Male Fertility Bloodwork: The 6 Tests Every Man Should Run
Standard fertility consultations often miss the most actionable blood markers — knowing what to test and what to look for is the difference between a diagnosis and a protocol.
Standard infertility workups typically include a semen analysis and perhaps testosterone — but several other blood markers provide critical information about the hormonal environment, nutritional status, and specific deficiencies that are driving impaired sperm parameters. This guide covers the 6 blood tests with the highest clinical relevance for male fertility and how to interpret them in the context of a supplementation protocol.
6
Key blood markers for male fertility
500–900
Optimal total testosterone range (ng/dL)
60–80 ng/mL
Optimal vitamin D level
FSH and LH: The Hormonal Drivers
FSH (follicle-stimulating hormone) stimulates spermatogenesis via Sertoli cells. Elevated FSH with low sperm count = primary testicular impairment. LH (luteinising hormone) drives testosterone production via Leydig cells. Low LH with low testosterone = secondary hypogonadism (pituitary-level problem). Both should be measured fasting, in the morning, and on the same sample as testosterone for context. Normal FSH: 1–12 IU/L. Normal LH: 1.7–8.6 IU/L.
Total and Free Testosterone
Total testosterone captures all testosterone in the blood, but testosterone bound to SHBG (sex hormone binding globulin) is biologically inactive. Free testosterone — the unbound, biologically active fraction — provides the clinically meaningful number. Optimal (not just normal) total testosterone for fertility: 500–900 ng/dL (17–31 nmol/L). Below 400 ng/dL warrants investigation and intervention. SHBG should be measured alongside total testosterone; high SHBG can make total T look adequate while free T is low.
Vitamin D (25-OHD)
Vitamin D deficiency is the single most prevalent nutritional deficiency in the UK and Northern Europe. Optimal for fertility: 60–80 ng/mL (150–200 nmol/L). Most men in northern latitudes test below 50 ng/mL, especially in winter. Testing 25-hydroxyvitamin D before starting supplementation confirms deficiency and allows dose calibration. Retesting at 3 months confirms adequate response to 5,000 IU/day (most men reach 60–70 ng/mL at this dose).
Zinc and Copper
Standard serum zinc is a poor indicator of intracellular zinc status — levels can be normal in serum while intracellular zinc is depleted. Red blood cell zinc (RBC zinc) is a more sensitive test. Copper should be measured if supplementing zinc above 30mg/day for extended periods, as zinc and copper share absorption pathways. Optimal serum zinc: 80–120 mcg/dL. Plasma zinc below 70 mcg/dL warrants supplementation.
Recommended Protocol
Supplement Based on Your Bloodwork
The Fatherhood Protocol includes a 12-week bloodwork schedule designed to track your response to every compound in the stack — testosterone, vitamin D, and sperm parameters at timed intervals.
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* These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease. Individual results may vary. Consult your healthcare provider before starting any new supplement regimen.