Ultra Marathon Supplements: What Ultra Runners Actually Use For 50K+

Ultra marathon training places extreme demands on the body. Runners preparing for distances beyond 50 kilometers often complete long training runs, back-to-back endurance sessions, and high weekly mileage. These efforts place stress on muscles, joints, and energy systems simultaneously, and the recovery window between sessions is often shorter than ideal.

For many ultra runners, the challenge is not just finishing a single long run. It is sustaining training consistency across weeks and months of preparation without accumulating injury, fatigue, or performance decline. Targeted supplementation, when combined with structured training and balanced nutrition, can support the systems that take the most stress during ultra marathon preparation. While creatine supplements and whey protein are among the most recognized names in sports nutrition, ultra distance running demands a more targeted approach that’s built around oxygen delivery, joint resilience, and sustained recovery rather than gym-focused performance metrics.

Athletes preparing for their first long-distance race often look into foundational strategies such as those outlined in our practical tips for first 50K ultra, which highlights the preparation approaches runners use to manage the demands of extended endurance events.

EPO-Boost: Oxygen Delivery For Ultra Endurance

No physiological factor matters more to ultra marathon performance than oxygen. At race distances of 50K and beyond, the body's ability to supply oxygen to working muscles over many hours determines how long a runner can sustain pace before fatigue forces a slowdown.

EPO-Boost is BRL Sports' flagship endurance supplement, formulated to naturally stimulate the body's own erythropoietin (EPO) production. This is the hormone responsible for red blood cell development (Schoener & Borger, 2024). More red blood cells mean greater oxygen-carrying capacity, which translates directly into more sustained output during the long miles that define ultra racing. In particular, this blend targets the four primary limitations on red blood cell production:

• EPO Stimulation: Four capsules of EPO-Boost contain 8 grams of echinacea purpurea, an amount shown in human trials to increase circulating EPO (Whitehead et al., 2005).
• Red Blood Cell Nutrients: This supplement supplies a spectrum of micronutrients essential for erythropoiesis, including folate, iron, Vitamin B12, and Vitamin B6 (Schoener & Borger, 2024).
• Iron Availability: Red blood cells require iron to carry oxygen, but availability is often a limiting factor during high-mileage training. EPO-Boost includes iron and herbs packed with iron (dandelion and yellow dock), plus Vitamin C to help improve dietary iron absorption (Moustarah & Daley, 2024).
• Antioxidant Support: Intense endurance training creates an inflammatory environment that might impede red blood cell production. EPO-Boost includes a blend of lycopene, lutein, PABA, alpha-lipoic acid, and choline to help maintain a stable internal environment during heavy training blocks.

EPO-Boost contains no banned substances and is fully compliant with the World Anti-Doping Agency (WADA), the United States Anti-Doping Agency (USADA), and all major sports governing bodies. For competitive ultra runners, this is of the utmost importance.

VO2-Boost: Maximize Oxygen Utilization And Delay Fatigue

Oxygen delivery and oxygen utilization are two distinct performance factors. EPO-Boost supports the former by increasing red blood cell production. VO2-Boost targets the latter, helping the body make the most efficient use of the oxygen already available.

VO2 max represents the body's maximum capacity to consume and utilize oxygen during sustained effort (Srivastava et al., 2024). For ultra runners, a higher VO2 max supports better pacing economy across long distances and faster recovery between hard training sessions. With this in mind, our VO2-Boost was formulated with six all-natural, research-aligned ingredients to support these aerobic performance systems.

• Rhodiola: As a natural adaptogen, rhodiola has been studied for its ability to lower perceived fatigue and support endurance during high-stress training.
• Cordyceps: This functional mushroom might support cellular energy production and oxygen utilization, promoting stamina across extended efforts.
• Quercetin: A flavonoid associated with improved oxygen uptake, quercetin has been studied for its suggested ability to support cardiovascular health and aerobic capacity.
• Catechins: Catechins are antioxidant compounds found in green tea that may support fat oxidation and sustained energy availability during prolonged efforts.
• Beta Alanine: Beta alanine helps buffer lactic acid accumulation, delaying the muscular fatigue that builds during climbs and surges late in a race.
• Echinacea: Echinacea may support immune function and recovery consistency across demanding training blocks.

For a deeper look at how endurance athletes build aerobic capacity through training and supplementation, see our guide on extreme endurance.

TriFuel: Hydration, Energy, And Recovery For Ultra Training

Ultra marathon training introduces a compounding recovery problem: high mileage, back-to-back runs, and frequent sessions deplete fluids faster than most athletes can replenish through food alone. If you’re looking to address hydration, energy, and recovery simultaneously, TriFuel can help you perform at your best.

Complete Electrolyte And Hydration Support

TriFuel replenishes the key minerals lost through sweat during prolonged training, primarily sodium, potassium, and magnesium. For ultra runners spending hours on the trail, maintaining electrolyte balance helps support muscular function, nerve signaling, and cardiovascular stability across long efforts (Casa et al., 2010).

Simple Carbohydrates For Sustained Energy

During extended endurance exercise, the body burns through carbohydrate stores rapidly. TriFuel includes simple carbohydrates from natural sources to provide quick, usable energy, helping fuel muscles through the long miles when glycogen depletion becomes a real performance limiter.

