Vitamin A (retinyl palmitate vs beta-carotene)
Summary
Supplements supply preformed vitamin A (retinyl acetate or palmitate, 70-90% absorbed) or beta-carotene (8.7-65% absorbed). Periodic vitamin A lowered child mortality by 12% in low- and middle-income countries. In smokers, 20-30 mg/day of beta-carotene raised mortality in two large trials. Preformed vitamin A has an adult UL of 3,000 mcg/day.
Key facts
- Preformed vitamin A (retinyl acetate, retinyl palmitate) and provitamin A beta-carotene; labels list mcg RAE[1]
- Preformed esters are 70–90% absorbed, beta-carotene 8.7–65%. 1 mcg RAE = 1 mcg retinol or 2 mcg supplemental beta-carotene. The UL applies only to preformed vitamin A[1]
- Child survival in low- and middle-income countries ↑ (A); harm in smokers with high-dose beta-carotene (B, two trials); removing beta-carotene from an eye-health formula ↔ (C)[2][3][4][5]
- Adult trials: 20–30 mg/day beta-carotene (CARET added 7,500 mcg RAE retinyl palmitate); child programs give periodic high doses[3][4][1]
- RDA 900 mcg RAE (men), 700 mcg RAE (women); 770 in pregnancy, 1,300 while breastfeeding. UL 3,000 mcg/day preformed vitamin A[1]
- Preformed vitamin A above the UL can cause birth defects; experts advise against more than 3,000 mcg RAE (10,000 IU)/day from supplements in pregnancy[1]
- Oral retinoids (acitretin, bexarotene) add to vitamin A toxicity; orlistat lowers absorption[1]
- 4 graded human outcomes on this page
- October 8, 2026
How it works
EstablishedRetinol and provitamin A carotenoids are converted in the body to retinal and retinoic acid. Vitamin A is needed for the light-sensing pigments of the retina, for immune function, cell growth and differentiation, reproduction, and the formation and upkeep of the heart, lungs, eyes and other organs. Excess preformed vitamin A is stored, mainly in the liver (established).[1]
What the human research says
Human trials only, one row per outcome. The form column shows what each trial actually tested. Grades follow our evidence-grading policy.
At a glance: strongest evidence per outcome
| Outcome | Grade | Effect | Strongest evidence | Rows |
|---|---|---|---|---|
| Immune | Grade A | Improved | Systematic review · n = 1,202,382 · 2022 | 1 row |
| Healthy aging | Grade B | Improved | RCT · n = 29,133 · 1994 | 3 rows |
Every graded row
| Outcome | Effect | Grade | Best evidence | PMID |
|---|---|---|---|---|
| Survival in children 6 months to 5 years in low- and middle-income countries | Improved | Grade A | Systematic review · n = 1,202,382 · 2022 Children aged 6 months to 5 years in 19 trials, mostly in Asia, Africa and Latin America Form: vitamin A supplementation (periodic doses) · Dose: Periodic high-dose vitamin A; amounts varied by age and trial · Duration: Most studies lasted about one year All-cause mortality was 12% lower with vitamin A (RR 0.88; 95% CI 0.83 to 0.93; high certainty), and diarrhoea deaths were also 12% lower. Measles incidence fell (RR 0.45, low certainty) but measles deaths did not differ significantly. | 35294044 (opens PubMed)Source [2] |
| Harms in male smokers with beta-carotene (ATBC) | Improved | Grade B | RCT · n = 29,133 · 1994 Male smokers aged 50 to 69 in southwestern Finland Form: beta carotene (with or without alpha-tocopherol) · Dose: 20 mg beta carotene per day · Duration: 5 to 8 years Lung cancer incidence was 18% higher with beta carotene (95% CI 3 to 36 percent), and total mortality was 8% higher, mainly from lung cancer and ischemic heart disease. | 8127329 (opens PubMed)Source [4] |
| Harms in smokers and asbestos-exposed workers (CARET) | Improved | Grade B | RCT · n = 18,314 · 1996 Smokers, former smokers and workers exposed to asbestos Form: beta-carotene plus retinyl palmitate · Dose: 30 mg beta carotene plus 25,000 IU retinol (as retinyl palmitate) daily · Duration: Mean follow-up 4.0 years Lung cancer risk rose (RR 1.28; 95% CI 1.04 to 1.57), as did death from any cause (RR 1.17) and from lung cancer (RR 1.46). The trial was stopped 21 months early. | 8602180 (opens PubMed)Source [3] |
| Eye-condition progression when beta-carotene is removed from the AREDS formula | No effect | Grade C | RCT · n = 4,203 · 2013 Adults aged 50 to 85 at risk of progression to advanced AMD (AREDS2) Form: AREDS formulation with vs without beta carotene (secondary randomization) · Dose: AREDS formulation variants; lutein 10 mg + zeaxanthin 2 mg in some arms · Duration: Median follow-up 5 years Eliminating beta carotene had no apparent effect on progression to advanced AMD. More lung cancers occurred with beta carotene than without (2.0% vs 0.9%), mostly in former smokers. | 23644932 (opens PubMed)Source [5] |
Forms
| Form | Elemental % | Absorption (human data) | GI tolerance | Studied for |
|---|---|---|---|---|
| Retinyl acetate and retinyl palmitate (preformed vitamin A) | Varies[1] | 70–90% absorbed from supplements (ODS); no head-to-head human data between acetate and palmitate in our sources.[1] | Counts toward the UL; chronic excess causes liver, skin and joint effects and can cause birth defects.[1] | CARET (with beta-carotene); child supplementation programs |
| Beta-carotene (provitamin A) | Varies[1] | 8.7–65% absorbed (ODS).[1] | Not known to cause birth defects; excess can turn skin yellow-orange (harmless). High doses raised harm in smokers.[1][3][4] | ATBC and CARET (smokers); original AREDS formula |
Studied doses
Doses studied in human trials ranged from 20 to 30 mg/day of beta-carotene in adult smokers, for about 4 to 8 years, and these amounts increased harm. Child programs in low-income settings give periodic high amounts of vitamin A. The adult UL for preformed vitamin A is 3,000 mcg/day.[3][4][2][1]
Intake reference: Adult RDA: 900 mcg RAE/day for men and 700 mcg RAE for women; 770 mcg RAE in pregnancy and 1,300 mcg RAE while breastfeeding (ages 19+). Adult UL: 3,000 mcg/day of preformed vitamin A.[1] The UL applies only to preformed vitamin A (retinol and retinyl esters), not to beta-carotene; no UL is set for beta-carotene, but the FNB advises against beta-carotene supplements for the general population. NIH ODS fact sheet (updated March 10, 2025).
