Quick answer: LH (luteinizing hormone) is a pituitary hormone that triggers ovulation in women and testosterone production in men. LH surges mid-cycle before ovulation. A high LH-to-FSH ratio can be seen in PCOS, high LH is typical after menopause, and low LH can point to pituitary or hypothalamic issues or low testosterone of central origin.
Key takeaways
LH is a pituitary hormone that triggers ovulation in women and testosterone production in men.
It surges mid-cycle before ovulation and is typically high after menopause.
A high LH-to-FSH ratio can be seen in PCOS, while a low LH may point to a pituitary or hypothalamic issue.
What is LH?
LH is made by the pituitary. In women it triggers ovulation and progesterone production; in men it signals the testes to make testosterone.
Why LH matters
LH matters for ovulation, progesterone production after ovulation, testosterone production in men, and fertility evaluation.
Understanding your result
Reference ranges vary by lab, age and sex. Your provider interprets your result against the lab’s range and your overall picture, rather than chasing a single number. Functional labs are optional. They can be helpful in more complex cases.
What low LH can mean
Low LH can reflect pituitary or hypothalamic issues, or under-eating, over-exercise or high stress. In men, it can mean low testosterone of central origin, and opioid or steroid use can lower it as well.
What high LH can mean
High LH is normal during the mid-cycle surge, and it can also reflect PCOS (often higher relative to FSH) or menopause. In men, it can point to testicular problems.
What affects LH
LH is affected by cycle day, hormonal birth control, energy availability and stress, and body weight.
Ways to support healthy levels
- Eat enough and manage stress to support ovulation
- Support insulin sensitivity if you have PCOS (see PCOS natural care)
- Men with low testosterone should have LH checked to find the cause
What does the research show about LH?
The European Male Ageing Study measured LH and testosterone in 3,369 men aged 40 to 79. About 11.8% had low testosterone with low or normal LH, a pattern strongly linked with obesity (body mass index of 30 or higher, relative risk ratio 8.74); 2.0% had low testosterone with high LH, linked mainly with age; and 9.5% had normal testosterone with high LH. The study was a one-time survey, so it shows patterns rather than causes. (Tajar et al., 2010)
The BioCycle Study followed 250 healthy, regularly menstruating women aged 18 to 44 with up to 16 timed blood draws over two cycles. In women who had one cycle without ovulation, the LH peak in their ovulatory cycle was about 38% lower, and estradiol and progesterone were 25% and 22% lower, than in women who ovulated in both cycles. Follow-up covered only two cycles and ovulation was not confirmed by ultrasound. (Hambridge et al., 2013)
Because LH pulses through the day and surges mid-cycle, it is usually interpreted with FSH, cycle timing and either testosterone or estradiol.
LH and healthy aging
LH patterns reflect how the brain and reproductive organs communicate. That signaling changes with age and stress, affecting hormones that protect bone, muscle and metabolism.
Related tests and articles: FSH, progesterone.
When to see a naturopathic doctor
It may be time to see a naturopathic doctor if you have irregular cycles or trouble conceiving, or signs of PCOS. The same is true for men with low testosterone symptoms, or if you have missed periods.
See a medical provider promptly for absent periods for three months (after ruling out pregnancy), headaches with vision changes, or loss of sexual development in teens.
LH at a glance
| Topic | What the article explains |
|---|---|
| Why it matters | Ovulation; progesterone production after ovulation; testosterone production in men; and fertility evaluation |
| What can affect it | Cycle day; hormonal birth control; energy availability and stress; and body weight |
| Supportive habits discussed | Eat enough and manage stress to support ovulation and men with low testosterone should have LH checked to find the cause |
Questions to bring to your clinician
These questions can help you get the most out of your next visit.
What does my LH result suggest when we look at it alongside my FSH and cycle timing?
What might my LH be telling us, given my health history and symptoms?
Which other labs would be worth pairing with my LH to get a clearer picture?
When would it make sense to recheck my LH, and what could I work on in the meantime?
Frequently asked questions
What does a high LH to FSH ratio mean?
It can be seen in PCOS, though it is not required for evaluation.
When does LH surge?
It rises shortly before ovulation.
Why test LH in men?
To find out whether low testosterone comes from the testes or the brain.
Do ovulation tests measure LH?
Yes. Home ovulation kits detect the LH surge in urine.
Sources
- Bhasin S, et al. Testosterone Therapy in Men With Hypogonadism: An Endocrine Society Clinical Practice Guideline. J Clin Endocrinol Metab 2018. PMID: 29562364. https://pubmed.ncbi.nlm.nih.gov/29562364/
- Direito A, et al. Relationships between the luteinizing hormone surge and other characteristics of the menstrual cycle in normally ovulating women. Fertil Steril 2013. PMID: 22999798. https://pubmed.ncbi.nlm.nih.gov/22999798/
- Hambridge HL, et al. The influence of sporadic anovulation on hormone levels in ovulatory cycles. Hum Reprod 2013. PMID: 23589536. https://pubmed.ncbi.nlm.nih.gov/23589536/
- Tajar A, et al. Characteristics of secondary, primary, and compensated hypogonadism in aging men: evidence from the European Male Ageing Study. J Clin Endocrinol Metab 2010. PMID: 20173018. https://pubmed.ncbi.nlm.nih.gov/20173018/
- Teede HJ, et al. Recommendations From the 2023 International Evidence-based Guideline for the Assessment and Management of Polycystic Ovary Syndrome. J Clin Endocrinol Metab 2023. PMID: 37580314. https://pubmed.ncbi.nlm.nih.gov/37580314/
- MedlinePlus: Luteinizing Hormone (LH) Levels Test
- NICHD: Polycystic Ovary Syndrome (PCOS)
This article is for educational purposes only and is not medical advice. It does not replace an individual evaluation. Talk with your healthcare provider before starting supplements or changing medications, especially if you are pregnant, nursing, or managing a health condition.
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