When my girlfriend and I started thinking about fertility (the story I wrote about in the fertility article), she ordered a full hormonal panel. AMH, FSH, oestradiol, thyroid, iron, vitamin D, folate. Her GP ran through the results in detail, discussed implications, and mapped out a pre-conception plan.
My GP said: "Are you generally healthy? Great. You're fine."
That was it. No blood tests. No hormonal panel. No nutritional assessment. No conversation about what I could do to optimise my contribution to the process. Just a pat on the back and an assumption that male fertility doesn't need investigating until it's proven to be a problem. In practice, that means after 12 months of trying with no result.
I pushed back. I asked for blood work. And it was useful. My vitamin D was on the lower end, my zinc hadn't been checked before, and having a testosterone baseline gave me a reference point.
But the experience made me realise something that the data confirms: the pre-conception conversation in Australia is almost entirely directed at women. And that's a problem. Roughly 40-50% of infertility cases involve a male factor, either as the primary cause or as a contributing element. Male fertility isn't a passive process. It's actively influenced by hormones, nutrition, metabolic health, and lifestyle, all of which are measurable.
This article covers what blood tests men should consider before trying to conceive, why those tests matter, and why waiting until there's a problem to investigate is an approach that's decades out of date.
A note before we get into it
General information only. I'm not a fertility specialist or a reproductive endocrinologist. Blood tests assess hormonal and nutritional factors relevant to male fertility, but they don't replace a semen analysis (which is the primary investigation of male fertility) or specialist assessment.
If you and your partner have been trying to conceive for 12 months without success (or 6 months if the female partner is over 35), both partners should be investigated. See your GP for referral.
Why men aren't part of the pre-conception conversation, and why they should be
The disparity is striking. Pre-conception care guidelines for women are detailed and well-established: check folate, check iron, check thyroid, check rubella immunity, check vitamin D, review medications, start folic acid supplementation. For men? Virtually nothing in the standard pathway.
This isn't because male fertility doesn't matter. It's because the clinical framework hasn't caught up with the evidence. The research is clear: paternal health at the time of conception influences not just the probability of conception, but also pregnancy outcomes and offspring health. Sperm quality is affected by hormonal status, nutritional status, oxidative stress, metabolic health, and environmental exposures. All of which are modifiable, and many of which are measurable.
The cultural framing doesn't help either. Fertility is positioned as a "women's issue." Men are expected to show up and... that's about it. The language of pre-conception health is directed at women. The testing pathways are designed for women. Men enter the conversation only when there's a problem, by which point months or years have passed.
A proactive approach is simple and inexpensive: test the relevant blood markers, address any deficiencies, optimise the modifiable factors, and enter the conception process in the best possible condition. It's what we expect of women. Men should expect it of themselves.
What blood tests reveal about male fertility
Blood tests don't measure sperm quality directly. That requires a semen analysis. But they assess the hormonal and nutritional environment that determines how well sperm are produced, how healthy they are, and how effectively the reproductive system functions.
Testosterone, FSH, and LH
The core reproductive hormones
Testosterone drives libido, supports sperm production, and maintains reproductive tissue. Low testosterone is associated with reduced sperm count and motility. However, the relationship isn't linear. Very high testosterone (particularly from exogenous sources like testosterone replacement therapy or anabolic steroids) can paradoxically suppress sperm production by shutting down the brain's signalling to the testes.
FSH (Follicle Stimulating Hormone) directly stimulates the Sertoli cells in the testes that support sperm production. Elevated FSH can indicate the testes are struggling to produce sperm (primary testicular failure). Low FSH may indicate a pituitary issue.
LH (Luteinising Hormone) stimulates the Leydig cells to produce testosterone. The FSH/LH/testosterone relationship tells a story about whether the reproductive axis is functioning normally.
A warning about TRT and steroids
If you're taking testosterone replacement therapy (TRT) or anabolic steroids and planning to conceive, discuss this with your GP or fertility specialist urgently. Exogenous testosterone suppresses FSH and LH, dramatically reducing or eliminating sperm production. This is one of the most important, and most frequently missed, male fertility conversations.