BCAAs For Muscle Repair

One of TriFuel's most important advantages for ultra runners is its inclusion of branched-chain amino acids (BCAAs): Leucine, Isoleucine, and Valine. BCAAs support muscle repair, reduce soreness, and help prevent muscle breakdown during high-volume training weeks (Luan et al., 2025). To top it all off, TriFuel's all-natural formula is free from artificial sugars and chemicals, plus it includes vitamins C and B6 to support immune function and energy production during demanding training blocks.

Flexify: Joint Support For The Miles That Add Up

Ultra marathon training is hard on joints. Long runs on trails, technical terrain, and repetitive downhill sections place significant pressure on knees, hips, and connective tissue over many weeks of preparation. For runners logging high mileage, maintaining joint health is what keeps training consistent. Here’s a look at what’s inside Flexify, our advanced joint support formula:

1. Glucosamine: As an amino sugar that helps maintain adequate collagen levels, glucosamine supports joint cartilage, which acts as a cushion protecting joints against the high-impact demands of long-distance running.
2. Chondroitin: Chondroitin helps maintain fluid and flexibility in the joints, blocks enzymes that break down cartilage, and retains the water needed to keep cartilage from becoming stiff.
3. MSM: Methylsulfonylmethane supports collagen formation and has been studied for its role in promoting joint comfort and mobility through the maintenance of healthy connective tissue.
4. Boswellia: The acids in boswellia have been shown in scientific studies to support key enzymes involved in maintaining joint tissue, helping manage discomfort in the hips, knees, and surrounding joints.
5. Turmeric: Curcumin, the active compound in turmeric, may help with joint discomfort by supporting the body's response to inflammatory enzymes.
6. Ginger Root: Ginger has been studied for its role in managing occasional joint swelling and discomfort, making it a natural option for runners dealing with the repetitive impact of high-mileage training.
7. Vitamin D3: Vitamin D3 builds and maintains strong bones, aids calcium absorption, and may play a role in relieving joint discomfort, particularly in the hip and knee joints most stressed during ultra marathon preparation. Each serving of Flexify contains the recommended 1,000 IU of Vitamin D3.

While fish oil is a popular standalone option for joint health, Flexify takes a more comprehensive approach, combining seven clinically validated ingredients that collectively address mobility, lubrication, cartilage support, and tissue repair in a daily tablet format.

Building Endurance With The Right Supplement Strategy

Preparing for an ultra marathon requires more than increasing mileage. The most consistent ultra runners combine structured training with nutrition strategies that support performance, recovery, and long-term joint health across the full preparation cycle.

EPO-Boost and VO2-Boost address the aerobic foundation with oxygen delivery, oxygen utilization, and fatigue resistance. From there, TriFuel handles hydration, energy, and recovery between demanding sessions. Finally, Flexify protects the joints and connective tissue that absorb the cumulative stress of high-mileage training.

Used together within a periodized program, these four products cover the full performance and recovery spectrum that ultra distance running demands. For a broader look at how endurance athletes approach supplementation, see our guide on the best supplements for runners.

Disclaimer:

These statements have not been evaluated by the FDA. Products are not intended to diagnose, treat, cure, or prevent any disease.

Sources:

1. Schoener, B., & Borger, J. (2024, July 14). Erythropoietin stimulating agents. In StatPearls [Internet]. StatPearls Publishing. https://www.ncbi.nlm.nih.gov/books/NBK536997/
2. Whitehead, M., Martin, T., Webster, M., & Scheett, T. (2005). Two weeks of oral echinacea supplementation significantly increases circulating erythropoietin: 231 Board #138 11:00 AM – 12:30 PM. Medicine & Science in Sports & Exercise, 37. https://doi.org/10.1249/00005768-200505001-00230
3. Moustarah, F., & Daley, S. F. (2024, January 8). Dietary iron. In StatPearls [Internet]. StatPearls Publishing. https://www.ncbi.nlm.nih.gov/books/NBK540969/
4. Srivastava, S., Tamrakar, S., Nallathambi, N., Vrindavanam, S. A., Prasad, R., & Kothari, R. (2024). Assessment of Maximal Oxygen Uptake (VO2 Max) in Athletes and Nonathletes Assessed in Sports Physiology Laboratory. Cureus, 16(5), e61124.https://doi.org/10.7759/cureus.61124
5. Casa, D. J., Stearns, R. L., Lopez, R. M., Ganio, M. S., McDermott, B. P., Walker Yeargin, S., Yamamoto, L. M., Mazerolle, S. M., Roti, M. W., Armstrong, L. E., & Maresh, C. M. (2010). Influence of hydration on physiological function and performance during trail running in the heat. Journal of athletic training, 45(2), 147–156.https://doi.org/10.4085/1062-6050-45.2.147
6. Luan, C., Wang, Y., Li, J., Zhou, N., Song, G., Ni, Z., Xu, C., Tang, C., Fu, P., Wang, X., Gong, L., & Zhang, E. (2025). Branched-Chain Amino Acid Supplementation Enhances Substrate Metabolism, Exercise Efficiency and Reduces Post-Exercise Fatigue in Active Young Males. Nutrients, 17(7), 1290. https://doi.org/10.3390/nu17071290