Young men across Australia and the world are chasing peak performance through a wave of wellness trends — from ice baths and saunas to supplement stacks and raw garlic — but experts warn that some of the most popular practices marketed as fertility boosters may actually be doing the opposite.
The self-optimisation culture that has swept social media, often dubbed "maxxing," has brought male fertility firmly into its orbit. Online communities now trade tips on everything from sleep hacking to testosterone optimisation, with growing numbers of men turning to saunas and cold-water "plunges" in the belief they will sharpen sperm health and improve the chances of conception. The evidence, however, tells a more complicated story.
Testosterone and fertility are not the same thing
One of the most significant misconceptions fuelling these trends is the assumption that boosting testosterone automatically improves fertility. That is not the case. While testosterone plays an essential role in normal male reproductive function, higher circulating testosterone levels do not translate directly into healthier sperm or better conception odds.
In fact, the relationship can run in the opposite direction. Taking supplemental testosterone — a practice increasingly popular among younger men — can actually suppress sperm production. Both the American Urological Association and the American Society for Reproductive Medicine advise against testosterone therapy for any man with current or future fertility goals.
This distinction becomes especially important when evaluating the fertility claims made around saunas and cold plunges. General wellbeing benefits, such as reduced stress, better sleep or improved mood, should not be mistaken for evidence of improved reproductive outcomes.
What the research says about heat and sperm health
The testes sit outside the body for a biological reason: sperm production is optimised at temperatures slightly below core body temperature. Introducing sustained heat disrupts that process.
A large 2024 study tracking more than 15,000 men and analysing over 28,000 semen samples found that exposure to extreme temperatures was associated with poorer semen quality, including lower sperm concentration, total count and motility.
More specifically focused research reinforces this concern. An Italian longitudinal study followed ten healthy men through two 15-minute Finnish sauna sessions per week — at temperatures between 80 and 90 degrees Celsius — over three months. The results showed declines in sperm count and motility, along with changes in mitochondrial function and sperm DNA packaging. The encouraging finding was that these effects reversed within six months of stopping sauna use.
A separate US-led study following couples trying to conceive found that while hot baths or hot tubs alone had limited impact on pregnancy rates, men with cumulative exposure to multiple heat sources had moderately reduced chances of conception.
Cold plunges: Popular, but no proven fertility benefit
If heat can impair sperm production, it might seem logical that cold exposure would provide the reverse effect. Current evidence does not support that conclusion.
A systematic review conducted by Australian researchers found that cold-water immersion may reduce muscle soreness and support short-term recovery after intense exercise. A separate Australian-led review published in 2025 reported possible benefits for stress, sleep quality and overall wellbeing. Neither review, however, found evidence that cold-water immersion improves testosterone levels, sperm quality or pregnancy rates. Both reviews were also constrained by small study sizes and inconsistent methodologies.
While targeted scrotal cooling has been investigated as a clinical treatment for male infertility, that is a highly specific medical application — a far cry from the generalised cold-plunge routines circulating on social media.
Separating wellness from reproductive health
The broader picture is that many popular men's wellness practices carry genuine benefits for general health, but those benefits are being routinely overstated when applied to fertility. Understanding the underlying biology — including the complex relationship between hormones, temperature and reproductive function — matters more than chasing trending routines.
For men seriously considering their fertility, the evidence points toward caution with high-heat environments and scepticism toward testosterone-boosting claims, rather than trust in the latest social media optimisation trend.
