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.

This article is part of the PlexusDx Education Hub — your resource for evidence-based guidance on hormones & fertility. Browse all Hormones & Fertility education

Follicle-stimulating hormone (FSH) is central to reproduction. In women it drives the growth of ovarian follicles each cycle; in men it supports sperm production. FSH levels differ from person to person, and part of that difference is genetic — written into the gene that makes FSH and the gene that builds its receptor.

What FSH does in reproductive health

FSH is released by the pituitary gland under signals from the hypothalamus. In women it recruits and matures ovarian follicles and helps set the tempo of the menstrual cycle; FSH rises sharply around menopause as ovarian reserve declines. In men it acts on Sertoli cells in the testes to sustain sperm production. Because FSH sits at the top of the reproductive hormone axis, small genetic differences in how it is made or sensed can shift fertility-related biology.

FSHB: the gene that sets FSH output

FSHB encodes the beta subunit that gives FSH its identity. A well-studied variant in the FSHB promoter, rs10835638 (often written -211 G>T), influences how much FSH the pituitary produces. The T allele is associated with lower circulating FSH and has been linked in research to differences in menstrual cycle length, age at menopause, and, in men, measures of testicular function. It is one of the most reproducible genetic signals in reproductive endocrinology.

FSHR: how sensitively your body reads FSH

Making FSH is only half the equation; cells must also respond to it. FSHR encodes the FSH receptor, and common variants change how sensitively that receptor works. The Ser680Asn variant (rs6166) is the best known: different genotypes are associated with differences in how the ovary responds to FSH, which is why researchers study FSHR in the context of ovarian response and cycle biology. Together, FSHB and FSHR shape both the signal and the reception.

Why an FSH-related variant is not a verdict

Carrying a variant associated with higher or lower FSH does not mean you have a fertility problem. These variants shift tendencies at the population level; individual reproductive health depends on age, ovarian or testicular reserve, overall hormone balance, body composition, and many other factors. FSH is also just one hormone in a coordinated system that includes LH, estradiol, and testosterone. Genetics adds context to that picture rather than replacing a clinical evaluation.

What to do with FSH genetic insight

If reproductive health is a priority, genetic tendencies are a useful starting point for a conversation with a qualified provider or fertility specialist, who can measure actual hormone levels at the right point in the cycle and interpret them alongside your history. Genetic insight helps you ask sharper questions; it does not diagnose infertility or predict whether you can conceive. That interpretation belongs with a clinician.

Where PlexusDx fits

The PlexusDx Precision Peptide Genetic Test analyzes 14 pathways, 49 peptides, 150+ genetic insights, including variants in reproductive hormone pathways. It offers pathway-level context — tendencies to discuss with a provider — not a diagnosis or a fertility prediction. PlexusDx tells you about your biology; it does not tell you what to put in your body. Results are delivered through the secure Results Portal.

Frequently Asked Questions

Which genes affect FSH levels?

Two stand out. FSHB, which encodes the FSH beta subunit, sets how much FSH the pituitary makes — the promoter variant rs10835638 is strongly linked to circulating FSH. FSHR, the FSH receptor gene, changes how sensitively cells respond. Variants in each shift reproductive hormone biology in complementary ways.

Does a variant mean I will have fertility problems?

No. FSH-related variants shift tendencies across populations, not individual outcomes. Fertility depends on age, ovarian or testicular reserve, overall hormone balance, and lifestyle. A genotype is a map, not a verdict. Only a qualified provider can evaluate fertility using hormone testing and your full clinical history.

Can genetic testing diagnose infertility?

No. Genetic testing describes pathway-level tendencies, not a diagnosis. Infertility is evaluated clinically with timed hormone labs, imaging, and history by a qualified provider or fertility specialist. Genetic insight is background context that can make that clinical conversation more informed, not a substitute for it.

Why does FSH rise around menopause?

As ovarian reserve declines, the ovaries make less estradiol and inhibin, the signals that normally tell the pituitary to ease off. Without that feedback, the pituitary releases more FSH. Genetic variants in FSHB can influence the timing and pattern, but the rise itself reflects changing ovarian function with age.

Want to understand the genetics behind your reproductive hormone pathways? The Precision Peptide Genetic Test maps named variants like those in FSHB and FSHR, giving you pathway-level insight to bring to a provider.

The Precision Peptide Genetic Test analyzes how your genes influence peptide-related biological pathways. It does not recommend, prescribe, or determine which peptides you should use. Consult a qualified healthcare provider before beginning any peptide protocol.

This article is part of the PlexusDx Education Hub. Browse all Hormones & Fertility education

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.