The Men's Sexual Health Bloodwork Panel: 8 Tests Your Doctor Should Be Running

Here's a pattern that plays out in clinics and telehealth platforms every day: a man reports ED, gets prescribed sildenafil or tadalafil, and is sent on his way. No bloodwork. No investigation into what's causing the problem. Just a pill to manage the symptom.

For many men, the pill works and that's sufficient. But ED is often a signal — sometimes the first signal — of an underlying metabolic, hormonal, or vascular issue that's worth identifying. A simple set of blood tests can reveal whether your ED is a standalone problem or the tip of an iceberg.

Here are the eight tests that a comprehensive sexual health evaluation should include, why each one matters, and what the results tell you.

1. Total Testosterone

The most basic hormonal measurement for men's sexual health. Total testosterone measures all testosterone in the blood — both bound (to SHBG and albumin) and free. Normal range is generally 300–1000 ng/dL, though "normal" varies significantly by age and individual baseline.

A result below 300 ng/dL is considered clinically low by most guidelines and may warrant treatment, particularly if accompanied by symptoms (fatigue, low libido, reduced muscle mass, ED). Results in the 300–400 range require clinical judgment — some men are symptomatic at 350 ng/dL while others are asymptomatic at 280.

Test this in the morning (7–10 AM) when levels are highest. A low result should always be confirmed with a repeat test on a different day.

2. Free Testosterone

Free testosterone represents the fraction that's biologically active — not bound to proteins and available to enter cells and exert effects. It's typically 2–3% of total testosterone.

Some men have normal total testosterone but low free testosterone due to elevated SHBG (sex hormone-binding globulin) — a protein that binds testosterone and removes it from circulation. This is particularly common in older men, men taking certain medications, and men with liver conditions. If total T looks fine but you're symptomatic, free T often reveals the discrepancy.

3. Sex Hormone-Binding Globulin (SHBG)

SHBG is the protein that binds testosterone (and estrogen) in the blood. High SHBG reduces bioavailable testosterone even when total testosterone appears normal. Low SHBG can artificially inflate total testosterone while potentially indicating insulin resistance or metabolic issues.

Together, total T + free T + SHBG give a complete picture of your hormonal status. Any one of the three in isolation can be misleading.

4. HbA1c (Hemoglobin A1c)

HbA1c measures your average blood sugar over the preceding 2–3 months. It screens for prediabetes and type 2 diabetes — two of the strongest risk factors for ED. A normal HbA1c is below 5.7%, prediabetes is 5.7–6.4%, and diabetes is 6.5% or higher.

Diabetes damages erectile function through multiple mechanisms: endothelial dysfunction, nerve damage, hormonal disruption, and chronic inflammation. Catching prediabetes early — through a simple, inexpensive blood test — allows you to intervene before the vascular damage that leads to both ED and cardiovascular disease progresses.

If your ED appeared gradually over months to years, and you carry excess weight around your midsection, HbA1c is one of the most important tests on this list.

5. Lipid Panel (Cholesterol)

A standard lipid panel measures total cholesterol, LDL ("bad" cholesterol), HDL ("good" cholesterol), and triglycerides. Elevated LDL and triglycerides, combined with low HDL, indicate atherogenic dyslipidemia — a state that promotes plaque buildup in arteries throughout the body, including the small arteries that supply erectile tissue.

Men with dyslipidemia are at significantly higher risk for vascular ED. And because the penile arteries are smaller than the coronary arteries, ED often appears years before the same process causes cardiac symptoms. Your lipid panel is both an ED diagnostic tool and a cardiovascular risk assessment.

6. Thyroid Panel (TSH at Minimum)

Thyroid dysfunction is an underappreciated cause of sexual dysfunction in men. Both hypothyroidism (underactive thyroid) and hyperthyroidism (overactive thyroid) can impair erectile function, libido, and ejaculatory control.

Hypothyroidism, in particular, reduces metabolic rate, can lower testosterone, and is associated with fatigue and depression — all of which contribute to ED. A simple TSH test screens for thyroid dysfunction, with further testing (free T4, free T3) if TSH is abnormal.

7. Prolactin

Prolactin is a hormone produced by the pituitary gland. Elevated prolactin (hyperprolactinemia) is a relatively uncommon but important cause of ED and low libido in men. High prolactin suppresses GnRH, which in turn reduces testosterone production.

Common causes of elevated prolactin include certain medications (particularly antipsychotics and some antidepressants), stress, and — rarely — pituitary tumors (prolactinomas). When prolactin is identified as the cause, treatment is often highly effective and specific.

This test is most valuable for men who have both ED and significantly reduced libido, particularly if testosterone is low without an obvious explanation.

8. Comprehensive Metabolic Panel (CMP)

A CMP provides a broad overview of metabolic health: kidney function, liver function, electrolytes, and blood glucose. While less specifically targeted at ED than the other tests, it screens for conditions that can contribute to erectile dysfunction — kidney disease, liver dysfunction (which affects hormone metabolism), and electrolyte imbalances that affect nerve and muscle function.

It's also a baseline health snapshot that helps your provider identify anything else that might be relevant to your treatment plan. At most labs, it costs less than $30 and is often included in standard annual bloodwork.

Getting Tested

Many telehealth ED platforms now include lab orders as part of their evaluation process — either through partner labs or by accepting results from your own doctor. If you're going to start ED treatment anyway, getting bloodwork first gives your provider the information to make the most targeted treatment recommendation and potentially identify something that needs attention beyond just the ED.

The providers below can help you get tested and interpret results as part of a comprehensive approach to men's sexual health.

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Vetted telehealth platforms offering prescription ED treatments. All links are affiliate partnerships.