Table of contents

• Why men are googling selenium, sperm tests and fertility clinics
• TL;DR – at a glance
• Selenium 101: what it actually does in the male body
  • The official EU health claim: “selenium contributes to normal spermatogenesis”
• Selenium status in the UK: are men actually low?
• What science really says about selenium and fertility
  • Mechanisms: how selenium supports sperm and testicular function
  • Clinical trials of selenium alone
  • Selenium in combination with other antioxidants
  • Pregnancy and live birth: the outcomes that actually matter
• Using selenium in real life: food first, supplements second
  • Food sources and practical intake for UK men
  • Supplement doses, forms and safety limits
• Who might benefit most – and who should be cautious
• Practical checklist for men trying to optimise fertility
• Bottom line: how strong are selenium benefits for male fertility?
• FAQ: long-tail questions about selenium and male fertility
• References

Why men are googling selenium, sperm tests and fertility clinics

Picture this: it’s 2am, your partner is asleep, and you’re on your phone quietly typing selenium benefits for men and selenium and fertility into Google. You’ve just had a semen analysis that showed “sub-optimal motility”, or you’re months into trying for a baby and starting to wonder whether your swimmers are doing their job.

You read that selenium is “good for sperm”, someone on a forum mentions “testicular antioxidant support”, and suddenly you’re three tabs deep into brazil nuts, supplements and acronyms like OAT (oligo-astheno-teratozoospermia).

Here’s the reality:

• Selenium does have an officially approved EU health claim for male reproduction – “selenium contributes to normal spermatogenesis” (the process of making sperm). [1]
• UK bodies like the NHS recognise that selenium plays a role in reproduction as well as immune function and protection from cell damage. [2]
• But the evidence on actual improvements in fertility outcomes – pregnancies and live births – is much more mixed than the marketing sometimes suggests. [3] [5] [6] [7] [8]

So yes, there are promising selenium benefits for men when it comes to sperm quality, especially in those with low selenium status – but it’s not a magic bullet, and it has to be used within safe limits and proper medical care.

TL;DR – at a glance

Key takeaway: Selenium is important for normal sperm production and testicular antioxidant defence, and supplements can modestly improve semen parameters in some men – but evidence that they reliably improve pregnancy or live-birth rates is limited and often low-quality.

At a glance

• In Europe, the only authorised fertility-related health claim is that “selenium contributes to normal spermatogenesis”. You can’t lawfully claim that selenium “treats male infertility” or “boosts fertility” on a label. [1]
• The NHS recommends 75 µg/day of selenium for men aged 19–64, normally achievable from a balanced diet including meat, fish or nuts. [2]
• The NIH Office of Dietary Supplements notes selenium is important for sperm structure and antioxidant defence, but clinical trials of supplements show conflicting results, and there is not enough evidence to state that selenium supplements significantly improve male fertility. [3]
• Mechanistic and animal studies, plus a recent 2024 review, support a strong biological link between selenium, sperm development, and testicular function. [4]
• Systematic reviews and meta-analyses of randomised controlled trials show that selenium (often with other antioxidants) can modestly improve sperm motility and morphology, but results vary between studies and certainty of evidence is often low. [5] [6] [7] [8] [9]
• UK dietary and fertility organisations emphasise a food-first approach, using supplements as a targeted add-on rather than the main treatment. [2] [13] [14]

If you want the nuanced version of selenium benefits for men and how thematically linked selenium and fertility really are, let’s dig in.

Selenium 101: what it actually does in the male body

Selenium is a trace mineral used to build selenoproteins – proteins containing the amino acid selenocysteine. These include powerful antioxidant enzymes such as glutathione peroxidases (especially GPx4) and selenoprotein P, which are heavily expressed in the testes and sperm. [3] [4]

The NIH summarises selenium’s role in male fertility like this:

• Selenoproteins are major structural components of mature sperm.
• Both low and high selenium levels in semen have been associated with impaired fertility in observational studies.
• Trials of selenium supplements have shown improvements in some sperm parameters in some studies, but not others, and overall there is insufficient evidence that supplements clearly improve male fertility. [3]

A 2024 comprehensive review in Heliyon pulls together human, animal and molecular data: selenium is crucial for normal testicular development, protects germ cells against oxidative stress, and supports sperm maturation and motility; both deficiency and excess can harm spermatogenesis. [4]

In other words, the biological link between selenium and fertility is strong and plausible – but biology alone doesn’t tell us what happens when real men take real supplements. That’s where clinical trials come in.

