Supplement

Vitamin A

Vitamin A is a fat-soluble vitamin that supports vision, immune defenses, and the health of skin and other linings. People mostly look at it for infant health, and with moderate evidence, trials found diarrhea symptoms improved and infant death risk fell. The effects were small, and the death-risk findings came from six trials of about 1,165 very-preterm or low-birth-weight babies, so they may not apply to every infant.

Sources: PMID 34582542; PMID 27552058

Updated 30 September 2026
How we grade
14 studies cited

Best evidence: Grade B
Conditions studied: 5
Outcomes: 16
Graded outcomes: 0210

Evidence by condition

Strong
Moderate
Limited
Very limited

5 conditions

Infant Health

Infant Health: outcomes studied for Vitamin A
Grade	Outcome	Effect	Size	Studies	People
	Infant Death Risk Small Improvement	Improves (the measure goes down)	Small effect	6 studies	1,165 people
Studies that measured infant death risk Vitamin A supplementation to prevent mortality and short- and long-term morbidity in very low birth weight infants.Cochrane Database Syst Rev · PMID 27552058 Vitamin A supplements for preventing mortality, illness, and blindness in children aged under 5: systematic review and meta-analysis.BMJ · PMID 21868478 Vitamin A supplementation for the prevention of morbidity and mortality in infants one to six months of ageCochrane Database Syst Rev · PMID 27681486 Vitamin A supplementation for preventing morbidity and mortality in children from six months to five years of age.Cochrane Database Syst Rev · PMID 35294044 Neonatal vitamin A supplementation for the prevention of mortality and morbidity in term neonates in low and middle income countries.Cochrane Database Syst Rev · PMID 28234402 Vitamin A supplementation in very-preterm or very-low-birth-weight infants to prevent morbidity and mortality: a systematic review and meta-analysis of randomized trials.Am J Clin Nutr · PMID 34582542
	Diarrhea Symptoms Small Improvement	Improves (the measure goes down)	Small effect		37,710 people
	Lung Function	Improves (the measure goes up)		1 study	986 people
Studies that measured lung function Oral vitamin A supplementation in preterm infants to improve health outcomes: A systematic review and meta-analysis.PLoS One · PMID 35377893
	Vision problems	Improves (the measure goes up)			22,972 people

Skin Health

Skin Health: outcomes studied for Vitamin A
Grade	Outcome	Effect	Size	Studies	People
	Collagen Content Small Increase	Improves (the measure goes up)	Small effect		33 people
	Hyperpigmentation	Changes; see studies		3 studies	406 people
Studies that measured hyperpigmentation Topical tretinoin for treatment of photodamaged skin. A multicenter studyArch Dermatol · PMID 2024983 Topical tretinoin (retinoic acid) treatment of hyperpigmented lesions associated with photoaging in Chinese and Japanese patients: a vehicle-controlled trialJ Am Acad Dermatol · PMID 8277035 Two concentrations of topical tretinoin (retinoic acid) cause similar improvement of photoaging but different degrees of irritation. A double-blind, vehicle-controlled comparison of 0.1% and 0.025% tretinoin creamsArch Dermatol · PMID 7544967
	Skin Quality	Improves (the measure goes up)		1 study	326 people
Studies that measured skin quality Improvement of naturally aged skin with vitamin A (retinol)Arch Dermatol · PMID 17515510
	Skin Thickness	Improves (the measure goes up)		1 study	128 people
Studies that measured skin thickness Topical tretinoin improves photoaged skin. A double-blind vehicle-controlled studyJAMA · PMID 3336176
	Skin Dryness	Improves (the measure goes up)			394 people
	Skin Elasticity	Improves (the measure goes up)			263 people
	Wrinkles	Improves (the measure goes up)			326 people

Multiple Sclerosis (MS)

Multiple Sclerosis Symptoms: improves

Multiple Sclerosis (MS): outcomes studied for Vitamin A
Grade	Outcome	Effect	Size	Studies	People	Studies list
	Multiple Sclerosis Symptoms	Improves (the measure goes down)		1 study	101 people
Studies that measured multiple sclerosis symptoms Effect of Vitamin A Supplementation on fatigue and depression in Multiple Sclerosis patients: A Double-Blind Placebo-Controlled Clinical TrialIran J Allergy Asthma Immunol · PMID 26996107

Pneumonia

Pneumonia Symptoms: improves
Bronchopulmonary Dysplasia Risk

Pneumonia: outcomes studied for Vitamin A
Grade	Outcome	Effect	Size	Studies	People
	Pneumonia Symptoms	Improves (the measure goes down)		1 study	1,713 people
Studies that measured pneumonia symptoms The Relationship of Vitamin A and Neonatal Respiratory Diseases: A Meta-Analysis.Clin Respir J · PMID 39434208
	Bronchopulmonary Dysplasia Risk		Small effect		554 people

