Vitamin B7 (Biotin)

What is Vitamin B7 (Biotin)?

Biotin or vitamin B7 is one of the 8 B vitamins which makes up the B complex family. It is also known as vitamin H Vitamin B7 is water-soluble which means your body does not store it and can be rapidly depleted.

Biotin comes from the Greek work “biotos” which means “life” or “sustenance”.

One of the main functions of all the B vitamins is converting carbohydrates into glucose which helps the body produce energy. B-complex vitamins are needed for healthy skin, hair, eyes, and liver. Many of the B-complex vitamins also play an important role in keeping the nervous system healthy and the brain functioning properly.

Biotin or vitamin B7 is an essential nutrient that helps convert food into fuel for the body. Biotin is needed to metabolize carbohydrates, fats, and proteins.

Although biotin can be derived from food there are gut bacteria in a healthy digestive system that can also help aid in manufacturing biotin.

Health Benefits of Vitamin B7

The following are some of the well known benefits of Biotin;

Healthy metabolism

Biotin supports a healthy metabolism which acts as co-enzyme (an enzyme co-factor) for carboxylases the enzymes which help with digesting essential macronutrients such as carbohydrates, protein and fats. [1]

Insufficient biotin can hinder or slow down metabolism which can lead to a host of illnesses such as chronic fatigue, weight gain and problems with digestion. [2]

Healthy skin, hair, nails

Biotin is commonly known for its various benefits for healthy skin, hair and nails. Biotin is involved in gene regulation and cell signalling linked to healthy hair, skin, and nails.

Biotin deficiency can lead to various skin conditions such as eczema and dermatitis. [3]

Biotin supplementation has shown positive results for brittle nail and the treatment of nail disease. [4] [5]

Biotin deficiency is also linked to hair loss or alopecia, however research on the significance of biotin for hair loss is limited as there are insufficient studies in this area as biotin deficiency is rare. [6] [7]

Biotin can be found in many hair and nail cosmetic products due to its hair and nail strengthening properties.

Supports building and repairing tissues and muscles

The B complex vitamins along with biotin can help to rebuild and repair tissues and muscles. Biotin can help reduce aches and pains in the muscles and joints which can be a sign that the body needs to rebuild or repair tissues and muscles.

Strengthens immune system

White blood cells of the immune system help the body protect against infections and foreign invaders. Low white blood cell count can increase the risks for infections which may be corrected by biotin intake. Biotin helps with the synthesis of white blood cells.[8]

Reduces inflammation

Many of the B complex vitamins are important in reducing inflammation which also includes Biotin. Studies have reported that nutritional biotin deficiency and genetic defects can cause inflammation of the skin and health conditions related to the dysfunction of the immune system. This suggests that biotin may help reduce inflammation of the skin and symptoms related to autoimmune conditions. [9]

Healthy pregnancy and breastfeeding

Biotin is an essential nutrient for pregnant women. Biotin can be found in many prenatal vitamin supplements in which case it is recommended to avoid additional biotin from supplements as high doses will likely pose risks to the baby.

Pregnancy and breastfeeding seems to increase the uptake of Biotin, with studies showing that approximately 50% of pregnant women developing a mild deficiency. [10] [11]

Animal studies have revealed that a deficiency of biotin could cause birth defects which can cause cleft palate and other malformations. There are currently insufficient studies on deficiency of biotin in humans causing birth defects. [12]

Reduces risk of diabetes

Biotin may help maintain blood sugar levels in people with diabetes. Studies have shown that biotin supplements taken with chromium can help improve blood sugar levels in people with Type 1 and Type 2 diabetes although more research needs to be done to confirm the efficacy of biotin supplementation for people with diabetes. Biotin stimulates insulin secretion which can help lower blood sugar levels.

The results from one study has shown that 600 microgram of chromium picolinate with biotin 2 mg administered as an adjuvant to current prescription anti-diabetic medication can improve glycaemic control in overweight to obese individuals with type 2 diabetes and especially in patients with poor glycaemic control on oral therapy. [13]

Another study showed that biotin administration in addition to insulin therapy had beneficial effect on glycemic control and reduces serum lipids concentrations in poorly controlled type 1 diabetic patients with no incidence of adverse side effects. [14]

Protects the brain and prevents cognitive decline

The B complex vitamins in combination work synergistically which can help boost and energy and regulate positive moods. In fact many of the deficiencies in the B complex family have been linked to impaired brain functions.

