Proxima C Endurance Fuel

Proxima C Endurance Fuel


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Tested and proven to be: Vegan, Gluten-Free, Non-GMO, No Artificial Sweeteners, Allergen-Free (no soy, dairy, nuts, egg, or shellfish)

Proxima C was designed to be the ultimate extended-duration endurance fuel.  It was designed specifically for ultra-running and other prolonged endurance activities.  Proxima C utilizes an unparalleled, no expense spared ingredient profile.  It’s truly a top-shelf formula.

If you’re looking for the best endurance fuel, you’ve found it.

Read here to learn how to mix Proxima C properly.  For more information on why Proxima C is the best fuel for ultra-runners, check out this blog!


Proxima C uses an unrivaled four-carbohydrate blend.  Scientific literature has established that multiple carbohydrate transport solutions are superior to single carbohydrate solutions.  Proxima C’s blend includes;

Cluster dextrin® (Highly Branched Cyclic Dextrin) is the primary fuel source in Proxima C, accounting for over 50%.  Cluster dextrin has several advantages over maltodextrin, including faster gastric emptying time, decreased rate of perceived exertion, increased time to exhaustion, and significantly lower instances of GI distress.  Compared to other carbohydrates, cluster dextrin has a lower glycemic impact, maintaining a slower, more sustained energy release.  This allows for improved fat oxidation while keeping blood sugar stable.  In comparison to simple sugars, cluster dextrin is also less sweet, reducing the risk of palate fatigue.    

Cluster Dextrin™ won the Ringier Technology Innovation Award in 2020 as an innovative ingredient for sports nutrition for its ability to enhance stamina, reduce intestinal discomfort, decrease perceived exertion, and suppress inflammatory stress in athletes.   

Best carbohydrates for ultra-runners

Fructose is a simple sugar that utilizes the GLUT5 transporter.  Utilizing this transporter allows for additional energy consumption without contributing to GI distress.  If you’re not taking in fructose, you’re not taking advantage of the GLUT5 transporter, the equivalent of having a reserve fuel tank and cutting the line.  

Dextrose is a simple, rapidly oxidized carbohydrate that delivers immediately usable energy and encourages glycogen preservation right out of the gate.  

Palatinose® is a breakthrough carbohydrate for long-duration endurance activities.  Research has shown Palatinose® improves fat oxidation during exercise. Palatinose® is a slow-release carbohydrate that provides a balanced, sustained energy supply.  The slower, consistent release of energy, improved fat oxidation, and lower glycemic impact make it great for prolonged endurance efforts.  Palatinose® is tooth-friendly, and naturally less sweet than simple sugars – preventing palate fatigue.

Palatinose for Endurance Athletes


GI issues are the #1 reason for DNF in ultramarathons.  Proxima C’s carbohydrate profile is exceptionally gentle on the stomach. 

Our primary carbohydrate, Cyclic Dextrin (accounting for over 50%), passes through the stomach more rapidly than any other form of carbohydrate and causes virtually no GI distress. 


You will likely notice right away that the taste of Proxima C is lighter and less sweet than most carbohydrate drinks you’ve tried.  

Palate fatigue in ultra-endurance sports is a major issue and is often a consequence of ingesting too many sweet calories. Proxima C’s carbohydrate blend is naturally less sweet than traditional carbohydrate drinks (more in carbohydrate blend dropdown). Additionally, we opted for a very light flavor profile (just enough to mask the electrolytes) to further reduce palate fatigue.


In addition to a revolutionary carbohydrate blend, Proxima C also includes a premium electrolyte profile that utilizes ideal quantities of the best versions of each electrolyte.  Rather than conform to the standard and select each form of electrolyte based on price, we select them based on bioavailability, gut tolerance, and the potential to sustain optimal performance for the LONG haul.  


Sodium (from sodium chloride and sodium citrate) – 310 mg

Sodium chloride provides chloride (an essential electrolyte), while sodium citrate provides a highly bioavailable form of sodium that increases fluid and electrolyte absorption.  Sodium is the most important electrolyte to replace during endurance activity.  Incorporating sodium citrate is far superior to using sodium chloride alone.

Chloride (from sodium chloride) – 360 mg

Potassium (from potassium phosphate) – 85 mg

In addition to providing potassium, phosphates increase oxygen transport to muscles and neutralizes acids, improving endurance and reducing fatigue.  Typical formulas use the cheaper forms – potassium citrate or chloride.

Calcium (from dicalcium malate) – 25 mg

Dicalcium malate is more easily absorbed and, therefore, gentler on the stomach than calcium carbonate – a cheaper form used in most endurance fuels.  

Magnesium (from Albion® dimagnesium malate) – 10 mg

Magnesium malate is gentler on the stomach than magnesium citrate (used in typical fuels) and has less GI-related side effects.


Unlike typical endurance fuels that contain only simple sugars (sucrose, dextrose, fructose), Proxima C utilizes primarily low glycemic, complex carbohydrates.  This results in a steadier energy source, eliminating large energy swings resulting from blood sugar dips and spikes caused by excessive high-glycemic, simple carbs.  

Some simple sugars are necessary and beneficial to endurance when used appropriately, but they shouldn’t be the sole fuel source for endurance athletes.  Proxima C uses an ideal ratio of low glycemic to high glycemic carbs created explicitly for long endurance efforts.


Finally, the addition of L-ornithine reduces ammonia accumulation resulting from prolonged exercise, which reduces fatigue and enhances endurance performance.

