How does Vitamin deficiency cause hair loss

Hair loss is devastating and anyone suffering from alopecia may be tempted to take it upon themselves and supplement their diet with vitamins and nutrients that are associated with hair growth. However, research indicates that not all supplements are effective in treating hair loss. For these reasons, it is highly recommended to seek a physician’s professional input on your condition so that a thorough analysis of your unique combination of causes of hair loss can be done. It is only after the underlying factors are well understood that an effective course of treatment can be charted.

Research has continuously linked hair loss to nutritional deficiencies within the body. Furthermore, different deficiencies have different consequences associated with them which all affect your hair growth. Sudden weight loss associated with decreased protein intake has been linked to acute telogen effluvium. On the other hand, niacin deficiency has been linked to diffuse alopecia, Overall, nutritional deficiency has been closely linked to chronic telogen effluvium, alopecia areata, and FHPL.

Female pattern hair loss (FHPL) is a common cause of hair loss in women. The condition affects more than 30% of women and carries with it a number of negative psychological consequences. Although it is common, research findings are still inconclusive on precisely what leads to the condition. Thus far, a number of biological and environmental factors have been linked to FPHL, including vitamin deficiencies. Because there are various reasons behind this condition, it is highly recommended that women go through a thorough examination to eliminate other factors and ascertain the most probable cause. It is critical to determine the correct course of action to treat this issue by getting to your doctor ASAP.

An in-depth examination of the link between vitamin deficiencies and hair loss is the first step to gaining a proper understanding of Vitamin Deficiency and how it relates to hair loss.

Summary of Vitamin Deficiency and Hair Loss

  • Iron: If anemia is present, hair loss could lead to Telogen effluvium, or Alopecia areata
  • Folic Acid (Folate): Rarely hair loss, but you may notice damaage to your hair, skin, and nails, but scentific links are not conclusive.
  • Zinc: Could assist with diminished hair growth, or speed of hair growth.
  • Niaicn (B3): It is thought to keep the skin and hair healthy.
  • Fatty acids: Including B-complex Biotin, and any deficiency could result in dermatitis, dry skin, dandruff and hair loss.
  • Selenium: This and other vitamins are thought to affect hair graying in young adults, Supplementing this could improve your hair color, however more than 400 Microgram could be toxic.
  • Vitamin D: Low levels of Vitamin D have been linked to the development of Alopecia areata (sudden hair loss)
  • Vitamin A: Not much is known, some data shows that consuming too much could lead to hair thinning.

Iron deficiency

Within the body, iron is a critical component in transporting oxygen from the lungs to the body. In fact, 75% of all iron in the body is for this purpose. It binds with hemoglobin found in red blood cells and gives red blood cells the ability to carry and transport oxygen. Iron deficiency is common in women since they experience menstruation. For menopausal women, iron deficiency can be an indication of internal iron loss or an inability of processing iron to a usable form. When you are deficient and you dont get enough iron into your diet, it can have a compounding effect over time.

Common symptoms associated with iron deficiency:
  • Extreme fatigue
  • Lack of concentration
  • Light-headedness
  • Weakness
  • Feeling breathless
  • Pale apperance
  • A weak immune system
  • Poor appetite
  • Lowered sex drive
  • iron deficiency can lead to anemia

Iron and Hair Loss

Iron deficiency without anemia is found in around 10 - 16% of females between 12 and 50. This is primarily caused by menstrual loss and pregnancy, and certain diets including going total vegan or vegetarian. The science between iron and hair loss is not well understood but it is believed to be the amount of ferritin which controls how iron is stored and released. Since our hair follicular cells are constantly dividing, and require a certain level of ferritin it is thought to play a role in abnormal hair growth.

Low iron levels can cause poor circulation of oxygenated blood to cells which are associated with stunted hair growth or thinning of hair. However, research on whether iron deficiency can cause hair loss is inconclusive. Where some research has found that it is related to various types of hair loss, others have found no significant links between the two. Because of this, it isn’t a requirement for doctors to screen for iron deficiency in patients with hair loss.

