Researchers discovered that selenium, a mineral found in foods like nuts and fish, may protect sperm health by activating a cellular defense system called ferroptosis. In studies with mice and human cells, selenium helped prevent damage to sperm-producing cells. Interestingly, men with low sperm counts had lower levels of a protective protein called GPX4, which selenium helps activate. While selenium didn’t dramatically increase sperm numbers in this study, it did improve the structure and health of reproductive tissues. These findings suggest selenium plays an important role in male fertility, though more research is needed to confirm how to best use this information clinically.

The Quick Take

  • What they studied: Whether selenium, a nutrient in our diet, helps protect sperm health by activating a cellular defense system that prevents damage to sperm-producing cells.
  • Who participated: Laboratory mice on different selenium diets, human sperm cells grown in dishes, and men with normal sperm counts compared to men with low sperm counts.
  • Key finding: Selenium activated a protective protein called GPX4 in sperm cells, and men with low sperm counts had significantly lower levels of this protective protein. However, selenium didn’t dramatically increase sperm numbers in the mouse studies.
  • What it means for you: Getting enough selenium from foods like Brazil nuts, tuna, and eggs may help protect sperm health, especially if you’re concerned about fertility. However, this is early research, and taking selenium supplements won’t necessarily fix fertility problems on its own. Talk to a doctor before starting any supplements.

The Research Details

This research combined three different approaches to understand selenium’s role in male fertility. First, researchers fed mice either very low selenium diets or normal diets with selenium supplements for six weeks and examined their reproductive tissues under a microscope. Second, they grew human sperm cells in laboratory dishes and exposed them to chemicals that damage cells, then tested whether selenium could protect them. Third, they compared selenium levels and protective proteins in semen samples from men with normal sperm counts versus men with low sperm counts.

The researchers used advanced techniques to measure specific genes and proteins involved in a cellular protection process called ferroptosis—essentially a cellular defense system that prevents harmful damage. They also used genetic engineering to confirm that selenium’s protective effects worked through a specific protein called GPX4.

Understanding how selenium protects sperm cells at the molecular level helps scientists figure out why some men have fertility problems and how to potentially treat them. By studying this in mice first, then in human cells, and finally in actual patient samples, the researchers could confirm that the effects they saw in the lab actually happen in real people. This multi-step approach makes the findings more reliable and meaningful.

The study used rigorous scientific methods including controlled laboratory conditions, statistical analysis to confirm findings weren’t due to chance, and genetic engineering to prove cause-and-effect relationships. The research was published in a peer-reviewed scientific journal. However, the mouse studies didn’t show a clear increase in sperm numbers, and the human studies were observational rather than experimental, meaning researchers couldn’t prove selenium directly caused the differences they observed. The sample sizes for human studies weren’t clearly reported, which limits how much we can generalize the findings.

What the Results Show

In mice fed a selenium-deficient diet, the prostate and testis tissues shrank significantly and showed structural damage under the microscope. When mice received selenium supplements, their testis tissues grew larger and looked healthier. Importantly, the genes responsible for producing the protective protein GPX4 were dramatically reduced in selenium-deficient mice but bounced back with supplementation.

In human sperm cells grown in dishes, selenium (specifically a form called selenomethionine) protected cells from damage caused by a chemical called Erastin. The selenium worked by increasing levels of the GPX4 protective protein. When researchers genetically removed GPX4, selenium no longer provided protection, proving that GPX4 was essential for selenium’s protective effect.

In men with low sperm counts, the protective GPX4 protein was significantly reduced in their semen compared to men with normal sperm counts. Interestingly, selenium levels in the semen were similar between the two groups, suggesting the problem wasn’t a lack of selenium itself but rather a failure to properly activate the protective system.

The study found that another protein called SLC7A11 was higher in men with low sperm counts, and this higher level was associated with increased fertility problems. This suggests that the balance between different protective proteins matters for sperm health, not just the presence of selenium. The research also showed that the relationship between selenium levels and sperm health is more complex than simply ‘more selenium equals better sperm’—it’s about whether the body can properly use selenium to activate protective systems.

Previous research suggested selenium was important for fertility, but this study provides a clearer explanation of how it works. Rather than just being a general nutrient, selenium appears to work through a specific cellular protection pathway. The finding that men with low sperm counts have reduced GPX4 protein aligns with other research showing this protein is crucial for sperm cell survival. However, this study goes further by showing that selenium levels alone don’t predict fertility problems—the ability to activate the protective system matters more.

The mouse studies used only one type of mouse and didn’t show a clear increase in actual sperm numbers, only improvements in tissue structure. The human studies were observational, meaning researchers couldn’t prove that low GPX4 causes low sperm counts—only that they occur together. The study didn’t test whether selenium supplements could actually improve fertility in men with low sperm counts. The sample sizes for human studies weren’t clearly reported, making it unclear how reliable the human findings are. Additionally, the study was conducted in laboratory and animal settings, which don’t perfectly replicate how the body works in real life.

The Bottom Line

Ensure adequate selenium intake through diet (Brazil nuts, tuna, turkey, and eggs are good sources) as part of overall healthy nutrition. If you’re concerned about fertility, discuss selenium supplementation with a doctor rather than self-treating, as the evidence for supplements specifically improving fertility is still limited. Current evidence suggests selenium is important for sperm health, but it’s not a standalone fertility treatment. Maintain other healthy habits like regular exercise, healthy weight, and stress management, which also support reproductive health.

Men concerned about fertility or with diagnosed low sperm counts should pay attention to this research. Men planning to have children may want to ensure adequate selenium intake. This research is less relevant for women’s fertility, though selenium is important for overall health. People with certain medical conditions or taking medications should consult their doctor before changing selenium intake, as too much selenium can be harmful.

If selenium deficiency is contributing to fertility problems, it may take several weeks to months of adequate intake to see improvements in sperm health, as sperm production takes about 74 days. Don’t expect immediate results from dietary changes or supplements. If you’re trying to conceive, give any dietary or supplement changes at least 2-3 months before assessing effectiveness.

Want to Apply This Research?

  • Track daily selenium intake by logging selenium-rich foods consumed (Brazil nuts, tuna, turkey, eggs, brown rice). Aim for the recommended daily intake of 55 micrograms and monitor consistency over 8-12 weeks.
  • Add one selenium-rich food to your daily diet—for example, eat 2-3 Brazil nuts daily or include tuna or turkey in meals 2-3 times per week. Set a daily reminder to consume your selenium source at the same time each day to build the habit.
  • Track selenium food sources weekly and note any changes in energy levels or overall health. If using supplements, log dosage and timing. For fertility-specific tracking, work with a healthcare provider to monitor sperm health through periodic testing rather than relying on app-based tracking alone.

This research is preliminary and was conducted primarily in laboratory and animal models. While the findings suggest selenium plays a role in sperm health, this study does not prove that selenium supplements will improve fertility in men or treat low sperm counts. If you are experiencing fertility concerns or low sperm counts, consult with a qualified healthcare provider or fertility specialist for proper diagnosis and treatment. Do not start selenium supplements without medical guidance, as excessive selenium intake can be harmful. This information is for educational purposes only and should not replace professional medical advice.