Cos De Baha - NZ Niacinamide 20% + Zinc PCA 4% Serum 30ml

Cos De Baha's NZ Serum is formulated around two complementary sebosuppressive active ingredients. Niacinamide (Vitamin B3) at 20% is one of the highest concentrations available in mainstream cosmetic formulas — this is 2 to 4 times higher than the doses in published clinical studies (2 to 10%), which constitutes an extrapolation worth noting: the sebosuppressive effect, on the barrier and on melanosome transfer, is biologically amplified, but the quantitative efficacy data beyond 10% remains limited. Zinc PCA (zinc-pyroglutamic acid complex) acts on the sebaceous glands through a mechanism distinct from that of niacinamide — their combination is synergistic for oily skin types. Caffeine (position 11 in the INCI) contributes to the refinement of pore appearance through mild vasoconstriction. Arbutin is present in a secondary concentration (not communicated by the manufacturer) — its depigmenting contribution remains complementary and subtle. Critical point: at 20% niacinamide, a flushing phenomenon (transient redness and sensation of warmth) is documented by the manufacturer itself. This reaction is linked to the cutaneous metabolism of high-dose niacinamide, generally benign and short-lived (10 to 20 minutes), but can be unsettling for an unsuspecting user. A prior patch test is essential. For skin that has already used 10% niacinamide, the introduction of 20% should still be gradual (once a week, then gradually increasing). Incompatibility with pure Vitamin C serums: niacinamide can interact with ascorbic acid at low pH (the conversion to nicotinic acid requires heat + time conditions, rare in vivo, but as a precaution, alternate morning/evening use). Pregnancy: topical niacinamide and Zinc PCA have no formal contraindications, but consult a doctor as a precaution.