The People's Perspective on Medicine

What Are the Pros and Cons of Biotin for Strong Nails?

Many people take biotin for strong nails, although there is limited scientific support for this use of the supplement. Can biotin interfere with tests?
Male’s hand holding on nail clippers,Man use nail clipper cutting their thumbs nail on background.

Biotin is a naturally occurring vitamin found in foods such as beef liver, eggs, salmon or pork. Some plants are also good sources of biotin, although levels are lower in sunflower seeds, sweet potatoes, almonds or spinach. As a supplement, this compound has garnered a reputation for helping nails and hair grow faster and become stronger. Is there evidence supporting the use of biotin for strong nails?

High-Dose Biotin for Strong Nails:

Q. I have found that 5000 micrograms of biotin daily is a miracle drug for my weak, brittle fingernails. My dermatologist recommended this.

Because of previous skin cancer, I wear sunscreen whenever I am outside. My family doctor told me to take 2000 IU of vitamin D3 to get my level up to the normal range. I am a healthy active man, so I plan to continue with my current supplements.

A. Thank you for sharing your experience with biotin, a B vitamin. This supplement is popular among people who want to improve their nails or hair (Journal of Cutaneous Medicine and Surgery, Nov/Dec. 2019). A review of the research on biotin for strong nails noted promising though not definitive results (Journal of Dermatological Treatment, June 2018).

The federal Office of Dietary Supplements notes that an adequate daily intake of biotin for adults is 30 mcg.

It goes on to state,

“Signs of biotin deficiency include skin rashes, hair loss, and brittle nails. Therefore, biotin supplements are often promoted for hair, skin, and nail health. However, these claims are supported, at best, by only a few case reports and small studies.”

Downsides of Biotin:

Even though you are taking a high dose of biotin, this nutrient appears quite safe. That said, it can interfere with some lab tests. Biotin artificially lowers the results of 25-hydroxyvitamin D tests. As a result, your doctor might conclude that you are not getting adequate vitamin D and advise you to increase your dose unnecessarily.

In addition, biotin may also lower the value of TSH (thyroid stimulating hormone). This compound is critical for the diagnosis and management of thyroid disorders. When TSH is low, the doctor infers that the thyroid is overproducing thyroid hormone. Consequently, the patient may be falsely diagnosed with hyperthyroidism. 

Most alarming, a high dose of biotin for strong nails might slow a diagnosis of heart attack. Doctors look at the level of troponin for this diagnosis. Unfortunately, biotin can lower it artificially. The diagnosis of congestive heart failure might also be more difficult.

If you ever need to have blood drawn, make sure the lab knows you are taking biotin. You’d be wise to stop taking your biotin for at least two days before visiting the laboratory for a planned test (Clinical Biochemistry, March 2019).

Learn More:

You can learn more about testing for thyroid problems in our eGuide to Thyroid Hormones. Likewise, our eGuide to Vitamin D and Optimal Health can tell you more about that vitamin and the tests. Dr. Low Dog’s book Fortify Your Life: Your Guide to Vitamins, Minerals, and More is the best resource on dietary supplements that we have seen. 

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About the Author
Terry Graedon, PhD, is a medical anthropologist and co-host of The People’s Pharmacy radio show, co-author of The People’s Pharmacy syndicated newspaper columns and numerous books, and co-founder of The People’s Pharmacy website. Terry taught in the Duke University School of Nursing and was an adjunct assistant professor in the Department of Anthropology. She is a Fellow of the Society of Applied Anthropology. Terry is one of the country's leading authorities on the science behind folk remedies. .
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Fortify Your Life: Your Guide to Vitamins, Minerals, and More
  • John JJ & LIpner SR, "Consumer perception of biotin supplementation." Journal of Cutaneous Medicine and Surgery, Nov/Dec. 2019. DOI: 10.1177/1203475419871046
  • Lipner SR & Scher RK, "Biotin for the treatment of nail disease: What is the evidence?" Journal of Dermatological Treatment, June 2018. DOI: 10.1080/09546634.2017.1395799
  • Gifford JL et al, "Strategies for mitigating risk posed by biotin interference on clinical immunoassays." Clinical Biochemistry, March 2019. DOI: 10.1016/j.clinbiochem.2018.12.007
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I tried Biotin for my weak, splitting nails. No improvement at all. However, I recently discovered that collagen supplements actually have strengthened my nails!

