Biotin Side Effects: How Safe Is This Supplement? - Dr. Axe

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Biotin Side Effects: Is It Safe to Take This Supplement?


Biotin side effects - Dr. Axe

Biotin, also called vitamin B7, is a nutrient that’s often taken to keep hair, skin and nails looking healthy.

It does more than support a good-looking appearance, however, considering it’s involved in many metabolic processes, including those that help us break down foods into useable nutrients and energy. Consuming enough biotin is also a way to support cardiovascular health as well as brain and nerve functions. One reason that’s true is because biotin helps the body build proteins.

If you take supplements geared towards promoting hair growth and skin health, chances are you’re consuming supplemental biotin whether you realize it or not. But what are the potential side effects of biotin? If you take too much, biotin side effects can possibly include worsened skin issues, indigestion and interactions with medications.

Find out below how to take biotin safely in a way that limits the risk for reactions.

Possible Negative Side Effects

Most people are thought to consume enough biotin from their diets, yet many still take extra in capsule form in hopes of limiting hair thinning, weak nails and dull skin.


The recommended intake of biotin is relatively low in comparison to some other nutrients, such as electrolytes (magnesium and calcium, for example) and vitamin C. This means that it can be easy to not only meet your needs, but to also exceed them.

Biotin is available in many skin and hair supplements, B complex vitamins (which include vitamin B6, vitamin B12, vitamin B2 riboflavin and vitamin B3 niacin), as well as multivitamins.

B vitamins are water-soluble, meaning any excess or unused amounts are usually eliminated through your urine pretty easily. This makes biotin toxicity, which is a dangerous overdose, rare but still possible if you take too much.

Overall biotin is safe for most adults to take. But what happens when you take too much biotin? The most common biotin side effects are:

  • Changes in skin tone and texture, including acne breakouts or rashes — This may be due to your body’s ability to absorb less vitamin B5 when you’re taking high doses of biotin; B5 (pantothenic acid) is known to help fight acne, so it’s not smart to hinder your ability to absorb and utilize it.
  • Skin rashes — These may form if you react poorly to certain biotin supplements, for example if you’re allergic to an ingredient or additive. Other signs of an allergy can include an itchy throat, watery eyes and congestion.
  • Nausea, cramping, diarrhea or indigestion — These side effects are most likely to occur if you take supplements on an empty stomach.
  • Lower vitamin C and B6 levels, which can compete with vitamin B5 for absorption.
  • Changes in blood sugar levels.
  • Interactions with medications, including anticonvulsants such as carbamazepine, phenobarbital, phenytoin and primidone.

Aside from what biotin supplements can do to you physically, they also have the potential to interfere with lab results in some cases. For example, there’s been some reports of inaccurate thyroid hormone tests after someone has taken high amounts of  vitamin B7.

Before having blood work done it’s best to speak with the technician or your doctor about any medications and supplements you’re taking.

How to Use Biotin Safely

Is it okay to take biotin everyday? As long as you stick to the recommended dosage, it should be.

“Recommended daily allowances” (RDAs or RDIs) of biotin have not been established due to a lack of sufficient evidence.  A general recommendation for adults is to take biotin in dosages of about 30 to 70 micrograms per day (see more below).

Some people choose to supplement with up to 10,000 micrograms of biotin per day, but this is much higher than the daily recommended value. This amount is sometimes used to treat certain conditions such as multiple sclerosis.

The proper dosage for you depends on your age and whether or not you have a biotin deficiency. According to the National Institutes of Health, the “Adequate Intake” (the level that is assumed to ensure nutritional adequacy) to obtain biotin benefits for different age groups is as follows:

  • 5 micrograms daily for infants
  • 6–8 micrograms daily for infants ages 7 months to 3 years old
  • 12–20 micrograms daily for children ages 4–13 years old
  • 25 micrograms for adolescents
  • 30 micrograms for male and female adults over 19 years old
  • 30 micrograms for pregnant women and 35 milligrams for women who are breastfeeding

Who needs biotin most?

Those prone to deficiencies in B vitamins are good candidates for supplementing with vitamin B7. If you fall into the groups below, or have a known biotin deficiency, talk to your healthcare provider about supplementing:

  • Pregnant women
  • Long-term users of certain anti-seizure medications or antibiotics
  • Those who drink excessive alcohol
  • Smokers
  • People with intestinal malabsorption issues or serious digestive disorders, such as Crohn’s disease, celiac disease or leaky gut syndrome.
  • Those with kidney disease or who have had stomach surgery.

How much biotin should you take for hair growth?

Always read directions when using any supplement, since strengths and dosages can differ from one brand to another.

Start by taking between 100 and 1,0000 mcg of biotin daily and increasing the amount of biotin foods you consume in a day. A general recommendation is try working your way up to taking about 2.5 to 3 milligrams (or 2,500 to 3,000 mcg) daily, which will cover your needs and then some.

To avoid side effects of biotin, don’t take higher amounts than necessary. And if you do notice adverse reactions, try lowering your dose, taking it only every other day, or giving yourself a break from supplementing for a few months.

One way to balance the effects of biotin is to take it with other B vitamins, such as in a B complex formula. To get the most benefits, purchase a high-quality multivitamin or supplement product that is made from real food sources and doesn’t contain fillers or possible allergens.


You can also naturally increase your intake of biotin by eating foods that are rich in this nutrient. These include: eggs, whole grains, nuts, organ meats, avocado, cauliflower, berries, fish, legumes and mushrooms.

Final Thoughts

  • Biotin or vitamin B7 is usually safe to take, but it can possibly cause reactions when taken in high amounts.
  • What are the side effects of too much biotin? These can include: acne, skin rashes, changes in other nutrient levels and digestive issues.
  • To avoid complications, stick to dosages of about 100 micrograms per day.
  • You can also increase your intake naturally from foods like whole grains, veggies, nuts, legumes, eggs and organ meats.

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