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.

A man running on a track during a race wearing a blue and white uniform.

#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 Runners

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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FREE $25 Gift Card

2 x Packs of Extreme Endurance

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Over 10+ years

Customer Reviews

Based on 1596 reviews
Brandy Y
Great product. New increases in FTP!

I was hesitant at first but gave Extreme Endurance a try. I took it consistantly and started see a shift upwards in FTP in about 3 weeks. It has also helped greatly with recovery. I'm a believer and a happy customer!

XC Mountain Biking

great product. I could defiantly feel the difference after a long race.

Micah Dunlevy
5 Way Bypass open heart surgery

50 weeks ago, family genetics caught up to me. Fortunately I caught it before a heart attack or stroke. I had my first surgery of my life a 5 way bypass. I had been training for the last seven years, trail running, mountain biking, road cycling, CrossFit, strength training and SUP. I had tried Xendurance prior and was pleased with. Now 50 weeks post surgery this product is tremendously helping get back my endurance, stamina and strength!

Thank you for sharing your experience with Extreme Endurance. We are so glad to hear that it has been helpful in your recovery journey after undergoing such a major surgery. We are honored to be a part of your fitness journey and are happy to see that our product has helped you get back on track. We wish you continued success in your health and fitness goals. Keep up the amazing work!

Gave me the edge to push for the win

Usually I gas out hard halfway down the track on a downhill mtb race, but I felt like I could just keep pushing at this season opener after about a month taking xendurance, and I felt like that really helped me secure the victory.

Amazing! We're thrilled to hear that Extreme Endurance gave you the boost you needed to secure the victory at your season opener. Our goal is to help athletes like you push through to the finish line with confidence and strength. Keep up the great work and we wish you continued success in your upcoming races!

Great prodcut

Just ran my first marathon , these helped with my recovery and all training leading up to it !

Amazing! We are glad to hear that you have found Extreme Endurance helpful in your fitness journey. Keep up the great work and we wish you continued success in all your future runs!

Definitely makes a difference!

I have absolutely felt an increase in stamina while training. I will definitely stay with Xendurance!

Awesome! We're so glad to hear that you've noticed great improvements while using Extreme Endurance! Thank you for sharing your experience with us. We're committed to helping our customers reach their training goals and we're thrilled that our product is helping you do just that. Keep up the great work!

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

60-Day Money
Back Guarantee