Which Vitamin Deficiency Causes Hair Loss? 

Hair loss can have many causes, but vitamin deficiency is one of the most overlooked. Low levels of vitamin D, iron, biotin, B12, or zinc can disrupt the hair growth cycle and lead to thinning. At Ziering Medical, addressing hair loss due to vitamin deficiency​ is part of our comprehensive approach to hair restoration. 

Understanding Vitamin Deficiency and Hair Loss 

Hair isn’t essential for survival, so when your body is low on nutrients, it prioritizes vital organs over hair follicles. This results in slower hair growth, weaker strands, and more hair shedding.

Vitamins and minerals fuel processes like cell turnover, collagen synthesis, oxygen delivery, and keratin production. All of which are critical for healthy hair. When you’re deficient, these processes are disrupted, and more hairs may enter the resting (telogen) phase prematurely. This leads to telogen effluvium, a condition marked by excessive hair shedding.

Several studies confirm the connection between nutrient deficiencies and hair loss:

• A 2013 review found that low levels of iron, zinc, and vitamin D were frequently associated with various types of hair loss, including telogen effluvium and androgenetic alopecia.
• A 2016 study found biotin deficiency in 38% of women complaining of hair loss, suggesting its importance in maintaining healthy hair follicles. 
• A 2024 meta-analysis revealed that people with alopecia frequently have vitamin D deficiency. 

Vitamin deficiency can directly affect hair follicle cycle, scalp health, and strand strength. Without the proper nutrients, your hair typically becomes one of the first things to suffer.

6 Vitamin and Mineral Deficiencies Linked to Hair Loss

Hair loss can be a warning sign of a vitamin and mineral deficiency. These six nutrients are linked to hair growth and when they’re low, shedding often follows.

1. Vitamin D

Vitamin D helps regulate the growth and cycling of hair follicles. It activates hair follicle stem cells, which are essential for starting the anagen (growth) phase. Low vitamin D levels have been linked to alopecia areata and chronic telogen effluvium. A deficiency may delay regrowth and contribute to shedding.

2. Iron

Iron supports hemoglobin production in red blood cells, allowing oxygen to be delivered to cells throughout the body, including the scalp and follicles. When iron levels drop, follicles may not get the oxygen and nutrients they need to function properly. Iron-deficiency anemia is one of the most common causes of hair loss, especially in women.

3. Vitamin B12

B12 is essential for red blood cell formation and DNA synthesis. It helps deliver oxygen to the scalp and follicles, supporting healthy hair growth. A deficiency can lead to poor circulation, slow follicle function, and hair thinning. It’s more common in people with dietary restrictions, such as vegans.

4. Biotin (Vitamin B7)

Biotin is involved in keratin production, the main structural protein of hair. It also supports the health of the scalp and skin. Although true biotin deficiency is rare, when it does occur, it can cause thinning hair, brittle strands, and even rashes on the scalp.

5. Zinc

Zinc helps regulate sebum (oil) production around hair follicles and is involved in tissue growth and repair. It also supports enzymes that keep hair follicles functioning. Zinc deficiency can lead to weakening of the follicle structure, resulting in shedding and delayed regrowth. It’s also been linked to alopecia areata.

6. Vitamin A

Vitamin A supports cell growth, including hair cells, and helps skin glands produce sebum to keep the scalp moisturized. However, too much or too little can cause problems. Low levels can slow hair growth and dry out the scalp, while excess vitamin A (often from supplements) can trigger rapid hair loss.

How to Know If You Have Hair Loss Due to Vitamin Deficiency

You can’t diagnose vitamin-related hair loss just by looking at your hair. The only way to confirm it is through a blood test. A hair loss doctor or a general physician can order labs to check for:

• Iron levels
• Vitamin D
• Vitamin B12
• Zinc
• Thyroid function (often tested together, as thyroid issues can mimic deficiency-related hair loss)

Don’t self-diagnose or start high-dose supplements without testing or guidance from a physician. Some nutrients, like iron or vitamin A, can cause harm if taken unnecessarily. Work with a hair loss specialist to identify the root cause and let them help you create a safe, targeted treatment plan.

