Does vitamin A support the immune system?

Yes, in the sense that the immune system needs it, and the clearest benefit is in children who are at risk of running short. A Cochrane review of trials in 1,202,382 children aged 6 months to 5 years in low- and middle-income countries found vitamin A supplements cut deaths from any cause by 12 per cent (risk ratio 0.88, 95% CI 0.83 to 0.93), on high-certainty evidence. The review abstract gives the ratio and not the absolute number of deaths. Outside that setting the picture is different: trials found no fewer colds, and trials that randomized children or adults one by one found no fewer deaths.

Established. Where vitamin A deficiency is common, the largest review found that giving young children vitamin A cut deaths and new cases of diarrhea and measles. NIH states that chronic deficiency makes measles and infection-associated diarrhea more severe and more deadly, which fits the places where the benefit shows up.

Myth. Trials do not show that a vitamin A supplement prevents colds or chest infections in children. Two Cochrane reviews found no drop in respiratory illness, one older review found more chest infections in normally nourished children, and in adults supplements raised an inflammation marker in the blood.

What the trials found

Children under five in low- and middle-income countries

The 2022 Cochrane review is the largest body of evidence. Besides fewer deaths, vitamin A lowered new cases of diarrhea by 15 percent (risk ratio 0.85, 95% CI 0.82 to 0.87) across 15 trials and 77,946 children, and new cases of measles by 55 percent (risk ratio 0.45, 95% CI 0.30 to 0.69). Both were rated low certainty, and the measles figure rests on 2 trials with 1,982 children. Respiratory disease did not change (risk ratio 0.99, 95% CI 0.92 to 1.06) across 11 trials and 27,540 children, and neither did hospital admissions for diarrhea or pneumonia. So the protection is specific to diarrhea and measles.

Why two big reviews disagree about deaths

A 2024 meta-analysis of 120 randomized trials looked at the same question differently. It kept trials that randomized individual people apart from trials that randomized whole villages or districts. In 78 individually randomized trials with 178,094 children, vitamin A did not change deaths (risk ratio 0.96, 95% CI 0.88 to 1.04). In 27 trials with 61,880 adults it did not either (risk ratio 1.04, 95% CI 0.97 to 1.13). The cluster trials showed fewer deaths (risk ratio 0.84, 95% CI 0.76 to 0.93), on very low certainty evidence. The two reviews are reading largely the same trials and weighing their designs differently.

Unsettled. Whether vitamin A lowers child deaths today depends on which kind of trial you trust more. The Cochrane estimate is rated high certainty, and the 2024 review rates its null result as moderate certainty. Both agree the benefit, if real, belongs to children at risk of deficiency.

Colds and chest infections

A 2024 Cochrane review of children up to 7 years old in India, South Africa, Ecuador and Haiti found no difference in the number of upper respiratory infections over two weeks (risk ratio 1.00, 95% CI 0.92 to 1.09) across 3 trials and 22,668 children. The evidence is low certainty, and the authors call the effect uncertain. An older Cochrane review of lower respiratory infections gave no pooled number. Two of its trials found vitamin A cut these infections in poorly nourished children and increased them in normally nourished ones. A 2022 meta-analysis of 115 studies in 199,055 healthy people across many nutrients found supplements had no or at most a very limited effect on respiratory infections. Its abstract does not report vitamin A separately.

Measles and pneumonia, as treatment

In children who already had measles, a Cochrane review found two doses of 200,000 IU on consecutive days cut deaths in children under two by 82 percent (risk ratio 0.18, 95% CI 0.03 to 0.61) and deaths from pneumonia by two thirds (risk ratio 0.33, 95% CI 0.08 to 0.92). Pooled across all the trials and ages, the drop in deaths did not reach significance (risk ratio 0.70, 95% CI 0.42 to 1.15), and a single dose showed no benefit. This is treatment of diagnosed measles in trials, not prevention. Each of those doses is 20 times the 10,000 IU (3,000 mcg RAE) daily limit for adults described below.

Pneumonia without measles is different. In 5 trials with 1,453 children, added vitamin A did not lower deaths (odds ratio 1.49, 95% CI 0.66 to 3.35, an odds and not a risk), and hospital stays were no shorter.

