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Head-to-head evidence comparison — which supplement is right for you?
Tretinoin (Retin-A) and Vitamin A are closely matched across evidence, studies, and safety.
Verdict
Mostly mechanism / observational
Top outcomes
Verdict
Probably helps
9 of 18 studies with measurable effects showed benefit.
Top outcomes
Shared outcomes (1)
Outcomes where both Tretinoin (Retin-A) and Vitamin A have evidence — compare verdict strength side-by-side.
Prescription topical: a pea-sized amount of 0.025%-0.1% cream or gel applied to clean, dry skin once nightly. Start low-strength and every-other-night to build tolerance. A prescription drug used under clinician direction — not a supplement regimen.
before-bed
Topical cream or gel, 0.025%-0.1% (prescription)
2500-5000 IU daily (retinol); up to 25000 IU (beta-carotene)
With fat-containing meal, Any time of day
Mixed carotenoids or low-dose retinyl palmitate
12-24 weeks
12-24 weeks
Months
8-12 weeks
2-4 weeks
2-4 weeks
4-8 weeks
With chronic excess
Topical tretinoin improves photoaged skin. A double-blind vehicle-controlled study.
JAMA (1988) · Rct
Randomized, double-blind, vehicle-controlled trial of topical tretinoin for photoaged forearm and facial skin
Tretinoin emollient cream: a new therapy for photodamaged skin.
J Am Acad Dermatol (1992) · Rct
Multicenter double-blind vehicle-controlled trial of tretinoin emollient cream for photodamaged skin
Long-term treatment of photoaged human skin with topical retinoic acid improves epidermal cell atypia and thickens the collagen band in papillary dermis.
J Am Acad Dermatol (2005) · Open label
Long-term topical retinoic acid on photoaged human skin assessed histologically
Effects of primary or secondary prevention with vitamin A supplementation on clinically important outcomes: a systematic review of randomised clinical trials with meta-analysis and trial sequential analysis
BMJ open (2024) · Meta analysis · n=672
Vitamin A did not reduce mortality in individually randomised trials (RR 0.99, 95% CI 0.93 to 1.05; I²=32%; p=0.19; 105 trials; moderate certainty), and this effect was not affected by the risk of bias.
Vitamin and Mineral Supplementation During Pregnancy on Maternal, Birth, Child Health and Development Outcomes in Low- and Middle-Income Countries: A Systematic Review and Meta-Analysis
Nutrients (2020) · Meta analysis · n=451723
IFA supplementation showed notable improvement in maternal anemia and the reduction in low birthweight, whereas LNS supplementation had no apparent effect on outcomes; further research that compares LNS and MMN supplementation could help understand differences with these commodities.
Vitamin A supplements for reducing mother-to-child HIV transmission
The Cochrane database of systematic reviews (2017) · Meta analysis · n=6601
Antepartum or postpartum vitamin A supplementation, or both, probably has little or no effect on mother-to-child transmission of HIV in women living with HIV infection and not on antiretroviral drugs.
Both Tretinoin (Retin-A) and Vitamin A are closely matched — the best choice depends on your specific health goals.
No known interactions between Tretinoin (Retin-A) and Vitamin A have been documented in our database. However, always consult a healthcare provider before combining supplements.