Vitamin A Excess: Toxicity, Pregnancy, Birth Defect Risk and Retinoid Medicines
Too much preformed vitamin A can harm the liver, bones and an unborn baby; official upper levels, pregnancy findings, retinoid medicines and how beta-carotene differs.
Content last updated . This page has not been medically reviewed.
Urgent points first
- A child who may have swallowed vitamin A supplements or products such as retinol skin cream: in the US call Poison Help at 1-800-222-1222, or 911 if the child is unwell. MedlinePlus says babies and children can become sick on smaller amounts and that swallowing retinol skin cream can poison a child. [1] For other countries see Poison help by country.
- Pregnancy or trying to conceive: the NHS (UK) says not to take cod liver oil or supplements containing vitamin A (retinol), and to avoid liver. [2] Talk with your midwife or doctor before any supplement.
- Prescription retinoid medicines such as isotretinoin: these are a separate and serious pregnancy risk, covered below. Never stop or change a prescribed medicine without your prescriber.
What "too much" means
This page is about preformed vitamin A: retinol and retinyl esters from liver, fortified foods and many supplements. [1] EFSA applies its upper level to preformed vitamin A only. [3] Beta-carotene from plants behaves differently (last section). For the whole vitamin see Vitamin A.Hypervitaminosis A means toxicity from excess vitamin A. A 2025 hepatology review describes acute toxicity from large single doses and chronic toxicity from prolonged overconsumption, with symptoms such as nausea, bone pain and liver damage. [4] MedlinePlus says acute poisoning most often occurs when an adult takes several hundred thousand IU, and chronic poisoning may occur in adults who regularly take more than 33,000 IU a day. [1]
Evidence labels used here: established harm, observational finding, mixed, insufficient evidence. A figure from a study is a study finding, not advice.
What the sources found
| Question | What the source found | Label |
|---|---|---|
| Liver | The 2025 review says the liver stores vitamin A in stellate cells; when overwhelmed, damage can progress from fatty liver to fibrosis and cirrhosis [4]. It is a review of mechanisms and reports, not a trial | Established harm at toxic intakes |
| Bones | NHS (UK): an average above 1,500 mcg a day over many years may make bones more likely to fracture [5]. population-based cohort of 2,322 men followed for 30 years: highest quintile of blood retinol had a rate ratio of 1.64 for any fracture and 2.47 for hip fracture versus the middle quintile [6]. Meta-analysis of 8 intake studies: high vitamin A and retinol intake linked to hip fracture; beta-carotene was not. Both high and low blood retinol were linked to hip fracture [7] | Observational finding; mixed |
| Birth defects | 1995 US study of 22,748 pregnant women: defects of tissues from the cranial neural crest were 4.8 times as common with supplement vitamin A above 10,000 IU a day than with 5,000 IU or less, with an apparent threshold near 10,000 IU a day [8] | Observational finding |
| Women of childbearing age | A 2000 review said teratogenicity from dietary vitamin A was reported in fewer than 20 cases over 30 years, yet advised avoiding unnecessary supplementation, and noted that low vitamin A in pregnancy also matters [9] | Mixed |
Limits. The pregnancy study relied on women's reports of diet and supplements in the first trimester, so it cannot prove cause. Its authors estimated about 1 baby in 57 had a malformation attributable to supplements above 10,000 IU a day. [8] Both too little and too much vitamin A in pregnancy have been linked to problems, according to a 2023 narrative review, which is why advice is to avoid excess, not vitamin A altogether. [10]
Retinoid medicines
Isotretinoin, used for severe acne, belongs to a class of medicines called retinoids and has its own strict rules. MedlinePlus says it must not be taken by anyone who is or may become pregnant, with a high risk of pregnancy loss, early birth and birth defects, and that in the US it is supplied through a program called iPLEDGE. [11] The same page lists vitamin A supplements among products that may interact with isotretinoin and says not to start them without discussing it with your healthcare provider. [11] The 1995 study notes that synthetic retinoids chemically similar to vitamin A cause birth defects in humans. [8]Do not use this page to judge your own medicine. See How interactions work and ask your prescriber or pharmacist.
Official upper levels
Upper levels are the most a person is expected to take daily over time without harm; they are not targets. See RDA, AI, DV and UL.| Source and year | Population | Amount per day |
|---|---|---|
| EFSA (EU) overview, version August 2025 (vitamin A opinion 2024) | Adults, pregnancy and lactation; preformed vitamin A | 3,000 mcg retinol equivalents [3] |
| Same | Children 1 to 3, 4 to 6, 7 to 10, 11 to 14, 15 to 17 years | 800, 1,100, 1,500, 2,000, 2,600 mcg RE [3] |
| NHS (UK), reviewed 2020 | Postmenopausal women and older men, food plus supplements | No more than 1,500 mcg [5] |
| MedlinePlus (US), reviewed 2025 | Adults: chronic poisoning may occur above | 33,000 IU, a poisoning statement, not an upper level [1] |
The US Tolerable Upper Intake Level from the NIH Office of Dietary Supplements could not be read this session, so it is not quoted. We did not find a source we could read that converts IU to mcg, so the figures are not converted here; see Vitamin units explained.
