LH — The Ovulation Trigger (and Testosterone Driver)
Luteinizing hormone is the spark plug of your reproductive system. In women, the mid-cycle LH surge is what actually releases the egg — no LH surge, no ovulation. In men, LH signals the testes to make testosterone. It works hand-in-hand with FSH, and the ratio between them can reveal a lot about what's going on under the hood.
Why Test Luteinizing hormone, LH?
LH testing helps diagnose fertility issues, assess miscarriage risk, confirm perimenopause or menopause, explain irregular or missing periods, and evaluate PCOS. In men, it's tested alongside testosterone to investigate low muscle mass, decreased drive, or suspected testicular dysfunction.
What Do High Luteinizing hormone, LH Levels Mean?
In women, high LH may indicate primary ovarian insufficiency, PCOS, perimenopause, menopause, Turner syndrome, or ovarian tumours. In men, it can signal testicular damage from chemo, radiation, infection, or alcohol, or Klinefelter's syndrome. High LH with high FSH in children may point to early puberty.
What Do Low Luteinizing hormone, LH Levels Mean?
Low LH in women may suggest pituitary dysfunction, eating disorders, or being significantly underweight. In men, it can indicate pituitary or hypothalamic issues. In children, low LH and FSH together can signal delayed puberty.
Symptoms to Watch For
- Irregular or absent periods
- Difficulty conceiving or recurrent miscarriage
- Hot flashes and menopausal symptoms
- Low testosterone signs in men
- Decreased sex drive
- Early or delayed puberty in children
Who Should Get Tested?
- Women with fertility concerns or menstrual irregularities
- Men with low testosterone or decreased libido
- Women investigating menopause or perimenopause
- Those being evaluated for PCOS
- Children with unusual pubertal development
How to Prepare for Your Test
For fertility evaluation, take this test on day 3 of your menstrual cycle (or between days 2-5). Should not be done during or shortly after antibiotic treatment. Bring valid ID. If you take a supplement containing biotin (often sold for hair and nails), pause it for two days before the test, as high doses can distort the result.
Order Your Blood Test
Test your Luteinizing hormone, LH levels with an accredited Swedish laboratory. Results within days, reviewed by Wellth.
Frequently Asked Questions
What does an LH surge mean?
How do LH and FSH work together?
Can hormonal contraceptives affect LH results?
Reviewed by
Wellth Team
Wellth
Our content is written and reviewed by Wellth, and fact-checked against peer-reviewed research and current Swedish clinical guidelines.
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The information on this page is provided for informational purposes only and does not constitute professional medical advice, diagnosis, or treatment. Wellth provides health information and testing services but is not a substitute for clinical care. Always consult a qualified healthcare provider if you have questions about a medical condition. If you are experiencing severe or urgent symptoms, contact your doctor or call 1177 Vårdguiden. Blood test results should be interpreted by a qualified healthcare professional in the context of your complete medical history.