Vitamin A
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Summary of Vitamin A
Primary information, health benefits, side effects, usage, and other important details
Vitamin A is not a single compound but a group of chemical compounds that are structurally similar. These compounds include retinol, retinaldehyde, retinoic acid, and provitamin A caretenoids which include beta-carotene, alpha-carotene, gamma-carotene and cryptoxanthin. Retinol and beta-carotene are some of the most common forms of vitamin A found in food and supplements, with the former being found in animals and the latter in plants.
Vitamin A is involved in the modulation of skin health, vision, the immune system, and gene transcription. Different forms of vitamin A will serve different functions. For example, it is retinoic acid that is involved in gene transcription and the maintenance of skin health; it is retinaldehyde that binds certain proteins to the cones and rods of the eye, allowing the eye to function in low-light environments.
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For topical application, the form of all-trans retinoic acid (Tretinoin) should be used in a facial cream/lotion containing it in the range of 0.01-0.10%, with the lowest concentration having low side-effects but less efficacy and 0.025-0.05% being the sweet spot. Topical application is once nightly.
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Human Effect Matrix
The Human Effect Matrix looks at human studies (it excludes animal and in vitro studies) to tell you what effects vitamin a has on your body, and how strong these effects are.
| Grade | Level of Evidence [show legend] |
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Robust research conducted with repeated double-blind clinical trials |
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Multiple studies where at least two are double-blind and placebo controlled |
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Single double-blind study or multiple cohort studies |
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Uncontrolled or observational studies only |
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Level of Evidence
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The amount of high quality evidence. The more
evidence, the more we can trust the results.
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Outcome |
Magnitude of effect
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The direction and size of the supplement's impact on
each outcome. Some supplements can have an increasing effect, others have a decreasing effect, and others have no effect.
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Consistency of research results
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Scientific research does not always agree. HIGH or
VERY HIGH means that most of the scientific research agrees.
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Notes |
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Notable
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Very High See all 3 studies |
The appearance of fine (small) wrinkles appears to be reliably reduced with topical application of a nightly vitamin A cream, with efficacy in all ages assuming fine wrinkles are present.
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Minor
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Very High See all 3 studies |
Skin dryness is a side-effect of topical application in some persons, increasing in frequency with higher doses; it is mild in severity and, while it may be associated with flaking, rarely causes dropouts.
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- | - See all 3 studies |
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- | - See 2 studies |
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Things to Note
Is a Form Of
Other Functions:
Also Known As
retinol, retinal, retinoic acid, tretinoin, beta-carotene
Caution Notice
Supplements or foods high in retinol should be consumed carefully due to its fat-soluble nature. It is more difficult to clear fat-soluble compounds from the body than water-soluble compounds. A medical practitioner should be consulted before ingesting high amounts of retinol.
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