Test it with Bloody Good:
Product: Testosterone Free/Total + SHBG · FSH Blood Test · LH Blood Test
Read more: Testosterone testing in men
Thyroid function
How it affects male reproduction
Thyroid hormones influence reproductive function in men, though less dramatically than in women. Both hypothyroidism and hyperthyroidism can affect sperm parameters, libido, and erectile function. Subclinical thyroid dysfunction is relatively common and worth screening for in the pre-conception context.
Test it with Bloody Good:
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Read more: Thyroid function tests explained
Zinc and folate
The nutritional heavyweights for sperm
Zinc is one of the most important nutrients for male fertility. It's involved in testosterone production, sperm formation, sperm membrane stability, and protection against oxidative damage. Zinc is concentrated in seminal fluid at levels 100 times higher than in blood. The testes are voracious consumers of it.
Folate (vitamin B9) is involved in DNA synthesis and integrity. Low folate has been associated with increased sperm DNA fragmentation and reduced sperm count in some studies. While the evidence is stronger for women (folate prevents neural tube defects), there's a growing case for male folate adequacy in the pre-conception period.
Test it with Bloody Good:
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Vitamin B12
DNA synthesis and sperm health
B12 supports DNA synthesis and red blood cell production. Low B12 has been associated with reduced sperm count, motility, and increased sperm DNA damage. This is especially relevant for vegetarian and vegan men.
Test it with Bloody Good:
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Read more: Vitamin B12 blood test explained
Vitamin D
Sperm motility and testosterone support
Vitamin D receptors are present in testicular tissue and sperm cells. Low vitamin D has been associated with reduced sperm motility and lower testosterone. Supplementing deficient men has shown improvements in sperm parameters in some studies, though evidence is still accumulating.
Test it with Bloody Good:
Product: Vitamin D (25-OH) Blood Test
Read more: Vitamin D testing explained
Iron studies
Why iron overload matters more than deficiency here
While iron deficiency is less common in men than women, iron overload (haemochromatosis) is the bigger concern in this context. Haemochromatosis is relatively common in Australians of northern European descent and can damage the pituitary gland and suppress testosterone production, directly impairing fertility. Elevated ferritin in a man warrants investigation.
Test it with Bloody Good:
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Read more: Iron and ferritin blood tests explained
HbA1c and fasting glucose
Metabolic health and fertility
Metabolic health directly affects male fertility. Insulin resistance and type 2 diabetes are associated with lower testosterone, erectile dysfunction, increased sperm DNA fragmentation, and reduced semen quality. Obesity, which is tightly linked to insulin resistance, suppresses testosterone through aromatisation of testosterone to oestrogen in fat tissue.
Addressing metabolic health before conception isn't just about your partner's pregnancy. It's about your fertility contribution.
Lifestyle factors that blood tests can't measure, but still matter
Blood tests assess the internal environment. But several fertility-relevant factors sit outside the blood panel.
Heat exposure. Sperm production is temperature-sensitive. The testes sit outside the body for a reason. Prolonged heat exposure (hot baths, saunas, tight underwear, laptop on lap, prolonged cycling) can impair sperm production. Evidence is moderate but consistent.
Alcohol. Heavy drinking reduces testosterone, impairs sperm quality, and increases oestrogen through liver effects. Moderate consumption appears to have minimal impact, but reducing intake in the pre-conception window is reasonable.
Smoking. Smoking reduces sperm count, motility, and morphology, and increases sperm DNA damage. The evidence here is strong.
Cannabis. THC affects sperm motility, morphology, and the acrosome reaction (the process that enables sperm to penetrate the egg). Regular use is associated with reduced fertility.
Medications. Several medications affect male fertility: SSRIs, testosterone/anabolic steroids, finasteride/dutasteride (5-alpha reductase inhibitors), sulfasalazine, some chemotherapy agents. Review all medications with your GP before trying to conceive.
