Is There Such a Thing as Too Much Biotin?

WRITTEN BY Jessica Bippen, MS, RD

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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

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.

Biotin for Healthy Nails - The Wellnest by HUM Nutrition

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.

Biotin-Rich Foods - The Wellnest by HUM Nutrition

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:

Breakfast
1 slice of sprouted bread
1/2 an avocado
1 egg for breakfast

Lunch
3 cups dark leafy greens
1/2 cup roasted broccoli
4 oz salmon for lunch

Snack
1/4 cup almonds

Dinner
1 medium sweet potato
1 cup black beans
1/4 avocado

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.

Ariana Grande GIF - Biotin for Nails - The Wellnest by HUM Nutrition

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.

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