Founder price ends 1 September. Lock $69.00 before it goes to $179.00 · Free shipping over $65 · Full refund before ship--DAYS--HRS--MIN
Founder release. First 500 only.STOP COOKING
STOP COOKING
YOUR COUNT
Heat and plastic quietly wreck sperm quality. NUMBNUTS removes both. A natural-fibre boxer with zero plastic on skin, and a cooling insert that keeps you cooler where it counts. No drugs. No subscription.
Built on peer-reviewed scienceHeat and plastic, fixedFree shipping over $65Refundable before ship
No card to reserve. Free shipping over $65. Full refund before it ships. Never plastic.
Natural fibre, never plasticCools where it countsBacked by published researchNo drugs, no hormonesFree shipping over $65Refundable before shipNatural fibre, never plasticCools where it countsBacked by published researchNo drugs, no hormonesFree shipping over $65Refundable before ship
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In a published study, healthy men who wore polyester around the scrotum dropped to zero sperm within months. They stopped, and it came back. Cotton and wool did nothing.1
Read this before you scroll past
Sperm counts have halved in 50 years. And the fall is speeding up.
This is not marketing fear. It is peer-reviewed, and it is the fastest men’s health crisis nobody is talking about.
−62%Total sperm count, on every continent, since 1973. Human Reproduction Update, 2023.
2× fasterThe decline since 2000 is running at more than double the old rate. It is accelerating, not slowing.
1 in 3Infertility cases involve a male factor. IVF is now a multi-billion-dollar industry built on the fallout.
You cannot change your genes. You can change the two things you put on the most heat-sensitive part of your body every single day: heat and plastic. See where you stand.
Population trends from peer-reviewed research (Levine et al., Human Reproduction Update). NUMBNUTS is a comfort product, not a medical device.
Grounded in published, peer-reviewed research•Fertility & Sterility•Human Reproduction•Human Reproduction Update•Asian Journal of Andrology•Reproductive Biology•Toxicological Sciences•
Grounded in published, peer-reviewed research•Fertility & Sterility•Human Reproduction•Human Reproduction Update•Asian Journal of Andrology•Reproductive Biology•Toxicological Sciences•
The problem
Two things are quietly cooking your count.
You cannot pick your genes. You can pick how much heat and plastic you put on the most temperature-sensitive part of your body. Most men get both wrong, every single day.
Read the full scienceHeat
Runs the factory too hot
Your testicles need to sit 2 to 4°C below body temperature to make good sperm. A laptop, a hot seat or a long drive pushes them over the line. Even a small, steady rise slows production down.2
Plastic
Traps heat and builds static
Most boxers are polyester and nylon. They hold heat in and build a static charge against your skin. In Dr Shafik’s research, that combination dropped sperm counts hard. Cotton and wool did not.1
Based on published research, including Shafik in Fertility and Sterility on fabric and fertility, and clinical reviews of scrotal cooling and semen quality. NUMBNUTS is a comfort product, not a medical device. Full references on request.
The fix
Drop the heat. Ditch the plastic. Done.
NUMBNUTS handles both at once, and you wear it like normal underwear.
Wear
Natural fibre on
Pull on the NUMBNUTS boxer. Soft natural fibre, zero plastic against your skin. The trapped heat and static are gone on day one.
Cool
Drop in the chill
Freeze a Chill Insert and slot it into the center sleeve. It holds cool for hours, far longer than ice, with no mess.
Repeat
Live your day
Desk, car, flight, gym bag. Cool where the heat actually builds. Then rinse, refreeze and reuse for years.
The other half of the problem
You would not sit in a plastic bag.
You would not sit in a plastic bag.
You might be wearing one.
Polyester, nylon and elastane are plastics. Not plastic-like. Plastic. Polyester is PET, the same family as a drinks bottle. Most underwear is made of it, and it sits against your skin all day.
What we are not saying. No study shows that your underwear puts microplastics inside your body, and the testis findings are an association, not proof of cause. What is established is simpler. Synthetic fabric is plastic, plastic sheds, and it is turning up in places nobody expected. You can choose what sits against your skin. That is the whole argument.
The kit
One kit. Both enemies, handled.
A natural-fibre boxer with zero plastic on skin, plus a reusable cooling insert that drops into a center sleeve. Wear it all day. Reuse it for years.
Everything in one drop
Cold where it counts, not a side pocket
What is inside Four parts.
Four parts.
Nothing you throw away.
Everything to fix both problems, built to reuse instead of bin.
- Natural-fibre boxer with a center cooling sleeve. No plastic on skin.
- 2 phase-change Chill Inserts. Rotate one while the other freezes.
- Insulated case for desk, gym bag or travel.
- Quick-start guide. No loose ice, no waste.
Why it wins
Most boxers do the exact opposite.
| NUMBNUTS | Regular boxers | Loose ice packs | |
|---|---|---|---|
| Natural fibre on skin | Yes | Usually plastic | n/a |
| Pulls heat away | Yes | No, traps it | Yes, messy |
| Wearable and discreet | Yes | Yes | No |
| Reusable for years | Yes | Yes | No |
| No static, no plastic | Yes | No | n/a |
500
founder spots
in this release
in this release
Free
to reserve and
lock your price
lock your price
100%
refundable any time
before it ships
before it ships
The one you can control
Age and genes are fixed.
Age and genes are fixed.
Heat is not.
A laptop on the lap, a hot seat, a long drive, a sauna round. That heat is the one input you can act on today, and it is the one NUMBNUTS is built to remove. Natural fibre, zero plastic on skin, cooling exactly where it counts.
