Losing your hair is a common and stressful experience. There are many supplements out there that claim to restore hair strength and growth. But it can be confusing to know which ones to take, or if they actually work. And the research around supplements and hair growth is often conflicting. Here, we dive deeper into the vitamins and mineral deficiencies linked to hair loss, how to know if you have one of these deficiencies, and whether you should consider a supplement.
Key takeaways:
- Several different vitamin and mineral deficiencies can cause hair loss. Examples include vitamin D, vitamin B, iron, and zinc.
- If your hair loss is due to vitamin deficiency, supplements may help restore hair growth.
- When taking a supplement for hair loss, it’s important to stick to the recommended amount. Taking too much can sometimes cause harmful side effects, and even worsen hair loss.
1. Vitamin D
Vitamin D plays a lot of different roles in the body. It helps bone growth, supports muscle and nerve function, and strengthens your immune system.
Vitamin D and hair loss
When vitamin D binds to its receptor in the body, it stimulates hair growth. When people have a genetic mutation in their vitamin D receptor, they have less body hair. And may not have any hair on their scalp or their body.
When people have androgenic alopecia — sometimes called male pattern baldness — researchers found that the severity of hair loss was worse if they had lower levels of vitamin D. Their findings also suggested that vitamin D deficiency led to this type of alopecia sooner.
Another study showed similar results in people with alopecia areata, another condition that causes hair loss. Their findings suggested that vitamin D deficiency may both cause and/or worsen hair loss in people with alopecia areata.
But not all the research agrees. A review of 14 studies found that vitamin D levels were lower in people with alopecia — but their vitamin D level didn’t correlate with the severity of hair loss. And another study found no relationship at all between vitamin D level and the development or severity of alopecia.
Most scientists agree that more research is needed to know if vitamin D supplements make a big difference in preventing hair loss. But if you’re experiencing hair loss, measuring your vitamin D level may still be useful to know if supplementation may help.
Other symptoms
Other symptoms of vitamin D deficiency include:
- Muscle aches
- Bone pain
- Weakness and fatigue
- Depressed mood
- Slow wound healing
- Changes in memory or concentration
In general, it takes several months of low vitamin D to experience symptoms.
Risk factors for deficiency
You’re most likely getting enough vitamin D from sun exposure and the foods you eat. You are more likely to have low levels of vitamin D if you:
- Spend little to no time in the sun
- Have darker skin
- Have conditions that decrease the absorption of vitamin D (such as inflammatory bowel disease)
- Are older, since your body makes less vitamin D as you age
- Have had gastric bypass surgery
- Have a larger body
How much vitamin D do you need a day
The recommended daily allowance (RDA) of vitamin D for adults (ages 19 to 71 years old) is 600 IU.
You can boost your vitamin D levels by:
- Spending time in the sun. Skin makes vitamin D when it’s exposed to sunlight. But still be sure to wear sunscreen with SPF 30 or higher.
- Drinking beverages with vitamin D added. Examples include fortified milk (cow, almond, oat, and soy milk), as well as orange juice.
- Eating foods rich in vitamin D. These include foods like fatty fish, egg yolks, and mushrooms.
You can also ask your primary care provider for a blood test to check your level. If it’s low, they may recommend a supplement.
2. Vitamin B2 (riboflavin)
Vitamin B2, also known as riboflavin, helps your body turn food into energy. It also helps your hair and skin cells grow.
Riboflavin and hair loss
It’s uncommon in the U.S. to have riboflavin deficiency. But still, low levels may lead to hair loss. Further research on riboflavin and hair loss is fairly limited. So it’s unclear if supplements would help restore hair growth.
Other symptoms
Other symptoms of riboflavin deficiency include:
- Swollen or cracked lips
- Fatigue
- Feeling depressed
- Sore throat
- Blurry vision
Risk factors for deficiency
People are at higher risk of riboflavin deficiency if they:
- Don’t eat dairy or eggs
- Follow a vegan diet
- Are nursing
- Are born with a rare condition that prevents the body from absorbing riboflavin
How much riboflavin do you need a day?