Although some may think that iron supplements or increased iron intake through dieting can help in reducing hair loss, it is a course of action not supported by medical literature. However, some clinical trials have found that treatment for hair growth is increased by treating iron deficiency. For women with hair loss, it is important to avoid taking iron supplements without consulting a physician. Without an appropriate diagnosis, you may inadvertently increase your iron levels beyond the healthy limit, causing other unexpected side effects.

Note: Other nutrients are needed to ensure that iron works effectively including : antioxidants, vitamins, calcium, omega 3 and amino acids. A diet rich in wholegrains, legumes, leafy green vegetables will provide you with adequate iron intake.


Zinc is a vital nutrient for the immune system and in facilitating enzyme activity in the body. Low levels of zinc have been found to be responsible for a broad range of physiological manifestations, including compromised immunity and physical growth, development of premature atherosclerosis (build-up of fatty cholesterol) as well as diminished hair regrowth.

Research has scarcely been able to clearly link zinc to hair loss. However, trials have found that zinc levels play a role in the rate of hair regrowth. Overall, zinc deficiency has been more frequently linked to alopecia areata and telogen effluvium. A number of studies have found patients with alopecia areata to have significantly lower levels of zinc compared to those without hair loss. A study also found that zinc levels are strongly correlated with the severity and chronicity of alopecia areata. In cases of TE, a study found that 9.6% of people with telogen effluvium had a zinc deficiency.

The success rate of using zinc supplements in combating hair loss are also mixed. In 1981, a study subjected individuals with alopecia areata to intake 220mg of zinc twice a day for three months. There were no significant improvements with that dosage. However, in 2017, another study administered 50 mg of zinc to individuals with alopecia for 12 weeks. The response to this dosage was positive, with observed hair regrowth in 60% of the subjects. In treating hair loss with zinc supplements, it is advised to first consult a doctor before taking on supplements as zinc toxicity is a potential negative side effect.

Vitamin A

Studies have found that consuming too much Vitamin A can lead to hair loss, one study which documented a 28 years old woman having renal dialysis was also suffering from hair loss, at the time she was taking vitamin A supplements (5000 International Units) which she stopped only to find her hair loss returned to normal. Another case of a 60 year old man suffering from non-scarring frontal alopecia was consuming 10,000 units of Vitamin A supplements per day

Vitamin D

Vitamin D is a fat-soluble vitamin, the majority of which is absorbed by the skin or through ingestion and activated by enzymes within the body for its use. It has been linked closely to the body immune system. Although understanding of the precise mechanisms through which vitamin D boosts the immune system is incomplete, research indicates that this nutrient is involved in immunoregulation and acts as an anti-inflammatory.

Findings also show vitamin D is involved in the active growth phase of hair (anagen) by observing the reactions of vitamin D receptors with keratinocytes on hair follicles. Furthermore, it is generally accepted in the medical community that vitamin D is related to hair loss and therefore having mandatory vitamin D screening for people with alopecia would be a good thing. In people with mutations in genes that regulate vitamin D receptors and those with rickets as a result of vitamin D deficiency, the lower vitamin D levels are responsible for total body and scalp alopecia as well as sparse body hair. This shows a clear relationship between vitamin D as a modulator and factor towards hair growth.

With regards to the different types of hair loss, vitamin D is closely linked to alopecia areata (AA) and androgenic alopecia. Due to the autoimmune nature of AA, researchers have discerned that vitamin D as an immune-modulator can be involved in moderating hair loss in AA. Therefore, low levels of the nutrient would be associated with hair loss. A 2014 study examined vitamin D levels in the form of serum 25(OH)D in patients with FPHL found 96.6% of those patients had insufficient or deficient levels of vitamin D and only 3.3% of patients had healthy levels. They further found that serum concentration was closely linked to the severity of hair loss.

