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Vitamin A

Vitamin A

Best for

Enrich breast milk for your baby

Barely detectable · 200000–400000 IU/day · 1 meta-analysis , n=837

42 papers · 4 claims · 63 outcomes scored · 1 positive

Outcomes

What vitamin a actually does, by outcome

Each row is one outcome with effect size, evidence base, the dose that worked in trials, and time to first effect. Magnitude tiers come from native-unit MCID where available, Cohen's d otherwise.

Outcome Effect Evidence Dose Weeks Rank
Enrich breast milk for your baby Barely detectable
trivial 		2 meta-analyses n=837 Meta-analyzed 200000–400000 IU — #1/2
Protect against macular degeneration Doesn't appear to help
trivial 		2 meta-analyses n=195k Meta-analyzed — 468 wk —
Lower cataract risk Probably doesn't help
trivial 		1 meta-analysis n=87k Meta-analyzed — — —
Raise protective carotenoid levels Not enough research
3 RCTs n=— 1.2–4000 IU 26 wk —
Buy well

Recommended Vitamin A products

Real products that dose Vitamin A where the research does, in a clean formulation, from brands we've audited. We only list ones we'd stand behind.

Chosen for adequate Vitamin A dosing vs. the studied range, a clean formulation (grade A–C), and independent brand-quality audits. Not sponsored.

Risk profile

Adverse events and known drug interactions

Safety events

intracranial hypertension severe
teratogenicity severe
Teratogenicity severe
Hepatotoxicity severe
Hypervitaminosis A severe
Teratogenic malformations (specific congenital anomalies) severe
Peliosis/hepatic fibrosis (histological liver damage) severe
Increased risk of congenital malformations with liver consumption in pregnancy (advice/evidence-based warning rather than quantified incidence) severe

Drug interactions

Ketoconazole major increases concentration
Liarozole major increases concentration
Talarozole major increases concentration
Fluconazole major increases concentration
Itraconazole major increases toxicity
Voriconazole major increases toxicity
Mitoxantrone major increases concentration
Antineoplastic Agents major increases concentration
β-Carotene Supplements major increases toxicity
other major increases toxicity

Co-studied with

Supplements that share evidence with vitamin a

Sources

  1. 1. Effects of beta-carotene supplementation for six months on clinical and laboratory parameters in patients with cystic fibrosis. (2001) ↑
  2. 2. Low-dose beta-carotene supplementation and deworming improve serum vitamin A and beta-carotene concentrations in preschool children of Bangladesh. (2010) ↑
  3. 3. Effects of Mixed Carotenoids on Adipokines and Abdominal Adiposity in Children: A Pilot Study. (2017) ↑
  4. 4. Randomised controlled trial of oral vitamin A supplementation in preterm infants to prevent chronic lung disease. (2001) ↑
  5. 5. Single megadose vitamin A supplementation of Indian mothers and morbidity in breastfed young infants. (2003) ↑
  6. 6. Effect of neonatal vitamin A supplementation on mortality in infants in Tanzania (Neovita): a randomised, double-blind, placebo-controlled trial. (2015) ↑
  7. 7. Eggs early in complementary feeding increase choline pathway biomarkers and DHA: a randomized controlled trial in Ecuador. (2017) ↑
  8. 8. EARLY VITAMIN A SUPPLEMENTATION IMPROVES THE OUTCOME OF RETINOPATHY OF PREMATURITY IN EXTREMELY PRETERM INFANTS. (2020) ↑
  9. 9. Vitamin A supplementation for preventing morbidity and mortality in children from six months to five years of age. (2022) ↑
  10. 10. Fresh Tomato (Lycopersicon esculentum Mill.) in the Diet Improves the Features of the Metabolic Syndrome: A Randomized Study in Postmenopausal Women. (2024) ↑

Generated August 14, 2026

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