Can Biotin Really Stimulate Hair Growth?

Biotin is a B vitamin often recommended for hair health. Since biotin deficiency can lead to thinning of the hair, proponents claim that taking biotin supplements (in pill or tablet form) or using biotin-enriched shampoo and hair products can thicken hair and stimulate hair and nail growth.

There isn't enough evidence to rate biotin's effectiveness in the treatment of hair loss, according to the National Institutes of Health (NIH).

However, hair loss is a symptom of biotin deficiency, so biotin supplementation is thought to benefit people with hair loss or thinning hair who have a biotin deficiency.

Manufacturers claim that shampoo, conditioner, and hair oils, masks, or creams containing biotin can thicken hair, increase fullness, and add shine. Despite these claims, there are no scientific studies to show that biotin shampoo or any other hair product can make your hair grow faster or thicker.

Related: Biotin for Nail Growth

Biotin deficiency is believed to be uncommon. Bacteria in the intestines usually provides more than the body's daily requirements and biotin is also in a variety of common foods. 

Most people can meet their daily biotin needs by consuming biotin-rich foods like brewer's yeast, nutritional yeast, liver, cauliflower, salmon, bananas, carrots, cooked egg yolks, sardines, nuts, legumes, and mushrooms.

The U.S. Food and Drug Administration (FDA) has not established a recommended dietary allowance (RDA) for biotin. According to the Food and Nutrition Board of the Institute of Medicine, 30 mcg is the daily adequate intake for adults 19 years of age and older, which can usually be achieved through dietary consumption.

Deficiency can occur in people who drink alcohol excessively or consume a great deal of raw egg white (which contains avidin, a protein that blocks the absorption of biotin). Two or more uncooked egg whites daily for several months has been known to result in biotin deficiency.

Genetic disorders of biotin deficiency (such as biotinidase deficiency), renal dialysis, and smoking may also increase your need for biotin. Certain drugs may reduce biotin levels, such as carbamazepine and other anticonvulsants, antibiotics, or isotretinoin.

Since biotin is produced in the intestines, people with inflammatory bowel disease or other conditions that can disrupt the balance of bacteria in the intestines may not be able to adequately produce biotin.

If you notice any symptoms of deficiency, consult your health care provider. Symptoms include thinning of the hair, brittle nails, dry skin, a red scaly rash (especially around the eyes, nose, and mouth), conjunctivitis, depression, exhaustion, hallucinations, and numbness and tingling of the arms and legs.

Biotin supplements can cause problems if you ingest too much. Side effects can include skin rashes, digestive upset, problems with insulin release, and kidney problems. According to a report published in the New England Journal of Medicine, biotin treatment was said to interfere with laboratory tests and mimic Graves' disease. As with any supplement, the safety of long-term or high-dose use isn't known. 

Although there is no recommended dietary allowance for biotin, proponents often recommend taking 2 to 5 mg (2000 to 5000 mcg) of biotin in supplement form daily in order to strengthen hair shafts and achieve results. Although biotin is a water-soluble vitamin (the excess is excreted in urine and feces), there is no evidence to support this recommendation and the safety of regular use of this amount isn't known.

As with other supplements, biotin hasn't been tested for safety in pregnant women, nursing mothers, children, and those with medical conditions or who are taking medications. You can find out more about how to use supplements safely here.

Most people get the daily recommended amount of biotin from their diet. Food sources of biotin (in micrograms per 100 grams) include:

• Egg yolk (53)
• Oats (27.0)
• Wheat germ (17.0)
• White mushrooms (16)
• Spinach (6.9)
• Cheese, brie (6.2)
• Milk (3.5)
• Pork (5.0)
• Carrot (5.0)
• Apple (4.5)
• Tomato (4.0)
• Beef (3.0)
• Chicken (2.0)
• Lettuce (1.9)

Thinning hair and hair loss can be very distressing. If you've noticed that you're losing your hair or that your hair is thinning, it's important to see your health care provider to determine the cause. Hair loss, particularly in women, can have an underlying cause other than biotin deficiency, like nutritional deficiencies, androgenic alopecia (also called pattern hair loss), and hormone imbalances (such as thyroid troubles).

Although you may be eager to halt the hair loss, taking biotin tablets or supplements without being assessed poses the risk that diagnosis and treatment of the underlying cause will be delayed. 

Although biotin deficiency is considered rare, it can result in hair loss that can be addressed with supplementation. If you have symptoms of biotin deficiency or are thinking of taking it, be sure to talk with your healthcare provider to assess your levels and discuss what's best for you.