Biotin: A Guide To Side Effects, Benefits For Hair & More

Functional Medicine Practitioner By William Cole, D.C., IFMCP
Functional Medicine Practitioner
Dr. Will Cole, D.C., IFMCP, is a leading functional medicine expert who specializes in clinically investigating underlying factors of chronic disease and customizing a functional medicine approach for thyroid issues, autoimmune conditions, hormonal imbalances, digestive disorders, and brain problems. Cole is also the bestselling author of Ketotarian and The Inflammation Spectrum.

Photo by Tatjana Zlatkovic

Your body is a well-oiled machine. Without proper maintenance and fuel, machines begin to slowly break down, and problems start to arise. An adequate well-rounded amount of nutrients are to your body like oil is to a machine. B vitamins in particular play a crucial role in helping your body function optimally.

Many delicate, intricate pathways like methylation—your body’s biochemical superhighway, a process that happens more than 1 billion times every single second—are fueled by B vitamins. It is responsible for helping you to detox, helping to decrease an inflammatory response, and in turn, avoiding a lot of autoimmune-inflammation, brain, and hormone problems. They also help to aid your body in breaking down fats, proteins, and carbohydrates for energy production.

What a lot of people don’t realize, however, is that unlike vitamin C or vitamin D, there are many types of B vitamins that each play their own important role in maintaining how your body functions. In particular, vitamin B7—commonly known as biotin—stands apart from the rest with its role in keeping skin, hair, and nails healthy and looking vibrant and youthful. In fact, biotin is often referred to by its nickname "vitamin H" from the German words Haar and Haut which mean, you guessed it—hair and skin. Other sources say that biotin was originally called vitamin H because when nutrients were first being discovered they were named in alphabetical order.

No matter where its name originated, biotin, like all the other B vitamins, is critical for our body to thrive. B7 is used for a myriad of pathways that determine the health of every single one of our trillions of cells. Without a doubt, biotin is essential for life.

Your body cannot synthesize biotin, so it must be obtained through diet, supplementation, and intestinal bacteria. Any protein-bound biotin from your food ends up being converted to free biotin, which is then absorbed within the small and large intestine. Once absorbed, it is then moved into the systemic circulation, picked up by the liver, to finally cross the blood-brain barrier into the central nervous system.

Since biotin is found in many different kinds of food, severe deficiencies in this nutrient can be rare. However, in my functional medicine clinic, I often see lower, suboptimal levels actually becoming increasingly more common. Why is that? Well, due to the fact that a lot of this conversion happens within your gut, many patients who struggle with inflammatory bowel diseases or other microbiome dysfunctions can have trouble maintaining adequate amounts of biotin. Other factors like antibiotics, which wipe out the beneficial bacteria in your gut, contribute to low levels of biotin since they also end up killing biotin-producing bacteria.

You can also be at risk for biotin deficiency if you:

Symptoms of biotin deficiency.

If you suspect a deficiency, symptoms can include:

  • Fatigue
  • Brittle hair
  • Hair loss
  • Digestive issues
  • Dry skin

Biotin is considered a coenzyme for carboxylases, which are enzymes that assist in metabolizing fats, carbohydrates, and proteins for energy production and processes such as gluconeogenesis, insulin release, fatty acid synthesis, and the use of branched-chain amino acids to produce neurotransmitters.

Low levels of biotin can become a problem when your metabolism is concerned. Metabolism is your body’s internal process that turns whatever food you eat into usable energy and any food that is not used for energy is stored as fat. Because biotin is needed for the proper function of this process, you can end up with a whole slew of health problems including fatigue, weight gain, and weight loss resistance.

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The benefits of biotin.

While a lot of the buzz around biotin focuses mainly on its ability to aid in enhancing appearance, there are many more aspects of your health in which biotin plays a significant role.

Biotin for immune health.

Biotin is essential for the development of white blood cells. These are the defense mechanisms of your immune system and work to protect your body against viruses and bacteria that make you sick. Your body actually contains two different types of white blood cells, called TH1 and TH2. Almost like a seesaw, TH1 and TH2 need to balance each other. When one becomes dominant, it can push you into the inflammatory autoimmune spectrum, putting you at risk for a number of health problems.

One reason this can happen is a lack of T-regulatory cells, which work to bring balance back to your immune system. And not surprisingly, biotin deficiency is associated with T-cell decay. This is bad news for anyone struggling through immune problems. And with close to 75 percent of your immune system being located inside your gut, it only makes sense that a deficiency in biotin is linked to poor immune function because of how much biotin is converted within the gut.

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Biotin for brain health.

Photo: Per Swantesson

Biotin, along with other B vitamins, plays a role in neurotransmitter activity and protect against neurodegenerative disorders like Alzheimer’s and aid in improving cognitive function. It also helps to regulate mood due to their role in synthesizing hormones responsible for a positive mood.

Deficiency in biotin can lead to neurological problems such as depression, loss of muscle coordination, seizures, and even biotin-responsive basal ganglia—a metabolic condition that causes lack of coordination and seizures—but all have been shown to improve with biotin supplementation.

Biotin for blood sugar.

Since biotin increases insulin production and stimulates glucokinase—an enzyme in the liver that promotes glycogen synthesis—it helps to lower blood sugar levels. In fact, biotin supplementation was shown to decrease fasting blood sugar in people with type 2 diabetes by 45 percent. Biotin has even been shown to improve diabetic neuropathy in diabetic patients.

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Biotin for inflammation.

Studies have shown that biotin deficiency can increase pro-inflammatory cytokines and contribute to chronic inflammation. It works by activating the inflammatory nuclear factor kappa B (NF-kB for short), which binds to your DNA and triggers a number of inflammatory cascades throughout the body. Research has shown that supplementing with biotin can decrease production of these pro-inflammatory cytokines. Here are more ideas for inflammation-calming tools, from an mbg article I wrote on the subject.

