Condition

Acne

Acne happens when hair follicles clog with oil and dead skin cells, letting bacteria thrive and the skin become inflamed, and hormones that boost oil explain why it often flares in puberty. The evidence is strongest for nicotinamide and zinc, and in three nicotinamide studies, acne symptoms improved. Those trials were fairly small and mostly compared a nicotinamide gel with an antibiotic gel, while tea tree oil and selenium have only limited evidence.

Sources: PMID 23786503; PMID 7657446

Supplements studied: 11
Graded outcomes: 8
Trials: 12
People studied: 1,156

Evidence by supplement

Strong
Moderate
Limited
Very limited

11 supplements

Nicotinamide

Nicotinamide: outcomes studied for Acne
Grade	Outcome	Effect	Size	Studies	People
	Acne Symptoms Moderate Improvement	Improves (the measure goes down)	Moderate effect	3 studies	331 people
Studies that measured acne symptoms Topical 4% nicotinamide vs. 1% clindamycin in moderate inflammatory acne vulgarisInt J Dermatol · PMID 23786503 Topical nicotinamide compared with clindamycin gel in the treatment of inflammatory acne vulgarisInt J Dermatol · PMID 7657446 1-Methylnicotinamide: a potent anti-inflammatory agent of vitamin originPol J Pharmacol · PMID 12856834
	Erythema Small Improvement	Improves (the measure goes up)	Small effect	1 study	175 people
Studies that measured erythema Niacinamide: A B vitamin that improves aging facial skin appearanceDermatol Surg · PMID 16029679
	Wound Healing	Improves (the measure goes up)			175 people

Vitamin B5 (Pantothenic Acid)

Vitamin B5 (Pantothenic Acid): outcomes studied for Acne
Outcome	Effect	Size	People
Acne Lesion Count Moderate Decrease	Improves (the measure goes down)	Moderate effect	300 people
Sebum Production Moderate Decrease	Improves (the measure goes down)	Moderate effect	200 people
Pore Size Small Decrease	Improves (the measure goes down)	Small effect	150 people

L-Carnitine

Blood Carnitine: improves
Urine Carnitine: improves

L-Carnitine: outcomes studied for Acne
Grade	Outcome	Effect	Size	Studies	People
	Blood Carnitine Large Increase	Improves (the measure goes up)	Large effect	2 studies	230 people
Studies that measured blood carnitine The effects of L-carnitine supplementation on performance during interval swimmingInt J Sports Med · PMID 8063466 L-carnitine supplementation in patients with cystic acne on isotretinoin therapyJ Eur Acad Dermatol Venereol · PMID 10642057
	Urine Carnitine	Improves (the measure goes up)			230 people

Tea Tree Oil

Acne Lesions: changes; see studies

Tea Tree Oil: outcomes studied for Acne
Grade	Outcome	Effect	Size	Studies	People	Studies list
	Acne Lesions 5% tea tree oil similar efficacy to 5% benzoyl peroxide but slower onset (fewer side effects)	Changes; see studies	Moderate effect		200 people

Selenium

Acne Symptoms: improves

Selenium: outcomes studied for Acne
Grade	Outcome	Effect	Size	Studies	People	Studies list
	Acne Symptoms Small Improvement	Improves (the measure goes down)	Small effect		56 people

Zinc

Acne Symptoms: improves

Zinc: outcomes studied for Acne
Grade	Outcome	Effect	Size	Studies	People	Studies list
	Acne Symptoms	Improves (the measure goes down)		4 studies	462 people
Studies that measured acne symptoms Multicenter randomized comparative double-blind controlled clinical trial of the safety and efficacy of zinc gluconate versus minocycline hydrochloride in the treatment of inflammatory acne vulgarisDermatology · PMID 11586012 Oral zinc sulphate therapy in acne vulgaris: a double-blind trialActa Derm Venereol · PMID 6163281 Low doses of zinc gluconate for inflammatory acneActa Derm Venereol · PMID 2575335 and 1 more on the Zinc page

Vitamin D

Acne Symptoms: improves

Vitamin D: outcomes studied for Acne
Grade	Outcome	Effect	Size	Studies	People	Studies list
	Acne Symptoms	Improves (the measure goes down)		1 study	44 people
Studies that measured acne symptoms Role of vitamin D supplement adjunct to topical benzoyl peroxide in acne: a randomized double-blinded controlled study.Int J Womens Dermatol · PMID 38957412

Resveratrol

Acne Symptoms: improves

Resveratrol: outcomes studied for Acne
Grade	Outcome	Effect	Size	Studies	People	Studies list
	Acne Symptoms	Improves (the measure goes down)		1 study	20 people
Studies that measured acne symptoms Resveratrol-containing gel for the treatment of acne vulgaris: a single-blind, vehicle-controlled, pilot studyAm J Clin Dermatol · PMID 21348544

Cocoa Extract

Acne Symptoms: improves

Cocoa Extract: outcomes studied for Acne
Grade	Outcome	Effect	Size	Studies	People	Studies list
	Acne Symptoms	Improves (the measure goes down)		1 study	13 people
Studies that measured acne symptoms Double-blind, Placebo-controlled Study Assessing the Effect of Chocolate Consumption in Subjects with a History of Acne VulgarisJ Clin Aesthet Dermatol · PMID 24847404

