Research-Based

Running Supplements for Endurance – The Complete Guide

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By Thomas Youngerman

Reviewed by Juliana Tamayo, MS, RDN - Last Updated

best supplement for endurance runners

The accepted definition of a distance or endurance runner is those who participate in events a minimum of 5k, or 3.1 miles, to more aggressive distances such as the half-marathon, 13.1 miles, the marathon, 26.2 miles, and ultramarathons from 50k to 100-milers. These athletes, as well as triathletes, cyclists, and distance swimmers, require exceptional stamina and mental toughness. The physical demands of their chosen activities dictate the need for specific training routines, hydration, and proper nutrition for energy, recovery, and optimizing performance. Many endurance athletes, both elite and recreational runners, turn to dietary supplements to address deficiencies, speed recovery and improve performance. 

This article addresses those needs. Adhering to a “food first” mentality, we discuss dietary considerations and fueling strategies. We then turn to the more controversial subject of nutritional supplements, what the sometimes-contradictory science says, and provide our curated list of the best supplements for endurance runners. Finally, we acknowledge some of the endurance and sports nutrition brand leaders.

Whether you’re a Boston Marathon veteran or preparing for your first 5k, we’re confident there are some valuable insights. 

Nutrition and Running

Nutrition for the endurance athlete is a complex and constantly evolving topic. Most coaches, nutritionists, and dieticians agree that food should be your first choice for fueling. Beyond that, the debate regarding the ideal runner’s diet continues. The following sections cover the basics of what to eat and when to eat and provide some basic recommendations regarding macro ratios. 

running feet

Dietary Considerations

Even the definition of macronutrients creates some controversy. We often refer to the three major macronutrients as carbohydrates, fats, and protein, which we discuss below. Some sources include alcohol as the fourth macronutrient, others add water, and still, others add vitamins, minerals, and fiber. Besides alcohol, the other categories are essential elements in your diet for good health.

A basic recommendation for the endurance runner would be 60-65% of calories from carbohydrates, 20% from fats, and 15-20% from protein. Stated differently, the endurance athlete needs 6–10 grams of carbohydrates and 1.2–2.0 grams of protein per kilogram of body weight.

Carbohydrates

A crucial component in a runner’s diet, carbohydrates are the body’s preferred fuel for energy. When consumed, carbs are converted to glucose, necessary to produce ATP (adenosine triphosphate) in your cells and become a ready energy source. Excess glucose is stored as glycogen in the liver and muscle cells to help power your workouts. During a distance run, your body converts stored glycogen back into glucose for energy as needed.

Fats

Fat is an essential macronutrient, responsible for many critical functions in the body, and is another important energy source. For those following a Keto or low-carb diet, you are familiar with the body’s use of fat for energy once glycogen stores are depleted.  The same concept applies during endurance exercise when your body turns to stored fat for energy through fat oxidation. Although efficient for the long-distance runner, fat plays a lesser role in high-intensity exercise. 

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Protein

Protein is perhaps the most misunderstood macronutrient for the endurance athlete. Attitudes have changed and continue to evolve regarding the importance, recommended quantity, and supplementation with protein. Although not a primary energy source during exercise, protein is essential for the endurance runner to maintain/ build muscle, for repair and recovery, and for injury prevention. 

Pounding the pavement for extended periods can result in significant muscle distress and potential catabolism. Sufficient protein intake enables the distance runner to rebuild muscle, eliminate muscle wasting, avoid injury, and enhance performance. 

Best Fuel for Runners

Endurance coaches and nutritionists have developed strategies for fueling pre, during, and post events to address energy, replenishment, and recovery.

For long endurance races, carb loading with complex carbohydrates such as potatoes, pasta, or multi-grains is recommended in the days leading up to the event.

