Vitamin D and Hair Health: Can Low Vitamin D Contribute to Shedding?

Finding more hair than usual in the shower drain or wrapped around your brush may be concerning and even unsettling. And many sources cite vitamin D as playing a part.

But the relationship between vitamin D and hair health is actually more nuanced than “take vitamin D and your hair grows back.” So, what’s fact and what’s fiction? What does the research suggest?

This article explores how vitamin D may play a role in the hair growth cycle, what the research actually says about deficiency and shedding, how to test your levels the right way, what supplementation can realistically do, and when it makes sense to consult with a licensed healthcare provider.

‍

How Vitamin D Affects Hair Follicle Cycling

The hair growth cycle goes through three phases:

1. Anagen (active growth): This is the longest phase, which typically lasts 2-6 years.
2. Catagen (transition): This phase involves a brief wind-down of growth, lasting around two weeks.
3. Telogen (resting and shedding): This phase lasts around three months and is where the follicle rests before the hair falls out and the cycle begins again.

At any given time, most of your hair is in the anagen phase; this is why healthy hair usually stays put. So, where exactly does vitamin D enter the picture?

Vitamin D receptors (VDRs), which are the docking sites that let cells respond to vitamin D, are present in hair follicles. Research suggests this signaling may play a role in the anagen growth phase.

When vitamin D levels run low, this signaling may be affected, which may affect normal hair cycling. This may help explain the observed association between low vitamin D levels and hair shedding. However, it’s worth noting that low vitamin D is rarely the sole factor involved.

‍

What Does the Research Say About Vitamin D Deficiency and Hair Loss?

Multiple observational studies report that people with certain hair loss conditions—including telogen effluvium (a type of temporary, diffuse shedding often triggered by stress, illness, or hormonal shifts) and alopecia areata (an autoimmune form of patchy hair loss)—tend to have lower serum vitamin D levels than people without hair loss. 

A 2021 review reported that most studies show an inverse relationship between vitamin D levels and non-scarring alopecias, meaning lower levels tended to be associated with hair loss.

Yet, association is not causation. Low vitamin D is common in the general population, and plenty of individuals who are deficient never experience hair loss.

Some small-scale studies suggest that correcting a deficiency may improve hair density over time, but results are limited, and more research is needed to understand whether vitamin D supplementation improves hair-loss outcomes. 

Key takeaway: Low vitamin D is associated with increased shedding in some studies, but correcting it may not fully address hair loss if other causes, such as genetics, hormonal changes, or autoimmune conditions, are also playing a part.

‍

Who Is Most at Risk of Vitamin D Deficiency?

You may be at higher risk if you experience or have any of the following factors:

• Limited sun exposure: This refers to spending most of your time indoors, living at higher latitudes, or getting through winter when UVB rays are weaker.
• Darker skin tone: Higher melanin reduces the skin’s ability to synthesize vitamin D from sunlight.
• Over 50 years of age: Vitamin D production in the skin can decline with age.
• Higher body weight: Vitamin D is fat-soluble and can be stored in fat tissue, which may lower circulating levels.
• Gastrointestinal conditions (such as celiac disease, Crohn's disease, or a history of bariatric surgery): These conditions may impair absorption of fat-soluble vitamins (like vitamin D).
• Kidney or liver disease: Both of these organs support vitamin D metabolism.
• Strict plant-based diets with few fortified foods: Dietary vitamin D comes mostly from fatty fish, egg yolks, and fortified foods and beverages.

If multiple risk factors apply to you, it may be worthwhile to discuss testing with your provider rather than assuming deficiency or self-supplementing based on symptoms alone.

‍

Symptoms of Low Vitamin D (And Why Hair Shedding Is Just One Signal)

Hair shedding is rarely the only sign or symptom of a Vitamin D deficiency. Common other symptoms may include:

• Persistent fatigue or low energy
• Muscle weakness, aches, or bone pain
• Frequent illness or slow recovery from infections
• Mood changes, including low mood or increased irritability
• Brain fog or trouble concentrating
• Slow wound healing

If you’re experiencing increased shedding and have risk factors or other symptoms that could be associated with vitamin D deficiency, a licensed healthcare provider can help determine whether testing is appropriate. However, hair loss on its own, particularly if it follows a specific pattern like a receding hairline or thinning at the crown, may have causes unrelated to vitamin D status and should be evaluated accordingly.