The official EU health claim: “selenium contributes to normal spermatogenesis”

Under Commission Regulation (EU) No 432/2012, the European Commission authorised the following selenium claim:

“Selenium contributes to normal spermatogenesis.”

This claim may only be used for foods that are at least a “source of selenium” according to EU nutrition rules. [1] It is an Article 13(1) general function claim, not a disease-reduction claim, which means:

• It refers to maintaining normal physiological function in healthy people.
• It does not mean that selenium “treats infertility”, “cures low sperm count” or “improves IVF success”. Using that sort of wording in the EU/UK would breach health-claims legislation.

So when we talk about selenium benefits for men in a UK or EU context, we have to stick to claims along the lines of:

• Selenium contributes to normal spermatogenesis.
• Selenium contributes to the protection of cells from oxidative stress. [1]

Anything beyond that – like promising specific improvements in sperm count or pregnancy rates – has to be clearly framed as research findings, not as authorised marketing claims.

Selenium status in the UK: are men actually low?

From an NHS point of view, selenium is needed for the immune system, reproduction, and protection of cells from damage. Recommended intakes are: [2]

• 75 µg/day for men aged 19–64
• 60 µg/day for women

The NHS notes that if you eat meat, fish or nuts, you should usually be able to get enough from food alone, and that taking up to 350 µg/day from supplements is unlikely to cause harm, though more could be toxic. [2]

However, UK dietary surveys suggest that average selenium intake has fallen over the last few decades, largely because we import less North American wheat (which tends to be richer in selenium) and rely more on European crops grown in relatively selenium-poor soils. A clinical article aimed at UK doctors on Patient.info notes that UK intakes have been declining over 30 years, and confirms the UK RDA of 75 µg/day for men. [15]

That context matters: when evaluating selenium benefits for men, those benefits are more likely to show up in men whose baseline selenium intake or status is low or marginal, which is plausible in parts of the UK.

What science really says about selenium and fertility

Mechanisms: how selenium supports sperm and testicular function

The 2024 Heliyon review and other mechanistic work outline several ways selenium may link selenium and fertility at the cellular level: [4]

• Antioxidant defence – selenium is a key part of glutathione peroxidases that neutralise reactive oxygen species (ROS) in testes and sperm. Excess ROS damage sperm membranes, DNA and motility.
• Structural role in sperm – GPx4 in particular acts as a structural protein in the midpiece of mature sperm, helping maintain the mitochondrial sheath needed for motility.
• Testicular development and hormone production – selenium influences Leydig and Sertoli cell function, which support testosterone production and germ-cell development.
• “Goldilocks” effect – both deficiency and excess selenium can disrupt testicular architecture and spermatogenesis in animal models, with optimal levels giving best sperm outcomes. [4]

So yes, from a biological perspective, selenium benefits for men make sense: enough selenium helps sperm develop properly and protects them against oxidative stress. But now we need to look at what trials actually show.

Clinical trials of selenium alone

Human trials of selenium alone (or selenium-dominant regimens) fall into three main buckets:

1. Healthy volunteers with normal fertility
2. Men with poor semen parameters (e.g. low motility)
3. Men with idiopathic infertility

The NIH fact sheet summarises several key studies: [3]

• A 48-week trial in 54 healthy men taking 300 µg/day of selenium yeast found no improvement in sperm concentration or motility versus placebo; semen volume actually fell slightly in both groups. [3]
• A Scottish 3-month trial in 69 men with low motility and low plasma selenium (around 8.1 µg/dL) gave 100 µg/day selenomethionine. Motility and chances of conception improved compared with placebo, but numbers were modest. [3]
• Another trial in 70 men with idiopathic infertility used 200 µg/day selenium yeast or 200 mg/day coenzyme Q10 without a placebo group; selenium increased total and progressive motility, but the study design limits how confidently we can interpret it. [3]

A large double-blind RCT in 468 infertile men with oligo-astheno-teratozoospermia compared 200 µg/day selenium, 600 mg/day N-acetylcysteine (NAC), the combination, or placebo for 26 weeks. Selenium and NAC improved several semen parameters and hormones, and the combination appeared additive. [10] However, a formal expression of concern about this paper was published in 2023, so its findings should be treated with caution. [10]

Zooming out:

• When you pool data across nutrients, a 2018 meta-analysis of RCTs found that selenium supplementation caused small but statistically significant improvements in total sperm motility (around 3.3 percentage points) and normal morphology (about 1.9 percentage points). [5]
• Selenium was one of several nutrients (alongside zinc, omega-3 fatty acids, CoQ10 and carnitine) that improved specific semen parameters, but evidence quality was limited and heterogeneity high. [5]