For shorter durations, sixty-ninety minutes, a pre-race, carbohydrate-rich snack (banana, energy drink, or gel) provides a ready source of glucose for energy and should suffice.

carbohydrates potatoes

Stay hydrated if your run is less than an hour, but additional carbs are not necessary intra-workout. Beyond one hour, active refueling strategies are recommended. You should take in thirty-sixty grams of carbs each hour of exercise with gels, chews, or a sports beverage per the NCBI (National Center for Biotechnology Information). Marathon competitors should consider even more carbs, up to eighty grams per hour, a clinically proven strategy to improve performance. 

Like strength athletes, endurance athletes have a “recovery window” post-workout to replenish nutrients. Within two hours after your event, the ideal meal features plenty of carbohydrates and a minimum of twenty-thirty grams of quality protein. Post-exercise protein supplementation with carbohydrates can increase muscle glycogen synthesis by 40–100%. 

Dietary Supplements for Runners

Years ago, attending a marathon as a vendor, I attempted to persuade participants that they should have a post-workout drink with protein and L-glutamine to refuel and speed recovery. Let’s say the runners, and their coaches were skeptical. Thank goodness I didn’t try to introduce creatine back then. 

Today nutritional supplementation is a far more common strategy in the endurance field with elite and amateur athletes. In a recent study, some 64% of endurance runners reported using supplements in the past year. There are three use cases for dietary supplements:

  1. To address deficiencies in the diet.
  2. To supplement your food intake to meet nutritional recommendations.
  3. Ergogenic aids to enhance your athletic performance. 

The endurance athlete has greater nutrient needs than the typical diet might provide for performance, energy, repair, and recovery. As discussed in the macronutrient segment, protein supplementation is obvious; however, there are other possible micronutrient deficiencies (vitamins and minerals). Interestingly, one study found that athletes who used nutritional supplements also reported better nutritional intake from their diet than non-users. 

The Science Behind Endurance Supplements

Not surprisingly, a universal message from the scientific community, including the IAFF (International Association of Athletics Federation), is that runners should get most of their nutrition from whole foods and avoid excessive supplement use. The Association acknowledges that nutritional guidelines for endurance athletes are continuing to evolve. They identify five supplements evidenced as beneficial to performance: caffeine, creatine, nitrates/beetroot juice, beta-alanine, and bicarbonate. 

supplement for endurance runners

The IAAF Report also weighs in on two other areas, protein and electrolytes. They establish new guidelines for protein consumption as opposed to the current RDA of .08 grams/kg per day:

  • 1.3 – 1.7 grams per kg of body weight for weight-stable endurance athletes.
  • 1.6 – 2.4 grams per kg for those wishing to gain lean muscle.

To be expected, the preferred source of protein is food; however, nutritional supplements that provide all the essential amino acids may be a convenient alternative. 

In addition to sodium bicarbonate (an electrolyte), the IAAF acknowledges the need for replacing other electrolytes lost during exercise, suggesting gels or sports drinks to achieve hydration and fueling strategies.

Best Running Supplements for Endurance

Protein

Historically, endurance athletes and their coaches have prioritized protein consumption less than carbohydrates, underemphasizing this essential nutrient. The outdated model was simply to prevent nutrient deficiency. Today, we know that the endurance athlete requires higher protein intakes. Adequate protein consumption is crucial for the athlete, endurance or resistance trained, to maintain muscle protein synthesis, for repair and maintaining muscle mass.

Although there are many types of protein on the market today tailored to specific diets such as the Keto, vegan, vegetarian, etc., from a scientific standpoint, dairy-based proteins (whey, casein, and whole milk) may be superior due to their higher leucine and EAAs (Essential Amino Acids) profile.

Once again, your primary source of protein should be from your diet. Lean meats, eggs, dairy products, and soy all stimulate muscle protein synthesis effectively; however, most people do not consume sufficient protein from the foods they eat. Two strategies to supplement your food intake are:

  1. A post-workout shake of fast-acting hydrolyzed whey. 
  2. A slower digesting casein protein before bed.

Vitamins and Minerals to Address Dietary Deficiencies

Not mentioned in the IAFF’s Consensus Report were vitamin and mineral micronutrients. Yet, your body requires the appropriate micronutrients to perform optimally. They play important roles in metabolic pathways and physiological mechanisms critical to your health and performance.  Even diligent athletes following a healthy diet may develop vitamin and mineral deficiencies.  Fortunately, you have options to address this issue. Many people, including athletes, take a multivitamin/mineral as an insurance policy against general deficiencies in the diet.   

