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Last reviewed: May 12, 2026 Last updated: May 12, 2026

Written by: Jay Hastings , CEO of PlexusDx

Jay Hastings is the CEO of PlexusDx, a precision health company focused on genetic testing, blood biomarker insights, and personalized wellness recommendations. He has more than 20 years of experience across healthcare innovation, genomics, laboratory operations, healthcare investing, and strategic finance. His work has included scaling healthcare startups, leading CLIA lab integrations, and helping expand consumer access to precision health tools.

Medically reviewed by: Jayden Lee, PharmD, EMBA

Jayden Lee, PharmD, EMBA, is the PlexusDx Medical Science Liaison with a PharmD and MBA specializing in pharmacogenomics and clinical product development, with a proven ability to bridge the gap between genomic research and practical patient outcomes. Dr. Lee has more than 10 years of professional experience in clinical pharmacy, academia, and research.

Biotin and the BTD Gene

Biotin, also called vitamin B7, is a water-soluble vitamin that helps convert food into usable energy. It plays a key role in fat synthesis, amino acid breakdown, and blood sugar regulation. The BTD gene makes the enzyme biotinidase, which recycles biotin from foods and from the normal turnover of biotin-dependent enzymes. Variants in BTD can reduce biotinidase activity and raise the chance of functional biotin deficiency, especially during life stages or situations with higher nutrient demand such as growth, pregnancy, illness, or intense exercise.

How biotinidase affects your body

  • Biotin recycling: Biotinidase frees biotin from proteins so your body can reuse it for key metabolic reactions.
  • Energy and metabolism: Adequate biotin supports carbohydrate, fat, and protein metabolism and contributes to stable blood sugar and energy production.
  • When lower activity matters: Reduced biotinidase activity can make it harder to maintain optimal biotin levels, which may show up as low energy, hair or skin changes, or challenges during periods of increased need.

Understanding your genetic result

The single nucleotide polymorphism rs13073139 in the BTD gene is linked with differences in biotinidase enzyme activity. Below are clear, genotype-specific explanations and practical steps you can take to support biotin status.

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, which may limit your ability to efficiently recycle biotin from food and normal cell processes. That can increase the risk of functional biotin deficiency during higher demand periods such as growth, pregnancy, intense training, or illness.

Practical steps:

  • Diet: Prioritize biotin-rich foods daily — thoroughly cooked eggs, dairy, legumes, nuts, seeds, whole grains, and green vegetables.
  • Gut health: Eat fiber-rich plants and include fermented foods to support microbiome bacteria that can produce biotin.
  • Cooking tip: Cook eggs fully to neutralize avidin, a protein in raw egg whites that interferes with biotin absorption.
  • Supplementation: Consider clinician-guided biotin supplementation if dietary intake is limited or during high-demand periods. Your clinician can recommend dose and duration.
  • Monitoring: Watch for signs of low biotin (fatigue, hair thinning, skin rashes) and discuss testing with your healthcare provider if concerns arise.
One effect allele — AG (likely reduced biotinidase activity)

If you have the AG genotype, you carry one copy of the effect allele and one non-effect allele. This genotype is associated with likely reduced biotinidase activity. Your body may not reclaim biotin as efficiently as someone without this variant, which can raise the risk of functional biotin deficiency during times of increased need.

Practical steps:

  • Diet: Include a variety of biotin sources — cooked eggs, dairy, legumes, nuts, seeds, whole grains, and leafy greens — several times per week.
  • Gut support: Maintain a fiber-rich diet and add fermented foods to encourage beneficial bacteria that assist in biotin production.
  • Active periods: During pregnancy, growth, intense training, or illness, increase attention to nutrient-dense meals and discuss supplementation with a clinician if needed.
  • Test and track: If you experience symptoms or have other risk factors, ask your healthcare provider about nutrient testing and follow-up.
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 activity, meaning your BTD enzyme likely recycles biotin efficiently. Even so, biotin is water-soluble and not stored long-term, so regular dietary intake remains important.

Practical steps:

  • Balanced diet: Continue including biotin-rich foods like cooked eggs, dairy, legumes, nuts, seeds, and whole grains on a regular basis.
  • Gut microbiome: Support your microbiome with fiber and fermented foods to complement dietary biotin.
  • Life stages: During growth, pregnancy, illness, or intense training, prioritize nutrient-dense meals. Discuss additional testing or supplementation with your provider if needs increase.
  • Food safety: Cook eggs fully to avoid avidin-related interference with biotin absorption from raw egg whites.

