The Hidden Health Risk in Your Cooling Underwear
Are your undies doing more harm than good? Here’s what every man needs to know about cooling underwear and sperm health.
By Saara Jamieson
Let me say this upfront: I love that we’re finally talking about men’s health. That testicular heat, sperm quality, and hormones are getting some long-overdue attention. And I’m thrilled men are out there searching for ways to feel cooler, healthier, and more supported.
But I need to be honest.
Most “cooling” underwear being sold today is doing the exact opposite of what it promises.
It may feel cool to wear - but that doesn’t mean it’s keeping you, or your sperm, safe.
Cooling Underwear and Fertility: What Most Men Don’t Know
A wave of new brands have hit the market lately, all shouting the same promises: sweat-wicking, performance, cooling, breathable.
But here’s the truth most people miss:
The materials used to create that “cooling effect” are often exactly what makes them harmful.
The vast majority are made from polyester blends - fabrics designed for feel and stretch, not male anatomy. These materials:
- Have been clinically shown to damage sperm and interfere with healthy production
- Create friction and static that can disrupt the sperm membrane
- Tend to trap body heat, even if they feel dry on the surface
- Offer no proper scrotal support, letting the scrotum drop into high-heat zones and cause testicular damage and pain
The fabric may feel cool - but it’s not helping you stay cool where it counts.
Is It Really That Comfortable? Let’s Be Honest
Let’s stop pretending clingy, flimsy, heat-trapping underwear is actually comfortable.
If you’ve ever found yourself readjusting, sticking, chafing, or sore - you already know the truth.
That barely-there feel?
- Often rides up, shifts, or rubs during movement
- Leaves the scrotum dangling or overheated
- Triggers groin fatigue when there’s no support
And polyester? It may feel smooth at first touch, but it doesn’t breathe, holds heat, and can cause itching, odour, or discomfort after just a few wears.
Not only that - think about when you pull a polyester shirt out of the drier and you get those static shocks, the same thing is happening around your scroutm, except that these micro-sized waves are also damaging and killing sperm cells. - Saara Jamieson
Real comfort doesn’t come from “cool to touch” marketing.
It comes from structure, support, and function-first design that works with your biology - not against it.
The Science is Clear: Heat Hurts Sperm
Sperm don’t like heat.
They need to live in an environment that’s 3–5°C cooler than your core body temperature.
Here’s what research tells us:
- A 1°C increase in testicular heat can reduce sperm health by 14%
- A 2–3°C rise can completely shut down sperm production
- Just 20 minutes sitting at a desk - or 12 minutes in a car - is enough to push your testes into that danger zone
If you’re wearing underwear that pulls your testes up against your body, or provides no real support at all? You’re creating a heat trap - all day, every day.
Support Matters: Why Design Is Everything
Your testicles are supported by a group of muscles called the cremaster muscles - and they weren’t meant to work overtime.
If your underwear offers no lift or structure:
- Those muscles fatigue
- The scrotum hangs into core body heat
- Over time, this can lead to pain, strain, or reduced sperm function
It’s not just about “feeling supported.”
It’s about functionally protecting your reproductive system - and protecting men's health.
What to Wear Instead: Choosing the Best Underwear for Fertility
If you're serious about protecting your:
- Fertility
- Hormone health
- Men's Health
- Mental Health
- Energy
- Future family...
Then what you wear every day - especially under your clothes - matters more than you think.
What to look for:
✅ Natural, breathable fabrics like cotton or bamboo blends
✅ External pouch that keeps the testes lifted and forward
✅ Anatomical support, not just stretchy compression
✅ Airflow by design, not chemical treatment
✅ Tested and trusted by medical professionals
Why We Created Cool Beans
After 3.5 years of infertility, multiple miscarriages, and a whole lot of grief - we decided to stop waiting for answers.
As a medical researcher - I built my own solution.
Cool Beans Underwear is designed:
- Useing natural fibres around the thighs and body
- Featured a breathable mesh pouch
- Gently lifts the scrotum away from core heat
- Supports the muscles that need it - and cools where it matters
Four months later - I was pregnant.
Cool Beans was born from that moment - and today, it’s the world’s first TGA-registered medical underwear for testicular health and male fertility.
💬 From One Family to Another...
You might be trying to conceive now. You might be years away.
But if your underwear isn’t supporting your health - it’s time to change that.
Cool Beans isn’t just underwear.
It’s a movement to rebuild men's health from below the belt up.
👉 Explore Cool Beans Underwear - Built by science. Worn for life.
❓ Frequently Asked Questions
Does underwear really affect male fertility?
Yes. Scrotal heat can significantly impair sperm production. The wrong underwear can raise temperatures enough to shut down healthy sperm function.
Is polyester bad for sperm?
Yes. Polyester has been linked to sperm damage, reduced motility, and impaired production. It also holds heat and builds static - two major threats to sperm health.
What’s the best underwear for sperm health?
Look for breathable fabrics, structured support, and an external pouch that lifts the testes away from the body. Cool Beans was specifically engineered to do all three.
Is nylon safe in underwear?
Yes - when used intentionally. Cool Beans uses a breathable nylon mesh in the pouch to allow airflow and prevent heat build-up. It's not natural, but it’s functionally superior.