FSH and LH test (follicle-stimulating hormone and luteinizing hormone) Biomarker Testing
It measures pituitary hormones that regulate ovaries or testes and ovulation or testosterone; order through Vitals Vault and test at a Quest location.
With Vitals Vault, you have access to a comprehensive range of biomarker tests.
FSH (follicle-stimulating hormone) and LH (luteinizing hormone) are two “messenger” hormones made by your pituitary gland. They tell your ovaries or testes how hard to work, which is why they show up in fertility evaluations, irregular period workups, and assessments of low testosterone or delayed puberty.
Your numbers are not interpreted in isolation. The same FSH or LH value can mean different things depending on your age, sex, where you are in a menstrual cycle, and whether you use hormonal contraception or testosterone.
This test is most useful when you pair it with symptoms and a few companion labs (often estradiol, progesterone, testosterone, prolactin, and thyroid testing). It can help you and your clinician decide what to check next and when retesting makes sense.
Do I need a FSH and LH test?
You might consider FSH and LH testing if you are trying to conceive and your cycles are irregular, you are not ovulating predictably, or you have had difficulty getting pregnant or getting a partner pregnant. It is also commonly ordered when you have symptoms that suggest a hormone signaling problem, such as missed periods, very heavy or very light periods, hot flashes at a younger-than-expected age, low libido, erectile dysfunction, or low energy with concerns about testosterone.
FSH and LH are also used in evaluations for PCOS (polycystic ovary syndrome), suspected premature ovarian insufficiency, perimenopause/menopause timing questions, and certain pituitary conditions. In adolescents, clinicians may use them to help assess delayed or early puberty.
If you are already on hormone therapy (for example, testosterone, estrogen/progestin contraception, fertility medications, or GnRH analogs), your results can shift in expected ways. In that situation, testing is often about monitoring and adjusting a plan rather than “finding a diagnosis.”
This lab can support clinician-directed care, but it cannot diagnose the cause of fertility or hormone symptoms by itself. Your history, timing of the blood draw, and related labs usually determine what the result means for you.
FSH and LH are measured with standardized immunoassays in CLIA-certified laboratories; results should be interpreted with clinical context and are not a standalone diagnosis.
Lab testing
Ready to order FSH and LH and schedule your draw?
Schedule online, results typically within about a week
Clear reporting and optional clinician context
HSA/FSA eligible where applicable
Get this test with Vitals Vault
If you want a clear starting point for fertility or hormone questions, Vitals Vault lets you order FSH and LH testing without waiting for an office visit. You can choose the test, complete checkout, and then get your blood drawn at a participating Quest location.
When your results are ready, you can review them in one place and use PocketMD to ask practical follow-up questions, such as whether your cycle timing could explain the value, what companion tests typically add clarity, and when a repeat test is worth doing.
FSH and LH are especially helpful when you are tracking changes over time. Vitals Vault makes it easy to re-order the same test later or expand to a broader hormone panel if your first set of results raises new questions.
- Order online and draw at a Quest location
- Clear result display with context for next-step questions
- PocketMD support for interpreting patterns and retest timing
Key benefits of FSH and LH testing
- Helps distinguish whether a hormone issue is more likely coming from the ovaries/testes versus the pituitary signaling to them.
- Adds context to irregular periods, missed periods, or suspected anovulation when timed appropriately in your cycle.
- Supports fertility planning by clarifying ovarian function patterns and guiding which follow-up tests matter most.
- Helps evaluate low testosterone symptoms by showing whether the signal to the testes is low, normal, or high.
- Can provide clues about perimenopause/menopause transition when interpreted alongside estradiol and symptoms.
- Improves interpretation of related labs (estradiol, progesterone, testosterone, prolactin, thyroid) by anchoring the “control signal.”
- Makes it easier to monitor trends over time and discuss next steps using PocketMD and your clinician.
What is FSH and LH?
FSH and LH are gonadotropins, meaning they are pituitary hormones that regulate the gonads (ovaries or testes). They are part of the hypothalamic–pituitary–gonadal (HPG) axis, a feedback system that uses signals from sex hormones (like estradiol and testosterone) to adjust how much FSH and LH your pituitary releases.
In ovaries, FSH supports follicle development and helps drive estradiol production. LH helps trigger ovulation and supports progesterone production after ovulation through the corpus luteum. In testes, LH stimulates Leydig cells to produce testosterone, while FSH supports Sertoli cell function and sperm production.
Because these hormones change with time, a single result is most meaningful when you know the context: your age, sex, whether you are cycling, the day of your cycle (if applicable), and any hormones or fertility medications you are using.
