The best alternatives to cotton boxers are MicroModal and Lyocell-blend briefs or trunks. They move moisture faster than cotton, feel lighter against the skin, and keep the area that needs to stay cool drier throughout the day.
Why men leave cotton behind
Cotton is comfortable at first, but it absorbs moisture and holds it. In warm weather, after a workout, or after a sauna session, that trapped moisture turns into sustained heat right where you don't want it. Research confirms that genital temperature sits naturally about 2 to 4°C below core body temperature, and that gap matters for normal testicular function. [1] Clothing that traps heat and moisture narrows that gap.
A large fertility-center study found that men who wore looser, less constrictive underwear had meaningfully higher sperm concentration than men in tighter styles, suggesting fit and airflow both play a role. [2] Cotton isn't the villain, but its moisture-retention is a real limitation.
How the main alternatives compare
| Fabric | Moisture wicking | Breathability | Feel | Notes |
|---|---|---|---|---|
| Standard cotton | Low | Moderate | Soft initially | Holds moisture; gets heavy |
| Polyester / nylon | High | Low | Can feel clammy | Wicks fast but traps heat; microplastic shedding is a documented concern [3] |
| MicroModal | High | High | Very soft, light | Wood-pulp derived; cooler and drier than cotton [4] |
| Lyocell (TENCEL) | High | High | Smooth, breathable | Naturally derived; strong sensory comfort profile [4] |
| Merino wool | Moderate | Moderate | Can itch | Good temperature regulation; heavier and pricier |
What to actually look for
- Fiber source. MicroModal and Lyocell are derived from wood pulp and consistently outperform synthetics on moisture management and skin feel. [4]
- Fit. Looser and less constrictive supports airflow. Compression-style cuts, regardless of fabric, restrict the natural cooling the area needs.
- Dye sourcing. Synthetic dyes in direct-contact garments are worth scrutinizing. Bluesign approved dyes indicate controlled sourcing through the supply chain.
- Stretch fiber. Most underwear uses conventional spandex. Bio-based stretch fibers are a cleaner option where available.
Oakman launches Fall 2026. Founding members get first access and founding pricing locked in. Reserve your spot.
Where Oakman fits
Oakman is built specifically for active men looking for scrotal cooling all day and want the option of a cold pack for cooling in the sauna or after heat exposure. The fabric is TENCEL MicroModal, naturally derived from wood pulp rather than plastic, blended with ROICA V550, a clean Japanese stretch fiber, rather than conventional spandex. The fit is athletic with a gusset, an extra panel that gives the testicles room and airflow. Dyes are bluesign approved, so what touches your skin is controlled all the way through the supply chain. The result is a brief that's cooler, drier, and softer than cotton, made to work alongside an active or heat-focused routine.
Oakman launches Fall 2026. The Founding 100 get first access. If you're already thinking about what you put on your body every day, this is worth being early for.
Related reading
Related reading
- When Is the Best Time of Day to Use a Sauna for Sleep Benefits?
- Best Materials for a Durable, Efficient DIY Sauna
Frequently asked questions
Does genital temperature affect sperm count?
Research shows that the genital area functions best when it stays cooler than core body temperature. Studies link sustained elevated genital heat to lower sperm concentration and reduced motility. [1][2]
Is MicroModal better than cotton for underwear?
MicroModal moves moisture away from the skin faster than cotton and feels lighter throughout the day. Peer-reviewed comparisons of eco-friendly apparel fibers show stronger sensory comfort and moisture performance for wood-pulp-derived fabrics versus conventional cotton. [4]
Does underwear style affect fertility?
A large study of 656 men at a fertility center found that men in looser underwear styles had higher sperm concentration than men in tighter styles. [2] Fit and airflow both appear to matter, not just fabric.
Are synthetic underwear fabrics a concern?
Polyester and nylon wick moisture quickly but tend to trap heat and have raised questions around microplastic shedding. [3] Natural-fiber alternatives like MicroModal and Lyocell avoid those issues while still outperforming cotton on breathability.
What underwear is best for sauna use?
After a sauna session, the body is warm and the area that needs to stay cool benefits most from breathable, moisture-moving fabric. Loose-fitting briefs in MicroModal or Lyocell are designed to help that area stay cooler and drier than cotton or synthetics would allow.
This article is for general educational purposes and is not medical advice. If you have specific concerns about fertility or your health, talk to a qualified clinician.
References
- Durairajanayagam D, Agarwal A, Ong C. (2015). Causes, effects and molecular mechanisms of testicular heat stress. Reproductive BioMedicine Online. [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]
- Comparative Assessment of Sensory Comfort Properties Across Eco-Friendly Textile Materials for Apparel. 2025. Journal of Natural Fibers (Taylor & Francis). [Link]
