LH (Luteinising Hormone)
| Clinical | Optimal | |
|---|---|---|
| Male | 1.7 - 8.6 IU/L | 1.7–8.6 IU/L |
| Female | Follicular: 2.4-12.6 IU/L; Ovulation: 14.0-95.6 IU/L; Luteal: 1.0-11.4 IU/L; Postmenopausal: 7.7-58.5 IU/L | Follicular: 2.4–12.6 IU/L, Ovulation: 14.0–95.6 IU/L, Luteal: 1.0–11.4 IU/L, Postmenopausal: 7.7–58.5 IU/L |
What is LH (Luteinising Hormone)?
Luteinising hormone (LH) is produced by the pituitary gland and works in partnership with FSH to regulate reproductive function. In women, a surge of LH triggers ovulation — the release of a mature egg from the ovary. After ovulation, LH supports the corpus luteum (the structure left behind), which produces progesterone.
In men, LH stimulates the Leydig cells in the testes to produce testosterone. It is the primary signal from the brain that tells the testes how much testosterone to make.
Like FSH, LH levels in women fluctuate significantly throughout the menstrual cycle, with a dramatic spike (the LH surge) just before ovulation. In men, levels are relatively stable. The LH-to-FSH ratio can also provide useful diagnostic information, particularly in conditions like polycystic ovary syndrome.
Why LH (Luteinising Hormone) Matters for Your Health
LH is the direct hormonal trigger for ovulation and testosterone production, making it essential for reproductive health in both sexes. Without an adequate LH surge, ovulation does not occur in women, and without sufficient LH stimulation, the testes cannot produce adequate testosterone in men.
The relationship between LH and the hormones it stimulates provides valuable diagnostic information. High LH with low sex hormones suggests the gonads are failing to respond (primary gonadal failure). Low LH with low sex hormones suggests the pituitary is underperforming (secondary hypogonadism).
For longevity, LH is most relevant as part of the broader hormonal picture. It helps clinicians understand whether hormonal imbalances originate in the brain (pituitary) or in the gonads, which is essential for appropriate treatment.
LH (Luteinising Hormone)& Your Wearable Data
Luteinising hormone (LH) triggers ovulation in women and stimulates testosterone production in men. The LH surge that causes ovulation may be indirectly detected by wearable temperature tracking: the post-ovulatory temperature rise of 0.2-0.5 degrees Celsius is a downstream effect of the LH-triggered shift from oestrogen to progesterone dominance.
In women using wearable cycle tracking, correlating LH blood test timing with cycle data is essential. LH varies enormously throughout the cycle, with the ovulatory surge reaching 3-10 times the baseline level. Your wearable's cycle predictions help ensure blood draws are timed appropriately for the phase being investigated.
In men, LH stimulates Leydig cells to produce testosterone. Low LH with low testosterone suggests pituitary or hypothalamic dysfunction (secondary hypogonadism), while high LH with low testosterone indicates testicular dysfunction (primary hypogonadism). Wearable data showing testosterone-deficiency patterns — declining strength, increased fatigue, poor recovery — helps prioritise when to investigate LH levels.
What High LH (Luteinising Hormone) May Suggest
In women, high LH during the mid-cycle is normal — it is the ovulation trigger. However, persistently elevated LH relative to FSH (an LH:FSH ratio above 2:1) in the follicular phase is a characteristic finding in polycystic ovary syndrome (PCOS). High LH in postmenopausal women is normal and expected.
In premenopausal women, persistently high LH may also indicate premature ovarian insufficiency (the pituitary working overtime to stimulate underperforming ovaries).
In men, high LH with low testosterone indicates primary testicular failure — the pituitary is sending strong signals, but the testes cannot respond adequately. Causes include previous testicular damage, genetic conditions, or age-related decline. High LH with normal testosterone may indicate the testes are compensating adequately for now, but monitoring is advisable.
What Low LH (Luteinising Hormone) May Suggest
Low LH in women suggests the pituitary is not sending adequate signals to the ovaries, which can prevent ovulation and cause irregular or absent periods. Causes include hypothalamic amenorrhoea (from stress, excessive exercise, or low body weight), pituitary disease, hyperprolactinaemia, and certain medications.
In men, low LH means the testes are receiving inadequate stimulation to produce testosterone. This is called secondary (or central) hypogonadism. Causes include pituitary tumours, exogenous testosterone use (which powerfully suppresses LH), obesity, opioid medications, and systemic illness.
Low LH in men taking testosterone is an expected physiological response — the pituitary detects sufficient testosterone and reduces its own signalling. This is why TRT suppresses fertility.
How to Optimise Your LH (Luteinising Hormone)
Food
Support pituitary-gonadal function with adequate caloric intake (energy restriction suppresses LH), healthy fats for hormone synthesis, zinc (oysters, red meat, pumpkin seeds), and vitamin D (oily fish, eggs). Avoid excessive soy consumption, which may modestly affect pituitary signalling in some individuals. Maintain balanced blood sugar, as insulin resistance can disrupt LH pulsatility.
Lifestyle
Address factors that suppress pituitary function: restore energy balance if underweight or over-exercising, manage chronic stress (cortisol suppresses LH), prioritise 7–9 hours of sleep (LH pulses are strongest during sleep), and achieve a healthy body weight. For women with hypothalamic amenorrhoea, reducing exercise intensity and increasing caloric intake are often the most effective interventions.
Supplements
Vitamin D (1,000–2,000 IU daily) supports pituitary function. Zinc (25–30 mg daily) supports gonadotropin release in deficient individuals. Vitex (chasteberry) may help regulate LH in women with certain cycle irregularities, though evidence is mixed. Ashwagandha may support LH through stress reduction. Address underlying causes before relying on supplements alone.
When to Speak to Your GP
Women: see your GP if periods are absent for more than 3 months (particularly if combined with low LH), if you are struggling to conceive, or if your LH:FSH ratio is elevated (possible PCOS). Men: see your GP if LH is low alongside low testosterone (pituitary investigation may be needed) or if LH is high with low testosterone (testicular assessment required). Both sexes: pituitary MRI may be recommended if both LH and FSH are inappropriately low.
References
- NHS. Polycystic ovary syndrome — Diagnosis. Updated 2024. nhs.uk
- NICE. Fertility problems: assessment and treatment. CG156. nice.org.uk
- BMJ. Balen AH, et al. The management of anovulatory infertility in women with polycystic ovary syndrome: an analysis of the evidence. Hum Reprod Update. 2016;22(6):687-708. pubmed.ncbi.nlm.nih.gov
- Endocrine Society. Teede HJ, et al. Recommendations from the international evidence-based guideline for the assessment and management of PCOS. Hum Reprod. 2018;33(9):1602-1618. pubmed.ncbi.nlm.nih.gov
Medical Disclaimer— This content is for general educational and informational purposes only. It does not constitute medical advice, diagnosis, or treatment. Omniwo Ltd is a wellness information service and is not a medical device, clinical laboratory, or regulated healthcare provider under MHRA guidelines. The “optimal ranges” presented on this page are based on published clinical guidelines (WHO, NICE, NHS) and peer-reviewed research; they represent functional wellness targets and may differ from standard laboratory reference ranges. Individual results should always be interpreted by a qualified healthcare professional (such as your GP) who understands your full medical history. Do not start, stop, or change any medication or supplement based solely on this information. If you are experiencing symptoms, seek medical attention promptly.