Folic Acid For Hair Loss – Treatment and Results

  • Medically reviewed by: Dr. Anil Simhadri
  • Written by: William Slator
  • Last updated: 28/12/2023

It is possible for a diet low in vitamins and minerals to have negative effects on hair growth. In terms of long-term nutrient deficiencies, you may even begin to notice hair breakage, thinning, and hair loss.

One nutrient deficiency that may trigger hair loss is vitamin B9.

This guide will introduce you to vitamin B9, more commonly known as folic acid. This will include a look at its role in the body and the health problems that may result from a deficiency.

What is Folic Acid?

Folic acid (FA), also known as vitamin B9, folacin, or pteroyl-L-glutamic acid, is one of the B vitamin complexes. Folic acid becomes bioactive for the body when it is metabolized by the liver, which converts it into dihydrofolic acid.

The body is not able to create folate, or vitamin B9, on its own; it needs to receive folate via the diet, or folic acid via supplementation. Folate is found naturally in many foods:

  • all cruciferous vegetables
  • spinach
  • avocado
  • beans
  • legumes
  • nuts
  • peas
  • citrus fruits including oranges, lemons, grapefruits
  • bananas

A serious deficiency is rarely found in the body. However, people often choose to take this vitamin as a supplement because the natural vitamin B9 that occurs in food can be damaged by a high temperature when food is cooked.

Many people take vitamin B9 supplements to boost the growth and condition of their hair, skin, and nails because the vitamin is required for the creation and repair of DNA, the coding of proteins, and the synthesis of new cells and tissues.

Vitamin B9 deficiency can compromise the health of the hair and skin and cause several conditions such as anemia, chronic diarrhea, or more serious cognitive and neurological issues and birth defects when a serious deficiency is maintained long-term.

Folic Acid Versus Folate

The terms ‘folic acid’ and ‘folate’ are often used interchangeably. However, they are two distinct terms.

In its natural form, such as found in leafy vegetables, vitamin B9 is known as folate. But when taken supplementally, this B vitamin is folic acid.

Aside from the difference in sources and names, there is also a difference in human metabolism.

When folate-rich foods are consumed, the majority of folate is converted to the active form of vitamin B9, levomefolic acid, or 5-methyltetrahydrofolate (5-MTHF). This is an efficient process, which means your body reaps the benefits more quickly and more fully.

On the other hand, folic acid cannot be converted within the digestive system (1). Instead, it must be metabolized within the liver which is inefficient and time-consuming (2). This means it is best to get your vitamin B9 from natural food sources. You should only rely on supplemental folic acid if necessary.

5-MTHF is an important precursor for the methylation cycle which is involved a wide range of crucial bodily functions, including (3):

  • Immune function
  • Maintaining DNA
  • Energy production
  • Mood balancing
  • Controlling inflammation

Some people have polymorphisms (changes) in the gene for MTHFR which means they cannot metabolize folic acid to its active form 5-methyltetrahydrofolate (5-MTHF) efficiently. For these people, it is safer to take folate from natural foods or take 5-MTHFR supplements.

So, what about folate for hair growth?

When speaking of folate deficiency and hair growth, it is often recommended that you supplement with folic acid.

What Causes Vitamin B9 Deficiency?

There are three main causes of vitamin B9 deficiency in adults.


A diet low in leafy greens and legumes is likely to be lacking in vitamin B9. Assuming there are no other reasons for a poor diet such as a medical condition such as Inflammatory Bowel Disease, this is the easiest cause of folate deficiency to resolve without medical intervention.

Medical Conditions

The most common cause of folate deficiency in adults with an otherwise balanced diet is medical conditions that cause poor nutrient absorption.

Folate is absorbed in the small intestine (4). But certain gastrointestinal conditions can make absorption difficult, if not nearly impossible. Medical conditions like Celiac and Chron’s can lead to significant damage to the walls of the intestines which, over time, decreases nutrient absorption. Unfortunately, these conditions can often go undiagnosed for years which increases the odds of permanent intestinal damage.

The solution for these individuals is to take a folic acid supplement, or a B-vitamin complex, regularly.


