Does biotin cause weight gain?

Despite some claims of people gaining weight while taking biotin supplements, there is not sufficient evidence connecting biotin intake to weight gain.

Outside of anecdotal claims, it's difficult to find any evidence that biotin causes weight gain on its own, and there simply aren’t many studies that investigate a connection between biotin and weight gain. While there may be a wide range of theories linking biotin supplementation to weight gain, research is very limited.

One theory that sometimes emerges is that some people who take biotin supplements believe that doing so allows them to eat more without gaining weight. Biotin helps the body convert the carbohydrates, fats and proteins you eat into energy. Some people believe that increasing their intake of B vitamins such as biotin can help them boost their metabolism. As a result, they may consume more calories than recommended, leading to weight gain.

It's unlikely that most healthy people would have a medical need for extra biotin. There's no recommended dietary allowance (RDA) since there's not enough evidence to suggest the need for a daily amount. However, there is an adequate intake (AI) level, which is the amount assumed to ensure nutritional adequacy. For most men and women older than 19, the level is 30 micrograms. It's very rare to have a biotin deficiency, as the vitamin is found in a variety of dietary sources, such as beef liver, cooked eggs, salmon, avocados, pork, sweet potatoes, nuts and seeds.

On the other hand, increasing the amount of biotin in your diet likely wouldn't be harmful. No side effects have been found for those who have taken up to 10 milligrams of biotin supplements daily. 

When it comes to health goals like losing or gaining weight, it's difficult to say whether you should purposefully avoid or increase any intake of biotin. Studies indicating that biotin causes weight gain are limited. Most claims associated with biotin are loosely supported by very little credible evidence. When it comes to your intake of biotin, especially regarding biotin supplements, it's always best to consult your healthcare provider so they can help you find the safest option for you and your health goals.

Published June 2022.