Many of the B vitamins play a very important role in the synthesis of hormones. Biotin in combination with adequate amounts of other B vitamins help memory function, protect against cognitive impairment. B vitamins can help defend against cognitive decline and neurodegenerative conditions such as Alzheimer’s disease, dementia and Parkinson’s disease.

High doses of biotin have also shown positive results for people suffering from Multiple-sclerosis although more research will be needed.


Supports heart health

Biotin can help lower LDL levels and increase levels of HDL cholesterol when taken with chromium. HDL are the beneficial and good cholesterol needed by the body for production and function of vitamin D as well as crucial hormone synthesis within the body. High levels of LDL cholesterol can build up plaque in the arteries increasing the risk of heart attacks and strokes. Biotin can help maintain healthy levels of HDL cholesterol supporting healthy heart functions. It is also beneficial for people who have diabetes as the condition increases the risk of heart disease due to damage to blood vessels and nerves that support a healthy heart. [16] [17]

A dose of 15000mcg of Biotin has shown to be effective in reducing blood triglyceride concentrations in patients with elevated triglyceride levels. [18]

Supports Thyroid Function

Biotin helps maintain healthy thyroid activity which assists with regulating sleep, energy, hunger and pain. Deficiency of biotin can lead to chronic fatigue and insomnia which may be due to the fact that biotin helps regulate thyroid function. [19] [20] [21] [22]

Agonists / Synergist

Vitamins: B Complex B2, B3, B5, B6, B12, folate

Minerals: Chromium, Magnesium, Manganese


Raw egg whites (Avidin), Alcohol, Smoking, Ketogenic diet, Lipoic Acid

Food Sources of Vitamin B7

Biotin can be found in many protein rich foods. Main sources of biotin include egg yolk, liver, kidney, chicken, salmon, yeast, sweet potato, avocados, cauliflower, green leafy vegetables, dairy, nuts and seeds.

Eggs are a good source of biotin only if the egg whites are cooked thoroughly to help deactivate avidin which is bound to biotin.

A healthy digestive system will contain certain bacteria in the gut which can produce biotin.

Biotin is heat sensitive and can get destroyed through cooking process as well as exposure to light.

The amounts recommended for vitamins and minerals are different for each country which can be found on the government website of host country. The nutritional data for each country are based on scientific research which are presented by the scientific academies in each country to help advise governmental departments for food and human nutrition.

Below is a list of some of the countries and the EU for which nutritional guidelines are available found on corresponding official government website (including the national academy of science website for the USA).


The  2015–2020 Dietary Guidelines for Americans -  Dietary Reference Intakes

Recommended Dietary Allowances and Adequate Intakes from Food and Nutrition Board, Institute of Medicine, National Academies

Dietary Reference Intakes (DRIs) Food and Nutrition Board, Institute of Medicine, National Academies

Dietary Reference Intakes (DRIs): Tolerable Upper Intake Levels (UL)


Dietary Reference Intakes includes Tolerable Upper Intake Levels


Nutrition Requirements

Safe Upper Levels (SULs) for Vitamins and Minerals

Australia and New Zealand

Nutrient Reference Values (NRVs) and Upper Level Intake 


Dietary Reference Values for nutrients

Tolerable Upper Intake Levels For Vitamins and Minerals

Vitamin B7 Supplementation

Biotin supplements are available in the form of powders, capsules, tablets, liquid and sometimes in transdermal patches. Biotin can be destroyed by heat and exposure to light.

Deficiency Symptoms of Biotin (Vitamin B7)

Vitamin B7 deficiency is very rare as low amounts are needed daily. It is available in common foods eaten around the world and in a healthy digestive system is naturally produced by bacteria in the intestine.

Symptoms of Biotin (Vitamin B7) deficiency include:

  • Fungal infection
  • Conjunctivis
  • Seborrhoeic dermatitis
  • Skin rash*
  • Eczema
  • Brittle hair
  • Brittle nail
  • Hair loss
  • Thinning hair
  • Anaemia
  • Birth defects
  • Muscle cramps or pain*
  • Heart problems
  • High cholesterol
  • Chronic Fatigue
  • Anorexia
  • Mild depression
  • Mood changes
  • Nerve damage
  • Cognitive decline
  • Impaired immune function
  • Low appetite
  • Insomnia
  • Hallucination
  • Numbness and tingling of the extremities
  • Ataxia
  • Seizures

*Scaly red rash biotin deficiency symptom will manifest in the face usually around the eyes, nose, and mouth and in the genital area.

