Medically reviewed by Kristin Hall, FNP
Written by Our Editorial Team
Last updated 2/02/2021
Your hair is one of your most important features. It’s also the feature that many people will look at first when they meet you.
When your hair is thin, short or just doesn’t look the way you’d like it to, looking for supplements and other products that promote hair growth is a natural, understandable response.
Folic acid, a synthetic form of the B vitamin folate, is a popular supplement that’s promoted as a helpful ingredient for promoting hair growth.
While nutrition does play a role in your hair’s growth cycle and general health, there isn’t a lot of reputable scientific research available right now on the effects folic acid may have on your hair’s growth cycle.
Below, we’ve talked about what folic acid is, as well as the scientific research that’s available on its effects on hair growth. We’ve also talked about other science-based treatments that you can use if you’d like to stimulate and speed up your hair’s growth cycle.
Folic acid is a B vitamin. It plays a key role in the creation of new cells, including the cells that make up your hair, skin, nails and other parts of your body.
You may have heard of a B vitamin called folate, or vitamin B9. Folic acid is a synthetic form of folate.
While folate is found in naturally occurring foods, folic acid is found in supplements and fortified foods.
As a woman, it’s important that you consume a certain amount of folic acid to maintain optimal reproductive health, especially if you’re currently pregnant or would like to become pregnant in the near future.
According to the CDC, all women of reproductive age should take 400 micrograms of folic acid per day.
Additionally, the CDC recommends eating food that contains folate, including fortified bread, rice, pasta and certain breakfast cereals.
Other healthy, readily available foods that contain folate include beans, citrus fruits and green, leafy vegetables.
Folate is important because it reduces the risk of certain birth defects.
Research shows that a high folate intake is effective at preventing neural tube defects, including birth defects that can affect your children’s brain and spine.
Folic acid supplements are widely available and inexpensive. You can find them online and in most health food stores.
To understand how folic acid may affect your hair, it’s important to know the basics of how your hair grows in the first place.
Every single hair on your scalp and body grows as part of a multi-stage cycle that’s referred to as the hair growth cycle. This cycle has four phases:
The anagen (growth) phase. During this phase, your hair grows out of the follicle to its full length.
The catagen (regression) phase. During this phase, your hair follicle begins to shrink and the hair detaches from your scalp.
The telogen (resting) phase. During this phase, the old, detached hair does not grow and a new hair starts to grow from the follicle in its place.
The exogen (shedding) phase. During this phase, the old hair falls out, with the new hair taking its place.
During the anagen phase, the cells that form each hair multiply rapidly, allowing the hair to grow to its full length.
The hairs on your scalp spend two to six years in this phase, while the hairs on your body typically complete the anagen phase of the growth cycle in just a few months.
On average, around 80 percent to 90 percent of your hair follicles are in the anagen phase at any given time, versus just 10 percent of follicles in the catagen or telogen phases.
Most hair growth treatments work by encouraging hairs to enter into the anagen phase of their growth cycle.
For example, the hair growth medication minoxidil works by reducing the length of the telogen (resting) phase of the hair growth cycle and causing hairs to enter the anagen (growth) phase early, stimulating growth and improving the thickness of your hair.
On the other hand, most forms of hair loss work by either damaging the hair follicle or forcing hairs into the telogen or exogen phases of the growth cycle.
For example, female-pattern hair loss (a female equivalent of male pattern baldness) causes hair loss through hormonal damage to the hair follicles that prevents them from creating new hairs.
This type of hair loss is permanent, making it important to treat it early.
Similarly, cicatricial alopecia, or scarring hair loss, causes hair loss by destroying hair follicles and replacing them with fibrous tissue.
Other forms of female hair loss, such as telogen effluvium, cause hair loss by forcing hairs to prematurely enter the telogen (resting) phase of the growth cycle before they’ve been able to grow to their full length.
For a hair growth supplement, medication or other treatment to be effective, it needs to either promote the growth of your hair or shield it from hormones, scarring or other types of damage that can cause hair loss.
Although there’s a large amount of scientific research on folic acid’s benefits during pregnancy, there’s relatively little data on its effectiveness as a hair growth treatment. Only a small number of studies are available, with the results of these studies mixed and far from conclusive.
One small-scale study published in 2017 looked at the possible relationship between folic acid, vitamin B12 and biotin in people with premature graying hair.
Using data from 52 volunteers, the researchers found that premature gray hair was associated with lower serum folic acid, vitamin B12 and biotin levels.