Stress. Chronic stress suppresses testosterone and may affect sperm quality through cortisol-mediated pathways. The evidence is moderate.
Environmental exposures. Pesticides, heavy metals, and endocrine disruptors (BPA, phthalates) have been associated with impaired sperm parameters in occupational and environmental studies.
When to test
Ideally: 3-6 months before you plan to start trying. This gives time to identify and address any deficiencies or hormonal issues. Sperm production takes approximately 72 days, so interventions need about three months to affect the sperm you're producing.
At minimum: when your partner starts her pre-conception workup. If she's getting tested, you should be too. Fertility is a team sport.
Immediately: if you're on testosterone replacement therapy or anabolic steroids. You need specialist guidance on cessation and recovery of spermatogenesis before attempting conception.
How to prepare
Fast for 8-12 hours if including glucose markers.
Test in the morning (before 10am). Testosterone peaks in the morning and declines throughout the day. Morning testing gives the most accurate and consistent reading.
Abstain from ejaculation for 2-3 days before if you're also planning a semen analysis (not required for blood work alone, but worth coordinating).
Mention all medications, supplements, and substances. TRT, anabolic steroids, finasteride, cannabis, and other substances directly affect the markers being tested.
Tests to consider through Bloody Good
Male pre-conception panel
Testosterone Free/Total + SHBG — reproductive hormone baseline
FSH Blood Test — testicular function
LH Blood Test — pituitary-gonadal axis
Thyroid Function Test (TFT) — metabolic and reproductive context
Vitamin D (25-OH) — sperm motility and testosterone
Zinc Blood Test — sperm production support
Vitamin B12 — DNA synthesis
Folate — DNA integrity
Metabolic context
HbA1c — metabolic health and testosterone
Iron Studies (Including Ferritin) — haemochromatosis screening
Full Blood Count (FBC) — baseline health
Or cover everything at once
The Bloody Good Test covers 100 biomarkers including testosterone, thyroid, vitamin D, B12, iron studies, HbA1c, liver, kidney, and more. Pair with standalone FSH, LH, zinc, and folate tests for the most thorough male pre-conception panel available through the platform.
What to do after testing
If testosterone is low: Investigate the cause. Lifestyle factors (sleep, weight, stress, alcohol) are the most common modifiable drivers. Do NOT start testosterone replacement therapy if you're trying to conceive. It will suppress sperm production. If hypogonadism is confirmed, discuss fertility-preserving options (hCG, clomiphene) with a specialist.
If FSH is elevated: This may indicate the testes are struggling to produce sperm. A semen analysis is the next step. Referral to a fertility specialist is appropriate.
If nutritional markers are low (zinc, B12, vitamin D, folate): Supplement and retest at 3 months. Improvements in sperm parameters from nutritional optimisation typically take 3 months to materialise, which is one full sperm production cycle.
If metabolic markers suggest insulin resistance: Address through diet, exercise, and weight management. Improving insulin sensitivity raises testosterone and improves semen parameters. This is one of the most impactful interventions for male fertility.
If iron is high (elevated ferritin without supplementation): Investigate for haemochromatosis. Untreated haemochromatosis can cause hypogonadism and infertility through pituitary iron deposition.
If everything's normal: Good baseline. You've confirmed that the hormonal and nutritional environment is supporting your fertility contribution. Continue maintaining healthy habits through the conception period and beyond.
Explore more biomarkers
If you want to go deeper into any of the markers covered here, the Bloody Good biomarker directory has detailed pages on what each test measures and how to think about results in general terms.
Browse the Bloody Good Biomarker Directory
This article provides general health information only and is not intended as medical advice, diagnosis, or treatment. Blood test results should be interpreted by a qualified healthcare professional in the context of your individual health circumstances, including symptoms, medical history, and medications. If you are experiencing persistent or concerning symptoms, consult your GP or seek medical attention promptly.