N-Acetylcysteine

Acne Symptoms: improves

N-Acetylcysteine: outcomes studied for Acne
Grade	Outcome	Effect	Size	Studies	People	Studies list
	Acne Symptoms	Improves (the measure goes down)			56 people

Milk Thistle

Acne Symptoms: improves

Milk Thistle: outcomes studied for Acne
Grade	Outcome	Effect	Size	Studies	People	Studies list
	Acne Symptoms	Improves (the measure goes down)			56 people

What the published studies found

1 automated reading

Automated reading of the published studies (Decosa evidence engine), for outcomes Winnowleaf has not graded yet. It is not a Winnowleaf grade and does not change one. How it is read

Zinc: acne
The best available review (2026) found an improvement in acne. That review studied patients with acne vulgaris. All 7 studies read agree. The evidence is limited.
7 studies counted of 10 read: 4 reviews and 3 trials (108 people in the trials).
1. Systematic review, 2026; patients with acne vulgaris: improves (the review the verdict rests on). available data support a potential clinical benefit Oral Zinc Supplementation in Acne Vulgaris and Hidradenitis Suppurativa: An Updated Comprehensive ReviewPubMed 42739037
2. Systematic review, 2020; 22 studies; patients with inflammatory dermatologic conditions: improves. beneficial in ten of 14 studies evaluating its effects on acne vulgaris Effects of Zinc Supplementation on Inflammatory Skin Diseases: A Systematic Review of the Clinical EvidencePubMed 31745908
3. Meta-analysis, 2020; patients with acne vulgaris: improves. significant improvement in mean inflammatory papule count Serum zinc levels and efficacy of zinc treatment in acne vulgaris: A systematic review and meta-analysisPubMed 32860489
4. Systematic review, 2013; patients with acne vulgaris: improves. zinc has antibacterial and anti-inflammatory effects The clinical effects of zinc as a topical or oral agent on the clinical response and pathophysiologic mechanisms of acne: a systematic review of the literaturePubMed 23652948
5. Randomised trial, 1989; patients with inflammatory acne: improves. significantly different result between zinc and placebo groups Low doses of zinc gluconate for inflammatory acnePubMed 2575335
6. Randomised trial, 1980; 54 people; 54 patients with acne vulgaris: improves. Compared to placebo this result is slightly better Clinical evaluation in acnePubMed 6451126
7. Randomised trial, 1978; 54 people; patients suffering from acne vulgaris: improves. Clinical comparison with placebo showed the result of zinc sulphate therapy to be slightly, but … Oral zinc in acne vulgaris: a clinical and methodological studyPubMed 82356
Automated reading of the published studies (Decosa evidence engine), run 30 Sep 2026. It reads abstracts, can miss studies, and a repeat run can differ.

Key findings

Acne SymptomsNicotinamideImproves (the measure goes down)
Acne Lesion CountVitamin B5 (Pantothenic Acid)Improves (the measure goes down)
Sebum ProductionVitamin B5 (Pantothenic Acid)Improves (the measure goes down)

The Acne Vulgaris protocol

2 primary supplements · 2 supporting supplements

Nicotinamide (Vitamin B3)750–1,500 mg daily (or 4% topical)
Zinc30–45 mg daily (gluconate or picolinate)

See the full protocol

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Studies cited

13 studies from PubMed

Oral zinc in acne vulgaris: a clinical and methodological studyActa Derm Venereol · PMID 82356
Low doses of zinc gluconate for inflammatory acneActa Derm Venereol · PMID 2575335
Oral zinc sulphate therapy in acne vulgaris: a double-blind trialActa Derm Venereol · PMID 6163281
Multicenter randomized comparative double-blind controlled clinical trial of the safety and efficacy of zinc gluconate versus minocycline hydrochloride in the treatment of inflammatory acne vulgarisDermatology · PMID 11586012
Role of vitamin D supplement adjunct to topical benzoyl peroxide in acne: a randomized double-blinded controlled study.Int J Womens Dermatol · PMID 38957412
Resveratrol-containing gel for the treatment of acne vulgaris: a single-blind, vehicle-controlled, pilot studyAm J Clin Dermatol · PMID 21348544
Niacinamide: A B vitamin that improves aging facial skin appearanceDermatol Surg · PMID 16029679
1-Methylnicotinamide: a potent anti-inflammatory agent of vitamin originPol J Pharmacol · PMID 12856834
Topical nicotinamide compared with clindamycin gel in the treatment of inflammatory acne vulgarisInt J Dermatol · PMID 7657446
Topical 4% nicotinamide vs. 1% clindamycin in moderate inflammatory acne vulgarisInt J Dermatol · PMID 23786503
Double-blind, Placebo-controlled Study Assessing the Effect of Chocolate Consumption in Subjects with a History of Acne VulgarisJ Clin Aesthet Dermatol · PMID 24847404
L-carnitine supplementation in patients with cystic acne on isotretinoin therapyJ Eur Acad Dermatol Venereol · PMID 10642057
The effects of L-carnitine supplementation on performance during interval swimmingInt J Sports Med · PMID 8063466