Vitamin A is an important micronutrient that comes in several forms, including retinols, retinals, and retinoic acids.

Dietary vitamin A is absorbed as retinol from preformed retinoids or as pro-vitamin A carotenoids, which are converted to retinol in the enterocyte. These are then delivered via chylomicrons to the liver for storage and subsequent release into the circulation and to its biologically active tissues bound to retinol-binding proteins (as shown in the figure below).

Vitamin A is an essential component of many important and diverse biological functions, including reproduction, embryonic development, cell differentiation, growth, immunity, and vision.

Vitamin A acts primarily through the nuclear retinoic acid receptors, retinoid X receptors, and peroxisome proliferator-activated receptors. Retinoids regulate the growth and differentiation of many cell types within the skin, and their deficiency leads to various skin manifestations such as abnormal keratinization of epithelial cells. In wounded tissue, vitamin A stimulates epidermal turnover, increases the rate of re-epithelialization, and restores epithelial structure. Retinoids have the unique ability to reverse the inhibitory effects of anti-inflammatory steroids on wound healing. In addition to the role of recruiting local inflammatory mechanisms to promote wound healing, retinoic acid has been shown to enhance the production of extracellular matrix components such as type I collagen and fibronectin, increase the proliferation of keratinocytes and fibroblasts, and decrease the levels of degrading matrix metalloproteinases.

In conclusion, retinoids appear to play some role in skin health and healing by activating the nuclear receptors and regulating gene transcription.

Zinder, R., Cooley, R., Vlad, L. G., & Molnar, J. A. (2019). Vitamin A and Wound Healing. Nutrition in clinical practice : official publication of the American Society for Parenteral and Enteral Nutrition, 34(6), 839–849. [Link]
Polcz, M. E., & Barbul, A. (2019). The Role of Vitamin A in Wound Healing. Nutrition in clinical practice : official publication of the American Society for Parenteral and Enteral Nutrition, 34(5), 695–700. [Link]