Newborns, pregnancy and adults

Pooled data from 11 trials in 163,567 newborns dosed in the first days of life showed no change in survival to 6 months (risk ratio 0.97, 95% CI 0.89 to 1.06) or 12 months (risk ratio 1.00, 95% CI 0.93 to 1.08). Results varied by region: deaths by 6 months were lower in South Asia (risk ratio 0.87, 95% CI 0.77 to 0.98), and in Africa there was a suggestion of more deaths (risk ratio 1.07, 95% CI 1.00 to 1.15).

In pregnancy, a Cochrane review found vitamin A may lower clinical infection in mothers (risk ratio 0.45, 95% CI 0.20 to 0.99) across five trials, on low-quality evidence, and lowered maternal anemia (risk ratio 0.64, 95% CI 0.43 to 0.94). It did not change maternal or perinatal deaths.

In adults, a meta-analysis of randomized trials found vitamin A supplements raised C-reactive protein, a blood marker of inflammation, by 0.84 mg/L (95% CI 0.29 to 1.39). The trials varied a great deal, and CRP is a marker, so this says nothing direct about infections.

Who should be careful

Not for everyone. High-dose vitamin A has side effects, and in some children it made things worse. Single large doses roughly doubled vomiting in the 48 hours after dosing (risk ratio 1.97, 95% CI 1.44 to 2.69, 4 trials, 10,541 children, moderate certainty). In newborns and infants it slightly increased bulging of the soft spot on the skull, and the abstract gives no size for that. In the Peru trial above, children with pneumonia given high doses needed oxygen more often, and the authors advise against it without deficiency or measles. In a Guinea-Bissau trial, girls given 50,000 IU at birth had 78 percent more allergic skin sensitization at 8 to 10 years (risk ratio 1.78, 95% CI 1.17 to 2.72). That was a finding in girls only, among 1,430 children tested at follow-up, when 39 percent of the original group could still be visited.

Pregnancy is the clearest limit. NIH advises women who are or might be pregnant, and those who are breastfeeding, not to take more than 3,000 mcg RAE (10,000 IU) of vitamin A supplements a day, and 3,000 mcg RAE of preformed vitamin A is also the upper limit for adults in general. The upper limits for preformed vitamin A count food and supplements together, and they rest on liver damage, birth defects and toxic effects in infants and children. If you take the acne drug isotretinoin, its FDA label tells you to avoid supplements containing vitamin A because the toxic effects add up.

What expert bodies say

The EU authorizes the label claim that vitamin A contributes to the normal function of the immune system. That describes a normal role in the body, and it does not say extra vitamin A strengthens immunity in people who already get enough. NIH links deficiency with worse measles and diarrhea and sets the pregnancy limit above. According to the reviews we used, WHO recommends supplements for young children only in populations at risk of deficiency and does not recommend dosing newborns. We did not find the WHO guideline in our local copy, so we did not quote it directly.

How we searched

What would change this answer

• Individually randomized trials of child deaths in places where deficiency is common today. They would settle the gap between the Cochrane review and the 2024 meta-analysis.
• Trials comparing doses. Both the Cochrane child review and a 2026 analysis of pneumonia trials asked for them.
• Any registered trial in progress. We searched the US trial registry for vitamin A with immunity, measles or infection and found none.

Sources

1. ev-vaim-01 · Meta-analysis or systematic review · Cochrane systematic review and meta-analysis of RCTs and cluster-RCTs · n = 1,202,382
   A meta-analysis for all-cause mortality included 19 trials (1,202,382 children). At longest follow-up, there was a 12% observed reduction in the risk of all-cause mortality for VAS compared with control using a fixed-effect model (risk ratio (RR) 0.88, 95% confidence interval (CI) 0.83 to 0.93; high-certainty evidence).
   
   Who: children aged 6 to 59 months living in the community in 19 low- and middle-income countries; synthetic vitamin A, usually about one year of follow-up
   Effect: all-cause mortality RR 0.88 (95% CI 0.83 to 0.93); high-certainty evidence
   Certainty: high certainty per GRADE; applies to populations at risk of deficiency, where WHO recommends supplementation; sick and hospitalized children excluded
   Cochrane Database Syst Rev, 2022 · checked 2026-10-06 · we read the abstract
2. ev-vaim-02 · Meta-analysis or systematic review · Cochrane systematic review and meta-analysis of RCTs · n = 77,946 (diarrhea); 1,982 (measles)
   VAS reduced the incidence of diarrhoea (RR 0.85, 95% CI 0.82 to 0.87; 15 studies, 77,946 children; low-certainty evidence), measles (RR 0.45, 95% CI 0.30 to 0.69; 2 studies, 1,982 children; low-certainty evidence), Bitot's spots (RR 0.42, 95% CI 0.33 to 0.53; 5 studies, 1,063,278 children; moderate-certainty evidence), night blindness (RR 0.32, 95% CI 0.21 to 0.50; 2 studies, 22,972 children; moderate-certainty evidence), and VAD (RR 0.71, 95% CI 0.65 to 0.78; 4 studies, 2262 children, moderate-certainty evidence).
   