‍

How to Test Your Vitamin D Levels

The standard vitamin D test is a serum 25-hydroxyvitamin D test (25(OH)D). It measures the total vitamin D circulating in your blood, capturing both D2 and D3.

If you’ve recently had this test, here’s generally what the numbers mean:

• 20-29 ng/mL: considered insufficient by many clinical guidelines
• 30-60 ng/mL: generally considered the optimal range 

The interpretation of 25(OH)D results can vary based on the clinical context and the guidance being used. A licensed healthcare provider can help interpret your result and determine whether supplementation is appropriate. Very high vitamin D intake can cause toxicity, so high-dose supplementation should not be started without appropriate medical guidance. 

The good news is this test is widely available and can be ordered by a primary care provider, a dermatologist, or through telehealth. 

Ultimately, a blood test can help confirm a deficiency, and a licensed provider can interpret the result in the context of your full health profile.

‍

Can Vitamin D Supplements Help With Hair Loss?

If your shedding is partly driven by a confirmed deficiency, correcting it may support healthier follicle cycling over time. Some studies have reported improvements in hair measures among some deficient individuals after supplementation, but as noted earlier, individual results may vary and evidence remains limited. 

At the end of the day, hair growth is slow. Even when vitamin D may be helping, noticeable changes in density or a drop in shedding typically take several months or longer. On top of this, shedding may not stop the moment you start supplementing.

If your hair loss is primarily androgenetic (the genetic, hormonal pattern kind), vitamin D supplementation alone may not address the underlying cause. And if you’re not deficient, taking extra vitamin D isn’t supported by evidence as a hair growth strategy. In fact, it can be risky since vitamin D may be toxic at high doses.

Beyond supplementation, you may also want to consider supporting your vitamin D levels through diet and sunlight. Food sources of vitamin D include fatty fish (salmon, mackerel, sardines), egg yolks, fortified dairy and plant milks, and UV-exposed mushrooms.

‍

Other Vitamins and Nutrients That May Affect Hair Health

If a deficiency is present, vitamin D is usually only one piece of the puzzle. And when researching vitamins for hair loss, a few other notable supplements may pop up, including:

• Iron: Ferritin (stored iron) levels below 30 ng/mL were associated with increased telogen effluvium in one study.
• Zinc: Involved in hair tissue growth and repair, zinc deficiency has been studied in connection with hair loss, while excessive zinc intake can also cause health problems, meaning it’s important to not supplement unnecessarily. 
• Biotin (Vitamin B7): Biotin is heavily marketed in hair growth supplements, yet evidence for improving hair growth in individuals without an underlying deficiency is limited, and biotin deficiency is uncommon.
• Vitamin B12: A deficiency, more common with plant-based diets or absorption issues, may also play a role.

Depending on your symptoms and medical history, a licensed provider may recommend laboratory testing to evaluate nutritional factors that could be relevant to hair loss. For more about specific hair growth supplements, see our guide about vitamins and nutrients for hair health.

‍

When Supplements Aren’t Enough (And What to Do Next)

Nutritional corrections address deficiency-driven shedding. But they may not address hair loss caused by androgenetic alopecia (the most common form of hair loss), alopecia areata, or other structural causes of follicle miniaturization.

If you’ve been supplementing for several months with no improvement, or your shedding follows a visible pattern (such as a receding hairline, thinning at the crown, or a widening part), there may be more at play. 

In either case, a licensed provider can help evaluate what’s going on. Provider-guided care for pattern hair loss may include prescription options such as oral minoxidil, oral finasteride (for men), or GHK-Cu foam, depending on your health profile and your provider’s clinical judgment. With Eden, we can connect you with a licensed healthcare provider who can evaluate your health information and determine whether treatment is clinically appropriate. Our process starts with a quick online intake.