Biotin has recently emerged as an interesting research topic, particularly as it is linked to something that affects millions of people: baldness.

Biotin, also called vitamin H, vitamin B7, or even vitamin B8, is involved in a wide range of metabolic processes. Like any vitamin, biotin is not stored in our bodies — it must be obtained regularly through diet. Biotin plays a role in how our body utilizes fats, carbohydrates, and amino acids.

It’s rare, though not impossible, for people to suffer from vitamin B7 deficiency. People who smoke, are pregnant, or drink alcohol regularly have a higher risk of being deficient in B7, but in the developed world, this is not a major problem. When an individual is indeed biotin-deficient, they will start to experience symptoms. These symptoms include changes in mood, pain, and aches in muscles, dry skin, hair loss, chronic fatigue, lack of muscle coordination, seizures, and lethargy.

Biotin deficiency has been linked with a number of metabolic issues. The symptoms aren’t usually severe, but they can range from hair thinning and brittle fingernails to skin rashes, most commonly on the face. Egg yolk, nuts, legumes, and seeds are all excellent sources of biotin.

The vitamin has gained a lot of attention — particularly in the 80s when countries started testing at birth. Here’s what we know about it so far.

Biotin and metabolism

As mentioned, biotin plays an important role in regulating some parts of metabolism. It helps break down carbs, fat, and amino acids, producing energy. Some studies have found that biotin, when combined with supplemental chromium, can accelerate the metabolic rate.

But don’t get your hopes up for weight loss just yet — this was a study on 447 people suffering from poorly managed type 2 diabetes, and supplements of biotin and chromium were suggested to “improve glycaemic control in overweight to obese individuals with type 2 diabetes.”

It’s encouraging, but it’s not entirely clear what this means for other people. It’s plausible that a healthy amount of biotin can be helpful, but more research is needed at this point.

Biotin and hair loss

This is perhaps where the most interest in biotin comes from. The vitamin is often recommended as a supplement against hair loss and nail problems, and there is some scientific data to support this, but it’s not entirely clear.

For instance, research has shown that biotin supplements are associated with improved hair and nail growth, but the participants’ biotin levels weren’t measured in the study, and it is possible that another factor is affecting the results.

Biotin and nails

Similar to hear, scientific evidence does exist, but it is not entirely clear. For instance, one study concluded that “none of the patients considered the treatment altogether ineffective” and “biotin in most of the cases provides an effective therapy also for human patients with brittle nails”.

However, there have only been a handful of studies on this topic — yet again, they are encouraging, but additional studies are required to shed more light on this effect.

Regulating blood sugar

Another area where biotin has shown promise is regulating blood sugar. Animal studies have suggested that biotin can stimulate the production of insulin, a hormone which lowers blood sugar.

This has further been confirmed in a 2016 study which concluded that biotin might help with glycemic control in people with type 1 diabetes.

The bottom line

At this point, biotin has been shown to be useful in a number of metabolic processes. Although the full extent of these processes is not fully understood, there is little downside to biotin.

At this moment, there is no evidence that biotin can cause toxicity in the human body, even with high-intake. Because it is a water-soluble vitamin, any excess will leave through the urine and there is no established upper limit for biotin.