Western men, ~40 years.
Levine et al., 2017. Association, not a guaranteeFor men (and couples) trying to conceive
Trying for a baby? Don't cook your count.
Heat lowers your sperm count, and every trying-to-conceive guide says the same thing: keep cool. NUMBNUTS makes it the easiest box to tick. Comes with a 60-night trial.
Backed by published science
First 500 founders
Ships September 2026
Ships September 2026Founder run
Full refundBefore it ships
Peer-reviewed researchHeat and sperm
Counts are falling, and everyday heat is one cause. Cool it down, it tends to come back.
The science
Heat raises the temperature down there. Cooling brings it back.
Laptop or hot seat.
Sheynkin et al., 2005Gentle, steady. No ice.
Garolla et al., 2013NUMBNUTS is a comfort product, not a medical device. It is not intended to diagnose, treat, cure, or prevent any disease, or to affect fertility. Figures above come from general research on heat and the male body, not studies of this product, and are not a promise of results. For fertility concerns, talk to your doctor.
How it works
Freeze. Slide. Cool. Rotate.
Inserts in the freezer.
One in the sleeve.
Daily cool-down.
One runs, one re-freezes.
Cold where the everyday heat hits. No loose ice.
Everyday heat
Built for the heat you sit in all day.
Laptops, hot seats, long flights, the sauna. Wear it through the heat to stay cold right where it builds, not after, when the day is done.
Why not just freeze something
A frozen ziplock won't cool you through a whole day.
NUMBNUTS
Gel / ice pack
Cold towel
Stays put, hands-free
Yes
No
No
Fabric layer, never bare on skin
Yes
No
Warms fast
Cost over time
One kit, reusable
Rebuy
Free, it shows
Kit plus everyday boxer
Two speeds of cool.
Speed one · The heat
The Cooling Kit
Laptop, hot car, long flight, sauna.
- Liner with cooling sleeve
- 2 phase-change Chill Inserts
Speed two · Every day
NUMBNUTS Basecool
Built to breathe.
- Natural fibre, loose cut
- Runs cooler than synthetic
Everyday cool.
Get both. Heat days and every day.
Get the Cooling Kit and Basecool togetherKit plus a Basecool 6-pack ($16.50 a pair).
Reserve preorder access
$69 today
Founder price. Goes to $179 at public launch.
The Cooling Kit
$208 value, you pay $69 today.
or 4 interest-free payments of $17.25 at checkout
- Cooling liner with center sleeve
- 2 phase-change Chill Inserts
- Insulated case and guide
- Founders bonus: free Chill Inserts 2-pack ($29 value)
Founder price holds for the first 500 reservations.
$0 risk. $69 charged today. Refund in full anytime before it ships. No questions.
Reserve my kit · $69- 1Reserve today
$69, not $179.
- 2We build and test
Results shared before we ship.
- 3Ships September 2026
Founders first.
Secure checkoutNo hidden feesFree shipping over $75
Secure checkout
Complete the kit
Choose your Cooling Kit.
Most popular
The Cooling Kit
$69 today
Everything you need to stay cool, plus a free Chill Inserts 2-pack.
- Cooling liner with center sleeve
- 2 Chill Inserts
- Insulated case and guide
- Free Chill Inserts 2-pack
Full refund anytime before it ships.
Cooling Kit + Refill
$89
Less freezer downtime.
- Everything in the Cooling Kit
- Plus an extra Chill Insert refill
- Shorter waits
Want extra rotation? Add a THIRD set of inserts (+$29).
From the founder
We built NUMBNUTS because the alternatives were a joke.
Sperm counts have fallen by more than half in fifty years, and heat is one of the few drivers a man can actually do something about. Saunas, hot commutes, a laptop where it should not be. The science has been clear for years. The products were not. Your options were a bag of frozen peas, an ice pack that burns, or nothing.
So we engineered the thing that should already exist: a wearable cooler that sits exactly where the heat does, holds a comfortable cool, and disappears under your clothes. No loose ice. No ice burn. No white-coat theatre. We lead with published research, we say it cools because we can prove that, and we will never claim it cures anything.
You are reserving before the first run ships, so here is our side of the deal. We charge upfront, we tell you the truth about timing, you can cancel before it ships, and you get sixty nights to try it once it lands. We do not buy reviews and we do not fake scarcity. If you have a question, it reaches me, not a bot.
N
Jaspal Rai
Founder, NUMBNUTS
hello@numbnutsclub.com
Where we are
Reserving early. Here is where it stands.
- DoneDesign and cooling spec set
- NowSampling and testing
- Sept 2026Ships to founders first
First 500 only. Founder price holds for the first 500 reservations, then it goes to $179. Refund anytime before it ships.
FAQ
What buyers ask first.
Does heat really affect sperm?
Yes. Testicles work best 2-3°C below core temperature. Heat lowers count and movement, generally reversible.
Does cooling actually help?
Heat lowers sperm measures, generally reversible (Garolla et al., 2013). Evidence on active cooling is limited, so we make no promise of results.
Is this a medical device or fertility treatment?
No. A wearable cooling product for comfort. It does not diagnose, treat, cure, or prevent any condition.
Will the inserts touch my skin?
No. The insert sits in the center sleeve, fabric in between. Never apply inserts directly to skin.
Can I cancel or return it?
Refund anytime before it ships, no questions asked.
Reserve the Cooling Kit
Keep your count up to you. Stay cool for $69.
Reserve my kit · $69Secure checkoutNo hidden feesFree shipping over $75