If biotin lowers the value of Vitamin D and TSH, does it lower the actual level that is in the blood? That answer is more worrisome. I take both of these medications, plus biotin. I’d like to see this addressed. I take biotin for my hair, and I have a friend who went through chemotherapy taking it and her hair was saved! Biotin definitely works. Thanks for this informative article.

Apparently, it is the test results that are lowered, and not the actual levels of vitamin D or of thyroid-stimulating hormone.

I got no results from a strong dose of biotin for several months. Burt’s Bees Lemon Butter Cuticle Cream worked a miracle for my awful nails within a week. I now put it on my nails a few nights a week at bedtime. I have not had a break in 3 months. Best of all, it’s topical rather than ingested.

There are many quite serious risks of taking high doses of biotin. Reader should become aware of this before using this supplement, especially in high doses.

I have always had weak fingernails until I started taking biotin several years ago. Now I rarely break one. My hair grows really fast, but with age I have lost some of it. My hairline has receded some, and my formerly very thick hair is getting thinner on the top. My suspicion is that, like so much else, it works for some of us and not others.

Over the years I tried many supplements and vitamins to improve my nails. They were very weak and would bend painfully or tear. I kept them short, usually by nail biting. Several years ago I started taking an iodine supplement. I was very surprised to see a marked improvement in the growth and strength of my nails after several months. I now have strong nails and can grow them out and use polish if I desire. No more nail biting either. If I had known iodine would do that I would have taken it years ago. My thyroid test has always come back normal. If I had an iodine deficiency I didn’t know it. I am curious why iodine worked when nothing else did.

I made a discovery while taking care of my horse: While putting a Hoof Flex on his hooves to strengthen and condition them, I would wipe some on my nails, also. Helped my nails tremendously! I just rub it in 1 – 2 times a week and you get really tough nails.

I started taking biotin a couple of years ago and it did strengthen my nails. However, I developed GERD around the same time. I didn’t initally connect the two, and was managing the GERD with apple cider vinegar tablets with each meal, not eating anything after dinner, sleeping elevated, etc. The gastroenterologist prescribed Protonix but I didn’t want to get hooked on a PPI so I didn’t take it. A few months ago I suddenly realized that the GERD had started at about the time that I started taking biotin. I stopped the biotin, and within a few weeks the GERD was completely gone, and I haven’t been bothered by it since.

I tried Biotin about six months ago, as my friends were saying how much it had helped them with hair and nail growth.
I was on it one day, and that night I woke with my heart pounding and feeling like I was having an anxiety attack. I though it was my imagination so tried it again the next night. Same thing. Looked up the side effects, and sure enough I had an answer. I had had hyper-thyroid years ago, and I have AFIB. Stopped the Biotin immediately and had no more problem.
Be sure to look up side effects on any herb or aids before use.

Always consult your doctor before self prescribing medications! Your whole body picture is different from others!

Took biotin in my multi-B supplement for years but my nails and hair have always been weak and thin. Sea Buckthorn, twice a day, makes all the difference in the world for me. My hair is silky and shiny, my nails are long and strong.

I started taking Biotin for my nails. They improved a lot, although in winter they are still not as good as I’d like. However, my hair, which used to barely grow, now grows like crazy! I actually get annoyed by how quickly it grows!

Not too long ago I got a blood test done, and my doctor told me to LOWER my dose of Vitamin D. I was taking magnesium glycinate and saw that it was a version mixed with Vitamin D. I was taking enough pills to meet the level of magnesium I was trying for. I didn’t realize that it was really a Vitamin D supplement with magnesium, not the other way round. I had to lower the dose until I ran out of those, got magnesium without D, and went back to my old vitamin D pill.

I will say that I credit the D, plus the flu shot, with helping me avoid colds and flu since 2012. The couple of times I’ve gotten something it went away pretty quickly.

I have had deep ridges in my fingernails for years–did not know why–read about biotin deficiency. Since I have started taken biotin, ridges seem less.

I took biotin for a year, and it did nothing for my weak nails. One day I rubbed coconut oil on and around my nails, and they got stronger right away. It was weird, actually, how fast they responded. I do that about once a week now. But I should have known that I didn’t need biotin because my hair is extremely thick.

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