Trying to Conceive?

Sperm quality matters. Let's make yours better.

Sitting Overheats Sperm

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

Introducing The Underdog

Underdog Prevents Overheating

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

Cool Testicles make Better Sperm


Soft and Comfortable

Padded neoprene sleeve and innovative wedge shape adapt to all body shapes.

Easy to Use

Small and discreet. Slips easily between the seat and pants. Eliminates wet pants. No special underwear required. 

Improve Fertility Naturally

Gentle and mild cooling restores the body's optimal temperature for sperm production. Non-invasive and no-risk. Augment or avoid IVF.

How It Works

Learn how The Underdog optimizes sperm production.

How It Works


Our Mission

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

We're on a mission to provide practical tools grounded in science to improve men's reproductive health. 

It's the most important journey of our lives. Let's get started. 

The Underdog is protected by US and international utility patents pending.

Underdog, The Underdog, Underdog Fertility and the Dogface Logo are trademarks of Underdog Fertility.