Vitamin D

What is Vitamin D?

A vitamin your skin makes in sunlight.

Key facts at a glance

How it's thought to work

Vitamin D receptors play a role in the hair cycle.

What the research says

Lower levels are seen in alopecia areata and telogen effluvium; trials are small.

How it's used

Supplements as advised after a blood test.

Association is not proof of a cure

Studies report lower vitamin D levels in some groups with alopecia areata or diffuse shedding, but that does not prove low vitamin D caused every case or that supplements regrow hair when levels are adequate. Study designs, populations and definitions of deficiency vary.

Testing and next steps

A clinician can decide whether a 25-hydroxy vitamin D test fits your history and how to correct a confirmed deficiency. High doses are not automatically better. If patterned thinning is also present, consider its evidence-based options separately; a vitamin and a FOLIGAIN® or other Minoxidil drug product solve different problems.

The good and the not-so-good

A quick, balanced look before you decide whether it belongs in your routine.

What it pairs well with

People often combine ingredients. These combinations are common — check with a pharmacist or doctor if you use prescription products.

• Iron
• Zinc

A friendly safety note

This page is general education, not medical advice. Patch-test new topicals, stop if your scalp becomes irritated, and see a doctor or dermatologist for sudden, patchy or painful hair loss. Talk to a professional before starting supplements if you are pregnant, breastfeeding, take medication or have a health condition.