So, in men with sub-optimal semen quality – particularly if they’re low in selenium – there is reasonable evidence that selenium can nudge selenium and fertility markers (motility, morphology) in the right direction. But effects are generally modest, and not every study shows benefit. [3] [5] [6]

Selenium in combination with other antioxidants

In clinical practice and in the supplement market, selenium is rarely given alone. It’s most often combined with:

• Vitamin E
• Zinc
• Coenzyme Q10
• Carnitine
• NAC and other antioxidants

A classic RCT in 690 infertile men looked at selenium (200 µg/day) plus vitamin E (400 IU/day) for three months. Around 60% of men had improved motility and morphology, and about 10.8% of couples conceived spontaneously during the study. [11]

A 2025 systematic review and meta-analysis focusing specifically on selenium + vitamin E in male infertility found that combinations generally improved sperm motility and morphology, but study quality was variable and doses and formulations differed widely. [12]

Several large umbrella reviews/meta-analyses of antioxidant therapy in male infertility give helpful context:

• A 2018 RCT meta-analysis found selenium modestly improved motility and morphology, but other nutrients (like carnitine and CoQ10) often had larger effects. [5]
• A 2022 network meta-analysis comparing eight antioxidants (folic acid, zinc, vitamin E, carnitine, selenium, CoQ10, NAC, vitamin C) concluded that carnitine and CoQ10 performed best for motility and concentration, while selenium had smaller but still favourable effects. [6]
• A 2023 systematic review of antioxidant supplementation on male fertility reported that most studies showed improvements in semen parameters and sometimes in outcomes of assisted reproduction, but results were inconsistent and often at high risk of bias. Selenium appeared beneficial, particularly as part of multi-antioxidant regimens. [7]

A 2022 study analysing dietary supplements for male infertility marketed in Italy found that most products contained multiple ingredients (2–17 per product), often at doses below those used in successful trials, and with variable evidence of efficacy. Selenium was one of the more frequently included “potentially active ingredients”. [9]

So, in practice, when we talk about selenium benefits for men, we’re often really talking about “selenium plus friends”. That matters when you write about it: improvements may not be attributable to selenium alone.

Table 1. Snapshot of evidence on selenium and male fertility

Pregnancy and live birth: the outcomes that actually matter

For couples, the real question about selenium and fertility is not “Will my sperm motility go up by 3%?” – it’s “Will we have a baby?”

A 2025 systematic review and meta-analysis in Nutrients looked at dietary supplements and male infertility specifically in terms of pregnancy, live birth and semen parameters. Across 50 studies: [8]

• Different supplements improved individual semen parameters (e.g. selenium, carnitine and CoQ10 improved motility).
• No convincing effect on pregnancy or live-birth rates was found for any supplement, including antioxidant combinations. [8]
• Overall certainty of evidence was low to very low, with many trials small, short, and at risk of bias.

In other words:

Supplements (including selenium) can improve sperm quality on paper, but we don’t yet have strong, consistent data showing that they reliably increase the chance of bringing home a baby.

That doesn’t mean selenium is useless – especially if your levels are low – but it does mean we should talk about selenium benefits for men in realistic terms: supporting normal spermatogenesis and nudging parameters, not promising miracles.

Using selenium in real life: food first, supplements second

Food sources and practical intake for UK men

The NHS lists good dietary sources of selenium as: [2]

• Brazil nuts
• Fish
• Meat
• Eggs

UK dietetic guidance on male fertility emphasises a generally healthy eating pattern: wholegrains, lean protein, plenty of fruit and veg, and sources of antioxidants such as vitamin E and selenium. [13] A fact sheet from Fertility Network UK similarly describes selenium as an antioxidant that helps protect the body from free radicals, noting that men with low sperm counts have been observed to have lower blood selenium levels. [14]

These organisations are not promising magic selenium and fertility improvements – they’re pointing out that optimising your overall diet (including selenium intake) is one part of a sensible fertility plan.

Did you know?

• A single Brazil nut can contain 68–91 µg of selenium, depending on where it was grown – potentially more than your entire daily requirement. [16]
• That means regularly eating “a handful of Brazil nuts” on top of a diet that already includes meat and fish can easily push you towards the upper safe limit.