However, the study didn’t establish any relationship between folic acid levels and hair loss or hair growth.
A different study published in the Journal of Drugs in Dermatology analyzed a link between low folate levels and telogen effluvium, a form of non-scarring hair loss in which hair rapidly enters the telogen (resting) phase of the growth cycle.
Although the researchers found a link between ferritin, vitamin D and zinc deficiencies and hair loss, they didn’t find any link between low folic acid levels and telogen effluvium.
Another small study from 2013 also looked at the possible relationship between vitamin B12 and folate levels and hair loss.
This study involved patients affected by alopecia areata -- a form of autoimmune hair loss that often involves hair shedding in a patchy pattern.
This study didn’t find any significant difference in vitamin B12 or folate levels between the group of patients with alopecia areata and the control group.
In contrast, a 2014 study published in the Indian Journal of Dermatology looked at differences in red blood cell folate concentrations in people with alopecia areata and people without noticeable hair loss.
This study found that the group of people with alopecia areata hair loss had a significantly lower mean level of red blood cell folate than the control group.
Interestingly, the researchers also noticed that the people with the most severe hair loss had the lowest red blood cell folate levels.
Overall, research into the effects of folic acid on hair growth is mixed. Most studies show little to no relationship between folic acid (or folate) levels and hair loss, particularly when compared to other hormones and nutrients that are closely linked to hair health.
However, there’s also a small amount of scientific research suggesting that folic acid may have some effect on growth.
While the science behind folic acid and hair is mixed, folic acid supplements still offer numerous health benefits, particularly if you’re pregnant or plan to become pregnant in the future.
The easiest way to use folic acid is to take a folic acid supplement. You can purchase folic acid from most health food stores, drug stores and online supplement vendors.
The CDC recommends that all women of reproductive age take 400 micrograms (mcg) of folic acid each day in addition to food that contains folate.
If you’re pregnant or nursing, the recommended dietary allowance for folate is slightly higher than for non-pregnant women. The Office of Dietary Supplements recommends the following folate levels for pregnant or lactating women:
During pregnancy, 600 mcg of folate or dietary folate equivalents (DFEs)
During lactation, 500 mcg of folate or dietary folate equivalents (DFEs)
Many common foods are rich in folate, the natural form of folic acid.
Good sources of dietary folate include dark green, leafy vegetables and other vegetables, fruit and fruit juices, beans, nuts, dairy products, eggs, peas, red meat and poultry.
Spinach, Brussels sprouts, asparagus, black-eyes peas and beef liver contain very significant amounts of folate, making them good additions to your diet if you’re concerned that you may have low folate levels.
For example, a half cup serving of boiled spinach contains approximately one third of the daily intake for folate.
Many common foods are fortified with folic acid and other nutrients.
Try to shop for breakfast cereals, bread, pasta, floud and other products that contain folic acid to make sure you reach your recommended intake.
While the science on folic acid and hair growth is mixed, there are real, science-based options available that you can use to improve your hair growth and prevent hair loss.
One of the most effective treatments for preventing hair loss and improving your hair growth is minoxidil, a topical medication that’s sold as a liquid or foam.
Minoxidil works by shortening the telogen phase of your hair growth cycle and making dormant hairs enter the anagen phase. It also extends the duration of the anagen phase, allowing your hair to grow for longer before shedding.
There’s also some scientific evidence that minoxidil can increase the length and diameter of your hair.
It usually takes around four months to see significant results from minoxidil. You can find out more about how minoxidil works, its benefits and how to use it for hair growth in our complete guide to minoxidil for female hair loss.
In addition to minoxidil, maintaining a healthy diet plays a key role in keeping your hair strong, thick and healthy. Our guide to the best foods for healthy hair lists specific foods and nutrients that can help you to reduce your risk of hair loss due to nutritional deficiencies.
Folic acid offers a range of health benefits, particularly if you’re pregnant or planning to become pregnant in the near future.
However, the science behind its potential benefits for hair isn’t very thorough. Right now, only a few small studies are available.
These have produced mixed conclusions, with most finding that there’s little to no relationship between folic acid levels and hair growth.
For general health, try to aim for the CDC’s recommendation of 400 micrograms of folic acid per day, or slightly more if you’re pregnant or nursing.
If you notice your hair thinning, talk to your healthcare provider. They’ll be able to recommend a safe, science-based treatment to help you manage hair loss and promote healthy hair growth.