Especially for runners, there are certain vitamins and minerals that are essential for energy, endurance, injury-avoidance, and recovery. 

  • Vitamins C and E – potent antioxidants that protect against exercise-induced free-radical damage. 
  • Vitamin D3 – essential for healthy bones, muscle performance, supports your immune function.
  • B12 – increases energy and aids in recovery. 
  • Calcium – for strong bones, key to preventing stress fractures in endurance runners.
  • Magnesium – also for bone health, energy production, muscle contraction, and transports energy to your muscles for endurance performance.
  • Zinc – promotes a healthy immune system, key as endurance exercise may stress the immune system. 
  • Iron – for stamina and to speed recovery from repetitive impact damage.

Electrolytes

For the distance runner, electrolytes are equally as important as macronutrients. The endurance athlete must monitor their hydration levels pre-, intra-, and post-training. Staying hydrated requires more than just H2O. Proper hydration and electrolyte replacement are crucial. Fluids, with added electrolytes, especially sodium and potassium, are required for proper absorption into the bloodstream to replenish those lost due to sweat during intense exercise. 

Proper hydration is key to maintaining cognitive function and endurance; it protects you from overheating and expedites your recovery. Taken without electrolytes, water may simply flush through the system. The electrolytes sodium, magnesium, potassium, and calcium help retain fluids and maintain the body’s fluid balance.

Caffeine

Caffeine is one of the two compounds (along with nitrates) cited by the IAFF as recommended for distance runners. It is an evidence-based stimulant that provides energy, supports cognitive function, and suppresses pain by increasing endorphins. Endurance athletes contend caffeine reduces the perception of effort, delays fatigue, and may even help with weight management. 

caffeine compound for runners

There have been numerous clinical studies that highlight the benefits of caffeine consumption on endurance performance. When supplementing with caffeine, we recommend either capsules or tablets versus powder to ensure the proper dosages. Start slowly and determine your body’s tolerance over time. Although caffeine is a diuretic, a recent study indicates it doesn’t create electrolyte imbalances or reduce heat tolerance.

Creatine 

Long a staple in the gym, strength athletes use this ergogenic aid to build muscle, increase strength, and speed recovery. Creatine monohydrate, the most clinically tested supplement ever, is evidenced to improve strength, speed, and power – not the typical attributes an endurance runner is seeking. However, as the IAFF concludes, creatine supplementation can benefit runners, although typically at shorter distances. 

That said, endurance runners using advanced training techniques, intervals, hills, and speed work will see decreased recovery time between sets and increased power output, resulting in improved performance on race day when adding creatine to their regimen. 

Nitrates

Nitric oxide is another popular supplement in the gym known for its effects on vasodilation, increased blood flow, and muscle pumps. For the endurance athlete, nitrates increase the efficiency of oxygen usage in your body during exercise. In addition, they benefit blood flow through vasodilation, 02 regulation in working muscles, glucose uptake, and muscle contraction/relaxation, lengthening the time to exhaustion. 

Popular forms of nitrates include L-arginine, L-citrulline, Tart Cherry, and Beet Root. Nitrates are found naturally in leafy greens, beetroot, and other vegetables, but taking them in more concentrated doses in supplements can be beneficial. 

Beta-Alanine

While nitrates reduce the energy required for muscle contractions, beta-alanine helps to buffer lactic acid buildup. This non-essential amino acid, a precursor to carnosine, is an effective supplement for endurance runners as it delays muscle fatigue caused by lactic acid. Beta-alanine is also known for its antioxidant properties.