For most UK men, a balanced diet plus perhaps an occasional Brazil nut is enough to hit the 75 µg/day target. [2] The case for extra supplements becomes stronger if:

• Your diet is low in animal products or nuts.
• You have confirmed low blood or plasma selenium.
• Your fertility specialist has suggested a time-limited trial of antioxidants.

Supplement doses, forms and safety limits

Globally, recommended intakes for selenium in adults are typically around 55–70 µg/day, while tolerable upper intakes have historically been set at 400 µg/day by US authorities. [3] [16]

More recently, the European Food Safety Authority (EFSA) has suggested a lower adult upper limit of 255 µg/day, based largely on the risk of hair loss (alopecia) at higher intakes. [3]

In the UK, the NHS currently advises that: [2]

• You should be able to meet your needs from a balanced diet.
• Taking 350 µg/day or less of selenium from supplements is unlikely to cause harm.

The NIH warns that chronic over-intake can lead to selenosis, with hair loss, brittle nails, garlic-like breath, fatigue and neurological symptoms. [3] [16]

Most clinical trials showing potential selenium benefits for men use doses in the 100–200 µg/day range, often for 3–6 months, sometimes longer. [3] [5] [10] [11]

Practical sweet spot for most men (not individual medical advice):
– Aim to cover 75 µg/day via diet where possible. [2]
– If you and your doctor decide to try a supplement, a 50–200 µg/day dose is typical in research and keeps you comfortably below most upper limits when combined with food. [3] [5]

If your diet isn’t reliably providing selenium, you might consider a once-daily supplement in that range – for example, a 200 µg capsule of selenium (as selenomethionine) such as a dedicated selenium 200mcg supplement, always used alongside broader lifestyle and medical care rather than instead of it.

And yes, that’s one place where real-world selenium and fertility concerns meet sensible supplementation.

Who might benefit most – and who should be cautious

Drawing on the systematic reviews and clinical commentary, here’s a sensible, evidence-aware way to think about selenium benefits for men in practice.

Men who may benefit

You’re more likely to see a useful effect if:

• You have documented low selenium status on blood testing. [3] [4]
• Your diet is low in animal protein and nuts (e.g. very restricted diets or long-term exclusion of these foods). [3] [15]
• You have subfertility with abnormal semen parameters (e.g. low motility or morphology), especially when your clinician has suggested a course of antioxidants based on your overall picture. [5] [6] [7] [8]
• You live in an area with selenium-poor soils and low usual dietary intake (which includes much of Europe). [3] [15]

In these men, a carefully dosed supplement may support normal spermatogenesis and modestly improve sperm parameters as part of a comprehensive fertility plan.

Men who should be cautious

Extra selenium may be unnecessary or potentially harmful if:

• Your dietary intake is already high, particularly if you eat Brazil nuts regularly or take multiple fortified products. [3] [16]
• You’re stacking several multivitamins and antioxidant formulas, each containing selenium, risking a total intake near or above the upper limit. [3] [9]
• You have certain medical conditions (e.g. kidney disease) or take medications that interact with trace elements – this is where your GP or specialist needs to advise. [3]

Some emerging research also raises concerns that very high selenium intakes may be linked to an increased risk of type 2 diabetes in some populations, although findings are inconsistent. [3]

Bottom line for risk: More is not always better. With selenium and fertility, you want enough to support normal antioxidant defence and spermatogenesis, not mega-doses.

Practical checklist for men trying to optimise fertility

Supplements are the icing, not the cake. Whether or not you use selenium, most guidelines and expert reviews agree on the following for male fertility: [3] [5] [7] [8] [13] [14]

TL;DR lifestyle checklist

• See your GP or fertility specialist. Rule out treatable causes (varicocele, hormonal disorders, infections) and get proper semen analysis.
• Don’t smoke. Smoking is consistently associated with poorer semen parameters and higher DNA fragmentation.
• Keep alcohol moderate. Heavy drinking harms sperm and testosterone.
• Aim for a healthy weight. Both obesity and under-nutrition can impair hormones and selenium and fertility dynamics.
• Protect the testes from heat. Avoid long hot baths, saunas before providing samples, and tight underwear all day.
• Eat a fertility-friendly diet. Plenty of vegetables, fruit, wholegrains, fish, nuts, and lean protein – this naturally covers selenium and other key nutrients. [13] [14]
• Manage stress and sleep. Chronic stress and poor sleep don’t help hormone balance or lifestyle adherence.

Only once those foundations are in place does it really make sense to talk about specific selenium benefits for men via targeted supplementation.

Bottom line: how strong are selenium benefits for male fertility?

