Evidence supporting the use of: Vitamin A
For the health condition: Hair (loss or thinning)

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Synopsis

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

Vitamin A is an essential nutrient important for various bodily functions, including vision, immune response, and cellular growth. Its role in supporting healthy skin and mucous membranes has led to interest in its potential for treating hair loss or thinning. Scientific evidence shows that vitamin A plays a role in the growth and maintenance of epithelial tissues, including the scalp and hair follicles. Retinoic acid, a metabolite of vitamin A, is involved in the regulation of hair follicle cycling and the differentiation of follicular cells.

However, the relationship between vitamin A and hair health is complex. While adequate vitamin A is necessary for normal hair growth, excessive intake is associated with hair loss (hypervitaminosis A). Few high-quality clinical studies directly examine vitamin A supplementation for hair loss in individuals with normal vitamin A status. Most scientific support comes from studies of individuals with vitamin A deficiency, where correcting the deficiency can restore normal hair growth. For the general population, supplementation is not recommended unless a deficiency is confirmed, as both deficiency and excess can negatively impact hair health.

In summary, while there is a scientific rationale for vitamin A's involvement in hair follicle health, robust clinical evidence in the context of hair loss treatment is limited. Thus, the use of vitamin A to support hair growth is only weakly supported by current scientific research, primarily in cases of deficiency.

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