Acne

Acne

Niacinamide holds Grade A on 15 studies and 1,200 participants. Most of that literature is topical rather than oral, and its recorded actions are anti-inflammatory, including suppression of cytokine release and reduction in sebum excretion rate. Zinc holds the second Grade A rating on 12 studies and 900 participants, with a longer history than most entries here; its role as a therapeutic principle in dermatology was being argued as early as the 1980s ^[1]. Zinc modulates neutrophil chemotaxis and has direct antibacterial activity against C. acnes, and narrative reviews continue to associate lower serum zinc with poorer outcomes in inflammatory skin disease ^[2].

The Grade C tier covers retinol at 6 studies and 400 participants, omega-3 fatty acids at 5 and 300, curcumin at 4 and 240, and pantothenic acid at 3 and 200. These are heterogeneous in rationale. Retinoids normalise follicular keratinization and are the mechanistic backbone of prescription acne therapy, but the oral supplement literature is far thinner than the pharmaceutical one. Omega-3s and curcumin act on the inflammatory limb. Broader reviews of trace elements and micronutrients in dermatology situate several of these within a wider pattern of nutritional influence on skin barrier and immune function ^[3].

Green tea extract, Lactobacillus rhamnosus and saw palmetto occupy Grade D on 2 to 3 studies each. Green tea polyphenols, principally epigallocatechin gallate, have an established dermatologic literature centred on antioxidant and anti-androgenic activity ^[4], but the acne-specific trials are few and small. A review of nutritional supplements across selected dermatological disorders reaches the same general conclusion for this category, that mechanism currently outruns clinical demonstration ^[5].

Two cautions deserve weight. Zinc has a genuine upper limit: excessive oral supplementation induces copper deficiency and has produced haematologic consequences in documented cases ^[6], so dose matters more here than with most entries on this page. And acne trials are unusually sensitive to regression to the mean, because participants typically enrol during a flare, which inflates apparent improvement in every arm.

Diet, hormonal fluctuation, family history and comedogenic cosmetics all modify the course of the condition independently of supplementation. Nodular or cystic acne carries a real risk of permanent scarring and post-inflammatory hyperpigmentation, and belongs with a dermatologist rather than with any supplement protocol.