Flexible and stays cold the entire session. I fold away the Velcro because I don’t want it to ruin my boxers. Would be great to be able to detach the Velcro or find a non-Velcro way to attach but still happy and use it’s for my daily sauna sessions.

TL;DR: Works, but cheap materials and flawed design make it not great.

I've been using this product for several months now and wanted to give it a good go before writing a review. I looked at several options for cooling packs/underwear, and went with this one because of its unique design, not needing any special underwear, and the fact that it came with a cooler pack to keep it cold while I was working out before my sauna.

It is adequate, but not great. The ice pack seems to last somewhere between 15 and 25ish minutes in a hot sauna before becoming room temperature, so if that's all you care about, this will do.

However, the materials and construction are not high quality. The cotton part in particular is very thin and I can't imagine it will last a long time.

The real fatal flaw in the construction is that plastic does touch your body. I wanted to avoid that entirely. Because of the very thin layer of cotton over the plastic velcro piece, and the low quality materials of the velcro itself, the corners of the plastic velcro bend up over the thin cotton covering and end up touching my skin.

If they used sturdier construction to where it didn't curl, this issue wouldn't happen.

I will continue to use this for the time being until I find a better product. If you are looking for something very "clean," look elsewhere. There's no information on the dyes used or the quality of cotton, and not to mention there is a lot of plastic in the thing because of the velcro and elastic band. An Oeko-Tex certification would provide peace of mind that harmful things aren't leeching into my body.

If you don't care about those things and just want something adequate enough, this works decently for its main intended purpose of keeping your testicles cooler than the temp of the sauna.

great

The gel pack feels high quality and the cotton pouch is much softer than expected. Good secure fit tucked under the waistband. Cold lasts longer than advertised in my experience; closer to 50 minutes in my gym's sauna. Great buy.

I do 30-minute sauna sessions post-workout and I was always second-guessing whether I should cut it short for fertility reasons. ChillNuts completely removed that doubt. It fits snugly under my shorts, the cold is intense and consistent, and the case makes it easy to bring everywhere. Wish I found this sooner.

I think about my health holistically and this fits right in. The 100% cotton material is breathable and comfortable. The fit above the shorts works well for me - clean and secure. The case is well-insulated and professional-looking, not embarrassing to pull out in a gym locker room.

Heat kills sperm. This keeps heat away. Done. Fits well. Cold lasts. Case is solid. 5 stars.

My partner and I spent a long time researching the effects of heat on male fertility and this product addresses the problem directly. I've been using it for two months. The cooling performance graph on the website is accurate — you're getting solid protection for 45+ minutes. The carry case is excellent and I take it to my gym every time.

Skeptical about comfort going in but it's surprisingly non-intrusive. The Peruvian cotton is soft and doesn't scratch or chafe. Fits snugly above the underwear with the velcro holding it in place throughout the session. Will keep buying.

Not sure why this doesn't have more reviews; it's a genuinely useful product for any guy who saunas regularly. Fit is comfortable and secure either over or under the shorts. The 150g gel pack is substantial and holds cold well. The insulated case is thick and keeps it frozen in my gym bag for 90+ minutes easily. Well worth the price.

Appreciate that someone actually made this. The heat-fertility connection is real and finally there's a practical solution. Fits well under gym shorts. Stays cold through a normal session.

I was prepared to be disappointed but I'm genuinely impressed. I've been sauna-ing 4x a week and using ChillNuts every session for the past month. The fit is secure when tucked below the shorts waistband, the cold is immediate and consistent, and I don't feel like I'm compromising my fertility anymore. Highly recommend.

The main appeal for me was the insulated carry case. Being able to bring this to my gym's sauna without it melting in my locker is huge. The pack itself fits securely and comfortably above the underwear. Cooling lasts a solid session. Dock one star only because the packaging could be nicer for a gift.

The slim profile is what sold me. Some similar ideas I've seen online look ridiculous and bulky. ChillNuts fits naturally under your shorts with no weird outline. The velcro attachment is clever, tucking it under the waistband works great above the shorts or below the shorts depending on what you're comfortable with. Cold lasts 40-50 minutes easily.

Short review: works well. Good fit. Stays cold. Case is handy. Happy with it.

The gel pack is denser and heavier than I expected in a good way. You can feel the cooling immediately when you put it on. I wear it over my underwear under my gym shorts and it barely registers as being there after a couple minutes. Great carry case too — fits nicely in my locker.

My wife and I are TTC and I refused to sacrifice my daily sauna sessions. ChillNuts let me have both. The product is well made; non-toxic gel, soft cotton outer, and a well-insulated case. Keeps my sperm count worries at zero while I still get the full heat benefits.

Can't believe this product didn't exist sooner. Solved the one problem I had with my sauna routine. It fits well over gym shorts and holds cold the entire session. The carry case is sturdy and stylish too.

First session felt a bit awkward figuring out the fit. Second session I nailed it; velcro lip under the waistband, pack sitting comfortably below. By the third session it was second nature. The cooling protection is legit and the case is genuinely useful at the gym.

My girlfriend bought this for me as kind of a joke but honestly it works really well. The fit is secure above the underwear, the cold lasts the entire session, and the case means I can throw it in my gym bag and not worry about it melting before I use it. The cotton material is genuinely comfortable. Good quality overall.

Tested the cooling time myself. Full 45+ minutes even in a 185°F sauna. That's impressive. Fit is good above the shorts with the waistband holding it securely. Would definitely recommend to any guy doing regular heat therapy.

My trainer introduced me to sauna after workouts and I got addicted fast. Then I started reading about the fertility implications. Tried ChillNuts and now I never sauna without it. Fits perfectly between my legs with the velcro tucked under my waistband. Doesn't move, doesn't fall, doesn't feel awkward. The case is a bonus — means I can take it to any gym, not just train at home.

Exactly what it claims to be. Good fit above the underwear. Cold lasts through a full session. Case is portable and well insulated. No complaints.

I'm deep into the sauna protocol world; daily sessions for HGH and heat shock proteins. The one thing that always nagged me was the fertility tradeoff. ChillNuts completely solves that. It fits cleanly over my shorts, stays put, and keeps temperature where it needs to be. The included case is something I didn't know I needed; now I take it everywhere.

Only minor thing is I wish the velcro was a bit stickier, occasionally readjust mid-session. But the cooling lasts way longer than I expected in a hot sauna. 45 minutes is no joke; I've tested it. Good product.

Was skeptical about comfort but it's actually quite discreet. Slim enough that it doesn't create any weird bulge under gym shorts. I wear it below my shorts and it just looks normal. The cotton pouch is soft and doesn't irritate. Temperature protection is the real deal.

No gimmick here. Gel pack is thick and heavy; holds cold seriously well. Slipped it over my shorts and went in for a 20 minute session. Felt comfortable the whole time.

I've read enough about scrotal hyperthermia to take it seriously. Been using ChillNuts for about six weeks now and I love how it integrates into my routine. Freeze it overnight, toss it in the case in the morning, and it's ready to go when I hit the gym sauna after my workout. The insulated case is genuinely well-made — thick walls, keeps the pack frozen through a whole gym session before I even use it.