Do biotin gummies help hair grow? What the evidence shows
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Biotin is the best-selling ingredient in hair, skin and nails gummies. A typical serving contains 2,500 mcg to 10,000 mcg. The amount an adult needs is 30 mcg. That is a difference of up to several hundred fold, and it is reasonable to ask what the extra is doing.
The answer from the research is uncomfortable for a popular product: for people who are not deficient, there is no good evidence that it does anything for hair. There is, however, a documented way it can cause harm, through its effect on blood tests.
The short answer
Biotin supplements improve hair and nails in people with biotin deficiency or certain rare conditions. Deficiency is uncommon. In healthy people, no controlled trial has shown that biotin makes hair grow faster, thicker or stronger. High-dose biotin can make some laboratory tests give false results, including tests used to diagnose heart attacks and thyroid disease.
What biotin is
Biotin, also called vitamin B7, helps enzymes that process fats, carbohydrates and amino acids. The Adequate Intake for adults is 30 mcg a day, and 35 mcg while breastfeeding. It is found in eggs, liver, salmon, pork, beef, seeds, nuts and sweet potatoes, and a normal diet supplies about the recommended amount.
The link with hair comes from deficiency. People who are truly deficient develop thinning hair, a scaly red rash around the eyes, nose and mouth, and brittle nails. Giving them biotin reverses it. The marketing extends that to everyone.
How common is deficiency?
Rare, in people eating a normal diet. The groups at risk are specific:
- People with biotinidase deficiency, an inherited condition screened for at birth in the United States.
- People with alcohol use disorder.
- Pregnant and breastfeeding women, a proportion of whom develop marginally low levels.
- People taking certain anticonvulsant medications long term.
- People who eat raw egg whites regularly over long periods. A protein in raw egg white binds biotin.
What the evidence shows
A 2017 review searched the medical literature for every report of biotin being used for hair or nail problems. It found 18 reported cases. In all of them, the patient had an underlying condition that caused poor hair or nail growth, such as an inherited enzyme deficiency or brittle nail syndrome, and improved on biotin.
The review found no randomized controlled trials showing that biotin helps hair in healthy people. The authors concluded that, despite its popularity, the evidence supports biotin only where there is a deficiency or a specific disorder.
The NIH takes the same position: there is insufficient evidence to support biotin supplements for hair, skin or nails in healthy people.
| Situation | Evidence that biotin helps |
|---|---|
| Diagnosed biotin deficiency | Yes |
| Rare inherited hair or enzyme disorders | Yes, in case reports |
| Brittle nails | A few small studies without placebo groups, at 2,500 mcg a day |
| Hair thinning in healthy adults | No controlled trials |
| Faster growth of normal hair | None |
Why people believe it works
- Hair shedding often resolves by itself. The commonest cause of sudden shedding is a stress on the body some months earlier, such as illness, childbirth or rapid weight loss. It usually recovers within six to nine months, with or without supplements.
- Hair grows about half an inch a month. After three months on any product, there is visible new growth.
- Gummies contain other things. Many include zinc, vitamin C or other nutrients, and people often change their diet or hair care at the same time.
Without a comparison group, it is impossible to know whether the supplement did anything. That is what placebo-controlled trials are for, and for biotin and hair in healthy people they do not exist.
How much is in a gummy
| Label amount | Percent Daily Value | Times the daily requirement |
|---|---|---|
| 30 mcg | 100% | 1 |
| 2,500 mcg | 8,333% | About 83 |
| 5,000 mcg | 16,667% | About 167 |
| 10,000 mcg | 33,333% | About 333 |
These amounts are not chosen because research found them effective. They are chosen because large numbers sell. Biotin is water-soluble and the excess is excreted. Our guide to what percent Daily Value means explains how to read figures like these.
The real risk: false blood test results
No upper limit has been set for biotin, because high intakes have not been shown to be toxic. That is often taken to mean high doses are harmless. They are not entirely.
Many laboratory tests use biotin as part of their chemistry. A large amount of biotin in a blood sample can interfere, pushing results falsely high or falsely low depending on the test. The FDA has issued safety communications about this. The tests affected include:
- Troponin, used to diagnose a heart attack. Biotin can produce a falsely low result. The FDA has reported a death in a patient whose heart attack was missed in this way.
