HSA | FSA CARDS ARE NOW ACCEPTED

FSHB and Testosterone: What Your Genotype Means for Hormones, Fertility, and Wellness

Testosterone plays a central role in muscle mass, libido, mood, energy, and fertility. The FSHB gene helps regulate follicle-stimulating hormone, or FSH, which in turn supports normal testosterone production and healthy sperm development. A common variant at rs10835638 in the FSHB gene can change how much FSH your body produces. That variation may influence free testosterone availability and some markers of reproductive health. Genetics is only one part of the picture. Diet, sleep, exercise, environmental exposures, and medical care also have major effects.

How FSHB Affects Testosterone and Fertility

FSH is produced by the pituitary gland and acts on the testicles to support sperm production and the hormonal environment needed for testosterone synthesis. The FSHB gene encodes a subunit of FSH. Certain changes in FSHB can reduce FSH output. Lower FSH can be associated with lower free testosterone and with altered fertility markers. The effect size from one variant is usually modest, but it may be meaningful when combined with other genetic and lifestyle factors.

What You Can Do to Support Testosterone and Reproductive Health

Whether or not you carry a risk variant, lifestyle measures can help preserve healthy hormone function and fertility. Focus areas below are practical and evidence friendly for most adults. Consult your healthcare provider before starting supplements or making major changes.

  • Balanced diet: Aim for adequate protein to support muscle mass and hormone synthesis. Include lean meats, fish, eggs, dairy, legumes, and plant proteins. Eating a variety of vegetables and fruits provides antioxidants and micronutrients that support overall reproductive health.
  • Key minerals: Zinc and magnesium are linked to normal testosterone levels. Include zinc sources like oysters, beef, pumpkin seeds, and fortified foods. Magnesium is found in leafy greens, nuts, seeds, whole grains, and legumes.
  • Healthy fats: Dietary fats are building blocks for steroid hormones. Include sources of monounsaturated and omega 3 fats such as olive oil, avocados, nuts, fatty fish, and flaxseeds.
  • Exercise: Regular strength training supports testosterone and muscle mass. Mix resistance training with aerobic activity for cardiovascular health and metabolic balance.
  • Sleep hygiene: Prioritize consistent, restorative sleep. Most adults need 7 to 9 hours nightly. Short or disrupted sleep can lower testosterone.
  • Sunlight: Morning sunlight helps regulate circadian rhythm and vitamin D status. Low vitamin D can correlate with lower testosterone. Safe sun exposure or vitamin D testing and replacement can be useful if levels are low.
  • Avoid endocrine disruptors: Minimize exposure to certain plastics and processed products that can contain chemicals affecting hormones. Use BPA free containers, reduce microwaving plastics, and limit highly processed foods.
  • Weight management: Excess body fat, especially visceral fat, can lower testosterone. A sustainable approach to diet and activity helps maintain healthy body composition.
  • Limit excess alcohol and smoking: Heavy alcohol use and tobacco can negatively affect testosterone and fertility. Reducing use supports hormone balance and sperm health.

Supplement Options People Consider

Supplements can help fill nutritional gaps but are not a replacement for medical care. Talk to your healthcare provider before starting supplements, especially if you have medical conditions or take medications.

  • Zinc: Often used short term if intake or lab tests suggest deficiency.
  • Magnesium: Helpful if dietary intake is low or if there are sleep and muscle recovery needs.
  • Vitamin D: Test 25(OH)D levels and supplement if deficient.
  • Ashwagandha: An herbal adaptogen some men use to support stress response and libido. Individual responses vary.
  • Shilajit: A mineral-rich resin used traditionally for male reproductive support. Efficacy and purity can vary between products.

When to Talk with a Healthcare Provider

  • Persistent low libido, erectile dysfunction, unexplained fatigue, or loss of muscle mass
  • Difficulty conceiving after a year of trying or known fertility concerns
  • Abnormal lab tests such as low total or free testosterone, abnormal FSH or LH, or abnormal semen analysis
  • Considering prescription therapies or hormone replacement

Your provider can order appropriate tests such as morning total and free testosterone, FSH, LH, prolactin, estradiol, and semen analysis when fertility is a concern. Interpretation should occur in context of symptoms, exam, and overall health.

Genetic Interpretation: rs10835638 (FSHB)

2 effect alleles — TT genotype

If you have the TT genotype for rs10835638, you carry two copies of the effect allele. This genotype is associated with lower free testosterone levels due to reduced FSH production. The FSHB gene regulates FSH which is vital for testosterone synthesis and reproductive health. Individuals with the TT genotype may have an increased genetic predisposition toward lower FSH activity which can reduce free testosterone availability. Potential impacts include lower energy, reduced muscle mass, decreased libido, and a higher chance of fertility challenges.

Actionable considerations: prioritize a diet rich in protein, zinc, and magnesium; maintain regular strength training; optimize sleep and morning sunlight exposure; reduce exposure to endocrine disruptors; and discuss targeted labs and monitoring with your healthcare provider.

1 effect allele — GT genotype

If you have the GT genotype for rs10835638, you carry one copy of the effect allele. This indicates an intermediate risk for lower FSH and free testosterone levels compared to those with two copies of the non-effect G allele. Your GT genotype suggests you may have moderately reduced FSH activity and a possible modest effect on free testosterone. You may notice changes in energy, libido, or muscle mass in some circumstances, but lifestyle has strong influence.

Actionable considerations: focus on adequate protein and micronutrients, consistent strength training, sleep hygiene, and avoidance of endocrine disruptors. Consider screening labs if you have symptoms or fertility concerns.

0 effect alleles — GG genotype

If you have the GG genotype for rs10835638, you carry two copies of the non-effect allele. This genotype is associated with typical FSH levels and normal testosterone production for this specific variant. Your GG genotype suggests a typical genetic predisposition for maintaining healthy FSH and free testosterone levels. This does not rule out other genetic or non-genetic factors that can affect hormones or fertility.

Actionable considerations: maintain the healthy diet, exercise, sleep, and environmental habits outlined above. Seek medical evaluation if symptoms of low testosterone or fertility concerns arise.

Important Notes and Next Steps

PlexusDx provides educational genetic information to help you understand potential predispositions. PlexusDx does not provide medical advice. Always consult your healthcare provider before making changes to medications, starting supplements, or pursuing hormonal treatments. If you are concerned about symptoms or fertility, ask your provider about appropriate testing such as morning total and free testosterone, FSH, LH, estradiol, vitamin D, and semen analysis when indicated. Combining genetic knowledge with clinical testing and personalized medical care provides the clearest path to understanding and optimizing your reproductive health and hormones.