   Who: children aged 6 to 59 months in low- and middle-income countries
   Effect: diarrhea incidence RR 0.85 (0.82 to 0.87), 15 studies; measles incidence RR 0.45 (0.30 to 0.69), 2 studies; both low-certainty
   Certainty: low certainty for incidence outcomes; measles estimate rests on 2 trials
   Cochrane Database Syst Rev, 2022 · checked 2026-10-06 · we read the abstract
3. ev-vaim-03 · Meta-analysis or systematic review · Cochrane systematic review and meta-analysis of RCTs · n = 27,540
   However, there was no evidence of a difference on incidence of respiratory disease (RR 0.99, 95% CI 0.92 to 1.06; 11 studies, 27,540 children; low-certainty evidence) or hospitalisations due to diarrhoea or pneumonia.
   
   Who: children aged 6 to 59 months in low- and middle-income countries
   Effect: respiratory disease incidence RR 0.99 (95% CI 0.92 to 1.06); no difference in hospitalization for diarrhea or pneumonia
   Certainty: low certainty; the protective effect is specific to diarrhea and measles, not respiratory infection
   Cochrane Database Syst Rev, 2022 · checked 2026-10-06 · we read the abstract
4. ev-vaim-04 · Meta-analysis or systematic review · Cochrane systematic review and meta-analysis of RCTs · n = 10,541
   There was an increased risk of vomiting within the first 48 hours of VAS (RR 1.97, 95% CI 1.44 to 2.69; 4 studies, 10,541 children; moderate-certainty evidence).
   
   Who: children aged 6 to 59 months receiving periodic high-dose vitamin A
   Effect: vomiting within 48 hours RR 1.97 (95% CI 1.44 to 2.69); moderate-certainty evidence
   Certainty: short-lived side effect of single large supplement doses, not of food intake
   Cochrane Database Syst Rev, 2022 · checked 2026-10-06 · we read the abstract
5. ev-vaim-05 · Meta-analysis or systematic review · systematic review with meta-analysis and trial sequential analysis of RCTs · n = 178,094 children; 61,880 adults
   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. In individually randomised trials, vitamin A had no effect on mortality in children (RR 0.96, 95% CI 0.88 to 1.04; I²=24%; p=0.28; 78 trials, 178 094 participants) nor in adults (RR 1.04, 95% CI 0.97 to 1.13; I²=24%; p=0.27; 27 trials, 61 880 participants). Vitamin A reduced mortality in the cluster randomised trials (0.84, 95% CI 0.76 to 0.93; I²=66%; p=0.0008; 15 trials, 14 in children and 1 in adults; 364 343 participants; very low certainty).
   
   Who: people of any age in randomized trials of preventive vitamin A versus placebo or no intervention
   Effect: children RR 0.96 (95% CI 0.88 to 1.04), 78 trials; adults RR 1.04 (0.97 to 1.13), 27 trials; cluster trials RR 0.84 (0.76 to 0.93), very low certainty
   Certainty: moderate certainty for the null result; disagrees with Cochrane 35294044 because it separates individually randomized from cluster trials
   BMJ Open, 2024 · checked 2026-10-06 · we read the abstract
6. ev-vaim-06 · Meta-analysis or systematic review · systematic review with meta-analysis of RCTs · n = 120 trials, 1,671,672 participants overall
   We included 120 randomised trials (1 671 672 participants); 105 trials allocated individuals and 15 allocated clusters. … Vitamin A slightly increased bulging fontanelle of neonates and infants.
   
   Who: neonates and infants in randomized trials of vitamin A supplementation
   Effect: slight increase in bulging fontanelle; no trial reported serious adverse events
   Certainty: size of the increase not given in the abstract; bulging fontanelle is a sign of raised intracranial pressure from large doses
   BMJ Open, 2024 · checked 2026-10-06 · we read the abstract
7. ev-vaim-07 · Meta-analysis or systematic review · Cochrane systematic review and meta-analysis of RCTs · n = 22,668 (main analysis)
   We are uncertain of the effect of vitamin A supplementation on the number of acute URTIs over two weeks (risk ratio (RR) 1.00, 95% confidence interval (CI) 0.92 to 1.09; I2 = 44%; 3 studies, 22,668 participants; low-certainty evidence).
   
