A nutritionist chimes in on biotin.
If you’ve looked at hair and nail supplements, you’ve probably seen biotin as the universal ingredient. But can it actually help give you long, luscious hair and hard-as-rock nails? And is it possible to overdo it on your biotin intake? Registered dietitian Jessica Bippen, MS, RD, gives her take.
- The Biotin Breakdown
- What is biotin?
- What are its benefits?
- What are the side effects?
The Biotin Breakdown
First, what is it?
Biotin (aka B7) is one of the many water-soluble B-vitamins that are necessary for your body to function. Its main role in the body is as an important cofactor that’s essential for metabolizing macronutrients. It gets absorbed in the small intestines and stored in the liver.
Why is it important to get?
Biotin plays an important role in metabolizing glucose, fatty acids, and amino acids. Its role as an enzyme in the metabolism of amino acids is crucial for protein creation, which results in building strong healthy hair and nails.
While the research is limited, small studies suggest that it can help reduce brittle nails that easily split or crack. The same goes for healthy hair. Studies show that individuals with a biotin deficiency can benefit from supplementing to help with hair growth. Hair is easily damaged by sun-exposure, over washing, and constant heat from the hair dryer or other styling tools. Biotin plays a role in building the protein that helps regrow healthy hair, which is why it has become such a popular hair and nail supplement.
How much do you need?
Adults need at least 30 mcg per day. If you’re eating a well-balanced diet that includes lean protein and plant-based foods like veggies, nuts, and seeds, you’re likely hitting your base level. Some of the top biotin-rich foods include eggs, avocado, whole grains like oatmeal, sweet potatoes, broccoli, almonds, onions, and peanuts.
For example, here’s a meal plan for one day that meets the recommended serving:
1 slice of sprouted bread
1/2 an avocado
1 egg for breakfast
3 cups dark leafy greens
1/2 cup roasted broccoli
4 oz salmon for lunch
1/4 cup almonds
1 medium sweet potato
1 cup black beans
Signs of Deficiency
Typically, a biotin deficiency is rare. However, if you’re not eating a well-balanced diet or are avoiding certain food groups, you may have a greater deficiency risk. In addition, those with a genetic disorder for biotinidase deficiency are at risk as it prevents the body from releasing free biotin. Pregnant and lactating women should also be mindful of their intake. At least a third of pregnant women develop a slight deficiency regardless of normal intake.
If deficient, symptoms typically come on gradually. These include thinning hair and hair loss on all areas of the body, brittle nails, and a scaly red rash around the eyes, nose, and mouth. In the most severe cases, a deficiency can lead to neurological conditions such as depression, lethargy, hallucinations, and tingling of the extremities.
Is there such a thing as too much?
Actually, there’s no upper limit for biotin because it’s water-soluble, which means your body only stores what it needs. The rest is excreted in your urine. There’s no evidence of high levels of biotin being harmful, which is why you’ll commonly see biotin supplements containing 5,000 to 10,000 mcg. These levels ensure your body gets as much biotin as it needs and absorbs it in the small intestines. Research has shown even mega-doses of 300 mg (that’s 300,000 mcg) to help with treating multiple sclerosis have no adverse side effects.
One caveat is that taking a lot of biotin can interfere with lab test results. The technology used to measure levels of thyroid hormones and vitamin D, for example, can show high or low test results. For this reason, it’s important to inform your doctor if you’re taking a biotin supplement.
Should you take a biotin supplement?
If you are avoiding certain biotin-rich foods or are experiencing brittle hair or nails, you may benefit from supplementing! Since biotin is water-soluble, you don’t have to worry about excess. The little extra boost may do wonders for your hair and nails.
If you’re taking a multivitamin, there’s a good chance it contains biotin, a water-soluble B vitamin also known as B7. And, while biotin is known to support healthy hair, skin and nails, it may interfere with certain common lab test results if you’re taking too much. The Food and Drug Administration recently issued a safety alert on this topic.
