Vitamin B7 (Biotin; Vitamin H)

Vitamin B7, also known as biotin or vitamin H, is a water-soluble B vitamin that the body cannot store in significant amounts. It acts as an essential coenzyme for several carboxylase enzymes involved in fatty acid synthesis, gluconeogenesis, and amino acid metabolism. This test measures the concentration of biotin in a simple blood sample, typically using a validated immunoassay or liquid chromatography tandem mass spectrometry (LC-MS/MS) method, to assess whether your levels are sufficient.

This test is for anyone experiencing unexplained hair thinning or loss, skin rashes, brittle nails, or neurological symptoms such as numbness, tingling, or muscle weakness, which can sometimes point to biotin deficiency. It is also useful for individuals with malabsorption conditions (such as Crohn's disease or coeliac disease), those on long-term anticonvulsant therapy, or people who have been consuming large amounts of raw egg whites, which can interfere with biotin absorption. Additionally, it can help clarify whether biotin supplementation is adequate or excessive, particularly when high-dose biotin is taken for hair or nail health, as very high levels can interfere with certain laboratory tests.

Biomarkers included

Vitamin B7
- Vitamin B7 (biotin; vitamin H)

Why it matters
Biotin is vital for energy metabolism, healthy hair and skin, and normal nervous system function. Deficiency is uncommon but can occur in specific groups, and symptoms are often subtle and easily attributed to other causes. Measuring biotin directly helps identify a true deficiency or confirm adequate status, guiding appropriate dietary or supplemental adjustments. Because high-dose biotin can distort the results of other immunoassays (for example thyroid or cardiac tests), knowing your biotin level is also important for accurate interpretation of other blood results.