Male hormone panel: how to read testosterone, LH, FSH and the rest

A male hormone panel answers two questions in order. Is the testosterone low, on a fasting sample drawn in the early morning and repeated on another day? If it is, do LH and FSH say the testes are failing or the brain has stopped asking them to work? Everything else on the panel (SHBG, estradiol, prolactin, PSA, hematocrit) either sharpens one of those answers or checks safety.

What is on a male hormone panel?

Why the time of the blood draw matters

Testosterone follows a daily rhythm, peaking in the early morning and falling through the day. In a study that sampled the same men on three mornings and three afternoons, testosterone at 4 pm was about 20 to 25% lower than at 8 am in men aged 30 to 40; the gap narrowed with age to about 10% at 70. ⁴ LH, FSH, SHBG and estradiol varied much less across the day. ⁴ The authors concluded testosterone should be measured in the morning at all ages, and the Endocrine Society recommends a fasting morning sample, since a meal can lower testosterone for a few hours. ¹

What counts as low testosterone on a blood test?

Two numbers circulate. The American Urological Association (AUA) uses a total testosterone below 300 ng/dL (about 10.4 nmol/L) on at least two early-morning tests, ideally from the same lab and method, as a reasonable cutoff in support of the diagnosis. ² The Endocrine Society points to a harmonized range of 264 to 916 ng/dL, built by recalibrating results from 9,054 men in US and European cohorts to a CDC reference method. ^{3 1} The two lines sit close together, and a result between them reads two ways.

We recommend diagnosing hypogonadism in men with symptoms and signs of testosterone (T) deficiency and unequivocally and consistently low serum total T and/or free T concentrations (when indicated).Bhasin S, et al. Endocrine Society clinical practice guideline, J Clin Endocrinol Metab 2018 ¹

Symptoms carry as much weight as the number. In the European Male Ageing Study of 3,369 men aged 40 to 79, low testosterone was linked most clearly to three sexual symptoms (fewer morning erections, low sex drive and erectile problems); requiring those symptoms plus a low level identified late-onset hypogonadism in about 2% of men. ⁸ Tiredness and low mood were common at every testosterone level. The low testosterone guide covers the symptoms in full.

Free testosterone and SHBG

About half of circulating testosterone is bound tightly to SHBG, and most of the rest loosely to albumin; only around 2% floats free. When SHBG is unusual, total testosterone misleads. A man with a high SHBG can have a normal total and a low free testosterone; a man with obesity and a low SHBG can have a low total and a normal free testosterone. The Endocrine Society suggests measuring free testosterone when the total is near the lower limit or when a condition alters SHBG, using equilibrium dialysis or an accurate formula. ¹

The common formula, from Vermeulen and colleagues, calculates free testosterone from total testosterone, SHBG and albumin and agrees well with equilibrium dialysis. ⁷ The free testosterone calculator runs that formula on your own numbers. Direct analog free testosterone immunoassays, still offered by some labs, are inaccurate, and the Endocrine Society advises against relying on them. ¹

Primary vs secondary low testosterone: what LH and FSH show

The brain and testes work as a loop. The hypothalamus signals the pituitary, the pituitary releases LH and FSH, LH tells the testes to make testosterone, and testosterone tells the brain to ease off. Reading testosterone together with LH and FSH places the fault. The Endocrine Society recommends exactly this step for every confirmed low result. ¹

A secondary pattern leads to a short list of further checks. The Endocrine Society names prolactin and transferrin saturation (for hemochromatosis) as the routine tests, with other pituitary hormones and a pituitary MRI in selected men, for example when testosterone is below 150 ng/dL. ¹ Many secondary cases are functional, linked to weight, sleep apnea, opioids or illness, and the loop can recover when the cause eases.

What FSH adds

FSH drives sperm production, so it speaks to fertility in a way testosterone does not. A high FSH with a normal testosterone can mean sperm production is impaired while testosterone production holds up. External testosterone and anabolic steroids suppress both LH and FSH, which is why sperm counts often fall on them; the Endocrine Society recommends against testosterone therapy in men planning a pregnancy in the near term. ¹

Where does estradiol fit on a male panel?