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Family medicine practitioner Matthew J. Goldman, MD, explains what the alert means, and what you need to know about biotin use.
Which tests might biotin supplements affect?
Many labs use immunoassay-based screening methods. This testing method measures the presence and concentration of a small molecule in a solution. If you have too much biotin free-floating in your system, it can throw these tests off.
In other words, the biotin in your system can replace what tests are measuring for in the solution and create false readings, Dr. Goldman says.
High levels of biotin can impact tests used to diagnose conditions such as:
- Thyroid disease
- Heart disease
- Other hormonal-related diseases
Results may appear falsely low or falsely high, depending on the specific testing method, Dr. Goldman says. And lab results influenced by biotin supplements are not always obvious to your healthcare provider or the lab conducting the test.
How much biotin is too much?
If you’re like most people, you can get all the biotin you need by eating a well-balanced diet, Dr. Goldman says. Daily biotin recommendations range from 5 to 35 micrograms, depending on your age and gender, and on whether you’re pregnant or lactating.
While most multivitamins contain about 30 micrograms of biotin, some supplements — especially those that promote hair, skin and nail health — may contain much higher doses, he says.
“Obtaining biotin naturally is much less likely to cause abnormal test results because you won’t get as high concentrations of biotin as supplements provide,” he says.
You can boost your biotin levels naturally by eating these biotin-rich foods:
- Sweet potatoes
How can you keep yourself safe?
Check your supplements to find out how much biotin they contain and consider how much you are getting from your diet, Dr. Goldman advises. If you’re getting more than the recommended daily allowance, talk with your doctor or a nutritionist about whether you should continue taking a biotin supplement.
And, make sure your doctors and lab technicians know what you’re taking.
“If you’re concerned about how the supplements you’re taking might affect future or previous lab results, speak to your healthcare provider and the lab performing the test. Let them know about any medications and supplements you take,” he says.
Your doctor also can advise you on whether you should stop taking your supplement ahead of an upcoming lab test. Most water-soluble vitamins flush out of your body in 24 to 48 hours, but it might take longer depending on the dose you’re taking.
“Making sure we’re all on the same page can help ensure you are receiving accurate lab results, and the best care,” Dr. Goldman says.
There are certain supplements that you just associate with their main function, like collagen for your skin and probiotics for your gut, and last but not least, biotin for your hair.
Despite being the first supplement rattled off as something that could help you get enviable strands, biotin’s a pretty enigmatic supplement—as in, most people probably can’t explain what it is or what it does. And that’s why I tapped some experts to get the lowdown on everyone’s favorite hair beautifying pill. Keep scrolling to hear more about the buzzy beauty supplement and its side effects.
What is biotin?
Biotin’s actually a water-soluble B vitamin—also called B7 or vitamin H—which means your body doesn’t store it and it’s critical in many processes for cellular metabolism as well as breaking down fats, proteins, and carbohydrates into energy, according to Corina Crysler, clinical nutritionist and owner of Moonshine Juicery.
If you’re not taking it in supplement form, you can find it in foods like eggs, nuts, seeds, whole grains, sweet potatoes, and leafy greens, according to Crysler.
If you want to start taking it, Crysler says there’s no recommended daily allowance but 30 to 70 mcg (micrograms) is a common daily need (though you’ll see many of the hair supplements clocking in at between 1000 and 10,000 mcg). “The truth is everyone can take and receive the benefits of biotin,” says Charles Passler, MD, a celebrity nutritionist.
What are its benefits?
Because of the impact it has on your body’s ability to metabolize nutrition, biotin can also play a big role in your mood and overall wellbeing, according to Dr. Passler. But what about your hair? “Biotin alone is not going to completely reverse overnight,” he says, though if one has a deficiency in biotin, studies have indicated that it could help. In addition to a healthy diet (which TBH is most important of all), Dr. Passler does recommend supplementing if you have dry or brittle nails, skin, or hair.
