β-Hydroxyisovaleric acid is primarily used in the field of biochemistry and medical research. It serves as a biomarker for the assessment of biotin deficiency in humans. Elevated levels of this compound in urine can indicate a lack of biotin, which is crucial for metabolic processes. Additionally, it is utilized in metabolic studies to understand disorders related to leucine metabolism. In the cosmetic industry, it is sometimes incorporated into formulations for its potential skin-conditioning properties, helping to improve skin texture and hydration. Its role in these applications highlights its importance in both health diagnostics and personal care products.