Interactions
Published interactions only: each row cites a source. No row means none was found in our sources, not that a combination is safe.
Medicines
- Oral retinoidsNIH fact sheetTaken with vitamin A supplements, these vitamin A-derived drugs can increase the risk of vitamin A toxicity.[1]
Medicines that can lower levels
- OrlistatNIH fact sheetLowers absorption of vitamin A, beta-carotene and other fat-soluble vitamins; the manufacturers advise a multivitamin with these vitamins.[1]
Who should be careful
- Pregnancy
- Preformed vitamin A above the UL can cause birth defects of the eye, skull, lungs and heart. Experts advise women who are or might be pregnant, and those breastfeeding, against supplements providing more than 3,000 mcg RAE (10,000 IU) a day.[1]
- Smokers and former smokers
- High-dose beta-carotene (20–30 mg/day) raised lung cancer and mortality in smokers and asbestos-exposed workers in two large trials, and more lung cancers were seen with beta-carotene in former smokers in AREDS2.[3][4][5]
- High intakes
- Chronic high intake of preformed vitamin A can cause dry skin, painful muscles and joints, fatigue, depression and abnormal liver tests; very large single doses cause headache, blurred vision, nausea and dizziness.[1]
- Before you start
- Talk to your pharmacist or clinician before adding this supplement, especially if you take prescription medicines, are pregnant or breastfeeding, or have a chronic health condition.[1]
Talk to your pharmacist or clinician before starting a supplement, especially if you take prescription medicines.
Articles about Vitamin A (retinyl palmitate vs beta-carotene)
Plain-English answers to common questions, built on the evidence above.
Frequently asked questions
What's the difference between retinyl palmitate and beta-carotene?
Retinyl palmitate and retinyl acetate are preformed vitamin A, 70–90% absorbed, and count toward the 3,000 mcg/day UL. Beta-carotene is converted to vitamin A in the intestine, is less absorbed (8.7–65%), has no UL and is not known to cause birth defects, but high doses raised harm in smokers.[1][3][4]
How do I read mcg RAE and IU on a label?
1 mcg RAE equals 1 mcg retinol or 2 mcg supplemental beta-carotene. 1 IU of retinol or supplemental beta-carotene equals 0.3 mcg RAE, so 10,000 IU of retinol is 3,000 mcg RAE.[1]
Should smokers avoid beta-carotene supplements?
Two large trials in smokers (ATBC, 20 mg/day; CARET, 30 mg/day plus retinyl palmitate) found more lung cancer and higher mortality with beta-carotene, and AREDS2 saw more lung cancers with beta-carotene, mostly in former smokers.[4][3][5]
Is vitamin A safe in pregnancy?
Vitamin A is needed in pregnancy (RDA 770 mcg RAE for adults), but preformed vitamin A above the UL can cause birth defects. Experts advise against supplements with more than 3,000 mcg RAE (10,000 IU) a day; beta-carotene is not known to cause birth defects.[1]
Does vitamin A help children's survival?
In low- and middle-income countries, periodic vitamin A lowered child mortality by 12% in a 2022 Cochrane review of trials in about 1.2 million children. This applies to children at risk of deficiency.[2]
Sources
- [1]Vitamin A and Carotenoids: Fact Sheet for Health Professionals. NIH Office of Dietary Supplements, 2025. fact-sheet
- [2]Vitamin A supplementation for preventing morbidity and mortality in children from six months to five years of age.. Cochrane Database Syst Rev, 2022. systematic-review
- [3]Effects of a combination of beta carotene and vitamin A on lung cancer and cardiovascular disease.. N Engl J Med, 1996. RCT
- [4]The effect of vitamin E and beta carotene on the incidence of lung cancer and other cancers in male smokers.. N Engl J Med, 1994. RCT
- [5]Lutein + zeaxanthin and omega-3 fatty acids for age-related macular degeneration: the Age-Related Eye Disease Study 2 (AREDS2) randomized clinical trial.. JAMA, 2013. RCT
What changed
- First draft. Every evidence-row PMID checked with NCBI E-utilities (esummary + efetch abstract) and re-read in an independent adversarial pass.