Can a vitamin D deficiency cause hair loss?

Vitamin D is an essential nutrient that plays a role in many of the body’s functions. A vitamin D deficiency may cause numerous problems, including hair loss.

In this article, we look at how vitamin D and hair growth are connected, if a deficiency causes hair loss, and if it is reversible.
Does vitamin D deficiency cause hair loss?
Vitamin D stimulates hair follicles, so a deficiency may lead to hair loss.

There is some evidence that having a vitamin D deficiency does cause hair loss and other hair problems. Vitamin D stimulates hair follicles to grow, and so when the body does not have enough, the hair may be affected.

A vitamin D deficiency may also be linked to alopecia areata, an autoimmune condition that causes patchy hair loss.

Research shows that people with alopecia areata have much lower levels of vitamin D than people who do not have alopecia.

Vitamin D deficiency can also play a role in hair loss in people without alopecia. Other research shows that women who have other forms of hair loss also had lower levels of vitamin D.
How does vitamin D affect hair?

Vitamin D affects the health of many parts of the body, including the skin and hair.

Vitamin D plays a role in the creation of new hair follicles. Hair follicles are the tiny pores from which new hairs grow. New follicles may help hair maintain thickness and prevent existing hair from falling out prematurely.

Because of this link, getting adequate amounts of vitamin D can support hair growth and regrowth.
Other vitamin D deficiency symptoms

People with a vitamin D deficiency may have no symptoms, or their symptoms may be nonspecific and change over time.

Symptoms of a vitamin D deficiency include:

changes in mood, including depression or anxiety
frequent fractures
slow wound-healing
loss of bone density
muscle weakness
new or worsening high blood pressure
constant fatigue
chronic pain
infertility
decreased endurance

A lack of sunlight or not eating enough foods rich in vitamin D are the most common causes of a vitamin D deficiency.

However, some people may have vitamin D deficiencies because of another underlying condition, including Crohn’s disease or celiac disease, which prevent the body from fully absorbing nutrients.

People with an underlying medical condition will experience symptoms of the primary cause and symptoms of a vitamin D deficiency, as well.

Certain medications may also cause the body to break down vitamin D before it can be used. Medications that may cause a vitamin D deficiency include:

antifungals
glucocorticoids
medications for HIV
anticonvulsants

If a medication is causing a vitamin D deficiency or hair loss, a person should speak to their doctor about alternatives.