Evidence supporting the use of: Vitamin A
For the health condition: Hair Care (general)

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Synopsis

Source of validity: Scientific
Rating (out of 5): 2

Vitamin A plays an essential role in the growth and maintenance of epithelial tissues, including the scalp and hair follicles. Scientifically, vitamin A is involved in the production of sebum, an oily substance produced by sebaceous glands that helps moisturize the scalp and keep hair healthy. Deficiency in vitamin A can lead to dry scalp, brittle hair, and even hair loss. Several studies in both humans and animals have demonstrated that vitamin A deficiency is associated with hair and skin issues, and that restoring adequate levels can help reverse these symptoms. However, it is important to note that while adequate vitamin A is necessary for healthy hair, excessive intake (hypervitaminosis A) can actually cause hair loss and other health problems. Thus, supplementation should be approached with caution and ideally under medical guidance.

Despite its biological plausibility and the evidence linking deficiency to hair problems, there is limited robust clinical trial data directly supporting the use of vitamin A supplements to improve general hair health in people who are not deficient. Most evidence comes from case reports, observational studies, and the well-established understanding of vitamin A's role in skin and epithelial health. Therefore, while the use of vitamin A for hair care is scientifically grounded when correcting a deficiency, its benefit as a general supplement for hair care in otherwise healthy individuals is not strongly supported by high-quality evidence.

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