Vitamin D deficiency alone isn’t enough to predispose a woman to alopecia. Research indicates that women with the genetic predisposition of vitamin D deficiency and FPHL are more at risk in developing alopecia. In contrast, women with only low levels of vitamin D and no genetic predisposition have a lower risk. Given the evidence, many doctors conduct a screening for vitamin D levels in patients with hair loss and go on to prescribe supplements as part of the treatment plan.

Vitamin E

There is very little research into Vitamin E and how it relates to hair loss, however Vitamin E is known to be an anti-oxidant which helps protect against free-radicals. A few scientists evauluated 15 patients with Alopecia areata (sudden patchy hair loss) and found slighly lower levels of Vitamin E in these patients as compared to normal healthy people without alopecia.


Selenium is an essential trace element which is a powerful antioxidant that is available in nuts, ham, pork, turkey and chicken. For most people thier normal diet should provide them with sufficient levels. Studies of six children were started on selenium therapy of 5–15 micrograms per day had found that alopecia had improved.

Selenium can also cause toxicity at certain levels which may cause nail brittleness, hair loss, fatigue, and irritability.

Amino acids and proteins

Amino acids and proteins are the most fundamental building blocks in cells. Amino acids serve as building blocks for proteins, which are essential to certain elements in the human body, including tissue building, hormone creation, fortifying the immune system, and providing essential cellular support. The body uses protein to make hair and nails, hence protein deficiency can be a critical indicator of hair loss.

Biotin, keratin, and collagen are key structural proteins in hair structure. They are what gives hair its hard top layer and flexibility. For biotin, keratin, and collagen to be produced, there must be healthy levels of amino acids to synthesize it. The key amino acids in keratin synthesis include lysine, arginine, cysteine, and methionine. Methionine and lysine can be sourced by a diet that includes these nutrients.

The lack of these essential amino acids and proteins is well known to affect hair and skin and has roots in genetic and environmental factors. A simple example is the skin and hair of malnourished children with kwashiorkor marasmus conditions. Their hair tends to be fine and scarce as a result of the lack of appropriate nutrition.


Biotin (known as vitamin B7) has long been praised for its benefits towards healthy hair and nails although there is not much evidence to back this up. You would be called deficient if you had a level of less than 200 ng/L (nanograms per liter). A few clever research papers showed that there were 18 reports of improved hair and nail growth after taking biotin supplements. It seems that unless you have a known deficiency of biotin, you would not really benefit from taking any supplements.

Signs for deficient levels of proteins and amino acids include hair loss, brittle nails, and skin rashes. Biotin and lysine are often recommended as a supplement to combat these symptoms and it has been found to be effective. A 2002 double-blind study on women with a high amount of hair shedding supplemented them with lysine and iron therapy to reduce the shedding. The intervention was effective, with the majority of women showing reduced levels of shedding as a result of the therapies.

Another research analyzed 18 cases of biotin use for hair and nails in patients with alopecia. They found that those who had an environmentally induced biotin deficiency responded quicker to biotin supplements while those with genetic predispositions took longer to respond, but still showed positive results.

Omega 3&6

Omega 3 are a group of fatty acids usually found in fish like herring or salmon, while Omega 6 are another type of polyunsaturated fat found in nuts and seeds. Taken in harmony they can be beneficial towards maintaining a healthy head of hair. A study was conducted on 120 healthy female patients who were given a supplementation of omega 3 and 6, after 6 months they found hair that hair density had improved.


Folate is part of the Vitamin B family, which is also called folic acid when it comes as a supplement. Adults are advised to get 400 mcg of folate per day but no more than 800 since some people may not tolerate that much. When you are deficient in folate you may notice damage to your hair, skin, and nails. Research has been conducted into the amount of folate and B12 levels in patients with Telogen effluvium, and only 2.6% of them were lacking vitamin B12 but none were folate deficient.


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