Biotin deficiency is rare in developed countries where most people are able to consume enough calories and a variety of different food groups, yet it’s still possible.
Some infants are born with biotin deficiency due to having an inherited enzyme deficiency, and adults can also develop deficiency later in life due to illnesses or medication use. In other words, this type of deficiency is either congenital or acquired.
What happens when you don’t get enough biotin? The most common symptoms of biotin deficiency include hair loss, fatigue, mood changes including depression, and in severe cases neurological impairment.
Some of the ways you can reduce your risk for biotin deficiency, or bring your levels up if need, are to eat enough protein-rich foods, avoiding ongoing use of certain medications, and to treat underlying health conditions that block biotin absorption.
Biotin (or vitamin B7) is a water-soluble vitamin that acts as a coenzyme in the body that’s needed for the metabolism of fatty acids, amino acids and glucose, meaning enough of it must be present in order to convert and use the macronutrients (fats, proteins and carbs) that we consume from our diets.
It’s part of the vitamin B complex — a group of key nutrients needed for healthy metabolic, nerve, digestive and cardiovascular functions.
Biotin deficiency occurs when someone either doesn’t consume enough biotin from their diet or they can’t properly absorb what they do consume. This type of deficiency is not very common — especially compared to deficiencies in other nutrients like iron, B12 or magnesium — for a few main reasons:
How much biotin do you need to prevent deficiency? While a dairy requirement of biotin has not been established, “safe and adequate intakes” have been suggested. According to the National Institutes of Health, the “Adequate Intake” (the level that is assumed to ensure nutritional adequacy) of biotin for different age groups is as follows:
Treating biotin deficiency is important because biotin has important roles in many metabolic, digestive, neurological and cardiovascular processes. For example, we need biotin for some of the following functions:
What are the symptoms of biotin deficiency? Signs of biotin deficiency can include:
The first symptoms of biotin deficiency to appear are usually the dermatological ones, which is why these are considered an important indicator. The neurological symptoms tend occur at more severe levels of biotin deficiency.
Biotin deficiency in dogs can also occur, which can cause symptoms like hair loss, diarrhea, loss of appetite and weight loss, dull coat, brittle hair, scaly skin, and skin rashes/dermatitis.
Is there a connection between biotin deficiency and hypothyroidism? It’s possible that some people may have both, but low biotin levels are not believed to be a primary cause of hypothyroidism.
There’s also evidence that taking very high doses of biotin can lead to incorrect results on various thyroid/endocrine laboratory tests, so working with your doctor if you have a history of thyroid dysfunction is important.
Does biotin deficiency cause hair loss?
Nutritional deficiencies, including an inadequate intake of protein and low intake of minerals like zinc, iron and selenium, essential fatty acids, and certain vitamins including biotin, are a known cause of hair loss/hair thinning (also called alopecia).
Biotin plays a major part in maintaining the health of our hair, nails and skin because it’s involved in protein synthesis, specifically the formation of keratin, a protein that maintains the structures of our hair.
While research on biotin for hair growth is still limited, there is some evidence from several studies that taking biotin supplements daily for about 3 to 6 months can help to promote hair growth and reduce hair loss/shedding. There’s also a connection between biotin deficiency and nails that are brittle and weak.
A 2017 review focused on the effectiveness of biotin for hair growth found that biotin supplementation can help people dealing with underlying health conditions that cause hair loss, but that supplementation may only really be effective for promoting hair growth if someone is deficient.
While biotin is commonly added to hair and skin beauty products like serums and shampoos, it’s believed to not be absorbed very well through the skin, which is why it’s best to obtain biotin from your diet, or a supplement if needed.
Biotin is water-soluble, which means it travels in the bloodstream and any excess or unused quantities present in the body are eliminated through urine. Therefore, the body doesn’t build up reserves of biotin, and it’s very difficult to consume too much; because of this, toxic levels (or biotin side effects) are very rare.
However, this also means that you must ideally ingest small amounts of vitamin B7 almost daily to keep your body’s supply high enough.
