Biotin (B7)
The beauty vitamin with metabolic depth. Biotin (vitamin B7) is famous for hair, skin, and nails, but its real job is serving as a cofactor for carboxylase enzymes that handle fatty acid synthesis, gluconeogenesis, and amino acid metabolism. Deficiency is rare thanks to gut bacteria that produce it.
What Biotin Does
Fatty Acid Synthesis
Acetyl-CoA carboxylase needs biotin. First step in making new fatty acids.
Gluconeogenesis
Pyruvate carboxylase needs biotin. Creates glucose from non-carb sources.
Amino Acid Metabolism
Propionyl-CoA carboxylase needs biotin. Processes branched-chain amino acids.
Gene Regulation
Biotinylation of histones affects gene expression. Epigenetic role.
Cell Signaling
Involved in cell proliferation and immune cell function.
Keratin Structure
Supports hair, skin, and nail protein synthesis. The beauty connection.
Sources & Deficiency
Food Sources
- Egg yolks: One of best sources (cook them)
- Liver: Highest concentration
- Nuts & seeds: Especially almonds, peanuts
- Salmon & sardines: Good fish sources
- Sweet potato, avocado: Plant sources
Deficiency Signs
- Hair loss: Thinning, brittle hair
- Skin rash: Scaly, red rash around eyes, nose, mouth
- Brittle nails: Easy cracking
- Neurological: Depression, lethargy, numbness
- Conjunctivitis: Eye inflammation
Important Cautions
Lab Test Interference
High-dose biotin falsifies thyroid tests, troponin, and other biotin-based assays. Stop 48-72h before labs.
Raw Egg Whites
Avidin in raw egg whites binds biotin tightly. Cooking denatures avidin. Don't eat raw whites regularly.
Antibiotics
Long-term antibiotics kill gut bacteria that produce biotin. May need supplementation.
Mega-Dosing
5000-10000 μg common in supplements. Far exceeds needs. May not help if not deficient.