Zinc

Anti-inflammatory effects. Zinc modulates innate immunity and reduces neutrophil activity and inflammatory signaling—key in acne’s inflammatory cascade. Reviews of zinc’s immune effects and dermatology literature summaries support this mechanism. ScienceDirect

Antimicrobial activity vs Cutibacterium acnes (formerly P. acnes). Multiple reviews describe zinc salts inhibiting C. acnes and its lipases, which can lessen inflammatory lesions. MDPI

Possible sebum regulation via 5-α-reductase inhibition (androgen pathway). Classic in-vitro work showed zinc can inhibit type I 5-α-reductase in human skin; this offers a plausible route for reduced oiliness, though clinical translation is modest. Oxford Academic

People with acne often have lower zinc levels. A 2020 systematic review/meta-analysis found significantly lower baseline serum zinc in acne vs controls, supporting a role for supplementation in those who are low. Wiley Online Library

Oral zinc (most studied):

• Who to consider: inflammatory acne (papules/pustules), especially if you prefer to avoid/limit antibiotics or you have a documented low zinc level.
• Common study dose: ~30 mg elemental zinc daily (often as zinc gluconate ≈ 200 mg providing ~28–30 mg elemental zinc) for 8–12 weeks, then reassess. Do not exceed the adult UL of 40 mg/day without medical supervision. Take with food to reduce nausea. Karger
• Timing with other meds: separate from tetracyclines/fluoroquinolones (≥2 hours before or 4–6 hours after) to avoid chelation that reduces absorption of both drug and zinc. Office of Dietary Supplements

Topical zinc:

• As monotherapy: evidence is limited/low-certainty; it may modestly help mild inflammatory acne. Cochrane
• In combinations: some benefit when paired with topical erythromycin (e.g., zinc acetate + erythromycin solutions used twice daily in trials). Combination arms outperformed erythromycin alone in lesion reduction over 8–12 weeks. Oxford Academic

Dietary zinc:

• Prioritize food sources (oysters, meat, dairy, fortified foods). Plant sources are less bioavailable due to phytates; eating fermented/sprouted grains or pairing with vitamin-C–rich foods may help absorption. Office of Dietary Supplements

Systematic reviews/meta-analyses

• Dermatologic Therapy (2020): People with acne had lower serum zinc; pooled data show signals that supplementation can improve severity, though study quality varies. Wiley Online Library
• Cochrane Review (2019 update) on topical agents: Found low-certainty evidence for topical zinc (often combined with nicotinamide or antibiotics); overall effect small vs standard therapies. Cochrane
• Narrative/clinical reviews: Conclude moderate/limited-quality evidence that oral and topical zinc can reduce inflammatory lesions; recommended as adjuncts (SORT grade B). JDDonline

Randomized controlled trials (examples)

• Zinc vs minocycline (Dermatology, 2001): 332 patients with inflammatory acne received 30 mg elemental zinc/day (as gluconate) vs minocycline 100 mg/day for 3 months. Both improved acne, but zinc was less effective than minocycline—useful where antibiotics are unsuitable. Karger
• Oral zinc sulfate vs placebo (double-blind): In classic trials (~12 weeks), zinc sulfate arms showed significant improvement vs placebo in a proportion of patients, supporting efficacy but with variable response rates. medicaljournalssweden.se
• Topical erythromycin + zinc vs erythromycin alone (BJD, 1989): The combination reduced lesion counts and global severity more than erythromycin alone over 12 weeks. Oxford Academic
• Ongoing/modern RCTs: Recent registered trials continue to test zinc gluconate/sulfate for mild–moderate acne using 20–30 mg elemental/day for 8–12 weeks, reflecting current dosing practice. ICHGCP