The Endurance-Boosting Supplement that Every Runner Needs

#1 Improve Workout or Race Time

Clinically proven to reduce lactic acid and improve running performance - Extreme Endurance is a must have for any runner.

Whether you are gearing up for your next marathon or want to set a new 5K PR, this is a must have product to put to the test.

#2 Increase VO2 Max 

Increase your pace and be able to hold on. Extreme Endurance makes it feel like you have a third lung while preventing your muscles from tightening up.

#3 Trusted By World Class Runners

Contributing to personal records, American records, and World Records - Extreme Endurance has been used by runners for over a decade to help break barriers.

Donavan Brazier set the American Record in the 800m after being on Extreme Endurance for two months.

#4 Improve Recovery Time / Less Muscle Soreness

Feels like putting on a brand new pair of running shoes every day.

Look forward to putting in more miles when you don't feel yesterdays workout.

By reducing Creatine Kinase (CK) levels by 6x means your muscles recover better during workouts and help speed up recovery.

#5  Clinically Proven + Tested By Informed Sport

Supported by 12 Clinical Studies and certified free of banned substances by Informed Sport. It feels like a performance enhancing drug, but isn't.

Goodbye Soreness

Hello Performance


Increase Performance

Improve Power & Vo2 Max 10-25%

Recover Faster

6X Reduction of Creatine Kinase

Less Muscle Soreness

26% Reduction in Lactic Acid

Endorsed by:

Trusted by

World Class Athletes

Proven In

12 Clinical Studies

Recover Faster

Fights free radical damage & supports crucial cellular functions.

Stamina Increase

Push your limits to go the distance, fight fatigue and set PRs.

Increase Power

Increase power output by 10-25% with a similar heart rate.

Deeper Breaths

Increase VO2 Max & Aerobic Threshold. Perform better for longer.

Deeper Breaths

Increase VO2 Max & Aerobic Threshold. Perform better for longer.

Reduce Lactic Acid

Extreme Endurance reduces lactic build up after intense workouts.

Age Slower

Promotes anti-aging by reducing damaging oxidative stress.

As proven in:

Journal of Athletic Achievement

ENA Conference, Vienna Austria

ENA Conference, Vienna Austria (2010)

Journal of Athletic Achievement (2016)

How to

Improve in 72 Hours

Perform a baseline workout.

Take 3 tablets in the AM and repeat in the PM. Train regularly.

Feel benefits in 72 hrs and redo baseline workout.

Test with the


Perform a baseline workout

Take 3 tablets in the AM & PM.
Train regularly

Redo baseline workout in 7 days + feel the results



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60 Day Starter Pack



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Experience the World’s #1 Supplement for Stamina, Performance & Recovery.

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2 x Packs of Extreme Endurance

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Over 10+ years

Customer Reviews

Based on 1529 reviews
Barton C. Williams
A genuine game changer!

I’ve been training for years and used a variety of supplements but “
Xendurance” has really helped my recovery and endurance for the vastly diverse cross training I do from running, gym, boxing, yoga, swimming, paddling and pogo workouts!

Wow! Thank you for sharing your experience with Extreme Endurance. We are thrilled to hear that our product has been a game changer for your diverse training routine. We pride ourselves on creating a supplement that truly enhances recovery and endurance for all types of workouts. Way to go! Keep up the amazing work

Richard Jun
Actually works!!! Leveled up my Crossfit game!

I'm 46 and in my second year of crossfit. Recovery and energy levels are a challenge at my age. I have used Xendurance for the last 6 months and noticed a big difference in my recovery. I also feel like I have an extra 10% to give at every work out! I qualifed for quarterfinals this year during the crossfit open.

Awesome! We are thrilled to hear that it has helped you level up your Crossfit game and improve your recovery and energy levels. We understand that age can be a challenge, but we are happy to know that our product has made a difference for you. Keep up the great work and we wish you continued success in your Crossfit journey. Congratulations on qualifying for quarterfinals this year! Keep pushing and we are here to support you every step of the way.

Ryan Killough
Noticeable Difference

Normally I am very hesitant to try new supplements without doing extensive research. However, with the people who recommended this product I decided to try it. I did the 1 week challenge that they ask you to try when you purchase the product. I tested a 3 mile run and then retested one week later. I was able to shave 50 seconds off of my time and I felt like it could breath better on my retest. Weather that is a placebo effect or an actual difference I'm not sure. One unexpected difference that I noticed is that I am not sore after intense workouts while taking this product. So in conclusion, there is a noticeable difference in lactic acid build-up in the muscles and there seems to be a difference in VO2 Max also. I would recommend it if you are interested. Give it a try and see what differences you notice.

Thank you for taking the time to share your experience with Extreme Endurance. We're thrilled to hear that you noticed a difference in your performance after using our product. Our 1 week challenge is a great way to see the potential benefits and we're happy to hear it worked for you! We hope you continue to see great improvements with our product. Keep crushing those goals!

Marykate Boylan
No more fatigue during workouts!

Love this product so far. I did a test doing a 2 mile assault bike before taking xendurance and then retested after 2 weeks dropping 8 seconds off my time! Can't wait to see how this will help me doing Murph workout!

Wow! We love hearing about the positive results from our products, and we're so glad that Extreme Endurance has helped you during your workouts. It's always exciting to see improvements in performance, and we can't wait to see how it continues to benefit you in the future. Keep up the great work!

Laura Allwes
Just a regular runner

I started taking these about 2 weeks ago. It honestly had my doubts but I have been proved wrong! I’ve always been a distance runner but get horrible lactic acid buildup. This has absolutely been a game changer. I can’t wait to see how I am after taking it for months!!!!!

Hi there,

Thank you for sharing your experience with Extreme Endurance! We're thrilled to hear that it has already made a positive impact on your running performance. We're confident that it will continue to be a game changer for you in the long run. Keep up the great work and happy running!

Laura Magnusson
Just Magic

Honestly. Just buy it. You want to get faster? Buy it. You want to go further and not feel as tired? Buy it. I cheated and timed myself before taking them and less than a week later I shave more than a minute off my pace. i have a half marathon race in a week and I can’t wait to see what time I get. I don’t care if it’s a placebo effect. I will be using these forever.

Wow, that's amazing! We are thrilled to hear about your success with our Extreme Endurance product! We believe in the power of our product and are happy to hear it's making a difference for you. Best of luck on your upcoming race, we can't wait to hear about your results!

Supplement facts

NON-GMO / Gluten Free / Preservative Free.

Contains no Yeast, wheat, corn, milk, eggs, soy, artificial colors, sugar, starch or flavorings.

100% Guaranteed

Backed by the XND 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