Forriboflavin, the RDA is:
- 1.1 mg for women
- 1.3 mg for men
Your body can absorb 27 mg at one time, so taking more than the recommended amount shouldn’t cause any harm.
3. Vitamin B3 (niacin)
Vitamin B3, also called niacin, is another B vitamin that’s important for metabolism. It supports your brain, gut, and immune system health.
Niacin and hair loss
Low levels of niacin are also rare in the U.S. But if you don’t get enough, you may develop a condition known as pellagra, which can cause hair loss.
Other symptoms
If you’re deficient in niacin, you may experience:
- Abnormal tanning when exposed to the sun (your skin can turn a dark red or brown)
- A rough feel to your skin or looking sunburnt
- Bright red tongue
- Gastrointestinal symptoms (vomiting, constipation, diarrhea)
- Headache
- Fatigue
- Trouble remembering things
Risk factors for deficiency
You may be more likely to have low levels of niacinif your diet is low in iron, riboflavin, or pyridoxine (vitamin B6). Your body needs all three to make niacin.
Other common conditions that increase the risk of niacin deficiency are:
- HIV
- Liver cirrhosis
- Alcohol use disorder
- Inflammatory bowel disease
- Anorexia
How much niacin do you need a day?
For niacin, the RDA is:
- 14 mg for women
- 16 mg for men
The upper daily limit is 35 mg. Too much niacin can be toxic and lead to:
- Decreased blood pressure
- Increased blood sugar
- Red, burning, itchy skin
- Increased bruising
- Headaches
- Blurry vision
- Dizziness
- Fatigue
- Liver problems
4. Vitamin B7 (biotin)
Vitamin B7, often referred to as biotin, helps your body turn food into energy. It also supports skin and hair health.
Biotin and hair loss
There’s a lot of information online about biotin supplements for hair growth. But no large studies explore if this will help for most people. Most research suggests that unless you have a known cause of biotin deficiency, it’s unlikely to help.
Other symptoms
If you have low levels of biotin, you may develop:
- A scaly, red rash around the mouth
- Nausea and vomiting
- A tingling feeling in your arms and legs
- Red, itchy eyes
Risk factors for deficiency
If you eat a balanced diet, it’s very unlikely you have low levels of biotin. Causes include:
- Rare genetic conditions
- Parenteral nutrition (a type of nutrition that goes through an IV)
- Long-term use of certain seizure medications or antibiotics
Almost everyone in the U.S. gets enough biotinthrough the foods they eat. Conditions that decrease your biotin levels include:
- Alcohol use disorder
- Pregnancy
- Nursing
How much biotin do I need in a day?
For biotin, the RDA is 2.4 mcg for adults. Doses larger than this haven’t been shown to cause any harm.
If you decide to take biotin supplements, be sure to discuss this with your primary care provider. Biotin supplementation can interfere with tests that look for thyroid and heart problems, as well as blood tests used to confirm pregnancy.
5. Vitamin A
Vitamin A is an antioxidant that plays a key role in several body systems, like your vision, immune system, and skin.
Vitamin A and hair loss
For most people, hair loss is unlikely due to their vitamin A levels. Most people don’t have a deficiency. But in rare cases, if you do have low levels of vitamin A, it can cause your hair to become brittle and weak. This makes it more likely to fall out.
Other symptoms
Other symptoms of vitamin A deficiency include:
- Difficulty seeing in the dark
- Frequent lung infections (pneumonia)
- Frequent urinary tract infections
- Fatigue
- Digestive problems, like diarrhea
- Small, rough bumps on your skin (most often on the shoulders or butt)
Risk factors for deficiency
If you have a condition that interferes with the absorption of vitamin A, you may be at higher risk of a vitamin A deficiency. This includes:
- Crohn’s disease
- Cystic fibrosis
- Ulcerative colitis
- Celiac disease
But vitamin A deficiency is otherwise rare in people who have a balanced diet.