Biotin for heart disease.

Biotin is needed for fat metabolism, which is important for thriving heart health. It can also work in conjunction with chromium to reduce LDL levels and increase HDL since inverse levels of each are markers for increased risk of heart disease. Research has shown that a dose of 15,000 mcg a day of biotin can also lower blood triglyceride levels.

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Biotin for beauty.

As I've said before, biotin stands above the rest of B vitamins when it comes to helping promote vibrant hair, skin, and nail health. Many beauty products add in biotin to capitalize on its benefits; however, there is very limited research to show how effective this vitamin is topically. Ingesting biotin is going to be your best bet if you want to restore your damaged hair and youthful glow.

Biotin for skin health.

Biotin is right there at the front line to fight the effects of aging with its role in fatty acid synthesis, which is crucial for healthy skin. The cells in your skin depend heavily on fat production for added protection against damage from constant exposure to wind, sun, and other harsh everyday environmental factors. Check out my skin health guide for more functional medicine tools.

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Biotin for hair growth.

Thinning hair and hair loss is a very common symptom associated with thyroid problems, which can be remedied with the addition of biotin. Even if you don’t have thyroid problems, if you have low levels of biotin, it can actually lead to hair loss. Thankfully it can be reversed with diet, supplementation, or addressing any underlying gut dysfunctions. Additionally, biotin is believed to naturally support healthy hair growth because it is involved in the production of keratin, the main component of hair. In one small study, women with thinning hair reported significant regrowth when supplementing with biotin as compared to those given a placebo. Biotin supplementation has not been extensively studied for hair growth though, and evidence is limited.

Biotin for nails.

Brittle, rigid nails are another symptom of thyroid problems. Biotin has been shown, even in those who aren’t dealing with thyroid issues, to increase thickness and firmness of nails.

Biotin for a healthy metabolism.

In every cell of your body, biotin is needed to break down the nutrients (protein amino acids, carbohydrates, and fatty acids) from your food for fuel. B7 is also über-important whenever we are doing different forms of fasting (such as intermittent fasting) or if you are in a ketogenic state (nutritional ketosis or fat burning). During these metabolic states, biotin is needed to produce new glucose for fuel through gluconeogenesis.

Are there any side effects of taking biotin?

Overall, biotin is a safe vitamin that has relatively few, if any, side effects. It is typically very difficult to even overdose due to the fact that it is water-soluble, and any excess amounts are released through your urine. But with any type of supplementation, I always recommend regular monitoring with diagnostic labs. For some people, extremely high doses of biotin can throw off thyroid test results and mimic Graves' disease in lab work. So it’s important to know where you stand in regards to your health so you and your doctor are aware of any potential implications. Knowledge is power. Especially when it comes to your health!

How to include biotin in your everyday life:

Photo: Toma Evsiukova

Since more research needs to be done to better determine the bioavailability of supplementing, with biotin there is no recommended dietary allowance; however, the National Institutes of Health recommends an adequate intake (AI) for each age group of:

  • Birth to 6 months: 5 mcg
  • 7 to 12 months: 6 mcg
  • 1 to 3 years: 8 mcg
  • 4 to 8 years: 12 mcg
  • 9 to 13 years: 20 mcg
  • 14 to 18 years: 25 mcg (30 to 35 mcg if pregnant and lactating)
  • 19+ years: 30 mcg

Taking a biotin supplement isn't always necessary since it is readily found in a variety of foods. I am a fan of getting our vitamins from real food sources whenever possible:

  • Beef liver: 30 mg to 3 oz.
  • Eggs: 13 mg to 1 whole
  • Salmon: 5 mg to 3 oz.
  • Avocado: 2-6 mg to 1 whole
  • Cheese: 0.4-2 mg to 1 oz.
  • Brewer's or Nutritional Yeast: 1.4-14 mcg to 7 grams

If you are interested in taking a supplement, biotin is usually part of all B-complex vitamins that contain all types of B vitamins such as B12, B6, niacin, and riboflavin. Since B vitamins all work together to support methylation, brain function, and more, that would be the best way to take biotin for optimal benefit. Also, since high doses of biotin are eliminated from circulation through urine, it is best to maintain a lower supplemental dose.

Spirulina is also another rich food source of a variety of B vitamins that is also plant-based. Found in both fresh and saltwater lakes throughout the world, it has been used as a highly revered food and remedy in ancient civilizations such as Mexico and Africa. When it comes to vitamin B content, it is second to none. It also contains all nine essential amino acids—the ones your body can’t make and you have to get from food. This makes it a secret beauty weapon that everyone should have in their toolbox.

So whether you get your biotin from foods or supplements, it is a super nutrient that has many far-reaching benefits for our health.

Here is an easy recipe to get in some of the highest biotin foods all on one plate!

Beef-Liver Mexican Egg Scramble


  • 1 cup ground beef liver
  • 4 eggs
  • ½ red onion, chopped
  • 1 jalapeno, seeded and chopped (optional)
  • Sea salt and pepper to taste
  • 1 teaspoon garlic powder
  • 1 teaspoon ghee
  • 1 small handful fresh cilantro, chopped
  • 1 whole avocado, pitted and sliced
  • Favorite salsa


  1. Heat ghee in skillet over medium heat.
  2. Add onions and jalapeño, and cook until soft.
  3. Add ground beef liver with sea salt, pepper, and garlic, and cook until done.
  4. Beat eggs in a separate bowl, add to skillet, and cook until done.
  5. Place egg scramble on plate and top with salsa, cilantro, and sliced avocado.

Want long, luscious hair? Check out the 5 foods to eat for your healthiest, shiniest hair.

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