Trying to Get Pregnant?

Sperm count and sperm quality matter when trying to conceive.

Boost male fertility the natural way.

Introducing The Underdog

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The Underdog fertility cooling ice pack in sleeve.

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Sitting Damages Sperm

Graph showing lower sperm count and decreased motility from testicular overheat.


The Underdog Prevents Overheating

Graph showing results of cooling testicles for improving sperm count using Underdog ice pack.

Benefits of The Underdog

Improve Fertility Naturally

Mild & gentle cooling

Non-invasive and no-risk

Use before natural conception

Use before IVF to improve the odds

Ultimate Comfort

Comfortable padded sleeve

Ergonomic wedge shape

Fits all body types

Easy to Use

Small and discreet

Slips easily between the seat and pants

No special underwear

No condensation

Better Sperm, Better Outcomes.

Are you ready to get started?


Promising enough that we are offering our men the option of using these devices ‎as a part of their therapy for infertility.

Dr. K. J.

I had my sperm tested again after 3 months of using your product somewhat consistently, and I had a much improved score. Originally I got a YO score of 30 and earlier today I got a YO score of 70 which is a pretty substantial improvement!


Healthy sperm are very sensitive to overheating. The Underdog keeps the testes at the perfect temperature. Wonderful and discrete. Highly recommended.

Dr. C. L.

It's my secret weapon that I like to tell patients about. Nice and comfortable. It feels great. If you're a man, you know you need this. If you're a woman, your partner's sperm will thank you for it.

Dr. M. S.

Quality build and packaging. The ice pack is comfortable enough to use for a few hours straight while keeping its "cool", and inconspicuous enough for the office.


It cools down my balls and raises sperm counts. Would highly recommend to those who want to conceive.


Pretty impressed with this product. First, it comes with two ice packs which is great for a long day. Next, it feels very comfortable when using. Temperature is perfect. Not too cold or hot.


Expert Recommendations

Trusted Fertility Expert Dr. Marc Sklar Recommends Underdog for Healthy Sperm

Oftentimes, men’s health gets overlooked when it comes to fertility. The responsibility - when it comes to fertility and getting pregnant - more times than not falls on the female partner. Not only is this one-sidedness unfair, it’s also not beneficial to your fertility if you’re struggling and we’re only addressing one half of the problem.

Natural Fertility Expert Dr. Charlene Lincoln Recommends Underdog to Boost Fertility

Dr. Lincoln includes The Underdog in her top tips to boost male fertility naturally. Here she describes the top 7 diet and lifestyle changes including using The Underdog that are key to improve sperm morphology, quantity and motility.

The Underdog Mission

Underdog Fertility was founded by three professionals touched by infertility who care deeply about helping others start a family.  

We're on a mission to create practical tools that improve men's health. 

Life is short, so let's get started!

The Underdog is protected by Patent No. US 11,540,939 B2, and international patents pending.

Underdog, The Underdog, Underdog Fertility and the dog face logo are trademarks of Underdog Fertility and protected by US registered trademark No. 5,833,529.

The Underdog product is a general wellness device, and is not intended for use in the the cure, mitigation, treatment, or prevention of underlying disease or medical conditions.