Biotin and Your BTD Gene: What Your Genotype Means for Energy, Skin, Hair, and Metabolism
Biotin, also called vitamin B7, is a water soluble nutrient that helps convert food into usable energy. It supports fat synthesis, amino acid breakdown, and blood sugar balance. The BTD gene makes the enzyme biotinidase, which recycles biotin from proteins and cellular turnover so your body can use it again. Variants in BTD can change enzyme activity and influence how well your body maintains biotin levels.
Why biotin and biotinidase matter
- Biotin is essential for enzymes that support energy production, healthy hair, skin, and nails, and normal metabolism.
- Biotinidase recovers biotin from dietary and cellular sources so it can be reused. If this recycling is reduced, you may rely more on dietary intake and gut production.
- Biotin is water soluble and not stored long term. Needs can rise during growth, pregnancy, illness, and intense exercise.
How to read this report
This section explains general implications of different genotypes at rs34885143 in the BTD gene and practical steps you can take. It is educational only. PlexusDx does not provide medical advice. Always consult your healthcare provider before changing supplements, medications, or medical testing.
Genetic interpretations
Two effect alleles (AA) — reduced biotinidase activity
If you have the AA genotype, you carry two copies of the effect allele. This is associated with reduced biotinidase enzyme activity. Lower recycling means your body may reclaim biotin less efficiently from food and normal cell turnover. That could increase the risk of a functional biotin shortfall, especially during higher demand such as growth, pregnancy, illness, or intense training.
What to prioritize
- Eat biotin rich foods regularly: cooked eggs, dairy, legumes, nuts, seeds, and whole grains.
- Support gut bacteria with fiber and fermented foods so microbial biotin production can help.
- Consider discussing a low to moderate dose biotin supplement with your clinician if concerns arise. Very high doses can interfere with some lab tests and clinical decisions.
- Watch for signs of low biotin: unexplained fatigue, hair thinning, brittle nails, skin rashes, or changes in mood. Bring symptoms to your healthcare provider.
One effect allele (AG) — likely reduced biotinidase activity
If you have the AG genotype, you carry one copy of the effect allele. This is associated with likely reduced biotinidase activity and a somewhat decreased ability to recycle biotin. You may still maintain adequate levels with a balanced diet, but your margin of safety is narrower during times of higher need.
What to prioritize
- Include biotin rich foods in regular meals: thoroughly cooked eggs, dairy, legumes, nuts, seeds, and whole grains.
- Promote a healthy gut microbiome with fiber rich vegetables, fruits, and fermented foods such as yogurt, kefir, or other fermented choices.
- If you experience hair, skin, nail, or energy concerns, discuss low to moderate biotin supplementation with your healthcare provider, especially during pregnancy or intense training.
- Tell clinicians about any biotin supplement use before lab testing because high dose biotin can distort certain lab results.
No effect alleles (GG) — typical biotinidase activity
If you have the GG genotype, you carry two copies of the non effect allele. This is associated with typical biotinidase enzyme activity. Your body should recycle biotin efficiently and maintain adequate levels through normal dietary intake and gut production.
What to prioritize
- Maintain a balanced diet with biotin rich foods like cooked eggs, dairy, legumes, nuts, seeds, and whole grains.
- Support gut health with a variety of fiber rich plant foods and fermented options to help microbial biotin synthesis.
- Remember that biotin is water soluble. Intake consistency matters during pregnancy, illness, and intense training when needs increase.
Dietary recommendations
- Regularly include cooked eggs. The protein matrix in raw egg white can bind biotin, so fully cooked eggs are a better source.
- Choose dairy such as milk, yogurt, and cheese when tolerated for additional biotin and complementary nutrients.
- Add legumes, nuts, and seeds as snacks or in meals to boost biotin plus fiber and healthy fats.
- Prefer whole grains over refined grains for a steady supply of B vitamins including biotin precursors.
- Eat a variety of fruits and vegetables to support overall nutrient status and gut microbiome health.
Supplement considerations
- Low to moderate biotin supplementation may be appropriate when dietary intake is low or during increased demand. Discuss dose and duration with your healthcare provider.
- A standard supplemental dose used for general support is much lower than pharmacologic doses used for some medical treatments. Avoid very high doses unless guided by a clinician.
- Tell any clinician ordering lab tests that you are taking biotin. High dose biotin can interfere with multiple lab assays, including some hormone and cardiac tests.
Lifestyle and gut health
- Support your microbiome. A diverse, fiber rich diet and fermented foods help beneficial bacteria that can produce biotin.
- Manage stress, prioritize sleep, and maintain regular physical activity. These support overall nutrient balance and metabolic resilience.
- During pregnancy, growth periods, illness, or heavy training, revisit dietary intake and supplement needs with your clinician.
When to check labs and talk to your clinician
- If you notice persistent fatigue, hair loss, brittle nails, skin changes, or new neurologic symptoms, discuss evaluation with your healthcare provider.
- Ask about nutrient testing if symptoms suggest deficiency or if you plan to start high dose biotin.
- Always inform clinicians about supplements before blood testing to avoid misinterpretation of results.
Final notes
Your BTD genotype indicates how efficiently your body recycles biotin. Whether you carry zero, one, or two effect alleles, simple diet and lifestyle steps can help maintain healthy biotin levels. If you have concerns or are considering supplements, especially during pregnancy, growth, illness, or intense training, consult your healthcare provider for personalized guidance.
Disclaimer: PlexusDx provides educational information about genetic predispositions only. This content is not medical advice. Always consult your healthcare provider before making changes to supplements, diet, or medical care.

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