The Connection Between MTHFR And Hair Loss

The MTHFR gene provides instructions for an enzyme that converts 5,10-methylenetetrahydrofolate into 5-methyltetrahydrofolate or 5-MTHF - the principal form of folate used to convert homocysteine into methionine. Common MTHFR variants, particularly C677T, can reduce this enzyme’s activity.¹ However, having an MTHFR variant does not automatically cause folate deficiency or hair loss; its effects depend partly on folate intake, vitamin B12 status and other health factors. People with the 677TT genotype may be more likely to have elevated homocysteine when their folate status is low.

Folate supports the production of DNA and RNA and is therefore important for normal cell division. Because cells in the hair follicle have a high turnover rate, inadequate folate could theoretically interfere with normal follicle activity.² Severe folate deficiency may also cause megaloblastic anemia, potentially affecting oxygen and nutrient delivery to growing tissues. These mechanisms provide a biologically plausible connection between low folate and hair loss, but they do not prove that folate deficiency is a common cause of hair shedding.

Clinical findings remain mixed. A small number of studies have found lower red blood cell folate levels in people with alopecia areata, while other studies have found no meaningful difference in folate levels between affected individuals and healthy controls. In one study of 973 people with telogen effluvium, only 2.5% of those tested had folate deficiency and folate levels were not significantly associated with the proportion of actively growing hairs.³ Another study of 115 patients with telogen effluvium found no cases of folate deficiency.⁴

Research directly examining MTHFR and hair loss is even more limited. One Turkish case-control study found that the C677T variant was more common among people with alopecia areata, but this isolated association does not establish that the variant caused their hair loss or that the finding applies to other populations or types of alopecia.⁵

Overall, MTHFR variants and low folate status may contribute to hair loss in some individuals, but neither should be assumed to be the cause. People experiencing hair loss should consult a healthcare professional and consider appropriate testing before taking folic acid, methylfolate or other folate supplements. Hair loss has many possible causes and taking high-dose folate without identifying the underlying problem may be unnecessary and may make it difficult to diagnose vitamin B12 deficiency.

The potential benefits of methylfolate for hair are indirect. If a person has a confirmed folate deficiency or a folate-related abnormality contributing to anemia or impaired cell division, restoring adequate folate status may help support normal hair follicle function. Methylfolate may be considered for some people with reduced MTHFR activity; however, carrying an MTHFR variant alone does not establish a need for methylfolate or mean that supplementation will improve hair growth.

Methylfolate has not been established as a treatment for hair loss.⁶ Available studies have primarily measured folate levels in people with conditions such as telogen effluvium and alopecia areata rather than testing whether methylfolate supplementation stimulates hair growth. In one large study of people with telogen effluvium, folate deficiency was uncommon and folate levels were not significantly associated with the proportion of actively growing hairs.⁷

People considering methylfolate for hair growth should first discuss appropriate testing with a healthcare professional. Folate and vitamin B12 status should be evaluated together, while other possible causes - including iron deficiency, thyroid disorders, hormonal changes, illness, medications, stress and inadequate protein intake - should also be considered. Methylfolate is most likely to be relevant when a genuine folate-related abnormality has been identified, rather than as a general hair-growth supplement.

Folate is needed for DNA synthesis, cell division and healthy red blood cell production. Because hair follicles contain rapidly dividing cells, adequate folate status is biologically important for maintaining normal hair growth. However, this does not mean that taking additional folate for hair growth will make hair grow faster or prevent hair loss when folate levels are already adequate.

Research examining folate and hair loss has produced inconsistent results. Some small studies have reported lower red blood cell folate levels among people with alopecia areata. However, other studies found no significant differences between affected individuals and healthy controls. In a study of 973 people with telogen effluvium, folate deficiency was present in only 2.5% of those tested and folate levels were not significantly associated with the proportion of actively growing hairs.⁸

A 2024 randomized, placebo-controlled study evaluated a supplement containing folic acid, biotin, vitamin B12, zinc, para-aminobenzoic acid (PABA) and Fo-ti in 65 women with thinning hair. After six months, hair density increased by 10.1% in the supplement group, compared with a 2% decrease in the placebo group. Participants also reported improvements in shedding and hair quality. However, because the supplement contained several active ingredients, the findings cannot be attributed specifically to folate.⁹

Therefore, folate may support normal hair follicle function when an actual deficiency exists, but it has not been established as a general hair-growth treatment. Correcting folate deficiency-related hair loss may address one possible contributing factor, although improvement cannot be guaranteed because hair loss is often influenced by several nutritional, hormonal, medical and genetic factors.

