Session check

Supplement

Vitamin A

Supports essential micronutrient pathways and deficiency-related physiology.[3445,3516,3540, etc.]

Superscript reference numbers link to the Sources bibliography.

Strong Evidence

Immune SupportBone HealthEnergyLongevity

Composite Rating

3.7/5

Blends evidence depth, community direction, safety friction, and completeness.

Evidence Intensity

100/100

High depth from human/RCT/meta counts

Community Direction

-7

Mixed / Neutral • confidence Moderate

Safety Friction

100/100

High signal from adverse/interaction markers

Data Completeness

100%

Studies 15 • mentions 13 • links 26

Not medical advice. This product is for educational and informational purposes only. It does not diagnose, treat, cure, or prevent any disease and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of a qualified healthcare provider with any questions regarding a medical condition.

FDA disclaimer: These statements have not been evaluated by the Food and Drug Administration. Dietary supplements are not intended to diagnose, treat, cure, or prevent any disease. Results may vary. Not intended for use by pregnant or nursing women, individuals under 18, or those with known medical conditions without physician consultation.

If you are experiencing a medical emergency, call 911 or your local emergency number immediately.

Implementation Blueprint

Goal alignment: Immune Support, Bone Health, Energy, Longevity.[95,262,306, etc.]

Dose guide: Human-study daily dose: 1 mg-150 mg/day (higher-confidence extraction from PubMed abstracts)..[95,262,306, etc.]

Category: vitamin.[95,262,306, etc.]

At-A-Glance Evidence Architecture[3445,3516,3540, etc.]

Clinical Depth

Humans: 7,573 • RCTs: 921 • Meta: 210

Cohort / Real-World

Cohort signals: 0

Safety Markers

Adverse signals: 1,748 • Interactions: 1,717

Evidence Tracking

Freshness, trend, and study timeline for this item

Evidence Tracking

Status

New Evidence

Trend

→ Stable evidence base

Depth

10598 total studies · 2 recent

Timeline

20192024

Top Signal Metrics[3445,3516,3540, etc.]

Animal-only studies

11,395

Total indexed

10,598

Human studies

7,573

In vitro / tissue

2,543

Safety adverse signals

1,748

Interaction signals

1,717

Community Direction Mix[95,262,306, etc.]

Weighted direction score: -7 (Mixed / Neutral)

Benefit

Evidence Quality Summary[3445,3516,3540, etc.]

High when >=2 human meta-analyses, or >=5 human RCTs with substantial human literature volume.

Animal-only studies

11,395

Total indexed

10,598

Human studies

7,573

In vitro / tissue

2,543

Safety adverse signals

1,748

Interaction signals

1,717

Randomized trials

921

Meta-analyses

210

Study Type Breakdown

Distribution of evidence by study design strength

Meta-AnalysesLevel 1a210

Randomized TrialsLevel 1b921

Human Studies (other)Level 3-46,442

All IndexedAll levels10,598

100

Evidence Strength: High

Composite of study volume, RCTs, and meta-analyses

Top Human Studies[3445,3516,3540, etc.]

PMID 35365361 • 2022 Jun

ESPEN micronutrient guideline.

Clin Nutr

Open PubMed

PMID 37644533 • 2023 Aug 29

Antioxidant vitamins supplementation reduce endometriosis related pelvic pain in humans: a systematic review and meta-analysis.

Reprod Biol Endocrinol

Open PubMed

PMID 38140375 • 2023 Dec 15

Improving Cognitive Function with Nutritional Supplements in Aging: A Comprehensive Narrative Review of Clinical Studies Investigating the Effects of Vitamins, Minerals, Antioxidants, and Other Dietary Supplements.

Community Report Frequency[95,262,306, etc.]

Benefit reports: 5

Adverse reports: 5

No-effect reports: 0

Mixed reports: 3

Unclear reports: 0

Signal confidence: 0.41

Top Reported Effects[95,262,306, etc.]

Benefits

better: 3
helped: 2
energy: 1
sleep: 1
calmer: 1
worked: 1
reduced: 1
helpful: 1

Adverse

acne: 2
constipation: 1
cramps: 1
palpitations: 1
rash: 1
side effects: 1

No Effect

didn't notice: 1

Insufficient empirical signal for a directional adjustment.

