YOUR SAUNA IS KILLING YOUR TEST
Bryan Johnson, the world's premier biohacker, recently found a shocking result: heat from sauna damages your testicles, lowers your testosterone, and hurt your fertility.
Save Your TestFounding batch opening soon. Limited first production run.
YOUR SAUNA IS KILLING YOUR TEST
Bryan Johnson, the world's premier biohacker, recently found a shocking result: heat from sauna damages your testicles, lowers your testosterone, and hurt your fertility.
Founding batch opening soon. Limited first production run.
Cooling Insert Pouch
Secure front pouch designed for a removable cooling insert.
Sauna-Specific Fit
Built to stay close to the body during high-heat sessions.
Cotton-Forward Comfort
Soft, breathable feel designed for sauna routines.
Sauna Sack™ Performance Boxer Brief
A black boxer brief with a secure front zipper pouch designed to hold a removable cooling insert during sauna and high-heat sessions.
Sauna Sack™ Performance Boxer Brief
- Secure zippered front pouch
- Designed for sauna and heat routines
- Cooling insert stays concealed when zipped
- Soft cotton-forward feel
- Minimal black waistband branding
- Remove insert before washing
Popular ✦
Four steps. Built into your routine.
Freeze Insert
Place the removable cooling insert in the freezer before your session.
Zip Into Pouch
Slide the insert into the front pouch and zip closed.
Sauna As Usual
Wear during your heat session.
Remove & Wash
Take the insert out before washing the underwear.
The sauna is good stress. The wrong kind of heat is not.
Healthy sperm production depends on temperature. The testicles are designed to sit cooler than the rest of the body — roughly 2–6°C below core temperature — because sperm production is highly heat-sensitive.
In one Human Reproduction study, healthy men used Finnish sauna at 80–90°C for 15 minutes, twice per week, for 3 months. Researchers found significant declines in sperm count and motility, plus measurable changes in mitochondrial function and sperm DNA packaging. The effects were reversible after sauna exposure stopped.
Bryan Johnson saw the same heat problem in his own data. In his sauna protocol, he reported that sauna without testicular cooling was associated with:
- 56% drop in total motile count
- 30% drop in sperm concentration
- 50% drop in motility
- 48% drop in normal morphology
- 9% drop in total count
His solution was simple: keep the sauna, cool the boys.
With testicular cooling added to his sauna routine, Bryan later reported:
- 600M total sperm count
- 162M sperm concentration
- 55% motility
- 330M total motile count
- 10% normal morphology
Sauna Sack takes that insight and turns it into a wearable system: a premium cotton-forward boxer brief with a secure front pouch designed to hold a removable cooling insert during high-heat sessions.
Built for heat. Designed to cool.
Sauna Sack is not a medical device and does not diagnose, treat, cure, or prevent infertility. It is a performance garment designed to help men manage heat exposure during sauna and high-heat routines.
Sperm production works best when testicular temperature stays below core body temperature.
Repeated Finnish sauna exposure was associated with significant sperm count and motility changes.
Bryan Johnson reported a 56% drop in total motile count after sauna without testicular cooling.
Sauna Sack uses a secure front pouch designed to hold a removable cooling insert during high-heat sessions.
Your sauna has a
heat problem.
The sauna is part of your routine. Sauna Sack helps you manage targeted heat exposure with a secure cooling pouch built into premium performance underwear.
Questions, answered.
Founding batch opening soon
Limited first production run.
Designed for sauna users
Built around real heat routines.
Built with real feedback
Shaped by men who actually sauna.
Clear preorder policy
Transparent timelines and refunds.
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