Why timing matters (especially if you menstruate)
FSH and LH fluctuate across the menstrual cycle. Many clinicians interpret baseline values on cycle day 2–4 because that window reduces the effect of the mid-cycle LH surge and provides a more stable comparison point. If your blood draw happens near ovulation, LH can be temporarily high even when everything is normal.
How FSH/LH fit with estradiol, progesterone, and testosterone
FSH and LH are “upstream” signals, while estradiol, progesterone, and testosterone are “downstream” outputs. A high FSH with low estradiol can suggest reduced ovarian function, while low or inappropriately normal FSH/LH with low testosterone can suggest a pituitary or hypothalamic contribution. The pattern often matters more than any single number.
What do my FSH and LH results mean?
Low FSH and/or LH
Low FSH and LH can mean your pituitary is not sending a strong signal to the ovaries or testes. This pattern may be seen with functional hypothalamic causes (such as significant calorie deficit, rapid weight loss, intense training, high stress, or chronic illness) and with some pituitary disorders. It can also occur if you are using hormones that suppress the HPG axis, including many forms of hormonal contraception, testosterone therapy, or certain fertility medications. If your symptoms are significant, clinicians often pair this result with prolactin, thyroid testing, and sex hormones to clarify the reason.
FSH and LH in range (for your age and context)
An in-range result often suggests the pituitary-to-gonad signaling loop is functioning as expected, but it does not rule out fertility or hormone concerns. For example, you can have normal FSH/LH and still have an ovulation timing issue, luteal phase concerns, thyroid-related symptoms, or semen parameters that need separate evaluation. If you are cycling, “normal” depends heavily on cycle day, so documenting timing can make the result more actionable. Your clinician may focus on patterns across multiple labs rather than treating an in-range value as the end of the workup.
High FSH and/or LH
High FSH and/or LH can indicate that your pituitary is working harder to stimulate the ovaries or testes, often because the gonads are not producing enough downstream hormones for the pituitary to “back off.” In people with ovaries, higher FSH (especially when measured early in the cycle) can be consistent with diminished ovarian reserve or the menopause transition, particularly when estradiol is low or symptoms match. In people with testes, high LH (with low testosterone) can suggest primary testicular dysfunction. Because normal ranges vary by lab and life stage, the most useful interpretation comes from the full pattern: symptoms, sex hormones, and repeat testing when appropriate.
Factors that influence FSH and LH
Cycle timing is one of the biggest drivers of LH and FSH variation, especially around ovulation. Age and reproductive stage (puberty, postpartum, perimenopause/menopause) also shift expected values. Medications and hormones can meaningfully change results, including oral contraceptives, fertility drugs, testosterone, estrogen therapy, and some treatments that affect dopamine or prolactin. Acute illness, significant weight changes, heavy endurance training, and sleep disruption can also alter the HPG axis and temporarily change your numbers.
What’s included
- Fsh
- Lh
Frequently Asked Questions
What is the difference between FSH and LH?
FSH mainly supports follicle development in ovaries and sperm-supporting function in testes, while LH helps trigger ovulation and stimulates testosterone production in testes. They work together as part of the pituitary signaling system that regulates reproductive hormones.
When should you test FSH and LH in your cycle?
If you menstruate and your clinician wants a baseline, testing is often done on cycle day 2–4. Testing near mid-cycle can show a normal LH surge, which can look “high” without being abnormal. If your cycles are irregular, your clinician may use symptoms, ultrasound, or additional labs to interpret timing.
Do I need to fast for an FSH and LH blood test?
Fasting is not usually required for FSH and LH. If you are combining this test with other labs (like lipids or glucose), follow the fasting instructions for the full order.
Can birth control affect FSH and LH results?
Yes. Many hormonal contraceptives suppress the pituitary signals that drive ovulation, which can lower FSH and LH compared with your natural cycle. If you are testing for fertility or cycle function, ask your clinician whether you should test on or off hormonal contraception and how long to wait after stopping.
What does a high FSH level mean for fertility?
A higher FSH, especially when measured early in the cycle, can suggest the ovaries need a stronger signal to recruit follicles. It can be consistent with diminished ovarian reserve or perimenopause, but it is not a standalone fertility verdict. Clinicians often interpret it alongside estradiol, AMH, antral follicle count, and your age.
What does a high LH to FSH ratio mean?
An elevated LH:FSH ratio can be seen in some people with PCOS, but it is not required for diagnosis and it is not specific. PCOS evaluation usually also considers symptoms (like irregular cycles or signs of androgen excess) and labs such as testosterone, DHEA-S, prolactin, and thyroid testing.
How often should I retest FSH and LH?
Retesting depends on why you tested in the first place. For cycle or fertility questions, clinicians may repeat testing in a specific cycle window or after a change in medication. For monitoring, repeating in 6–12 weeks is common when you are trying to confirm a pattern, but your clinician should tailor timing to your situation.