Polyamide-8

Polyamide-8 is a synthetic polymer film former/texture agent used at low percentages in cosmetics (commonly a few percent) to improve wear and feel, and it is generally not a biologically active irritant. Clinical experience and patch-testing trends for high–molecular weight polymers like this show low direct irritation because they have minimal skin penetration, though compromised barriers can still react to occlusive film formers or impurities. Given the low intrinsic reactivity but non-zero risk in highly eczematous skin, it best fits a very gentle (0.2) profile rather than truly inert. Safety Notes: Polyamide-8 is most commonly used as a film-forming/texture and wear-improving polymer in leave-on color cosmetics and skincare primers, where it can appear at low levels (~0.1–0.5%) as part of a polymer blend to enhance slip and reduce tack. In higher-performance long-wear, smoothing, or water-resistant leave-on formulations (primers, foundations, some specialty moisturizers), it can be used at a few percent, with high-strength consumer products observed up to ~5% where the polymer is a major structuring/film-forming component. Rinse-off products tend to use it less frequently and typically at the low end when present, due to limited benefit versus cost and sensorial impact.