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.

How SHBG Gene Variations Affect Testosterone Availability

Testosterone is a key hormone that affects muscle mass, libido, mood, energy, and fertility. Much of the testosterone in the bloodstream is bound to a protein called sex hormone binding globulin or SHBG. When testosterone is bound to SHBG it is inactive. Only unbound, or free, testosterone can enter cells and carry out its effects. Variations in the SHBG gene can change how much SHBG you produce, which in turn alters how much testosterone is bound versus free. This article explains what those genetic patterns mean and offers practical, evidence informed lifestyle and supplement strategies to support healthy testosterone availability.

Why SHBG Matters

SHBG serves as a regulator of hormone activity. Higher SHBG typically means more testosterone is bound and less is available to tissues. That can show up as lower libido, reduced muscle mass, fatigue, or mood changes in some people. Lower SHBG can increase free testosterone, which may be desirable for certain symptoms but can also have downsides if levels become too high. Understanding your SHBG genotype gives useful context for how lifestyle and targeted choices may help maintain balanced hormones.

Practical Ways to Support Healthy Free Testosterone

  • Diet: Emphasize a high protein intake with lean meats, fish, eggs, and legumes. Adequate protein supports muscle and may favor healthy testosterone balance.
  • Limit endocrine disruptors: Avoid unnecessary exposure to plastics and synthetic chemicals that can raise SHBG and interfere with hormone signaling. Use glass or stainless steel for food storage and limit handling of receipts.
  • Alcohol: Limit alcohol intake. Excessive alcohol can raise SHBG and reduce free testosterone.
  • Sleep: Aim for 7 to 8 hours of quality sleep each night. Poor sleep lowers testosterone production and may increase SHBG.
  • Exercise: Regular moderate resistance training and high intensity interval training help maintain and raise free testosterone and support muscle mass and mood.
  • Anti inflammatory diet: Eating whole foods, omega 3 rich fish, vegetables, fruits, and minimizing processed foods supports overall hormonal balance.
  • Weight management: Maintain a healthy body composition. Excess body fat, especially visceral fat, can alter hormone metabolism and SHBG levels.

Supplements to Consider If Symptoms Occur

Supplements may help when symptoms of low free testosterone appear, but they are not a substitute for medical evaluation. Speak with your healthcare provider before starting any supplement. Options commonly discussed include:

  • Boron: May increase free testosterone in some people by affecting SHBG and hormone metabolism.
  • Ashwagandha: An adaptogen that can support stress resilience and has been associated with increased testosterone in some studies.
  • Shilajit: A mineral rich resin used traditionally that some research links to improved testosterone markers.
  • Zinc: Important for testosterone production. Zinc deficiency can lower testosterone, so correcting low zinc can help.

Genetic Interpretations for rs6259

Two effect alleles: AA

Genotype: AA. You carry two copies of the effect allele associated with higher SHBG levels. This tends to increase the amount of testosterone that is bound and reduce the fraction that is free and biologically active. You may be more likely to notice symptoms associated with reduced free testosterone such as lower libido, reduced energy, difficulty gaining or maintaining muscle, or changes in mood.

Practical steps

  • Prioritize high quality dietary protein from lean meats, fish, eggs, and legumes to support muscle and hormone balance.
  • Minimize exposure to plastics and synthetic chemicals that can further raise SHBG.
  • Limit alcohol intake to moderate levels.
  • Aim for 7 to 8 hours of quality sleep nightly.
  • Engage in regular resistance training and include some high intensity interval sessions each week.
  • Consider discussing supplements such as boron, ashwagandha, shilajit, or zinc with your healthcare provider if you have symptoms of low free testosterone.
  • If symptoms are significant, ask your provider about hormone testing including total and free testosterone, SHBG, and other relevant labs.
One effect allele: AG

Genotype: AG. You carry one copy of the effect allele which is associated with a likely increase in SHBG and a corresponding tendency for more testosterone to be bound. The impact is typically milder than with two effect alleles but may still influence free testosterone and related symptoms in some people.

Practical steps

  • Follow a protein rich diet emphasizing lean meats, fish, eggs, and legumes to help maintain healthy hormone balance.
  • Avoid unnecessary exposure to plastics and hormone disrupting chemicals.
  • Limit alcohol and prioritize consistent 7 to 8 hours of quality sleep each night.
  • Maintain regular strength training and moderate aerobic exercise to support testosterone production and body composition.
  • If you experience symptoms such as low energy, low libido, or decreased muscle mass, consider discussing supplements like boron, ashwagandha, shilajit, or zinc with your healthcare provider and ask about hormone testing if appropriate.
Zero effect alleles: GG

Genotype: GG. You carry two copies of the non effect allele, which is the typical pattern associated with standard SHBG binding activity. Your genotype suggests a typical balance between bound and free testosterone.

Practical steps

  • Continue lifestyle habits that support healthy testosterone: a diet rich in protein, regular resistance exercise, good sleep habits, and limiting alcohol.
  • Reduce exposure to known endocrine disruptors in plastics and household chemicals.
  • Consider proactive measures such as an anti inflammatory diet and maintaining healthy body composition to preserve hormone balance as you age.
  • If symptoms of low testosterone occur, work with your healthcare provider to evaluate symptoms and consider laboratory testing before starting supplements.

Testing and When to Talk to Your Provider

If you have symptoms such as persistent low libido, fatigue, loss of muscle mass, or mood changes, discuss them with your healthcare provider. They may order blood tests that include total testosterone, free testosterone or calculated free testosterone, SHBG, and other hormones as indicated. Genetic information is one piece of the picture and is most useful when combined with symptoms, labs, and a clinical evaluation.

PlexusDx provides educational information about genetic predispositions only. This content is not medical advice. Always consult your healthcare provider before making changes to your diet, supplements, exercise, or medical care.

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 Testosterone and SHBG rs6259

How do SHBG gene variations (rs6259) affect free vs. bound testosterone?

SHBG binds testosterone in the bloodstream and makes it inactive. Variations in the SHBG gene can influence how much SHBG you produce, which changes the balance between bound testosterone and free (biologically active) testosterone—potentially impacting libido, energy, mood, and muscle maintenance.

What symptoms may be linked to having the rs6259 AA or AG genotype?

The rs6259 effect allele is associated with higher SHBG, which generally means more testosterone is bound and less is free. With AA, this effect is typically stronger and may relate to lower libido, reduced energy, difficulty gaining or maintaining muscle, and mood changes. With AG, the impact is often milder but can still contribute to symptoms connected to reduced free testosterone.

What lifestyle and supplement strategies support healthy testosterone availability when SHBG is higher?

Support free testosterone by prioritizing a protein-rich diet, limiting alcohol, improving sleep (7–8 hours), doing regular resistance training and some high-intensity interval work, managing body composition, and reducing exposure to endocrine disruptors (e.g., avoiding unnecessary plastic contact with food). If symptoms suggest low free testosterone, supplements commonly discussed include boron, ashwagandha, shilajit, and zinc—though you should talk to a healthcare provider first, and consider lab testing such as total and free (or calculated free) testosterone and SHBG.

What tests can help me learn more about Testosterone and SHBG rs6259?

The Hormone, Thyroid, and Reproductive Health Genetic Test delivers over 85 personalized genetic insights through a comprehensive Hormone & Fertility Genetic Report, explaining inherited tendencies related to hormonal balance, reproductive function, and endocrine signaling. The Mens Hormone and Fertility Health 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.