Vitamin D is a nutrient that helps the body absorb calcium. It is found in food and made by the body when skin is exposed to sunlight. Vitamin D deficiency can occur if you don’t get enough vitamin D from food or supplements, or if your body can’t absorb it properly.
Symptoms of vitamin D deficiency can include fatigue, muscle weakness, bone pain, and hair loss.
The good news is that hair loss due to vitamin D deficiency is usually reversible. Once levels of vitamin D are increased, hair follicles will typically begin to function properly again and hair will start to regrow. It can take several months for new hair growth to become visible, so be patient as you wait for your results.