A pituitary hormone that triggers ovulation and testosterone production.
Luteinizing hormone, or LH, is a gonadotropin made by the pituitary gland, a small gland at the base of the brain. The pituitary releases LH in response to signals from the hypothalamus, and LH then travels in the blood to the ovaries and testes. In women, a sharp rise in LH around the middle of the menstrual cycle triggers the ovary to release an egg, which is ovulation. In men, LH tells the Leydig cells in the testes to make testosterone. LH works closely with another pituitary hormone, follicle-stimulating hormone (FSH), to control the reproductive system.
LH is a useful window into how well the reproductive system is working, from the pituitary down to the ovaries or testes. Because levels change a lot across the menstrual cycle, the result is read together with where you are in your cycle and with related hormones.
High LH can mean the ovaries or testes are not responding well, so the pituitary pushes harder. In women this pattern is common around and after menopause, and in primary ovarian insufficiency. In men it can point to a problem in the testes themselves. A high LH relative to FSH is one of the signals sometimes seen in polycystic ovary syndrome.
Low LH, especially together with low oestradiol or testosterone, suggests the signal from the pituitary or hypothalamus is weak. This can happen with pituitary problems, significant stress, very low body weight, intense training, or certain medications. Looking at LH alongside FSH helps separate a gland problem (ovary or testis) from a pituitary or hypothalamic one.
Aniva reads your result against research-backed ranges, not just the lab's wide normal. The reference shown below is specific to this biomarker.
LH is reported in international units per litre (IU/L). Ranges depend on sex and, for women, the phase of the menstrual cycle, so your result is best read against the day of your cycle. These figures are guidance and vary between laboratories and assays, so always compare against the range printed on your own report.
| Group | Reference range (IU/L) |
|---|---|
| Men (adult) | 1.7 to 8.6 |
| Women, follicular phase | 2.4 to 12.6 |
| Women, mid-cycle (ovulation) peak | 14.0 to 95.6 |
| Women, luteal phase | 1.0 to 11.4 |
| Women, postmenopausal | 7.7 to 58.5 |
Values are approximate and assay dependent. Children and adolescents have different ranges that are not shown here.
Your LH result, read alongside your cycle phase and related hormones, helps you understand your reproductive and hormonal health. For women it can show whether ovulation is likely happening, give context on irregular or absent periods, and indicate the transition into menopause. For men it gives insight into testosterone production and testicular function. Paired with FSH, oestradiol or testosterone, LH helps point to whether any imbalance is coming from the ovaries or testes themselves or from the pituitary gland that signals them.
A few things can affect an LH result. LH is released in pulses through the day, so a single sample is a snapshot and can vary; sometimes more than one measurement is needed. In women, the result only makes sense against the cycle day, and the mid-cycle surge is brief. Hormonal contraception and other hormone treatments lower LH. Recent use of GnRH analogues, used in fertility treatment and some other conditions, strongly changes LH levels. High-dose biotin supplements can interfere with some immunoassays and give a falsely high or low reading, so it is usually advised to pause biotin before testing.
LH is most informative when read alongside other hormones. FSH helps tell apart an ovarian or testicular cause from a pituitary one. Oestradiol gives context in women, and testosterone does the same in men. Prolactin is worth checking too, since a high prolactin can suppress LH and explain low levels.
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