Let’s zoom out and be brutally honest:

• Biology: Selenium is essential for normal sperm production and testicular antioxidant defence. No argument there. [3] [4]
• Authorised claim: In the EU and UK, you are allowed to say “selenium contributes to normal spermatogenesis”, and that is the correct, legally safe wording. [1]
• Clinical data:
  • Selenium (alone or with other antioxidants) can modestly improve sperm motility and morphology in some men, especially those with poor baseline parameters or low selenium status. [3] [5] [6] [7] [10] [11] [12]
  • The evidence that these changes translate into higher pregnancy or live-birth rates is weak and inconsistent. Large systematic reviews find no convincing benefit on these “hard” outcomes so far. [8]
• Safety: Within reasonable intakes (diet plus ≤200 µg/day in supplements for most men), selenium is generally safe; chronic high intakes can cause toxicity, and EFSA now suggests a more cautious upper limit than before. [2] [3] [16]

So, yes:

There are meaningful, evidence-backed selenium benefits for men in terms of supporting normal spermatogenesis and possibly nudging semen quality – especially in those with low status. But selenium is a small part of a much bigger fertility picture, not a standalone cure.

Used sensibly, as part of a diet- and lifestyle-driven plan, selenium and fertility absolutely belong in the same conversation – just not in the “miracle fix” category.

FAQ: long-tail questions about selenium and male fertility

1. How long would I need to take selenium before seeing a change in semen parameters?

Most trials run for 3–6 months, which matches the roughly 74-day cycle of spermatogenesis plus time for sperm to mature. [3] [5] [10] [11] Any potential selenium benefits for men on motility or morphology are usually assessed after at least three months of supplementation.

2. Is there a “best” form of selenium for male fertility – yeast vs selenomethionine vs selenate?

Trials have used various forms (selenium yeast, selenomethionine, sodium selenite), and there’s no clear winner for fertility outcomes. [3] [5] The most important factor is total dose and your starting selenium status.

3. Can I just eat Brazil nuts instead of taking a supplement?

Potentially – but with caution.

• One Brazil nut can provide close to or more than the entire daily requirement for selenium. [16]
• Two or three a day plus a meat- and fish-containing diet and a multivitamin could push you towards or beyond upper safe limits. [2] [3]

If you rely on Brazil nuts, keep it to one nut most days, and consider what else you’re taking. For more controlled dosing related to selenium and fertility, a capsule with a known microgram amount is often easier to manage.

4. Should every man trying to conceive take selenium “just in case”?

No. Large systematic reviews highlight that while some men benefit in terms of semen parameters, the overall evidence on fertility outcomes is Not There Yet™, and antioxidant over-use could, in theory, disturb normal redox balance. [7] [8]

Better to:

• Focus on the basics (diet, smoking, alcohol, heat, weight).
• Discuss supplements – including selenium – with a GP or fertility specialist if there’s a specific indication (poor semen analysis, dietary issues, low selenium).

5. Can selenium boost testosterone?

Some trials (like the Safarinejad 2009 study) reported increases in testosterone alongside improved semen parameters. [10] Others did not. [3]

Overall, there isn’t strong enough evidence to market selenium as a “testosterone booster”, and no authorised EU claim supports that. Any testosterone effects are likely secondary to improved testicular health rather than a direct hormone-boosting effect.

6. Is selenium helpful for older men’s fertility?

Ageing is associated with increased oxidative stress and often worsening semen quality. Reviews suggest antioxidants – including selenium – may be more relevant in this context, but there are few high-quality, age-specific trials. [4] [7] [8]

For older men, the same principles apply: optimise lifestyle, address medical issues, consider a time-limited, moderate-dose antioxidant regimen under specialist guidance – not indefinite mega-dosing.

7. Are there groups who should definitely avoid selenium supplements?

You should be particularly cautious (and seek medical advice) if:

• You already take several fortified products with selenium.
• You have kidney disease or other conditions affecting mineral balance.
• You have had past signs of selenium excess (hair/nail changes, GI upset) potentially linked to supplements. [3] [16]

For most healthy men, a food-first approach plus carefully chosen supplementation when appropriate is a reasonable, balanced way to approach selenium benefits for men and broader selenium and fertility questions.