Here’s the grain of salt: Crysler notes that there are limited clinical studies that show a marked improvement for hair growth in healthy individuals. “More studies need to be done to show the effectiveness of biotin,” she says.
What are the side effects?
If you’re not consuming biotin in your everyday diet, rest easy because chances are, you’re getting enough of the nutrient. “Deficiency in biotin is rare, as you only need a small amount,” says Crysler. “The thing is, there’s limited testing that’s been done on biotin deficiencies. Thinning hair or skin rashes may be symptoms, though, hence why it’s been used as a hair loss supplement.” However, if you’re not suffering from a deficiency it’s probably not going to do you a ton of good to start taking it all of the sudden.
Because it’s water soluble, the excess gets eliminated through your urine, according to Crysler—so it’s really hard to overdo it. Another doctor concurs: “The good news about biotin supplementation is that it has not been shown to have any side effects, even at very high levels,” says Sarah Jamison, MD, a board certified ER physician and health and wellness expert. Though there is one potential downside. “Excessive consumption of biotin at most can cause interference with laboratory testing of certain chemicals in the body,” Dr. Jamison tells me. Even in small doses it can do this. So to avoid showing incorrect results on a lab test or getting misdiagnosed, be sure to alert your doctor of the supplements that you’re taking.
Despite the super-small chance of side effects, however, a doctor’s gotta list the slight chances: “Upset stomach, acne, drug interactions, frequent urination, high blood sugar, skin rash, and allergic reactions are the most common potential side effects,” notes Dr. Passler. “Although these side effects are not common for most individuals, it’s important to be aware of the possibilities.” And there you have your brush up on biotin.
Originally posted August 2, 2018, updated June 25, 2019.
Besides biotin, these are 10 supplements for thicker, fuller hair. And these are the best supplements for clear, glowing skin.
Clinical Application and DANGERS of High Dose Biotin
- High-dose biotin treatment can cause insidiously misleading laboratory results by fully mimicking the typical laboratory pattern of Graves’ disease and sometimes persisting for several days after biotin application
- A Somewhat Bizarre Case of Graves Disease Due to Vitamin Treatment
- A Single 10 mg Oral Dose of Biotin Interferes with Thyroid Function Tests
- High-dose biotin in infants mimics biochemical hyperthyroidism with some commercial assays
- The FDA has received a report that one patient taking high levels of biotin died following falsely low troponin test results when a troponin test known to have biotin interference was used
Biotin, also known as vitamin B7, is a water-soluble vitamin often found in multi-vitamins, prenatal vitamins, and dietary supplements marketed for hair, skin, and nail growth. Most people get enough biotin from the foods they eat. However, certain groups are more prone to deficiency, such as patients with a rare genetic disorder called “biotinidase deficiency”, alcohol dependence, and pregnant and breastfeeding women.
Biotin deficiency is very rare in the United States and can cause thinning hair and loss of body hair; brittle nails; a rash around the eyes, nose, mouth, and anal area; skin infection; pinkeye; high levels of acid in the blood and urine; nervous system disorders; and seizures. Symptoms of biotin deficiency in infants include weak muscle tone, sluggishness, and delayed development.
The Food and Nutrition Board (FNB) based its determination of Adequate Intake (AI) for all populations on the amount of biotin in human milk consumed by infants and then used body weight to extrapolate AIs for other groups. Table 1 lists the current AIs for biotin .
