Hair growth can literally have its ups and downs over the course of a lifetime. When you’re young and in overall good health, your hair seems to grow rapidly.

As you age, the growth process can slow down for various reasons, including decreased metabolism, hormone changes, and changes in the hair follicles that are responsible for generating new hairs.

Still, the fact is that healthy hair depends a lot on nutrition. Just as getting the right nutrients helps keep your skin and internal organs healthy, nutrients can affect your hair growth too.

Folic acid (vitamin B-9), when taken regularly as recommended, is just one of the nutrients that can promote overall healthy hair. Learn what else can help promote healthier, fuller-looking hair.

Folic acid is primarily responsible for healthy cell growth. These cells include those found inside your skin tissues as well as in your hair and nails. Such effects on your hair has spurred interest in folic acid as a possible hair-growth treatment measure. Additionally, folic acid helps keep red blood cells healthy.

Folic acid is the synthetic form of folate, a type of B vitamin. When found naturally in foods, this nutrient is called folate. The manufactured version of this nutrient in fortified foods and supplements is called folic acid. Despite the different names, folate and folic acid function in the same way.

Research establishing folic acid as a hair-growth method is minimal. One study, published in early 2017, looked at 52 adults with premature graying. The researchers behind the study found deficiencies in folic acid and vitamins B-7 and B-12.

However, additional controlled studies are needed to determine whether folic acid alone can help with hair growth.

The recommended daily dosage of folic acid for adult men and women is 400 micrograms (mcg). If you don’t get enough folate from whole foods in your diet, you may need to consider supplementation. Too little folate can lead to a condition called folate-deficiency anemia. This may cause symptoms, such as:

  • headaches
  • irritability
  • pale skin
  • pigmentation changes in your hair and nails
  • severe fatigue
  • soreness in your mouth
  • thinning hair

If you’re not deficient in folate, you don’t have to take a folic acid supplement for healthy hair. Any more than 400 mcg a day won’t make your hair grow faster.

In fact, taking too much folic acid can be unsafe. A folic acid overdose can occur when you take too many supplements or eat a high amount of fortified foods, but not if you eat folate in natural foods. Taking more than 1,000 mcg per day can hide signs of vitamin B-12 deficiency, leading to nerve damage, according to the Office on Women’s Health.

Folic acid is typically included in vitamin B complex supplements. It’s also found in multivitamins and sold as a separate supplement. All supplements vary, so make sure there is 100 percent of the daily value you need included. Speak to your healthcare provider about appropriate intake for your needs and which supplements may be best for you.

The Centers for Disease Control and Prevention (CDC) also recommend that women take 400 mcg of folic acid a day while pregnant. They suggest starting it a month prior to conception, if possible.

You may have noticed that many women who are pregnant experience healthier hair growth. This is likely due to folic acid and not the pregnancy itself.

More importantly though, folic acid helps keep both mom and baby healthy, while also preventing potential neurological birth defects. Your doctor will likely suggest a daily prenatal vitamin that includes folic acid.

Supplementation is available if you’re deficient in vitamin B-9. However, for most people, it’s relatively easy to get enough of this vitamin through a healthy, balanced diet.

Certain whole foods are natural sources of folate, such as:

  • beans
  • broccoli
  • citrus fruits
  • green leafy vegetables
  • meat
  • nuts
  • poultry
  • wheat germ

Keep in mind that the more processed a food is, the less amount of folate and other nutrients it’s likely to contain.

However, if you’re looking to get more folic acid in your diet, you can look for certain fortified foods that have 100 percent of the daily value of this nutrient and more. Options include fortified cereals, white rice, and breads.

Orange juice is another good source of folate, but it also contains a lot of natural sugar.

While folic acid is an integral part of the nutrients your body needs to make new cells, this nutrient may not treat hair growth alone. Instead, focus on making sure you get enough folic acid for your overall health. In turn, your hair will benefit too.

See your doctor if you have specific concerns with hair growth. If you’re suddenly losing large amounts of hair and have bald spots, this could indicate an underlying medical issue such as alopecia or a hormonal imbalance. Such conditions can’t be treated with folic acid.