   Who: children up to 7 years old in lower-middle-income countries (India, South Africa, Ecuador, Haiti)
   Effect: number of acute URTIs over two weeks RR 1.00 (95% CI 0.92 to 1.09); low-certainty evidence
   Certainty: low to very low certainty; trials at high or unclear risk of bias
   Cochrane Database Syst Rev, 2024 · checked 2026-10-06 · we read the abstract
8. ev-vaim-08 · Meta-analysis or systematic review · Cochrane systematic review of RCTs, narrative synthesis · n = —
   Two studies reported that vitamin A significantly reduced the incidence of acute LRTI with children with poor nutritional status or weight, but increased it in normal children.
   
   Who: children up to 7 years old in randomized trials of vitamin A for preventing acute lower respiratory tract infection
   Effect: reduced LRTI incidence in children with poor nutritional status (2 studies); increased incidence in normal children; no pooled estimate
   Certainty: no pooled numbers; authors conclude vitamin A should not be given to all children to prevent LRTI
   Cochrane Database Syst Rev, 2008 · checked 2026-10-06 · we read the abstract
9. ev-vaim-09 · Meta-analysis or systematic review · Cochrane systematic review and meta-analysis of RCTs · n = —
   There was no significant reduction in the risk of mortality in the vitamin A group when all the studies were pooled using the random-effects model (RR 0.70; 95% CI 0.42 to 1.15). Using two doses of vitamin A (200,000 IU) on consecutive days was associated with a reduction in the risk of mortality in children under the age of two years (RR 0.18; 95% CI 0.03 to 0.61) and a reduction in the risk of pneumonia-specific mortality (RR 0.33; 95% CI 0.08 to 0.92). There was no evidence that vitamin A in a single dose was associated with a reduced risk of mortality among children with measles.
   
   Who: children with measles in randomized trials, vitamin A or placebo with standard treatment
   Effect: mortality under age 2 RR 0.18 (95% CI 0.03 to 0.61); pneumonia-specific mortality RR 0.33 (0.08 to 0.92); all studies pooled RR 0.70 (0.42 to 1.15)
   Certainty: pooled all-age mortality not significant; single dose showed no benefit; treatment of diagnosed measles, not prevention
   Cochrane Database Syst Rev, 2005 · checked 2026-10-06 · we read the abstract
10. ev-vaim-10 · Meta-analysis or systematic review · Cochrane systematic review and meta-analysis of randomized and quasi-randomized trials · n = 1,453
    Five trials involving 1453 infants and children were included. There was no significant reduction in the mortality associated with pneumonia in children treated with vitamin A compared to those who were not (pooled odds ratio (OR) 1.49; 95% confidence interval (CI) 0.66 to 3.35). In addition, there was a lack of a statistically significant effect on duration of stay in hospital (weighted mean difference (WMD) 0.08; 95% CI -0.43 to 0.59).
    
    Who: infants and children under 15 with non-measles pneumonia, adjunctive vitamin A
    Effect: pneumonia mortality OR 1.49 (95% CI 0.66 to 3.35); no effect on hospital stay
    Certainty: small number of trials; OR is odds, not risk
    Cochrane Database Syst Rev, 2005 · checked 2026-10-06 · we read the abstract
11. ev-vaim-11 · Randomized controlled trial(s) · randomized double-blind placebo-controlled trial · n = 95
    Children receiving vitamin A (n = 48) had lower blood oxygen saturation (the mean difference on day 3 in hospital was 1.1%), higher prevalence rates of retractions (37% in the vitamin A group vs 15% in the placebo group on day 3), auscultatory evidence of consolidation (28% in the vitamin A group vs 17% in the placebo group on day 3), and were more likely to require supplemental oxygen (21% in the vitamin A group vs 8% in the placebo group on day 3) than children in the placebo group (n = 47). … No differences were seen in duration of hospitalization or in chest x-ray changes 14 days after admission. No deaths occurred, and toxicity of vitamin A was not seen. … This study indicates that high-dose vitamin A supplements cause modest adverse effects in children recovering from pneumonia and should not be used therapeutically in such patients unless there is clinical evidence of vitamin A deficiency or concurrent measles infection.
    
