Collagen is a protein responsible for healthy joints and skin elasticity, or stretchiness. It’s in your bones, muscles, and blood, comprising three quarters of your skin and a third of the protein in your body.

Biotin is a vitamin found in foods like eggs, milk, and bananas. Biotin deficiency can cause thinning of the hair and a rash on the face. Biotin is an important part of enzymes in the body that break down substances like fats, carbohydrates, and others.

As you age, your existing collagen breaks down, and it gets harder for your body to produce more. As a result, many people turn to collagen supplements. These supplements are usually powders, though there are also capsules and liquid supplements available.

There isn't a good test for detecting low biotin levels, so it's usually identified by its symptoms, which include thinning hair and red scaly rash around the eyes, nose, and mouth. Biotin is used for biotin deficiency. It is also commonly used for hair loss, brittle nails, and other conditions.

Collagen is also produced naturally in the body by combining amino acids, the building blocks of proteins found in food.