References

1. European Commission. Commission Regulation (EU) No 432/2012 of 16 May 2012 establishing a list of permitted health claims made on foods, other than those referring to the reduction of disease risk and to children’s development and health. Off J Eur Union. 2012;136:1–40. Available from: https://eur-lex.europa.eu/legal-content/EN/TXT/?uri=CELEX:02012R0432-20210517
2. NHS. Vitamins and minerals – selenium [Internet]. London: NHS; 2017 [cited 2025 Nov 24]. Available from: https://www.nhs.uk/conditions/vitamins-and-minerals/others/
3. Office of Dietary Supplements, National Institutes of Health. Selenium – Health professional fact sheet [Internet]. Bethesda (MD): NIH; 2025 Sep 4 [cited 2025 Nov 24]. Available from: https://ods.od.nih.gov/factsheets/Selenium-HealthProfessional/
4. Yuan S, Zhang Y, Dong P-Y, Chen Y-M, Liu J, Zhang B-Q, et al. A comprehensive review on potential role of selenium, selenoproteins and selenium nanoparticles in male fertility. Heliyon. 2024;10:e34975. Available from: https://doi.org/10.1016/j.heliyon.2024.e34975
5. Salas-Huetos A, Bulló M, Salas-Salvadó J. The effect of nutrients and dietary supplements on sperm quality parameters: a systematic review and meta-analysis of randomized clinical trials. Adv Nutr. 2018;9(6):833–848. Available from: https://pubmed.ncbi.nlm.nih.gov/30462179/
6. Su L, Qu H, Cao Y, Zhu J, Zhang S-Z, Wu J, et al. Effect of antioxidants on sperm quality parameters in subfertile men: a systematic review and network meta-analysis of randomized controlled trials. Adv Nutr. 2022;13(2):586–594. Available from: https://www.sciencedirect.com/science/article/pii/S2161831322000783
7. Dimitriadis F, Borgmann H, Struck JP, Salem J, Kuru TH. Antioxidant supplementation on male fertility—A systematic review. Antioxidants (Basel). 2023;12(4):836. Available from: https://pubmed.ncbi.nlm.nih.gov/37107211/
8. Michaelsen MP, Poulsen JL, et al. The effect of dietary supplements on male infertility in terms of pregnancy, live birth, and sperm parameters: a systematic review and meta-analysis. Nutrients. 2025;17(10):1710. Available from: https://pubmed.ncbi.nlm.nih.gov/40431450/
9. Garolla A, Bettella A, Cosci I, Sartini B, Engl B, Pizzol D, et al. Systematic review and critical analysis on dietary supplements for male infertility: from a blend of ingredients to a rationale strategy. Front Endocrinol (Lausanne). 2022;12:824078. Available from: https://www.frontiersin.org/articles/10.3389/fendo.2021.824078/full
10. Safarinejad MR, Safarinejad S. Efficacy of selenium and/or N-acetyl-cysteine for improving semen parameters in infertile men: a double-blind, placebo controlled, randomized study. J Urol. 2009;181(2):741–751. Available from: https://pubmed.ncbi.nlm.nih.gov/19091331/
11. Moslemi MK, Tavanbakhsh S. Selenium–vitamin E supplementation in infertile men: effects on semen parameters and pregnancy rate. Int J Gen Med. 2011;4:99–104. Available from: https://pubmed.ncbi.nlm.nih.gov/21403799/
12. Oskouei BS, et al. Combined selenium and vitamin E supplementation’s effects on male infertility: a systematic review and meta-analysis [Internet]. Research Square; 2025 [cited 2025 Nov 24]. Available from: https://www.researchsquare.com/article/rs-6681128/v1
13. British Dietetic Association. Food fact sheet: male fertility [Internet]. Birmingham: BDA; 2023 [cited 2025 Nov 24]. Available from: https://www.bda.uk.com/static/4d16eadb-85fd-4c07-8a0d0f83879623a9/2d4807b9-23c4-48ec-b1d864e936ce83ac/Male-Fertility.pdf
14. Fertility Network UK. Dietary information – a guide for men and women trying to conceive [Internet]. London: Fertility Network UK; 2016 Oct [cited 2025 Nov 24]. Available from: https://fertilitynetworkuk.org/wp-content/uploads/2016/10/FACTSHEET-Dietary-Information-October-2016.pdf
15. Patient.info. Selenium. In: Nutrition – vitamins and minerals [Internet]. Patient Platform Limited; 2022 [cited 2025 Nov 24]. Available from: https://patient.info/doctor/nutrition/selenium
16. Office of Dietary Supplements, National Institutes of Health. Selenium – consumer fact sheet [Internet]. Bethesda (MD): NIH; 2025 Jun 18 [cited 2025 Nov 24]. Available from: https://ods.od.nih.gov/factsheets/Selenium-Consumer/