The best underwear for men trying to conceive combines breathable natural fibers, an athletic fit with a gusset for airflow, and active cooling options to maintain optimal scrotal temperature, which is critical for sperm production.
Why Scrotal Temperature Matters for Sperm Production
Sperm production is highly sensitive to temperature, operating optimally several degrees Fahrenheit below core body temperature. [1] When scrotal temperature rises, sperm count, motility, and morphology all decline measurably. [2] This is why the testicles sit outside the body, to maintain that critical thermal gap. Tight, non-breathable underwear closes that gap by trapping heat and moisture against the skin.
The Impact of Fabric and Fit
Studies show that men who wear looser, airflow-friendly underwear have significantly higher sperm concentration than those in tight, synthetic options. [3] Synthetic fabrics like polyester are less breathable, can feel clammy, hold heat against the skin, and shed microplastics, which have been detected in 100 percent of human testis samples in recent research. [4] Natural fibers, by contrast, breathe better, and a natural fiber like MicroModal doesn't shed microplastics the way synthetics do.
Real-World Heat Sources
Daily activities like prolonged sitting, sauna use, or wearing tight clothing can raise scrotal temperature enough to disrupt sperm production. [5] The effect is reversible, but it accumulates over time. The key is minimizing unnecessary heat exposure through fabric choice and fit. An athletic brief with a gusset, for example, provides room and airflow without sacrificing support.
The Practical Takeaway
Whole-body heat has benefits, but the testicles thrive when kept cooler. The solution isn’t to avoid heat entirely but to manage scrotal temperature deliberately. Whether that means swapping synthetic fabrics for breathable natural ones or using active cooling during sauna sessions, the fix is mechanical, not behavioral.
Where Oakman Fits
Oakman is designed to address this exact problem, starting with its removable cold pack in a medical-grade nylon shell that sits in a front pocket and rests against the scrotum through a layer of soft fabric during heat exposure, cooling the testicles where it matters most. The brief itself is made from Siro-spun TENCEL-branded MicroModal, a natural wood-pulp fiber that breathes better than synthetics and doesn’t shed microplastics. An athletic gusset ensures the testicles have room and airflow, keeping scrotal temperature lower throughout the day. Together, these features create an environment closer to the one the testicles are designed for.
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Frequently asked questions
Does underwear really affect sperm health?
Studies show that men who wear breathable, airflow-friendly underwear have higher sperm concentration than those in tight, synthetic options. Fabric and fit directly influence scrotal temperature, which is critical for sperm production.
How long does it take for sperm production to recover after heat exposure?
Recovery typically takes 2 to 3 months once scrotal temperature returns to normal. The effect is reversible, but minimizing unnecessary heat exposure keeps that area cooler.
Are boxers better than briefs for fertility?
Boxers generally keep scrotal temperature lower than tight briefs, but an athletic brief with a gusset can provide similar airflow while offering better support. The key is avoiding heat-trapping fabrics and fits.
Can sauna use affect fertility?
Frequent sauna use can temporarily reduce sperm count and motility due to elevated scrotal temperature. The effect is reversible, but active cooling during sessions keeps the testicles cooler while the body takes the heat.
This guide is educational and not medical advice. Heat's effect on testicular cell function and sperm is shown in cellular and animal research; whether it shifts a healthy man's testosterone levels long-term is not established. These statements have not been evaluated by the FDA. Oakman is not intended to diagnose, treat, cure, or prevent any disease or condition, including infertility or changes in testosterone, and makes no claim to increase testosterone or improve fertility or sperm quality. Individual results vary. Consult a qualified healthcare professional before changing your health routine.
References
- Durairajanayagam D, Agarwal A, Ong C. (2015). Causes, effects and molecular mechanisms of testicular heat stress. Reproductive BioMedicine Online. [Link]
- Garolla A, et al.. (2013). Seminal and molecular evidence that sauna exposure affects human spermatogenesis. Human Reproduction. [Link]
- Minguez-Alarcon L, et al.. (2018). Type of underwear worn and markers of testicular function among men attending a fertility center. Human Reproduction. [Link]
- Hu CJ, Garcia MA, Nihart A, et al. (Yu XZ senior author). (2024). Microplastic presence in dog and human testis and its potential association with sperm count and weights of testis and epididymis. Toxicological Sciences. [Link]
- Jung A, Schuppe HC. (2007). Influence of genital heat stress on semen quality in humans. Andrologia. [Link]