Folic acid is the synthetic form of vitamin B9 used in many supplements and fortified foods. The body converts it through several enzymatic steps into folate forms involved in DNA synthesis, cell division and red blood cell production. Although these functions are relevant to normal hair follicle activity, they do not establish folic acid as a hair-growth treatment.

Does folic acid help with hair loss? It may be beneficial when a confirmed folate deficiency is contributing to anemia or poor nutritional status. Correcting the deficiency may help restore the conditions needed for normal hair growth. However, there is no strong clinical evidence that folic acid stimulates new hair growth, accelerates hair growth or reverses thinning hair in people with adequate folate levels.¹⁰

Common MTHFR variants may reduce the efficiency of producing 5-MTHF, but they do not mean that a person cannot process folic acid. Whether folic acid, methylfolate or another form is appropriate should be based on nutritional needs, laboratory findings, tolerance and professional guidance - not on an MTHFR result alone.

People should be cautious about taking high-dose folic acid for hair loss without medical advice. Large amounts of folic acid may correct the anemia caused by vitamin B12 deficiency while allowing associated neurological complications to remain undetected. Folate and vitamin B12 status should therefore be evaluated together, especially before using a high-dose supplement.

Folinic acid, also known as 5-formyltetrahydrofolate, is a reduced form of folate commonly supplied as calcium folinate.¹¹  Unlike folic acid, it does not require reduction by the DHFR enzyme before entering the body’s active folate pool. It can contribute to folate-dependent processes such as nucleotide synthesis and cell division, which are important for normal hair follicle function.

However, there is no direct clinical evidence that taking folinic acid for hair growth stimulates new hair production, prevents shedding or reverses thinning hair. Its potential benefits are indirect and most relevant when inadequate folate status is contributing to nutritional or hematological abnormalities.

Although folinic acid bypasses DHFR, its conversion into 5-MTHF still requires an MTHFR-dependent step. It should therefore not be described as completely bypassing MTHFR. Folinic acid may provide a useful non-methylated folate option for people seeking an alternative to folic acid or methylfolate, although it has not been specifically studied as a treatment for hair loss.

Hair loss is multifactorial and low folate or an MTHFR variant is only one possible consideration. Before attributing hair shedding to folate metabolism, other common causes should be evaluated.

Possible causes include:

• Hereditary hair loss: Male- and female-pattern hair loss commonly causes gradual thinning and often runs in families.
• Hormonal changes: Pregnancy, childbirth, menopause and conditions that affect androgen levels may alter the normal hair-growth cycle.
• Physical or emotional stress: Major illness, high fever, surgery, severe emotional stress or rapid weight loss can trigger telogen effluvium, causing increased shedding several months later.
• Nutritional deficiencies: Inadequate iron, protein, zinc, vitamin D, vitamin B12 or folate may contribute in some individuals. However, supplementation is most appropriate when a deficiency or inadequate intake has been identified.
• Thyroid and other medical conditions: Both an underactive and an overactive thyroid can cause thinning hair. Autoimmune diseases and other systemic conditions may also affect hair growth.
• Alopecia areata: This autoimmune condition occurs when the immune system attacks hair follicles, frequently causing round or patchy areas of hair loss.
• Scalp conditions: Fungal infections, psoriasis, severe dermatitis, inflammation and scarring alopecias can damage hair follicles or interfere with hair growth.
• Medications and medical treatments: Chemotherapy is a well-known cause, but other medications can also contribute to hair shedding. Medication should not be discontinued without consulting the prescribing professional.
• Hair-care practices: Tight braids, ponytails, extensions, repeated chemical treatments and excessive heat can damage hair or cause traction alopecia.
• Aging: Hair growth naturally slows with age and individual strands may become finer.
  
  

Persistent, sudden, patchy or rapidly worsening hair loss should be evaluated by a healthcare professional or dermatologist - particularly when it occurs with scalp pain, redness, itching, scaling, sores, or loss of the eyebrows or eyelashes. Taking multiple supplements without testing may not address the cause and excessive amounts of certain nutrients, including selenium and vitamins A and E, may worsen hair loss.