Athletes and gym-goers swear by this endurance supplement, and the results will blow you away.

Monday, September 25 ‍
by Megan H


If you exercise regularly, you probably have three major problems keeping you from your PRs: maintaining your energy levels throughout your workout, soreness and slow recovery times, and hitting plateaus. Fortunately, there is an all-natural, research-backed solution to take you to the next level that has been trusted by serious athletes for more than 10 years.

“Ran almost 2 minutes faster this year on the same course I ran a year ago. Thanks!” -Jeff, verified customer

There’s a lot of pseudo-science in the performance supplement space.

Many products on the market either don’t do what they say they’ll do or will come with a host of side effects. Here’s what makes our flagship product, Extreme Endurance, different:

It’s backed by 12 unique clinical studies (two of which are published, Gold Standard, double-blind, and placebo-controlled).

It’s formulated with 100% natural ingredients for ANYONE of any fitness level.

It’s one of the most researched and proven sports supplements in the world. 

Experience Benefits in as Little as 72 Hours.

After rigorous scientific testing and over a decade of customer feedback, people who take Extreme Endurance can expect:

Less muscle soreness - Studies have reported up to a 26% reduction in lactic acid, reducing soreness and enhancing physical performance.

Enhanced athletic performance - Extreme Endurance is proven to make oxygenation more efficient, leading to increased stamina.

Faster recovery - Studies have reported a 6x reduction of Creatine Kinase, indicating faster recovery times.

The Beta Alanine Problem.

Since its discovery in 1911, Beta Alanine has been used by athletes looking to improve their performance and stamina. While its initial finding that buffering acidity can lead to enhanced stamina was a crucial breakthrough in the performance supplement space, its side effects and limited benefits make it inferior to alternatives on the market.

Slow Absorption Rate - It takes 4-10 weeks of large, daily doses of Beta Alanine to get the desired impact.

Side Effects - Beta Alanine has been proven to cause paresthesia (bodily numbness and tingling).

No Extra Benefits - Beta Alanine does not host any of the benefits of Extreme Endurance including, reduced muscle trauma, reduction of exercise acid, and reduction of cramping.

Our Solution? Extreme Endurance.

We formulated the ultimate supplement for athletic performance. Extreme Endurance starts working in as little as 72 hours and hosts a series of unmatched benefits, including:

  • Anti-aging effect due to reduced oxidative stress

  • Cellular support from the elimination of free radicals

  • Increased aerobic threshold from increased VO2 Max for a longer, healthier life

  • More energy and stamina during exercise

  • Reduced muscle trauma

  • Faster recovery rates

  • Reduced muscle cramping and pain


We want you to experience the difference for yourself, so we bundled our bestselling products and gift cards at a competitive price.

Best Value

Ultimate Endurance Bundle

60 Day Supply



$78 in Savings + $100 Product Rewards

Take Advantage of The Savings:

25% OFF Extreme Endurance

FREE Omega+D3

Team XND Membership

FREE 2x $50 Rewards


Most Popular

Level Up Bundle

60 Day Supply



$39 in Savings + $25 Product Rewards

Improve Your Fitness:

FREE Omega+D3

FREE $25 Gift Card


Smart Starter Bundle



$10 Product Rewards

Try out Extreme Endurance:

FREE $10 Gift Card



Don’t just take our word for it. See how our community of athletes thrives with Extreme Endurance.

  • Abdiel Crespo 


    If you are looking to recover faster and feel stronger and with a better engine you must have Extreme Endurance on your side. It is the only supplement that you should not stop taking.

  • Veronika D’Alfio


    Perfect product. Been taking it for a week and already fed the difference. I bought a few products and will be getting more, also signing up for a membership soon. Thanks

  • Natalie Collar


    I started using Extreme Endurance in October 2020 after I noticed a difference in one of my teammates at a fitness competition. I won’t be without it now. I have noticed a significant improvement in my endurance and breathing not only during workouts but just in my daily living. And I’m 60 years young!!!

  • Shawna Norton


    I LOVE this product. As a competitive CrossFitter looking to get to the next level, I need to be doing everything within my power to support my training. I feel like Extreme Endurance allows me to keep pushing and to continue to test my limits!








Recover Faster, Live Better

  • Fights free radical damage & supports crucial cellular functions

  • Promotes anti-aging by reducing damaging oxidative stress

  • Increases aerobic threshold and VO2 max for a longer, healthier life

  • Starts working within 48–72 hours

100% Guaranteed & Backed by the Xendurance Promise

  • Scientific Efficacy: Proven by rigorous scientific research and tested by unbiased 3rd parties.

  • State-of-the-Art Manufacturing: We only partner with Good Manufacturing Practice (GMP) certified and/or equivalent facilities.

  • Accessibility for All: We strive to make our product line available to athletes of all abilities!

  • Certified Drug Free By Informed Sport: 3rd party tested to guarantee free of banned substances

Step your game up with...

Extreme Endurance

Customer Reviews

Based on 1093 reviews
Lars Voit
Legit product.

Extremely improved performance really can notice the difference especially on the assault bike. A must for any CrossFit athlete.

Thank you for your review of our Extreme Endurance product! We are glad to hear that you have found it to be a beneficial addition to your CrossFit arsenal.

Ron Brown

This product is amazing! Did my first Ironman with it and I didn’t even feel that very tired afterwards. Recovery was amazingly fast!

Hi Ron,

Thank you for your kind words! We're so glad that this product was able to help you achieve your goals.

Philip Clark
Was skeptical at first?

Having a Master's degree in exercise science, I'm always skeptical when trying supplements even when I know the research behind them. I am happy to say that I have been very pleased with the results I've gotten from using xendurance. After using xendurance for 3 or 4 days, I noticed that I wasn't as sore after a hard gym session. Additionally, I noticed that my heartrate was five to six beats lower on zone two bike rides despite pushing the same amount of watts or even slightly higher. On a recent bike ride I beat my personal best time up an eight mile climb that averages just under 6 % grade by 9 minutes. Amazing! I am sold on this product and highly recommend it to anyone wishing to increased their performance and recovery.

HI Philip,

Thank you for your review of Extreme Endurance! We are thrilled to hear that you've found the product helpful and that your results have been positive. We recommend that you continue to use Extreme Endurance to reach your fitness goals!

Andrew Renschen
Will not go without it.

I started taking extreme endurance about six months ago after I started CrossFit. I have made some insane progress in that time and I can absolutely tell a difference while incorporating EE. this was especially evident when I ran out, the week that I didn’t have it I was dogging in my workouts. I won’t run out again!

Jose Torraca
Best thing ever!

I’m 41 years old and I’ve been using this product for a while now. I can honestly say you won’t find anything better out there to help you out with lactic acid and soreness. I workout 7 times a week and it’s been in great part thanks to this!

Hi Jose,

Thank you for your review! We're glad to hear that our product has helped you out and that you find it helpful.

Cristina C.
Blown away by the results!

I was a little bit skeptical at the beginning about the results you could get from the extreme endurance and Lean + until I found myself running 17 miles 2 weekends in a row!! The most o was able to run before was a half marathon and with huffing and puffing, not I ran 17miles and the next day I was ready for another workout! I’m hooked!!

Hi Christina,

Thank you for your positive feedback! We're so happy to hear that you're enjoying the results of our product. We hope you'll continue to use it to achieve your fitness goals.