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

Luteinizing hormone (LH) is one of the master switches of reproduction. It triggers ovulation, sustains the menstrual cycle, and drives testosterone production in men. When fertility challenges or irregular cycles appear, LH is often part of the story — and so are the genes that build LH, its receptor, and the brain signals that release it. This article explains what LH does, which genetic factors shape it, and how to think about pathway-level insight versus clinical diagnosis.

What luteinizing hormone does

LH is produced by the pituitary gland at the base of the brain. In women, a mid-cycle surge of LH is the direct trigger for ovulation — the release of an egg from the ovary — and afterward LH supports the corpus luteum, which produces progesterone to prepare the uterus for a possible pregnancy. In men, LH stimulates the testes to make testosterone. Its close partner, follicle-stimulating hormone (FSH), works alongside it, and the two are released in a carefully timed rhythm.

The brain-pituitary-gonad axis

LH does not act in isolation. It is the middle link in the hypothalamic-pituitary-gonadal axis. The hypothalamus releases gonadotropin-releasing hormone (GnRH) in pulses; those pulses tell the pituitary how much LH and FSH to release; and the sex hormones produced downstream feed back to fine-tune the whole loop. Disruptions anywhere along this axis — stress, body weight, thyroid function, or genetics — can shift LH levels and change cycle regularity.

Genetic factors that shape LH signaling

Several named genes govern how LH is produced and received. LHB encodes the beta subunit that gives LH its specific identity; variants here can alter the hormone's structure and activity. LHCGR encodes the LH/choriogonadotropin receptor on ovarian and testicular cells — the docking site LH must bind to have any effect — and variants can change receptor sensitivity. GNRHR, the receptor for GnRH, sets how strongly the pituitary responds to the brain's signal. Variation in FSHR, the FSH receptor, also matters because LH and FSH act as a coordinated pair.

These genes are studied in the context of conditions like polycystic ovary syndrome (PCOS), where an elevated LH-to-FSH ratio is a common feature, and in some inherited forms of delayed puberty or altered fertility.

LH across the menstrual cycle

Tracking LH is central to understanding fertility. In the follicular phase, LH stays relatively low while an egg matures. Rising estrogen then triggers the LH surge that causes ovulation, which is why home ovulation predictor kits detect LH in urine. After ovulation, LH supports progesterone production. When this rhythm is disrupted — by chronically high LH, a blunted surge, or an abnormal LH-to-FSH ratio — cycles can become irregular and conception can become more difficult.

What genetics can and cannot tell you

Genetic insight can describe tendencies in your reproductive-hormone pathways — how your LH and receptor genes are wired. It cannot diagnose infertility, PCOS, or any hormonal disorder, and it does not treat or prevent them. LH, FSH, and related hormones must be measured through blood work and interpreted by a qualified healthcare provider, ideally a reproductive endocrinologist or gynecologist, who can connect the numbers to your symptoms and goals.

What pathway-level genetic insight reveals

The PlexusDx Precision Peptide Genetic Test analyzes 14 pathways, 49 peptides, 150+ genetic insights across hormone and signaling pathways — including variants in genes like LHB, LHCGR, and GNRHR that shape reproductive-hormone biology. It reports on how your genes influence these pathways, not on a diagnosis or a fertility treatment. That upstream context can make your conversation with a provider more specific and productive. PlexusDx tells you about your biology; it does not tell you what to put in your body. Genetics is a guide, not a guarantee.

Frequently Asked Questions

What does luteinizing hormone do?

Luteinizing hormone triggers ovulation in women, supports progesterone production afterward, and stimulates testosterone production in men. Made by the pituitary gland, it works alongside follicle-stimulating hormone within the brain-pituitary-gonad axis to regulate the menstrual cycle, fertility, and reproductive health across the lifespan.

Which genes affect LH levels?

Key genes include LHB, which builds LH's beta subunit; LHCGR, the receptor LH must bind to act; and GNRHR, which sets how strongly the pituitary responds to the brain's GnRH signal. Variation in FSHR also matters because LH and FSH work as a coordinated hormonal pair.

Can genetics explain irregular periods?

Genetics can contribute to reproductive-hormone tendencies, including an altered LH-to-FSH balance seen in conditions like PCOS. But irregular cycles have many causes — stress, weight, thyroid function, and more. A genetic test describes pathway biology; a qualified provider is needed to evaluate and diagnose the cause of irregular periods.

Does a genetic test measure my LH level?

No. A genetic test reads DNA variants in hormone pathways, not hormone concentrations. Your actual LH level is measured through a blood test at a specific point in your cycle. Genetic insight adds context about how your LH-related pathways are wired, which complements — but does not replace — lab testing.

Ready to understand your own biology at the pathway level? Take the Precision Peptide Genetic Test to see how your genes influence peptide-related pathways — education and insight, never a diagnosis. Genetics is a guide, not a guarantee.

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, and it does not diagnose, treat, or prevent any disease. 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.