmetics and personal care, camphor is most often present at trace levels (~0.01–0.1%) as a fragrance/masking component in creams, lotions, and hair/scalp products, with some anti-blemish or cooling leave-on products commonly around ~0.1–1%. The highest consumer OTC concentrations are seen in topical analgesic/rub products (e.g., camphor/menthol/methyl salicylate rubs) where camphor is typically 3–11% and 11% is a common labeled maximum in widely sold OTC products; higher levels are generally restricted to drugs/professional use and are not typical for cosmetic leave-on skincare due to irritation/sensitization risk.