Weight 3 lbs


Ultra-Endurance Carbohydrate Blend – 25 grams (100 kcal)

Cluster Dextrin® (Highly Branched Cyclic Dextrin)



Palatinose® (Isomaltulose)

Electrolyte Profile

Sodium (as sodium chloride and sodium citrate) – 310 mg

Chloride (as sodium chloride) – 330 mg

Potassium (as potassium phosphate) – 85 mg

Magnesium (as DiMagnesium Malate from Albion®) – 10 mg

Calcium (as DiCalcium Malate) – 25 mg

Endurance Performance Enhancer

L-Ornithine HCL – 50 mg

Additional Ingredients (flavoring) –  organic beet root powder, organic stevia extract, Aersosil 200F, Sipernat® 50s, Citric Acid Anhydrous, natural flavors

Suggested Use

Cluster Dextrin® can clump when not mixed sufficiently. To avoid clumping – Only fill your bottle half full initially, add the desired number of scoops, and shake vigorously for 10-15 seconds. Then fill the bottle. Or, for optimal results, use a blender bottle.

Mix 2-3 scoops/hour with 500-750 ml of water during long endurance efforts. 

For runs lasting less than 2 hours, 1-2 scoops/hour is enough.  

Determine your starting point by considering how many calories/hour you usually take in successfully. Start at the low end and adjust from there if you’re not sure. 

Remember, your gut can be trained to take in more carbohydrates. Never take in more during a race than you’ve proven to handle during training.

5 reviews for Proxima C Endurance Fuel

  1. Brenden Macy (verified owner)

    Picked up Proxima C after last year’s Cowboy 200 to begin using in training for this year’s Cowboy 200. I’ve historically had issues using liquid calories and nutrition, lots of GI issues and sloshing, even when mixed in a higher concentration to reduce the volume in my gut. Proxima C has been excellent in various concentrations, and hasn’t left me feeling sloshy or otherwise “upset” – you know what I mean. As someone with Chronic Kidney Disease, electrolyte balance is of critical importance for me, I can’t have too much sodium. Proxima C has a great balance of electrolytes, focusing more on chloride and magnesium, which is perfect. I can still get a bit of sodium here, I can use additional salt as needed, and remain well-balanced without risking additional damage to my kidneys. In spite of the directions, I have mixed up to 5 scoops in just 550ml of water with no issues, great for that 4 hour long run where you don’t have access to a drop. Even in that concentration, the flavor isn’t overwhelming, and just a sip goes a long way. I’ve had some of my best training runs using Proxima C, I’m converted!

  2. David Failing (verified owner)

    I’ve been using Proxima C to fuel weight lifting workouts and will roll it in to my long runs as I train for multiple 100+ mile races this summer. The flavor is mild and enjoyable, and the powder mixes much more easily than competitors’ cluster dextrin products.

  3. Tasha Eichman (verified owner)

    I’ve been using Proxima C as my primary fuel for about the last month and LOVE it! I have a very sensitive stomach, especially once I start running. Consuming other liquid and solid fuels was always a huge challenge. Proxima C is super gentle on my stomach and has an amazing light taste. I’m finally able to consume enough calories, carbs, etc. with Proxima C. Amazing product and I’m looking forward to longer races using Proxima C.

  4. Mark Norfleet (verified owner)

    I’ve used Proxima C as my primary fuel for my last two ultras of 62 and 47 miles and have been very happy with it. Zero stomach distress and good even energy levels throughout the events. I’m looking forward to using it during three upcoming events which are all over 100 miles!

    • Admin

      Awesome! Thank you so much for taking the time to review Proxima C, Mark! Good luck with your upcoming races; please let us know how they go!

  5. Andrew Becker (verified owner)

    LOVING Proxima C! I have done multiple long runs using it and have nothing bad to say. The taste is awesome, I don’t notice a bonk when using it, and it is super easy on my stomach. I’m so glad it was released. This is my new fuel.

    • Admin

      Awesome! So glad to hear you are loving Proxima C! It really is a secret weapon for the long haul! Thanks, Andrew!

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Proxima C Endurance Fuel
Our SOurces

Furuyashiki, T., Tanimoto, H., Yokoyama, Y., Kitaura, Y., Kuriki, T., & Shimomura, Y. (2014). Effects of ingesting highly branched cyclic dextrin during endurance exercise on rating of perceived exertion and blood components associated with energy metabolism. Bioscience, Biotechnology, and Biochemistry, 78(12), 2117–2119.

König, D., Zdzieblik, D., Holz, A., Theis, S., & Gollhofer, A. (2016). Substrate Utilization and Cycling Performance Following PalatinoseTM Ingestion: A Randomized, Double-Blind, Controlled Trial. Nutrients, 8(7), E390.

Shiraki, T., Kometani, T., Yoshitani, K., Takata, H., & Nomura, T. (2015). Evaluation of Exercise Performance with the Intake of Highly Branched Cyclic Dextrin in Athletes. Food Science and Technology Research, 21(3), 499–502.

Sugino, T., Shirai, T., Kajimoto, Y., & Kajimoto, O. (2008). L-ornithine supplementation attenuates physical fatigue in healthy volunteers by modulating lipid and amino acid metabolism. Nutrition Research (New York, N.Y.), 28(11), 738–743.

Wilburn, D., Machek, S., & Ismaeel, A. (2021). Highly Branched Cyclic Dextrin and its Ergogenic Effects in Athletes: A Brief Review. Journal of Exercise and Nutrition, 4(3).