There are many potential causes of biotin deficiency which include:

Eating raw egg whites over long periods of time. Avidin a compound of egg white binds to biotin reducing the body's ability to absorb biotin.

Smoking can cause a deficiency due to excessive biotin catabolism which is more likely in women.

Excessive use of antibiotics which can damage the balance of the intestinal flora which will reduce the natural production of biotin. Short bowel syndrome has been associated with poor absorption of biotin.

Excessive alcohol consumption can also significantly reduce biotin levels which is also associated with reduced amounts of other B vitamins.

Long term and excessive consumption of antidiuretics or inadequate levels of antidiuretic hormone can also cause biotin deficiency.

Ketogenic diet or a low carbohydrate diet may cause a biotin deficiency [25]

Lipoic acid may reduce the activities of biotin-dependent carboxylases. [26]

Lipoic acid may inhibit the uptake biotin and pantothenic acid which are SMVT substrates. [27] [28]

Biotin deficiency may also be linked to the following health conditions:

  • Hair loss / Alopecia
  • Heart disease
  • Seborrheic dermatitis
  • Diabetes
  • Multiple sclerosis
  • Cancer
  • Anemia
  • Crohn’s disease
  • Parkinson’s disease
  • Peripheral neuropathy
  • Rett syndrome
  • Vaginal candidiasis
  • Epileptic disorders [29]

Various genetic disorders cause a biotin deficiency which include biotinidase deficiency, multiple carboxylase deficiency and holocarboxylase synthetase deficiency. [30] [31] [32]

Long term use of anti-seizure medications which include phenytoin, primidone and carbamazepine can cause biotin deficiency.

Biotin deficiency can also occur during pregnancy although severe deficiency is rare. [33]

Toxicity Symptoms and Side Effects of Vitamin B7

Currently no upper limits have been set due to insufficient evidence of high intakes of biotin causing toxicity. Due to the fact that biotin is a water soluble vitamin the body will simply excrete it through urine and faeces.

Symptoms of vitamin B7 toxicity include:

  • Increased need to urinate
  • Unusual sweating frequency
  • Rapid nail and hair growth
  • Slower release of insulin
  • High blood pressure
  • High blood sugar levels
  • Skin rashes
  • Reduced vitamin C levels
  • Reduced B6 levels
  • Cystic acne
  • Stomach cramps
  • Diarrhea
  • Nausea

There has been one reported case of high amounts of Biotin in combination with Pantothenic Acid causing a condition known as eosinophilic pleuropericardial effusion.

Excessive amounts of biotin can significantly cause a slower release of insulin and increase blood sugar levels which can be dangerous for patients who have diabetes or high blood pressure.

Biotin may cause allergic reactions in some people which includes nausea, rash, pains in the chest, swelling of throat and face although this is rare.

Excessive amounts of biotin has also been linked to cystic acne which may be due to a deficiency or insufficient amounts of Vitamin B5 (Pantothenic acid) as both these vitamins are required in correct amounts to work synergistically. It can also be a sign of more biotin in the body than is needed.

Biotin can also cause problems in the digestive system with symptoms such as diarrhoea and nausea. Although mild nausea may occur when first taking biotin supplements this tends to wear off over time.

Toxicity can be caused by excessively high amounts of biotin through supplementation over a long period of time.

Precautions and Warnings

Biotin should not be taken with seizure medications as this may interfere with medication

Pregnant women may not need any additional biotin supplements as most prenatal supplements already contain biotin which can be checked on the label.

Biotin can cause interactions with various medications and it is recommended to speak with your doctor if you are pregnant or taking any medication before supplementing with biotin.

Caution should be taken with anti-seizure medications as they can induce a biotin deficiency. It is advisable to check biotin levels. Anti-seizure medications include phenytoin, primidone and carbamazepine. Biotin can also interact with cholesterol and diabetes medication reducing their efficacy.

The FDA has warned that biotin may interfere with certain lab tests causing incorrect test results which may go undetected. The issue is likely with those who are supplementing with high doses of biotin. It has been noted that higher than the recommended daily allowance may cause interference with lab tests. Prior to taking lab tests be sure to discuss with your health practitioner if supplementing with biotin [34].