How much vitamin A do you need a day
The RDA of vitamin A is:
- 700 mcg of retinol activity equivalents (RAE) for women
- 900 mcg RAE for men
There are two main sources of vitamin A:
- Preformed (active) vitamin A: This form of vitamin A is immediately available to the body. It’s found in animal products like dairy, eggs, fish, and organ meat like liver. In dietary supplements, you may see preformed vitamin A listed as retinyl palmitate or retinyl acetate.
- Provitamin A carotenoids: Your body turns these compounds into active vitamin A. They’re found in plant-based products, like fruits and vegetables. There are different types of carotenoids, depending on the food you eat or supplement you take. The most common carotenoid found in supplements is beta-carotene.
Some supplements contain only preformed vitamin A. Others contain only provitamin A carotenoids. And some contain both.
The daily upper limit of preformed vitamin A is 3,000 mcg. And this includes the amount of preformed vitamin A you’re getting from any source — whether it’s food or supplements. But a person is unlikely to get too much preformed vitamin A through diet alone. This usually only happens with supplements.
Taking too much preformed vitamin A can be harmful and may lead to:
- Headaches
- Blurry vision
- Dizziness
- Muscle aches
- Nausea
There’s no limit to the amount of provitamin A carotenoids you can have in a day. But you may see some changes if you do consume a high amount. For example, if you eat a lot of carrots, your skin may turn an orange color. But this isn’t dangerous (and goes away after you eat fewer carrots).
6. Vitamin E
Vitamin E is an antioxidant that helps support your immune system, nerve function, and it even helps prevent abnormal blood clotting.
Vitamin E and hair loss
The connection between vitamin E and hair loss remains controversial. One study found that in people with alopecia, vitamin E levels are lower. But another study showed no difference in vitamin E levels between people with and without alopecia. So more research is needed here.
Other symptoms
Signs of vitamin E deficiency can be subtle. Symptoms include:
- Not being able to see clearly in the dark
- Decreased reflexes
- Muscle weakness
- Loss of feeling in your arms and legs
Risk factors for deficiency
Certain conditions that affect fat absorption may lead to low vitamin E levels. This is because vitamin E requires fat to be absorbed by the body. Examples include:
- Cystic fibrosis
- Crohn’s disease
- Rare genetic diseases, like abetalipoproteinemia
- Short bowel syndrome
How much vitamin E do you need a day
It’s recommended that adults get 15 mg of vitamin E daily. Most people who eat a balanced diet get enough vitamin E.
There are two kinds of vitamin E:
- Natural vitamin E (d-alpha-tocopherol)
- Synthetic vitamin E (dl-alpha-tocopherol)
Natural vitamin E can be found in foods like nuts, sunflower seeds, vegetable oils, and green vegetables. Supplements can be made with natural or synthetic vitamin E.
Some supplements list vitamin E in IU instead of mg. In this case, 15 mg of vitamin is equal to:
- 22 IU of natural vitamin E
- 33 IU of synthetic vitamin E
There’s no upper limit for how much vitamin E you can take. But very high doses can increase the risk of bleeding, so it’s suggested that adults take no more than 1,000 mg per day. This is equal to 1,100 IU per day of synthetic vitamin E or 1,500 IU of natural vitamin E.
Large amounts of vitamin E may be harmful in other ways, too. One study found that men who took 400 IU of vitamin E had an increased risk of prostate cancer.
7. Iron
Iron is a mineral that helps your body produce red blood cells. This is why people with low blood counts — called anemia — often need iron supplements.
Iron and hair loss
In general, the medical community agrees that hair loss is a known symptom of iron deficiency. But if you dive into the research a little deeper, study results don’t always find a convincing link.
Several studies have suggested that iron deficiency plays a role in hair loss. More specifically, research has suggested that people with hair loss from stress (also called telogen effluvium) are more likely to have iron deficiency. But another study found no difference in iron levels between women with hair loss and those without it.
When it comes to other causes of hair loss, one review found that women with alopecia were more likely to have low ferritin — a condition that’s often the first sign of iron deficiency. A different review found no relationship between iron deficiency and alopecia.
And yet another study showed that iron deficiency was more common in premenopausal women who had female pattern hair loss.
