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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 · 64 outcomes scored · 1 positive

Evidence overview

Evidence overview Not enough research

Vitamin A does not have enough research to support clear consumer benefits across its studied outcomes, despite a modest postpartum breast-milk signal.

  • Across 2 studies (n=837), postpartum vitamin A supplementation enriched breast milk vitamin A levels by a barely detectable amount.3
  • Vitamin A spans 42 papers and 64 consumer-facing outcomes, with most claims still in early or no-effect tiers.
  • High-dose preformed vitamin A raises safety concerns in pregnancy and liver disease, limiting casual use.1

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 —

Forms & standardisation

Look for the exact form on the label. Retinol, retinyl acetate, and retinyl palmitate are preformed vitamin A and raise status more directly, while beta-carotene sits in the provitamin lane and your body converts it more slowly1. That distinction matters because the preformed forms also carry the bigger toxicity risk, especially in pregnancy1.

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

Frequently asked

Common questions

Is beta-carotene the same as vitamin A?

No. Beta-carotene is the plant precursor your body converts into vitamin A, while retinol and retinyl esters are the ready-to-use forms1.

Does vitamin A help your eyes?

It matters a lot if you are low, because your retina uses it to make light-sensing pigment1. If you already have enough, studies do not show a meaningful payoff for cataracts or macular degeneration1.

Is vitamin A safe in pregnancy?

High-dose preformed vitamin A is the version to avoid in pregnancy because it can cause birth defects1. Do not self-dose it unless your clinician tells you to.

Sources

  1. 1. Vitamin A - Health Professional Fact Sheet
  2. 2. Vitamin A Deficiency - MSD Manual Professional Edition
  3. 3. Vitamin A supplementation during the postpartum period

Generated May 15, 2026

Related

More evidence for Vitamin A

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