- Thyroid tests. Biotin can produce a pattern that mimics an overactive thyroid.
- Some hormone tests, including certain pregnancy and fertility tests done in laboratories, and tests for vitamin D.
The American Association for Clinical Chemistry has published guidance for laboratories on the problem. The amounts in hair gummies, 5,000 mcg and above, are in the range that can interfere. The amount in a multivitamin, around 30 mcg, is not a concern.
What to do
- Tell your doctor and the laboratory that you take biotin before any blood test.
- Ask whether to stop beforehand. For high-dose supplements, doctors commonly advise stopping for two to three days before a test.
- In an emergency, tell the staff about any supplement you take, and carry a list.
- Check all your labels. Biotin is in many “beauty” and “energy” products, and people often take it from more than one.
What about nails?
The evidence for nails is slightly better than for hair, and still weak. A few small studies gave 2,500 mcg of biotin a day to people with brittle, splitting nails and reported firmer, thicker nails after several months. None had a placebo group, so the improvement cannot be separated from natural change or from other things the participants did. If brittle nails are your concern, the same advice applies: a short trial is unlikely to hurt, and you should tell your doctor before any blood test.
If your hair is thinning
See a doctor or dermatologist before buying supplements. Hair loss has many causes, and several are treatable.
- Iron deficiency, common in women with heavy periods.
- Thyroid disease.
- Hormonal changes, including after childbirth and around menopause.
- Pattern hair loss, which is inherited and affects both men and women. Proven treatments exist.
- Medication side effects.
- Very low calorie or low protein diets.
A blood test can check iron and thyroid function. If you have been taking high-dose biotin, mention it first, for the reason above.
Reading a hair gummy label
- Find the biotin amount and convert it to a multiple of 30 mcg.
- Look at the other ingredients. Vitamin C contributes to normal collagen formation, and zinc contributes to the maintenance of normal hair. Those are accepted functions of adequate intake.
- Add up overlapping nutrients with your other supplements, especially vitamin A and zinc, which do have upper limits.
- Count the sugar.
Not every beauty gummy relies on biotin. Goli Superfruits Beauty Gummies, for example, list vitamins A, C and E, zinc and a fruit blend. Our Goli Superfruits Beauty Gummies review reads that label.
The research is in the biotin ingredient guide. For the other common beauty ingredient, see collagen gummies vs collagen support gummies. Related reviews are on the beauty gummies page.
The short version
- Adults need 30 mcg of biotin a day. Deficiency is rare.
- Biotin helps hair when there is a deficiency or a specific disorder.
- No controlled trial shows it helps hair in healthy people.
- Hair gummies often contain 80 to 330 times the requirement.
- High doses can cause false blood test results, including for heart attack and thyroid.
- Tell your doctor you take it, and see one about hair loss.
Common questions
Do biotin gummies make hair grow faster?
There is no evidence that they do in people who are not deficient.
How long does biotin take to work for hair?
In people with a deficiency, improvement is seen over months. In healthy people, no effect has been shown at any duration.
Is 5,000 mcg of biotin too much?
It is not known to be toxic, but it is about 167 times the daily requirement and can interfere with laboratory tests.
Should I stop biotin before a blood test?
Tell your doctor. For high-dose supplements they commonly advise stopping two to three days beforehand.
Can biotin cause acne?
Some people report breakouts on high-dose biotin. This has not been confirmed in controlled studies.
What actually helps thinning hair?
It depends on the cause. See a doctor to check for iron deficiency, thyroid disease and pattern hair loss, which have proven treatments.
Sources
- NIH Office of Dietary Supplements. Biotin: fact sheet for health professionals.
- Patel DP, et al. A review of the use of biotin for hair loss. Skin Appendage Disord. 2017.
- US Food and Drug Administration. Biotin interference with troponin lab tests: assays subject to biotin interference.
- Li D, et al. AACC guidance document on biotin interference in laboratory tests. J Appl Lab Med. 2020.
These statements have not been evaluated by the Food and Drug Administration. Products discussed here are not intended to diagnose, treat, cure or prevent any disease. This page is not medical advice. It is written for adults 18 and over.