Some drugs can reduce the absorption of vitamins and minerals in your diet. The following are medications that may limit the absorption of vitamin B9 in its natural form (folate) in your body (5):

  • Anti-inflammatory (Non-steroidal) pills (abbreviated to NSAIDs) including Ibuprofen and Naproxen.
  • Sulfasalazine: A medication that is used to treat inflammatory disease of the bowel (IBD).
  • Antacids, H2 Blockers, and Proton Pump Inhibitors: These are substances, which neutralize the acidity within the stomach.
  • Bile Acid Sequestrants: These are substances that reduce cholesterol.
  • Anti-seizure medications.
  • Diuretic medications such as Triamterene, or Dyrenium.
  • Some antibiotics such as Trimethoprim; this is an antibiotic, which is commonly prescribed to cure an infection of the urinary tract; and Cycloserine.

If you take any of the above medications, speak with your doctor about regular blood draws to monitor your B vitamin levels.

If supplementation with folic acid is necessary, keep in mind that folic acid can interfere with the efficacy of other medications. These include:

  • Tetracycline: This is an antibiotic. Folic acid disturbs the metabolism of tetracycline and therefore reduces the absorption of this antibiotic by the body, which lowers its effectiveness. This is true for all of the B-complex vitamin supplements.
  • Phenytoin: This is an anti-seizure treatment, also known as Dilantin, which is affected by folic acid supplements. Taking folic acid along with phenytoin can increase the risk of seizures.
  • Pyrimethamine: This medication, also known as Daraprim, is used as a preventive treatment of malaria and as a treatment for toxoplasmosis. Folic acid can reduce the effectiveness of this medication.
  • Chemotherapy medications: For patients who are currently taking chemotherapy treatment they must consult with their oncologist before they take any supplements. Folic acid, in particular, can increase the levels of Capecitabine (also known as Xeloda) and 5-fluorouracil to dangerous levels within the body.

Before your doctor prescribes any of the above medications, you must disclose the supplements you are currently taking.

How Does Vitamin B9 (Folate) Deficiency Affect Hair Growth?

The effects of B9 deficiency are similar to that of iron deficiency and low ferritin levels.

When folate is deficient in the body, the structure of red blood cells is affected and this structural change renders them unable to transport an adequate supply of oxygen and nutrients around the body.

This can lead to anemia, but also hair loss, because healthy blood cells are required to transport the level of oxygen and nutrients that are required to produce ATP (adenosine triphosphate) within the cells within the scalp (6).

ATP is a nucleoside triphosphate that carries chemical energy around the cells and plays an important part in cell growth.

When oxygen and nutrient levels are low, the cells will require another source of energy to produce ATP, which can increase the body’s production of testosterone. In this process, testosterone is converted to DHT (dihydrotestosterone) and this is known to cause androgen-related hair loss (7).

Low levels of B9 in the body cause important cellular processes to decline, which slows down the rate of cell division and hinders the growth of new cells. This means new hairs cannot be produced quickly enough to replace the hair strands that have broken or fallen out.

Chronic deficiency of folate ultimately leads to the death of the hair cells.

Other important cells in the scalp are also affected by B9 deficiency, particularly oil-secreting cells and papilla cells. These play an important role in maintaining scalp health and in the production of new hairs and the regulation of the hair growth cycle, respectively (8).

A lack of folate can also cause megaloblastic anemia, which results in premature graying of the hair due to structural changes within the red blood cells.

Para-Amino Benzoic Acid (PABA) is a substance in folic acid that is sometimes taken as a supplement to reverse greying hair.

How Does This Vitamin Promote Hair Growth?