Men make estradiol mostly by converting testosterone in fat tissue, so it tends to run higher with more body fat and rises on testosterone therapy. Estradiol helps keep bones strong and supports sex drive, so a low estradiol is not a goal. It is measured mainly when breast tissue is growing, or when symptoms on therapy raise the question. As with women's panels, standard estradiol immunoassays are less accurate at low levels, so a single surprising value is worth confirming.

Why is prolactin on a testosterone panel?

A high prolactin switches off the signal that drives LH, so it can cause low testosterone, low sex drive and erectile problems. The Endocrine Society says one prolactin result taken without excessive venipuncture stress is usually enough to establish a high level, and that medicines (such as some antipsychotics and anti-nausea drugs), an underactive thyroid (TSH) and kidney disease should be ruled out before a pituitary cause is pursued. ⁵ A mildly high prolactin with no symptoms is often macroprolactin, a large and mostly inactive form. ⁵

What does monitoring on testosterone therapy look at?

For men already prescribed testosterone, the panel changes purpose: it tracks whether the level lands in range and whether the known side effects are appearing. The schedule below is what the Endocrine Society guideline describes; your prescriber sets the actual plan, and any change to treatment belongs with them. ¹

Hematocrit is the number most often flagged. Testosterone stimulates red cell production, and a hematocrit above 54% thickens the blood. The guideline lists a baseline hematocrit above 48% (above 50% at high altitude) as a reason for caution before starting, and treats a value above 54% on therapy as a reason for the prescriber to pause or adjust treatment and look for a cause such as sleep apnea or smoking. ¹ Hemoglobin on the same blood count usually moves with it.

PSA usually rises a little in the first months of therapy as the prostate responds to testosterone, then levels off. That is why the guideline looks for a confirmed rise above 1.4 ng/mL in the first year rather than any rise at all, and after the first year folds PSA back into standard prostate screening. ¹

How to read your male hormone panel, step by step

1. 1Check how the sample was takenNote the draw time, whether you had eaten, and whether you were ill, short of sleep or on opioids, steroids or high-dose biotin. A late-morning or afternoon draw, or one after breakfast, can read low.
2. 2Place total testosterone against the cutoffsBelow 300 ng/dL is the AUA line; 264 ng/dL is the harmonized lower limit. Between them, or near either, a repeat early-morning test settles more than any reading of the first.
3. 3Look at SHBG and free testosteroneA high or low SHBG changes what the total means. Calculated free testosterone is more trustworthy than a direct analog assay.
4. 4Read LH and FSH against the testosteroneHigh LH and FSH with low testosterone point to the testes. Low or normal LH and FSH with low testosterone point upstream, which brings prolactin and transferrin saturation into play.
5. 5Add estradiol, PSA and hematocrit for contextThese matter most around breast symptoms and before or during therapy. Compare PSA and hematocrit with earlier values, since the change matters as much as the level.
6. 6Put the symptoms beside the numbersA low result with no symptoms, or symptoms with a normal result, both point to a conversation rather than a conclusion.

What else can move a testosterone result?

• Time of day and food: afternoon and post-meal samples read lower. ^{4 1}
• Weight: higher body fat lowers SHBG and total testosterone, and weight loss often raises both.
• Medicines: opioids and glucocorticoids suppress the brain signal; past anabolic steroid use can keep LH and FSH low for months.
• Sleep and illness: sleep apnea, shift work and acute illness lower testosterone.
• High-dose biotin: it can distort immunoassays for testosterone, estradiol, LH, FSH and TSH. The biotin guide explains it; mention it to the lab.
• The lab and method: results differ between assays, which is why the AUA prefers repeat tests at the same lab. ^{2 3} The guide to reference ranges covers why ranges differ.

The most useful thing to bring to an appointment is two early-morning fasting results with SHBG, plus LH and FSH from one of those draws. With that set, a clinician can usually say whether testosterone is low, whether the cause sits in the testes or upstream, and which further test, if any, comes next.

Free in LifeFromAdd the lab results you already have, and LifeFrom reads each marker next to the others it moves with, in plain language, with the sources it used. Free, on the web or in the app.

Start on the web Download the app