- Full refund any time before it ships
- Free shipping worldwide over $65
- Founder price until 1 September
$69.00$179.00
Founder price · ships September 2026
Pre-order now · $69.00
Take the 60-second Heat Check
Not sure yet? The quiz gives you your heat score first. No card either way.
The detailsIt goes in the middle.
It goes in the middle.
Not a side pocket.
No loose ice. No awkward setup. Freeze the insert, slide it into the center sleeve and go.
What is in the kit
How the sleeve works
The movement
Welcome to the Cold Club.
This is the world we are building. Cold lockers, run-club drops and pop-ups in your city. The first 500 founders hold that status for life: first access to every drop, the founders’ Discord, and first invites when the pop-ups land in your city.
Claim founder status
Your kit is your membership card. Only 500 exist.
Brand campaign imagery.
Who this is for
Most guys scroll past.
Most guys scroll past.
Founders fix it.
Same research. Same heat. Same boxers in the drawer. Two very different men in five years.
The guy who waits
Finds out in a waiting room
Keeps the polyester. Keeps the laptop where it is. Tells himself he’ll deal with it when it matters, then finds out where he stands years from now, in a clinic, when the options are expensive and the pressure is real.
The founder
Handles it tonight
Fixes the two inputs he actually controls: heat and plastic. Gives every 74-day sperm cycle from here cooler, plastic-free conditions to run under. Walks into the trying-for-kids conversation prepared, not hoping.
You cannot change your genes. You can change what tonight looks like. Become a founder.
Straight talk
We are not going to fake the reviews.
We are pre-launch, so we will not buy five-star reviews or invent testers. The day a founder earns a five-star, it goes right here.
No paid reviewsEarned, or not shown
Instead of influencers, we show you the research: Fertility and Sterility, Human Reproduction, and decades of work on heat and fabric.
Backed by sciencePeer-reviewed, not hype
Refundable any time before it ships. No subscription, ever. If it is not for you, you pay nothing. The risk is ours.
Zero riskFounder guarantee
The founder offer
Two enemies. One kit. Founder price.
$69.00 $179.00 Founder price
It goes to $179.00 at public launch. Pre-order today at the founder price. You are fully refundable any time before it ships, and shipping is free worldwide on orders over $65.
Built for the man who wants to walk into the trying-for-kids conversation prepared, not hoping. Your body starts a fresh 74-day sperm cycle either way. The kit decides what conditions it runs under.
- Natural-fibre boxer + cooling sleeve Included
- 2 phase-change Chill Inserts Included
- Insulated case + quick-start guide Included
- Shipping on orders over $65 Free
- Founder price, held for the first 500 Locked
- Refund any time before it ships Guaranteed
Get the Cooling Kit
Ships Sept 2026$69.00$179.00today
Founder price held for the first 500
Pre-order now · $69.00Free worldwide shipping over $65 · Full refund any time before it ships
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Just want the boxer?Basecool from $24.00 · sizes S to XXL→ Not ready to buy?
Why we built it
We got tired of being told to just relax and wait. Heat and plastic are two things you can fix today. So we built the kit that fixes both, and made it something you actually want to wear.
Jaspal Rai, Founder, NUMBNUTS. One Third Group.
FOUNDER
PROMISE
PROMISE
Zero risk
Reserve now. Decide later.
Reserving is free and locks the founder price. Pre-order and you are refundable in full, no questions, any time before it ships in September 2026. Shipping is free worldwide on orders over $65. No subscription, ever.
Questions
Straight answers.
What exactly is NUMBNUTS?
A two-part kit for sperm quality. A natural-fibre boxer with no plastic against your skin, plus reusable cooling inserts that keep you cooler where it counts. It is a comfort product, not a medical device.
Why does natural fibre matter?
Most boxers are polyester or nylon. They trap heat and build a static charge against your skin. In published studies that hurt sperm counts, while cotton and wool did not. Ours uses natural fibre on purpose.
Does cooling really help?
Your testicles work best a few degrees below body temperature. Clinical reviews link scrotal cooling to better sperm count, motility and shape. NUMBNUTS keeps you in that cooler range without the mess of loose ice.
Are sperm counts really declining?
Yes. A 2023 meta-analysis in Human Reproduction Update found total sperm counts have fallen more than 60 percent since 1973 across every continent, with the decline accelerating since 2000. Male factors are involved in roughly one in three infertility cases.
How is reserving free?
Join the founder list with your email and we hold your price before public launch. No charge, no card. Prefer to lock a kit today? Pre-order, and it is refundable before it ships.
When does it ship, and what does shipping cost?
September 2026, first production run, with tracking the day it leaves. Shipping is free worldwide on orders over $65. Below that it is $7.95 in the United States and $14.95 elsewhere, and it is always shown before you pay. Reserving now locks the founder price before it rises to $179.00 at public launch.
Does NUMBNUTS offer free shipping?
Yes, on orders over $65, worldwide. Below that threshold shipping is $7.95 in the United States and $14.95 elsewhere, shown before you pay. The Cooling Kit qualifies for free shipping on its own.
Is it discreet?
Yes. It wears like normal underwear and the insert sits in the center sleeve. Nobody has to know.
What is your refund policy?
Full refund, no questions, any time before it ships. One email to hello@numbnutsclub.com does it. Reserving by email costs nothing.
Free guides
Not ready to buy? Read first.
Everything we know about heat, fabric and sperm, with the studies linked. No email required.
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Founder release. 500 spots.