Respiratory Health

Pneumonia Symptoms: improves
Bronchopulmonary Dysplasia Risk

Respiratory Health: outcomes studied for Vitamin A
Grade	Outcome	Effect	Size	Studies	People
	Pneumonia Symptoms	Improves (the measure goes down)		1 study	1,713 people
Studies that measured pneumonia symptoms The Relationship of Vitamin A and Neonatal Respiratory Diseases: A Meta-Analysis.Clin Respir J · PMID 39434208
	Bronchopulmonary Dysplasia Risk		Small effect		554 people

What the published studies found

2 automated readings

Automated reading of the published studies (Decosa evidence engine), for outcomes Dr. Grey has not graded yet. It is not a Dr. Grey grade and does not change one. How it is read

Skin aging
The studies read are too weak to tell whether Vitamin A changes skin aging. The strongest review read studied people with facial skin aging. The evidence is very weak.
Side effects: 2 of the 7 studies that reported on them found more with Vitamin A (discomfort, erythema).
4 studies counted of 11 read: 1 review and 3 trials (132 people in the trials).
1. Systematic review, 2021; 9 studies; people with facial skin aging: unclear: evidence too weak to tell (the review the verdict rests on). weak evidence for retinol potentially having a mild ameliorating effect on fine facial skin wrinkle … Evidence for the Efficacy of Over-the-counter Vitamin A Cosmetic Products in the Improvement of Facial Skin Aging: A Systematic ReviewPubMed 34980969
2. Randomised trial, 2026; 38 people; women aged 40-61 with mature facial skin: improves. increased epidermal thickness (+12.4 μm), epidermal density Barrier Function and Biophysical Effects of 0.104% and 0.247% Retinol Creams in Mature Facial Skin: A Prospective StudyPubMed 42653210
3. Crossover trial, 2010; 46 people; korean women with periorbital wrinkles: improves. retinyl retinoate-treated wrinkles improved compared with Improvement in skin wrinkles from the use of photostable retinyl retinoate: a randomized controlled trialPubMed 19849696
4. Randomised trial, 2009; 48 people; 48 volunteers: improves. improved all major aging signs assessed in our study Antiaging action of retinol: from molecular to clinicalPubMed 19648781
Automated reading of the published studies (Decosa evidence engine), run 30 Sep 2026. It reads abstracts, can miss studies, and a repeat run can differ.
Warts
Too few usable studies were found to tell whether Vitamin A changes warts. 3 studies were read and none could be counted.
Automated reading of the published studies (Decosa evidence engine), run 30 Sep 2026. It reads abstracts, can miss studies, and a repeat run can differ.

Key findings

Infant Death RiskInfant HealthImproves (the measure goes down)
Diarrhea SymptomsInfant HealthImproves (the measure goes down)
Collagen ContentSkin HealthImproves (the measure goes up)

Shop the evidence-backed picks

Third-party tested Vitamin A products, in the forms the graded studies used where we can match them.

Grade B

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Studies cited

14 studies from PubMed

Topical tretinoin for treatment of photodamaged skin. A multicenter studyArch Dermatol · PMID 2024983
Topical tretinoin (retinoic acid) treatment of hyperpigmented lesions associated with photoaging in Chinese and Japanese patients: a vehicle-controlled trialJ Am Acad Dermatol · PMID 8277035
Two concentrations of topical tretinoin (retinoic acid) cause similar improvement of photoaging but different degrees of irritation. A double-blind, vehicle-controlled comparison of 0.1% and 0.025% tretinoin creamsArch Dermatol · PMID 7544967
Topical tretinoin improves photoaged skin. A double-blind vehicle-controlled studyJAMA · PMID 3336176
Improvement of naturally aged skin with vitamin A (retinol)Arch Dermatol · PMID 17515510
Effect of Vitamin A Supplementation on fatigue and depression in Multiple Sclerosis patients: A Double-Blind Placebo-Controlled Clinical TrialIran J Allergy Asthma Immunol · PMID 26996107
Vitamin A supplementation to prevent mortality and short- and long-term morbidity in very low birth weight infants.Cochrane Database Syst Rev · PMID 27552058
Vitamin A supplements for preventing mortality, illness, and blindness in children aged under 5: systematic review and meta-analysis.BMJ · PMID 21868478
Vitamin A supplementation for the prevention of morbidity and mortality in infants one to six months of ageCochrane Database Syst Rev · PMID 27681486
Vitamin A supplementation for preventing morbidity and mortality in children from six months to five years of age.Cochrane Database Syst Rev · PMID 35294044
Neonatal vitamin A supplementation for the prevention of mortality and morbidity in term neonates in low and middle income countries.Cochrane Database Syst Rev · PMID 28234402
Vitamin A supplementation in very-preterm or very-low-birth-weight infants to prevent morbidity and mortality: a systematic review and meta-analysis of randomized trials.Am J Clin Nutr · PMID 34582542
Oral vitamin A supplementation in preterm infants to improve health outcomes: A systematic review and meta-analysis.PLoS One · PMID 35377893
The Relationship of Vitamin A and Neonatal Respiratory Diseases: A Meta-Analysis.Clin Respir J · PMID 39434208