Reddit evidence: 7 mentions (confidence 0.41) across Supplements, Biohackers.

Amazon signal: 0 products scanned (confidence 0.00).

GNC signal: 0 products scanned (confidence 0.00) [BLOCKED].

Community Evidence Examples[95,262,306, etc.]

post • r/Supplements • unclear

Does taking a selenium supplement for selenium deficiency depletes vitamin A stores? I have selenium deficiency and will start supplementing with 100mcg of daily selenium. However, I read that selenium depletes Vitamin A stores in the live…

Open mention

post • r/Biohackers • unclear

Fixing folate deficiency completely changed my life Edit: I woke up this morning and played a song from my childhood, and I felt such a flood of nostalgic and emotion I cried lol. It's so emotional because everything has been so ROBOTIC an…

Open mention

post • r/Supplements • unclear

Micellized Vitamin A supplement without castor oil, citrus or gums? The title pretty much covers it. I need to sometimes aggressively supplement Vitamin A, and the micellized drops seem like the answer, but I have bad reactions to castor o…

Retail Signal Examples

amazon

Amazon search for Vitamin A

Rating: n/a | Reviews: n/a

Open product

Primary Source Links

Evidence Sources

Scientific Evidence Notes[3445,3516,3540, etc.]

1. PubMed evidence summary: Vitamin A

PUBMED • Humans + preclinical triage

Counts aggregated from automated literature sweep and tiering rules.

Outcome: Tier HIGH; humans 7573, RCTs 921, meta-analyses 210.[3445,3516,3540, etc.]

Open source

2. ESPEN micronutrient guideline.

PUBMED • 2022 • Human evidence curation set

PMID 35365361 from Clin Nutr.

Outcome: See linked PubMed abstract for methods and outcomes.[3445,3516,, etc.]

Safety and Pitfalls

Elevated adverse/interactions signal in literature; review medications and conditions before use.[95,262,306, etc.]
High interaction-signal count detected in literature search.[95,262,306, etc.]
Potential side effect: acne[95,262,306, etc.]
Potential side effect: constipation[95,262,306, etc.]
Potential side effect: cramps[95,262,306, etc.]
Potential side effect: palpitations[95,262,306, etc.]
Potential side effect: rash[95,262,306, etc.]
ODS safety note: Provitamin A carotenoids are plant pigments that include beta-carotene, alpha-carotene, and beta-cryptoxanthin [ 1 ].[95,262,306, etc.]
ODS safety note: Most of the body’s vitamin A is stored in the liver in the form of retinyl esters [ 1 ].[95,262,306, etc.]
ODS safety note: However, these levels are not always reliable indicators of vitamin A status because they do not decline until vitamin A levels in the liver and other storage sites are almost depleted and because acute and chronic infections can decrease serum and plasma retinol concentrations [ 1 ].[95,262,306, etc.]
ODS safety note: Most vitamin A is stored in the liver, so measuring vitamin A levels in the liver is the best way to assess vitamin A adequacy [ 1 ].[95,262,306, etc.]
ODS safety note: In clinical studies, specialized research laboratories can measure liver vitamin A reserves indirectly using isotope-dilution or dose-response methods, in which plasma levels of retinol, a tracer surrogate, or both are measured over several days after the administration of vitamin A [ 1 ].[95,262,306, etc.]
ODS safety note: One mcg RAE is equivalent to 1 mcg retinol, 2 mcg supplemental beta-carotene, 12 mcg dietary beta-carotene, or 24 mcg dietary alpha-carotene or beta-cryptoxanthin [ 5 ].[95,262,306, etc.]
ODS safety note: To convert IU to mcg RAE, use the following [ 11-13 ]: 1 IU retinol = 0.3 mcg RAE 1 IU supplemental beta-carotene = 0.3 mcg RAE 1 IU dietary beta-carotene = 0.05 mcg RAE 1 IU dietary alpha-carotene or beta-cryptoxanthin = 0.025 mcg RAE RAE can only be directly converted into IUs if the sources of vitamin A are known.[95,262,306, etc.]
Legacy caution group: Oxalate kidney stone formers at high doses[95,262,306, etc.]
Legacy caution group: Hemochromatosis patients at high doses[95,262,306, etc.]