Treatments for Vitamin-Related Hair Loss

Once lab tests confirm a deficiency, your treatment will focus on restoring nutrient levels and supporting healthy hair growth.

1. Improve your diet. 

A nutrient-rich diet is the foundation for long-term hair health. Focus on whole foods like lean red meat, lentils, leafy greens, fatty fish, eggs, dairy, nuts, and seeds. These foods provide essential nutrients like iron, vitamin D, B12, zinc, and biotin. Avoid crash diets or extreme restrictions, which often lack these essentials and can trigger further hair loss. 

2. Take doctor-recommended supplements. 

Supplementation should only be done based on confirmed deficiencies. For example, your provider may prescribe iron supplements for low ferritin, high-dose vitamin D3 if your levels are significantly low, or B12 shots if you’re deficient. 

Biotin and zinc may also be recommended, but only if necessary. Over-supplementing, especially with iron or vitamin A, can actually worsen hair loss or cause other health problems, so avoid self-prescribing without lab confirmation.

3. Consider topical treatments. 

Topical treatments like minoxidil can help support hair regrowth while your body restores its nutrient levels. Minoxidil works by stimulating follicles and increasing blood flow to the scalp. You may also benefit from hair-strengthening shampoos and conditioners rich in peptides that support hair growth. 

Z-Factors is another excellent option to consider. Unlike PRP, which requires drawing blood and can trigger inflammation, Z-Factors is a non-invasive, topical treatment that doesn’t require anesthesia. 

It uses a blend of naturally occurring nanoparticles, including growth factors, cytokines, extracellular vesicles, peptides, proteins, and hyaluronic acid to support hair regrowth. This makes Z-Factors a safer and more comfortable alternative for patients seeking effective hair restoration without the risks associated with PRP.

4. Address lifestyle factors. 

Stress, poor sleep, and overuse of heat or chemical treatments can slow hair health and growth recovery even if your vitamin levels improve. Managing stress, getting quality sleep, and being gentle with your hair all support regrowth. 

Worried About Thinning Hair? Schedule a Consultation at Ziering Medical.

For over 20 years, Ziering Medical has been the #1 choice for hair restoration in Beverly Hills with additional clinics in New York City, NY, and Greenwich, CT. We offer advanced hair loss evaluations and personalized, innovative treatments backed by decades of experience. 

Call us or visit a Ziering Medical clinic near you to book a consultation. We serve patients all over the greater Tri-state area of New York, New Jersey, and Connecticut, as well as the greater Southern California area from Los Angeles and Beverly Hills to Newport Beach and San Diego.

Frequently Asked Questions

What vitamin deficiency causes hair loss​?

Hair loss is most commonly linked to low levels of vitamin D, iron, B12, biotin, zinc, and sometimes, vitamin A.

Can vitamin D deficiency cause hair loss?

Yes. Several studies show that vitamin D deficiency can disrupt the hair growth cycle and trigger shedding. It’s linked to conditions like telogen effluvium and alopecia areata.

How do I know if my hair loss is from a deficiency or something else?

Blood tests are the only reliable way to identify a deficiency. Your Ziering physician will help rule out other causes like hormones, stress, or genetics.

Can hair grow back after vitamin-related hair loss?

Yes. Once the deficiency is corrected, hair usually starts to regrow. However, if your hair loss is caused by male pattern baldness,  or another underlying condition, correcting a deficiency alone may not be enough. In those cases, medication, hair restoration procedures, and other hair loss therapeutics may be needed.

How long does it take to see hair regrowth after correcting a deficiency?

Hair growth typically resumes within 3 to 6 months, but it depends on the severity of the deficiency and whether other factors are involved.