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How SHBG Genetics Affect Your Testosterone and Wellbeing

Testosterone supports energy, mood, muscle mass, bone health, and reproductive function. In blood, most testosterone is bound to a protein called sex hormone-binding globulin or SHBG. Only the unbound portion, often called free or bioavailable testosterone, is active at tissues. Variations in the SHBG gene change how much SHBG your liver makes, which directly shifts how much free testosterone is available. That can influence symptoms and long-term health risks in different ways for people of different sexes.

Why SHBG matters

  • High SHBG = more testosterone bound and less free testosterone available for cells to use.
  • Low SHBG = more free testosterone but may come with different metabolic consequences.
  • Total testosterone tests do not always reveal free testosterone status. Measuring SHBG plus total and free testosterone gives a clearer picture.

Genetic variation at rs12150660

The rs12150660 variant in the SHBG gene influences SHBG production. Below are the common genotypes and how they typically affect SHBG and free testosterone.

2 effect alleles (GG) — Higher SHBG, lower free testosterone

If you have the GG genotype, you carry two copies of the effect allele. This is associated with higher SHBG production by the liver and a lower amount of free, bioavailable testosterone. Total testosterone may still fall within a normal range, but the fraction available to tissues is reduced.

Potential effects

  • Lower energy, reduced libido, or decreased muscle mass if free testosterone becomes low enough to cause symptoms.
  • In women, higher SHBG can be metabolically protective but may contribute to lower libido or changes in bone density over time.
  • In men, elevated SHBG with low free testosterone can increase risk for metabolic and cardiovascular issues if not addressed.
1 effect allele (GT) — Moderately higher SHBG, somewhat lower free testosterone

If you have the GT genotype, you carry one copy of the effect allele. You are likely to have moderately elevated SHBG with a corresponding modest reduction in free testosterone compared with those without the G allele. Total testosterone may look normal while free testosterone is somewhat lower.

Potential effects

  • Possible mild symptoms like lower energy, reduced muscle recovery, or subtle changes in mood or libido depending on your sex and overall health.
  • In women, a moderate SHBG increase may help metabolic health but could affect bone health or sexual desire in some cases.
  • In men, watch for emerging metabolic symptoms or low-energy signs if free testosterone becomes insufficient.
0 effect alleles (TT) — Typical SHBG, higher free testosterone

If you have the TT genotype, you carry two copies of the non-effect allele. This is associated with typical SHBG production and a higher proportion of free testosterone compared with the other genotypes at this locus. This pattern generally supports healthy energy, muscle mass, mood, and metabolic balance.

Practical note

  • Your genetic profile suggests a favorable baseline for free testosterone. Maintaining healthy lifestyle habits is usually sufficient to support optimal hormonal function.

Diet and nutrition strategies to support balanced testosterone

  • Aim to reduce refined sugars and highly processed carbs. Lowering sugar intake helps improve insulin sensitivity, which can indirectly normalize SHBG and sex hormone balance.
  • Prioritize protein at each meal to support muscle mass and hormone production. Include lean meats, fish, eggs, dairy, legumes, and plant proteins.
  • Include healthy fats for hormone synthesis, such as avocados, olive oil, nuts, seeds, and fatty fish. Avoid excess trans fats.
  • Eat a variety of colorful vegetables and fruits to reduce inflammation and provide micronutrients important for hormone regulation.
  • Consider foods that support liver health, since SHBG is produced in the liver: cruciferous vegetables, fiber-rich whole grains, and antioxidant-rich foods.

Supplements and nutrients to consider

Supplements can help when dietary intake or blood levels are low. Discuss supplements with your healthcare provider before starting.

  • Zinc: supports testosterone production and overall hormonal health. Found in oysters, red meat, pumpkin seeds, and legumes.
  • Magnesium: helps with sleep, muscle recovery, and hormone balance. Sources include leafy greens, nuts, seeds, and whole grains.
  • Vitamin D: plays a role in testosterone levels and immune health. Get safe sun exposure and consider supplementation if blood levels are low.
  • Boron: may support free testosterone by influencing hormone metabolism. Found in nuts, fruit, and legumes.
  • Omega-3 fatty acids: anti-inflammatory fats from fatty fish or algae supplements support metabolic and cardiovascular health.

Lifestyle actions to lower inflammation and support hormones

  • Regular exercise: combine resistance training to preserve and build muscle with aerobic activity to improve metabolic health. Resistance training can help raise free testosterone and improve body composition.
  • Prioritize restorative sleep: aim for consistent nightly sleep duration and quality. Poor sleep raises inflammation and can lower free testosterone.
  • Limit alcohol intake: excess alcohol increases SHBG and can disrupt hormone balance.
  • Avoid endocrine disruptors: reduce exposure to certain plastics, BPA, phthalates, and other chemicals by choosing glass or stainless steel for food storage and minimizing use of heavily scented personal care products.
  • Maintain a healthy weight: excess body fat affects sex hormone metabolism and SHBG levels; modest weight loss when appropriate can improve free testosterone.

Testing and monitoring

  • To understand hormone status beyond genetics, test total testosterone, free testosterone (or free testosterone calculated from total and SHBG), and SHBG directly.
  • Track symptoms alongside lab values. Genetics set a baseline tendency but lifestyle, health conditions, medications, and age determine current hormones.
  • Recheck labs after making targeted lifestyle or supplement changes to see what is affecting your free testosterone and SHBG.

When to consult your healthcare provider

  • If you have persistent symptoms such as low libido, fatigue not explained by other causes, unexplained muscle loss, or mood changes, discuss testing and evaluation with your provider.
  • Do not start hormone replacement therapy or make major changes to prescription medications without medical supervision.

PlexusDx provides genetic information to help you understand potential predispositions but does not provide medical advice. Use this information as an educational resource and consult your healthcare provider for diagnosis, medical decisions, and personalized treatment. Genetics are one piece of the puzzle; lab tests, medical history, and clinical evaluation are essential for safe, effective care.