Who should take extra care
- Pregnancy and breastfeeding: read the NHS advice above; see also Vitamins in pregnancy and Prenatal and postnatal vitamins. Check the vitamin A form on a prenatal label.
- Older adults and anyone with bone loss: the NHS bone advice applies. [5]
- Liver disease or heavy alcohol use: we did not find a readable source with specific advice, so ask a clinician. See Liver safety.
- Surgery and kidney disease: no specific vitamin A guidance was found in the sources we read; ask your care team.
- Duplicates add up: the NHS notes many multivitamins and fish liver oils contain vitamin A. [5] See Cod liver oil.
Beta-carotene is different
NHS says there is no evidence that beta-carotene from food is harmful. [12] Large amounts can turn skin yellow or orange, which fades when intake falls. [1] Supplements are another matter for smokers: a Finnish trial of 20 mg a day in male smokers found 18% more lung cancer [13], and NHS advises people who smoke or were exposed to asbestos not to take beta-carotene supplements. [12]Talk to a professional
If you take supplements or fish liver oil, are pregnant, or take a retinoid medicine, ask a clinician or pharmacist to check your total vitamin A. See Quality testing and certifications for choosing products.Frequently asked questions
How much vitamin A is too much?
It depends on the country and group. EFSA (EU) lists 3,000 mcg RE a day for adults; the NHS (UK) advises no more than 1,500 mcg a day from all sources for postmenopausal women and older men. [3][5]
Is liver safe in pregnancy?
The NHS lists liver and liver products among foods to avoid because they are high in vitamin A. [14]
Can carrots cause vitamin A toxicity?
Not in the sources we read: beta-carotene from food has no evidence of harm, though a lot of it can tint skin. [12][1]
Does isotretinoin mean I should avoid vitamin A supplements?
MedlinePlus says vitamin A supplements may interact with isotretinoin and not to start them without talking to your provider. [11]
What are signs of too much vitamin A?
A 2025 review lists nausea, bone pain and liver damage. Seek medical care; in the US call Poison Help at 1-800-222-1222 about a possible overdose. [4]
References
- MedlinePlus, U.S. National Library of Medicine. Vitamin A (encyclopedia article, reviewed 1/21/2025). Read 2026-10-22.
- NHS (UK). Pregnancy vitamins and supplements. Read 2026-10-22.
- European Food Safety Authority. Overview on Tolerable Upper Intake Levels as derived by the Scientific Committee on Food (SCF) and the EFSA NDA Panel. Version 11, August 2025 (Table 3, vitamins). Read 2026-10-22.
- Vitamin A toxicity review, 2025. Vitamin A toxicity and hepatic pathology: A comprehensive review. World J Hepatol. PMID 40901583. Read 2026-10-22.
- NHS (UK). Vitamins and minerals: Vitamin A. Page last reviewed 3 August 2020. Read 2026-10-22.
- Michaëlsson et al. 2003. Serum retinol levels and the risk of fracture. N Engl J Med. PMID 12540641. Read 2026-10-22.
- Wu et al. 2014. The relationship between vitamin A and risk of fracture: meta-analysis of prospective studies. J Bone Miner Res. PMID 24700407. Read 2026-10-22.
- Rothman et al. 1995. Teratogenicity of high vitamin A intake. N Engl J Med. PMID 7477116. Read 2026-10-22.
- Azaïs-Braesco and Pascal 2000. Vitamin A in pregnancy: requirements and safety limits. Am J Clin Nutr. PMID 10799410. Read 2026-10-22.
- Vitamin A-mediated birth defects narrative review, 2023. Vitamin A-Mediated Birth Defects: A Narrative Review. Cureus. PMID 38226115. Read 2026-10-22.
- MedlinePlus, U.S. National Library of Medicine. Isotretinoin (drug information). Read 2026-10-22.
- NHS (UK). Vitamins and minerals: Others (beta-carotene). Page last reviewed 3 August 2020. Read 2026-10-22.
- Alpha-Tocopherol, Beta Carotene Cancer Prevention Study Group. 1994. The effect of vitamin E and beta carotene on the incidence of lung cancer and other cancers in male smokers. N Engl J Med. PMID 8127329. Read 2026-10-22.
- NHS (UK). Foods to avoid in pregnancy. Read 2026-10-22.