    Who: children 3 months to 10 years admitted with community-acquired pneumonia, Lima; 100,000 to 200,000 IU then half that dose next day
    Effect: supplemental oxygen day 3: 21% vs 8%; retractions 37% vs 15%; no deaths, no difference in hospital stay
    Certainty: small trial; authors advise against therapeutic vitamin A in pneumonia without deficiency or measles
    Pediatrics, 1998 · checked 2026-10-06 · we read the abstract
12. ev-vaim-12 · Meta-analysis or systematic review · individual participant data meta-analysis of RCTs · n = 163,567
    Investigators of 11 published randomised placebo-controlled NVAS trials (n=163 567 children) reanalysed their data … Overall there was no effect of NVAS on infant survival through 6 (risk ratio (RR) 0.97; 95% CI 0.89 to 1.06) or 12 months of age (RR 1.00; 95% CI 0.93 to 1.08) but results varied by study population characteristics … NVAS significantly reduced 6-month mortality among the trials conducted in Southern Asia (RR 0.87; 95% CI 0.77 to 0.98) … There was a suggestion of increased infant mortality in trials conducted in Africa (RR 1.07; 95% CI 1.00 to 1.15).
    
    Who: newborns in randomized placebo-controlled trials in low- and middle-income countries, dosed in the first days of life
    Effect: 6-month mortality RR 0.97 (0.89 to 1.06); 12-month RR 1.00 (0.93 to 1.08); South Asia RR 0.87 (0.77 to 0.98); Africa RR 1.07 (1.00 to 1.15)
    Certainty: benefit only where maternal deficiency is moderate to severe; WHO does not recommend newborn supplementation
    Arch Dis Child, 2019 · checked 2026-10-06 · we read the abstract
13. ev-vaim-13 · Meta-analysis or systematic review · Cochrane systematic review and meta-analysis of randomized and quasi-randomized trials · n = 5 trials
    Overall, when trial results are pooled, vitamin A supplementation does not affect the risk of maternal mortality (risk ratio (RR) 0.88, 95% confidence interval (CI) 0.65 to 1.20; four trials Ghana, Nepal, Bangladesh, UK, high quality evidence), perinatal mortality (RR 1.01, 95% CI 0.95 to 1.07; one study, high quality evidence) … There is evidence that vitamin A supplements may reduce maternal clinical infection (RR 0.45, 95% CI 0.20 to 0.99, five trials; South Africa, Nepal, Indonesia, Tanzania, UK, low quality evidence) and maternal anaemia (RR 0.64, 95% CI 0.43 to 0.94; three studies, moderate quality evidence).
    
    Who: pregnant women in randomized trials in South Africa, Nepal, Indonesia, Tanzania and the UK
    Effect: maternal clinical infection RR 0.45 (95% CI 0.20 to 0.99); maternal anemia RR 0.64 (0.43 to 0.94); no effect on maternal or perinatal mortality
    Certainty: low quality for the infection outcome; supplements in pregnancy must stay under the UL because of birth defect risk (see ev-vaim-18)
    Cochrane Database Syst Rev, 2015 · checked 2026-10-06 · we read the abstract
14. ev-vaim-14 · Meta-analysis or systematic review · systematic review and meta-analysis of RCTs · n = 13 studies
    Among 13,219 articles 13 studies were included for analysis of CRP and TNF-α, as well as 9 studies included for IL-6 in quality and quantity. The pooled WMD analysis of CRP demonstrated that vitamin A supplementation significantly increased CRP concentration with (WMD: 0.84 mg/L; 95% CI 0.29-1.39, I2 = 0.96.2% and p value < 0.003).
    
    Who: adults in randomized trials of vitamin A supplementation, various doses and durations
    Effect: CRP WMD +0.84 mg/L (95% CI 0.29 to 1.39); no significant change in TNF-alpha overall
    Certainty: very high heterogeneity; CRP is a marker, not an infection outcome
    Sci Rep, 2022 · checked 2026-10-06 · we read the abstract
15. ev-vaim-15 · Randomized controlled trial(s) · long-term follow-up of a randomized placebo-controlled trial · n = 1,430
    In 2013, we visited the 1692 (39%) children now aged 8-10 years who were still living in the study area … Of the 1430 children with a valid skin prick test, 228 (16%) were positive … However, NVAS was associated with significantly increased risk among females (RR 1.78 [1.17-2.72]) but not among males (0.86 [0.64-1.15], P-value for interaction between NVAS and gender = 0.005).
    