Diet recommendations

  • High-biotin foods: Cooked eggs, liver and other organ meats, dairy products, nuts (especially almonds and peanuts), seeds, legumes, whole grains, and some vegetables such as cauliflower and sweet potatoes.
  • Meal pattern: Aim for regular, nutrient-dense meals rather than long fasting periods to support steady vitamin availability.
  • Cooking: Avoid frequent consumption of raw egg whites. Heat deactivates avidin and reduces risk of biotin binding.
  • Fiber and fermented foods: Add whole fruits, vegetables, beans, whole grains, and fermented foods like yogurt, kefir, sauerkraut, or kimchi to promote a healthy microbiome that supports vitamin production.

Supplement considerations

  • When to consider supplements: If dietary intake is low, you have increased needs, or if testing/clinician assessment suggests low biotin, a supplement under clinical guidance can help restore optimal levels.
  • Consult your clinician: A healthcare provider can recommend an appropriate dose and rule out interactions with other medications or conditions.
  • Form and safety: Biotin is generally well tolerated because it is water-soluble, but clinicians may monitor levels if high-dose supplementation is used long-term.

Lifestyle and monitoring

  • Watch for symptoms: Low energy, unexplained hair thinning or brittle nails, and skin changes can be signs to raise with your clinician.
  • Life stage awareness: Pregnancy, infancy, adolescence, and periods of intense training or illness increase nutrient demand — plan diet and testing accordingly.
  • Testing: Discuss laboratory testing for biotin status and biotinidase activity with your healthcare provider if you have symptoms or a family history of metabolic issues.
  • Medication review: Some medications or prolonged antibiotic use can affect gut bacteria and nutrient status; review medications with your clinician.

Next steps

Use your genetic information to inform conversations with your healthcare provider. Focus on a balanced diet, gut health, and awareness during higher demand periods. If you are considering supplements or have signs of low biotin, ask your clinician about testing and personalized guidance.

PlexusDx provides educational information about genetic predispositions only and does not provide medical advice. Always consult your healthcare provider before starting or stopping any supplement, making significant diet changes, or if you have health concerns. Your clinician can interpret genetic results in the context of your overall health, medical history, medications, and current laboratory testing.

If this genetic variant is present in your PlexusDx results, the following tests and reports are commonly used to explore it further:

🧬 Genetic Tests:

🧪 Blood Tests:

📄 Genetic Report:

Frequently Asked Questions About Biotin and BTD rs13073139

How does the BTD rs13073139 variant affect biotin recycling?

The BTD gene helps produce biotinidase, an enzyme that recycles biotin so your body can reuse it for key metabolic reactions. rs13073139 is linked with differences in biotinidase activity—AA is associated with reduced activity, AG with likely reduced activity, and GG with typical activity—so carriers of effect alleles may be more prone to functional biotin deficiency, especially when nutrient demand is higher.

What biotin-rich foods and meal habits support people with reduced biotinidase activity?

To support biotin status, prioritize regular intake of biotin-rich foods such as cooked eggs, dairy, legumes, nuts and seeds, whole grains, and vegetables like cauliflower and sweet potatoes. Choose nutrient-dense meals rather than long fasting, and support your microbiome with fiber and fermented foods (e.g., yogurt, kefir, sauerkraut, kimchi). Also cook eggs thoroughly because raw egg whites contain avidin, which can interfere with biotin absorption.

When should I consider biotin testing or supplementation if I have the rs13073139 variant?

If you have symptoms associated with low biotin (such as low energy, hair thinning, brittle nails, or skin rashes) or you’re in a higher-demand life stage (growth, pregnancy, illness, or intense training), discuss laboratory testing for biotin status and/or biotinidase activity with your healthcare provider. If dietary intake is limited or clinician assessment suggests low levels, supplementation may be considered under medical guidance; biotin is generally well tolerated, but dosing and duration should be personalized.

What tests can help me learn more about Biotin and BTD rs13073139?

The Optimal Diet and Weight Loss Genetic Test delivers over 295 genetic insights related to nutrition response, body composition, metabolism, and fitness. The Diet and Nutrition Genetic Report translates your results into personalized, actionable guidance. Your healthcare provider can also recommend targeted blood tests based on your specific pathway results and health history to complement your genetic insights with current biomarker data.

Medical and Editorial Standards

Medical review process: This article was reviewed for medical accuracy, scientific clarity, evidence alignment, and appropriate discussion of genetics, medications, supplements, biomarkers, and health-related claims.

Sources and evidence: PlexusDx educational content is developed using peer-reviewed research, clinical literature, reputable medical references, and, where applicable, public health or regulatory guidance. References are included at the end of the article when scientific, medical, or health-related claims are discussed.

Commercial transparency: PlexusDx offers genetic testing, blood biomarker testing, personalized supplement recommendations, and related precision wellness services. Product mentions are intended to help readers understand available options and should not be interpreted as medical advice.

Important disclaimer: PlexusDx educational content is for informational purposes only and should not be used as a substitute for professional medical advice, diagnosis, or treatment. Always consult a qualified healthcare provider before making decisions about medications, supplements, genetic testing, lab testing, or health-related care.