High Dose Biotin
Several studies have found no adverse effects of 10–50 mg/day of biotin, even up to 200 mg/day oral or 20 mg/day intravenously when administered to patients with inherited biotin metabolic diseases and acquired biotin deficiency
The recommendations for adequate intake in adults has been estimated to be 30 µg/day ,. This usual dietary intake is not expected to be high enough to affect immunoassays based on the streptavidin-biotin binding. However, patients with inherited metabolic diseases like propionic acidemia, biotinidase deficiency, and patients with parenteral nutrition receive a higher dosage of biotin, with daily oral doses in case of inherited metabolic diseases ranging from 10 to 40 mg per day , . Supraphysiological biotin administration is also used in certain auto-immune conditions aimed at reducing hair loss or fortifying hair and nails (up to 20 mg per day). It is sometimes listed as an unnamed supplement to improve hair, nails, and skin, and is not considered a medication by the patient, therefore not worth mentioning . More recently, very high doses of biotin (300 mg per day) have been used in clinical trials in multiple sclerosis and demyelinating pathologies . Although the therapeutic mechanism for high-dose biotin in biotin-thiamin–responsive basal ganglia disease (BTBGD) remains unknown, high doses of biotin alone (5-10 mg/kg-d) had been used in the successful treatment of this disease .
Excess biotin has not been shown to have any toxic effects in humans. However, high plasma biotin (>30 µg/L) can lead to clinically misleading interferences with streptavidin-biotin immunoassays.
Dangerous Lab Interference causing false-positive/negative
Biotin in blood or other samples taken from patients who are ingesting high levels of biotin in dietary supplements can cause clinically significant incorrect lab test results. High dose biotin may interfere with diagnostic assays that:
- Use biotin-streptavidin technology
- Are commonly used to measure levels of hormones (such as thyroid hormone)
- Measure other analytes such as 25-hydroxyvitamin D, producing falsely normal/abnormal results
The results of many hormonal immunoassays (troponin, natriuretic peptides, therapeutic drug assays, serology tests) may be misleading because of biotin interference. Many non-hormonal immunoassays may also be inaccurate in biotin-treated patients, showing falsely low tumor markers and ferritin levels, falsely high vitamin B12 and folate levels, and falsely negative serologies. Many immunoassays provide highly inaccurate results if tested less than two days after the ingestion of biotin (seven days for thyroid receptor antibodies). As a result, biotin administration must be discontinued at least two days prior to sampling.
Recent case reports have described lab results falsely indicating Graves disease and severe hyperthyroidism in patients taking 10–300 mg biotin per day, including six children receiving high doses of biotin (2–15 mg/kg per day) to treat inherited metabolic disease. According to the Food and Drug Administration (FDA), a patient with a high intake of supplemental biotin died following a troponin test that gave a falsely low result, because the test was subject to biotin interference.
The FDA advises healthcare providers to ask their patients about any supplements they may be taking that contain biotin and to consider biotin interference as a possible source of error if laboratory test results do not match the clinical presentation of the patient.
Tables 2 and 3 lists current assays that may be impacted by high-dose biotin.
Table 2: Potential some potential errors in hormone testing, due to biotin interference
Table 3: Assays prone to biotin interference
What can be done to suspect and overcome these interferences?
The possibility of an analytical artifact may be inferred from various signs :
- Lack of coherence with the clinical presentation; e.g. a thyrotoxic biochemical profile in a patient who is clinically euthyroid. The anomaly may extend to several other endocrine investigations to heighten suspicion of assay interference.
- Comparison of physiologically dependent variables: lack of the usual balance between the hormone and its regulating factor, evoking, for example, the very rare syndrome of inappropriate secretion of TSH.
- Extremely unusual analyte concentration.
- Markedly different results given by different analytical methods: as mentioned above, these analytical errors are method-dependent, because they impact specifically streptavidin-biotin based immunoassays.
One method of biotin neutralization is highly efficient and may be easily performed in any clinical laboratory, either to investigate unexpected hormonal profile, or to prevent artifact for known biotin supplementation.
Another method enables laboratories to confirm biotin interference in the appropriate clinical setting. Moreover, it enables laboratories to remove the interference and report accurate and reliable results, without the need for patients to withhold beneficial therapy prior to blood tests.
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- Biotin (vitamin B7): Safety communication – may interfere with lab tests