So, it’s still very unclear how iron deficiency contributes to hair loss.
Other symptoms
Other symptoms of low iron levels include:
- Increased fatigue
- Difficulty concentrating
- Trouble remembering things
- Feeling very hot or very cold
Risk factors for deficiency
Risk factors for iron deficiency include:
- Women older than 50 years
- Women with heavy menstruation
- Pregnancy
- Following a vegetarian or vegan diet, because many iron-rich foods are animal products
- Any condition that causes ongoing blood loss, such as inflammatory bowel disease
- A surgery that causes you to absorb less iron, like gastric bypass surgery
- Taking medicines that increase the likelihood of bleeding, like nonsteroidal anti-inflammatory drugs (NSAIDs)
How much iron do you need daily
Your daily iron needs depend on whether you eat a plant-based or animal-based diet. It also varies based on age and sex. The recommended daily amounts for people who eat animal products are:
- 18 mg for women 19-50 years old (the RDA is higher because of menstruation)
- 8 mg for men 19-50 years old
- 8 mg for all adults 51 years and older
If you don’t eat animal products, then you should get twice the numbers listed above. This is because it’s harder for your body to absorb iron from plant sources. So, for example, a 19-year-old woman who follows a vegan diet should get 36 mg of daily iron.
It’s important to stick to the recommended amounts. In very large doses, iron can be harmful, since the body isn’t able to break it down. This can lead to iron overload, where the extra iron builds up in organs like the heart and liver and damages them.
The upper limit of all sources of iron is 45 mg for adults ages 19 years and older.
8. Zinc
Your body uses zinc to heal wounds, keep skin healthy, boost your immune system, and support your metabolism.
Zinc and hair loss
Like iron, research is mixed on the link between zinc deficiency and hair loss.
Several studies have found that people with alopecia are more likely to have low zinc levels. They also showed that supplementing with zinc improved their hair growth. But others have shown no relationship between zinc levels and the likelihood or severity of alopecia.
The research on people with other causes of hair loss is also murky. For example, one study showed that people with telogen effluvium had worse hair loss if their zinc was low. And another study found no difference in zinc levels between people with the condition and those without it.
Other symptoms
Symptoms of zinc deficiency include:
- Loss of smell
- Loss of taste
- Poor wound healing
- Problems thinking clearly
- Trouble remembering things
How much zinc do you need a day
If you’re eating a well-balanced and varied diet, you’re probably getting enough zinc. Adults need 11 mg of zinc daily. Certain people may need zinc supplements if they:
- Have a history of stomach or weight-loss surgery
- Have conditions that decrease zinc absorption, like Crohn’s disease or ulcerative colitis
- Don’t eat meat, since this is a good source of zinc
- Frequently drink alcohol, since alcohol decreases zinc absorption
- Are pregnant or nursing, to support the growth of their baby
If you’re curious if you have zinc deficiency, talk with your primary care provider about checking your level with a blood test.
If you need to supplement zinc, avoid taking more than 40 mg daily, which is the upper limit. Too much zinc — even in the short-term — can cause:
- Stomach upset (nausea, vomiting)
- Decreased appetite
- Headaches
- Dizziness
Can taking too many vitamins cause hair loss?
If you take too much of certain vitamins and minerals, it can lead to hair loss. In particular, these include:
- Vitamin A
- Vitamin E
- Selenium
So, always be mindful of how much supplementation you’re taking. You’ll want to be sure you’re meeting daily allowances and not going above the recommended upper limit.
The bottom line
If you’re eating a balanced diet, it’s unlikely for you to develop a vitamin or mineral deficiency. But if you notice that your hair is thinning or shedding, it’s worth considering the possibility of a nutritional deficiency. The first step is to discuss your symptoms with your primary care provider. Many of these vitamins and minerals can be checked with a blood test. This is the best way to know if you should consider supplements, and if these supplements will help restore hair growth.
By Cherilyn Davis, MD, a board-certified pediatrician in New York City. She has held local and national roles at the American Medical Women’s Association including board member of the physician division and physician chair of social media.