    Who: children aged 8 to 10 years randomized at birth to 50,000 IU retinyl palmitate or placebo with BCG vaccine
    Effect: atopy in girls RR 1.78 (1.17 to 2.72); boys RR 0.86 (0.64 to 1.15); overall RR 1.10 (0.87 to 1.40)
    Certainty: 1,692 of 4,345 randomized children (39%) still in the study area were visited, 1,430 had a valid skin test; subgroup finding by sex
    Allergy, 2015 · checked 2026-10-06 · we read the abstract
16. ev-vaim-16 · Meta-analysis or systematic review · systematic review and meta-analysis of trials · n = 199,055
    The search produced 15,163 records of which 93 papers (based on 115 studies) met the inclusion criteria, resulting in 199,055 subjects (191,636 children and 7,419 adults) from 37 countries. … Supplementation of nutrients in the general population has either no or at most a very limited effect on prevention of RTIs.
    
    Who: healthy children and adults in 37 countries; vitamin A, folic acid, B12, C, D, E, beta-carotene, zinc, iron, LCPUFA
    Effect: no or at most very limited prevention of respiratory infections; benefits seen only for zinc in Asian children and vitamin D in North American adults
    Certainty: vitamin A result not given separately in the abstract
    Allergy, 2022 · checked 2026-10-06 · we read the abstract
17. ev-vaim-17 · Position of an expert body · government fact sheet · n = —
    Another effect of chronic vitamin A deficiency is increased severity and mortality risk of infections (particularly measles and infection-associated diarrhea) [26].
    
    Who: people with chronic vitamin A deficiency, mainly children in low- and middle-income countries
    Effect: higher severity and mortality of measles and infection-associated diarrhea
    Certainty: explains why benefits appear only where deficiency is common
    NIH Office of Dietary Supplements, Vitamin A and Carotenoids Fact Sheet for Health Professionals · checked 2026-10-06 · we read the section
18. ev-vaim-18 · Position of an expert body · government fact sheet · n = —
    Experts advise women who are or might be pregnant and those who are lactating not to take high doses (more than 3,000 mcg RAE [10,000 IU] daily) of vitamin A supplements [1].
    
    Who: women who are or might be pregnant and lactating women
    Effect: avoid supplemental vitamin A above 3,000 mcg RAE (10,000 IU) a day because of birth defect risk
    Certainty: limit applies to preformed vitamin A; same 3,000 mcg RAE is the adult UL
    NIH Office of Dietary Supplements, Vitamin A and Carotenoids Fact Sheet for Health Professionals · checked 2026-10-06 · we read the section
19. ev-vaim-19 · Position of an expert body · government fact sheet · n = —
    The FNB based these ULs on the amounts associated with an increased risk of liver abnormalities in men and women, teratogenic effects, and several toxic effects in infants and children.
    
    Who: all age groups; adult UL 3,000 mcg RAE of preformed vitamin A
    Effect: UL basis: liver abnormalities, teratogenic effects, toxic effects in infants and children
    Certainty: UL covers preformed vitamin A from food and supplements together; basis as quoted
    NIH Office of Dietary Supplements, Vitamin A and Carotenoids Fact Sheet for Health Professionals · checked 2026-10-06 · we read the section
20. ev-vaim-20 · Position of an expert body · FDA-approved drug label · n = —
    Drug Interactions Vitamin A: Because of the relationship of isotretinoin capsules to vitamin A, patients should be advised against taking vitamin supplements containing vitamin A to avoid additive toxic effects.
    
    Who: patients taking oral isotretinoin
    Effect: avoid vitamin A supplements during isotretinoin therapy
    Certainty: label text; the same caution appears on acitretin and tretinoin labels
    Isotretinoin capsules, FDA-approved label (DailyMed), effective 2024-06-26 · checked 2026-10-06 · we read the section
21. ev-vaim-21 · Position of an expert body · regulatory register entry · n = —
    POL-HC-6480 Vitamin A Vitamin A contributes to the normal function of the immune system Authorised
    
    Who: EU Register on nutrition and health claims, substance vitamin A
    Effect: Authorized
    Certainty: the claim describes a normal physiological role; it does not say extra vitamin A boosts immunity in people who are not deficient
    EU Register on nutrition and health claims, claim POL-HC-6480, snapshot 2026-09-21 · checked 2026-10-06 · we read the section