There are quite a few ways that folate/folic acid is believed to promote hair growth. Here are just a few (9):

  • Vitamin B9 plays a vital role in the growth of cells and tissues of all types. Not just the hair cells, but also cells within the nails, skin, and internal organs. B9 is required for the division and regeneration of cells that are responsible for hair growth.
  • Folate/Folic acid works in conjunction with other vitamins, including vitamin B12 (biotin) and vitamin C, to assist the body in the synthesis, breakdown, and metabolism of proteins. Hair is composed entirely of protein.
  • Folate is required for some critical methylation processes in the body, including the manufacture and maintenance of RNA, DNA, and proteins. These are the building blocks of healthy hair.
  • Folate is important for healthy blood flow because it’s used in the formation of red blood cells. When folate levels are adequate, the blood cells are well-formed and thus able to transport the required amount of nutrient and oxygen-rich blood to the scalp. This is then used for the critical cell processes that improve the quantity and quality of hair growth.

As you can see, vitamin B9 plays a major role in many bodily functions. But are there any scientific studies to back up its benefits for hair?

Animal Studies Into Folic Acid And Hair Growth

There are limited animal studies on vitamin B9 supplementation in the promotion of hair growth. However, one study does offer hope.

Study: Folic acid therapy for alopecia in a Charolais calf (1988)

Researchers from Ontario Veterinary College in Canada conducted a study that involved folic acid therapy on a Charolais bull calf (10).

The three-week-old calf had a “history of progressive hair loss and clinical signs, including crusts and brown patches similar to those in folic acid deficiency syndrome in man.”

To test the theory that vitamin B9 deficiency was at play, the researchers treated the calf with 1 mg/kg/day of an oral folic acid supplement.

Within two weeks, the researchers noted a gradual disappearance of the crusting and brown patches. And within two months, there was a steady growth of hair.

As concluded by the researchers, “folic acid … may serve as an effective therapeutic agent in some types of alopecia triggered by a deficiency of either folic acid or the co-enzymes involved in the synthetic pathway of DNA.”

Does the lack of further studies on the topic mean that folate is not important for hair growth?

Absolutely not!

It would be nice, however, for more in-depth studies to be performed on the subject.

How Much Vitamin B9 Is Enough?

When determining your nutritional needs, the amount of vitamin B9 will depend on various factors.

The recommended daily amount of vitamin B9 for adults is 400 micrograms (11). For women who are pregnant or planning to become pregnant, the recommendation increases to between 400 and 800 micrograms.

The majority of vitamin B9 should be in the form of folate which you will find in foods like spinach, avocado, and citrus fruits. From there, you can use a folic acid supplement to fill the gap.

What to Look for in a Folic Acid Supplement

If you are unable to get enough folate in your diet, then a folic acid supplement is essential to your health. What should you look for in a folic acid supplement?

For best results, a multivitamin is best.

If you suffer from a vitamin B9 deficiency, the chances are higher for other vitamin and mineral deficiencies to also exist. One commonly linked deficiency is vitamin B12 (12).

Vitamin B12, or cobalamin, is essential to the production of red blood cells just like B9. The symptoms of vitamin B9 deficiency are very similar to those of vitamin B12 and, as such, it is common to have one deficiency misdiagnosed as the other.

In addition, treating a deficiency of vitamin B9 can mask the symptoms of a B12 deficiency without treating it. This can lead to serious health complications down the line.

The solution is to supplement with both vitamin B9 and B12.

As folic acid and cobalamin are both essential to overall health, as well as hair growth, you can easily find this combination of vitamins in supplements. If you are having trouble, then take a look at vitamin products aimed at hair growth as these will often include the pair.

Other vitamins to consider in your multivitamin are niacin (B3), iron, and biotin (B7).

If you will be taking a B9 supplement long-term (three months or longer), then consider taking a B-complex vitamin as well. This will ensure that your B vitamin levels remain balanced.

Is Vitamin B9 Supplementation Right for You?

If you believe that vitamin B9 deficiency is the cause of your hair loss, then it makes sense that you would want to supplement it with folate and/or folic acid. There are many benefits to supplementation, though you should speak with your doctor before you proceed.

The best way to increase your vitamin B9 levels is with natural foods that are rich in folate, such as leafy greens, nuts, and legumes. But if your diet is limited, or you are not able to absorb folate due to a chronic condition, then folic acid supplements will do.

The addition of vitamin B9 may not make an immediate difference. However, as folate has so many benefits for hair growth, you must remain consistent in your efforts.

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