Vitamin A
Vitamin A retinol for humans
In nature, vitamin A exists in two forms: retinol (ready to use vitamin A) and carotene (provitamin A, which can be considered as a plant form of vitamin A). Red plant pigment (beta-carotene) gives the vitamin a pale yellow color. 
The deficiency of Vitamin A causes a weakening of spatial orientation in the twilight, decreases the contrast of the colors and concentration. Lack of vitamin A causes unexplained migraines, general lethargy, and fatigue, as well as the lack of appetite and apathy. Retinol deficiency in the blood reduces the level of progesterone produced, which leads to infertility in women.
Vitamin A can be purchased in capsules as an aid in the treatment of ichthyosis, eczema, poor hair state and skin condition. The use of retinol helps in the treatment of various degenerative and inflammatory processes of the skin: burns, injuries, and frostbites. Vitamin A in capsules shall be used in case of serious problems with the retina and optic nerve, tearing disorders, bacterial and viral conjunctivitis.
Cosmetic properties of Vitamin A
The lack of vitamin A causes poor vision, while the skin becomes rough and dry on the calves and hands. It becomes rough due to keratinization of hair follicles. Nails can also be dry and dull. The dryness of the cornea of the eye causes conjunctivitis in the majority of cases. In addition, there is weight loss and growth retardation in children.
Vitamin A for hair is probably one of the most important vitamins for hair. In case of the lack of it, the skin flakes, becomes tight and irritated, and the hair starts to break. The necessary content of vitamin A in the body gives the hair shiny look and elasticity while protecting the hair from the destructive effects of UV rays.