Three proteins are important for the proper amounts of biotin to be maintained in the body. These proteins are: biotinidase, the sodium-dependent multivitamin transporter (SMVT) and holocarboxylase synthetase (HCS). These proteins work together to make sure that biotin is released from foods that we eat and then absorbed through the gastrointestinal system.
What would cause a biotin deficiency? Some of the most common biotin deficiency causes include:
Another unusual and relatively common cause of biotin deficiency is eating lots of raw eggs, especially raw egg whites, which contain a type of protein that binds to biotin and makes it unavailable. This protein is denatured through cooking, which is why eating cooked eggs is not a risk factor.
Genetic/Inherited Biotin Deficiency:
Congenital or genetic biotin deficiency is a rare disorder due to an autosomal recessive trait that leads to a lack of either holocarboxylase synthase or biotinidase enzymes that are involved in the absorption of free biotin.
This type can occur within the first six weeks of life (defined as the neonatal type) and be severe or life-threatening, or develop after three months of life.
A diagnosis of biotinidase deficiency is performed in newborns through screening. Prenatal testing can also be done using a sample of fluid from the womb.
Normal serum (blood) biotin concentrations range from 400 to 1,200 ng/L. Deficiency is technically considered to be a level of less than 200 ng/L.
Diagnosing a deficiency can be difficult because biotin levels can fluctuate daily, therefore results from a blood test are not considered to be an accurate marker. Another way to test for biotin deficiency, which some experts believe is more accurate, is to measure urinary excretion of the metabolite, 3-hydroxyisovaleric acid.
How is biotin deficiency treated? Some examples of biotin deficiency treatment options include:
There are several different types of biotin that are available in supplements, but the only naturally occurring kind is found in food sources. The single best and safest way to prevent biotin deficiency is to eat biotin-rich foods. Here’s a list of the best sources to eat regularly:
Overall, aim to eat a varied, healthy diet that includes a variety of protein sources, vegetables, fruits, whole grains, dairy products if you tolerate them, nuts and seeds. Eggs and some organ meats are good sources of biotin, as are many nuts, seeds, seafood, and lean meats.
As mentioned above, while eating whole eggs/egg yolks is a good way to obtain biotin and other B vitamins, egg whites provide no biotin and actually have the ability to deplete the effects of B vitamins.
Biotin deficiency and nausea, abdominal pain and other GI issues can affect people with inflammatory bowel diseases, such as disorders like Crohn’s disease, colitis, celiac disease or leaky gut syndrome. Some of the ways that malabsorption issues tied to GI disorders are treated include:
Biotin can interact with certain medications, so if you’re taking daily medications that may have an adverse effect on biotin levels, monitor symptoms and work with your doctor.
For example, anticonvulsant treatment for at least one year has been associated with significantly lower serum biotin levels. Taking antibiotics for an extended period can also lower levels.
Discuss supplementation with your doctor, or the possibility of changing medications, if medication use is lowering your biotin levels.
Biotin is available in dietary supplements containing biotin only, in B-complex vitamins, and in some multivitamins. In supplement form, biotin dosage recommendations range from about 1 mg to 3 mg per day (or 1,000 to 3,000 mcg), which is plenty to cover someone’s daily needs.
Biotin dosage recommendations depend on a few factors, including your age and whether or not you have a known biotin deficiency. Start by taking 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 mg (or 2,500 to 3,000 mcg) daily.
If you’re experiencing biotin deficiency symptoms talk to your doctor about potential underlying causes and treatment options such as supplements. Taking very high doses of B vitamins from supplements can impact levels of other nutrients in your body, so it’s always advised to only take the recommended dose, unless your doctor advises you otherwise.
Biotin pills or supplements are considered safe when the dosage is within the recommended amounts. Several studies have found no adverse effects even when someone is taking a high dose of 10–50 mg/day.
However, it’s still possible to experience minor adverse reactions like indigestion, nausea, cramping or diarrhea. Taking a very high dose for an extended period of time may possibly cause biotin overdose symptoms like skin rashes, lower vitamin C and B6 levels, and high blood sugar levels.