Like creatine, some of beta-alanine’s crucial benefits are effective during the distance runner’s more high-intensity training techniques such as tempo runs, intervals, and resistance training. Beta-Alanine reduces muscle acidity, allowing the runner to go harder and longer. 

L-Glutamine

Our final top pick for an endurance runner’s supplement regimen is L-glutamine. This most abundant amino acid found naturally in the body is vital for reducing muscle breakdown, gut health, and boosting the endurance athlete’s immune system function – important as after prolonged periods of exercise, your immune system may be more susceptible to infection.

Glutamine plays an essential role in repair and recovery following intense exercise and helps alleviate muscle soreness – remember that marathon we attended years ago armed with protein and glutamine for post-workout. 

Repair, recovery, gut health, immune function, and reducing DOMS (delayed onset muscle soreness). We consider L-glutamine essential, even in the absence of clinical data supporting specific benefits for the distance runner. 

Additional Supplements for Endurance Runners

Research studies indicate that endurance athletes who supplement tend to be healthier with a better nutritional profile and fewer nutrient deficiencies than those who abstain. Although we cite examples of how these supplements may benefit the endurance athlete, the following recommendations apply to anyone concerned with general health and wellbeing. 

variety supplement for endurance runner

Antioxidants

Intense exercise increases your oxygen intake and will raise the level of free radicals in your body, causing muscle fatigue, cell damage, and inflammation. Antioxidants neutralize these exercise-induced free radical scavengers, preventing oxidative damage and premature aging.

As usual, consuming antioxidant-rich foods is the preferred method. However, vitamin C, E, beta-carotene, resveratrol, and green tea are excellent supplement options.

Biotics

Probiotics are defined as “live food ingredients” that provide a beneficial effect to the host organism. There is a plethora of information on gut health, the microbiome, pre-, post-, and probiotics, and maintaining a healthy balance of gut bacteria. Probiotics occur naturally in fermented foods, think yogurt, kimchee, sauerkraut, and miso, or can be taken in supplement form. Lactobacillus and Bifidobacterium are the primary species used in supplements.

In addition to their significant role in immunity (70% of your immune system is in your gut), maintaining a healthy GI tract is crucial for the long-distance runner. 

Fish Oil

Fish oil, which contains omega-3 fatty acids, is one of the essential supplements for general health. It plays a role in heart health, cognitive function, joint health and has anti-inflammatory properties. Fish oil helps alleviate muscle stiffness, swelling, and soreness for runners, according to a new study in the Journal of the International Society of Sports Nutrition. 

BCAAs and EAAs

For years, the standard intra-workout supplement in the gym was BCAAs, the branched-chain amino acids, leucine, valine, and isoleucine. Today, a new debate rages as to which is more effective, BCAAs or EAAs, essential amino acids. For background, amino acids are organic compounds, the building blocks of protein. Your body needs twenty different amino acids to develop and function properly. Nine of these building blocks are essential; that is, they cannot be made in your body, meaning you must access them through your diet or supplementation.

Clinical trials show that BCAAs are critical in promoting MPS (muscle protein synthesis), reducing muscle breakdown, and enhancing recovery from exercise. However, more recent research indicates that EAA protein sources rather than BCAAs alone are superior for stimulating MPS. 

Regardless of your choice, BCAAs or EAAs, these aminos taken either pre- or intra-workout can help preserve the endurance runner’s muscle and aid in repair and recovery.

Joint Supplements

Distance running stresses your ankle, knee, and hip joints. In addition to fish oil, specific joint supplements include the time-tested Glucosamine, Chondroitin, and MSM Methylsulfonylmethane; with newer compounds Hyaluronic Acid, Turmeric, and Boswellia being prevalent in many formulas today.

Assessing Your Supplement Needs

We think we’ve covered the endurance basics and more general products in this “Best of” article for long-distance runners. Below is a quick guide to help identify specific needs/gaps and the products best suited to address the issue:

  • Need extra energy – Caffeine and Vitamin B12
  • For greater endurance – Beta-alanine and/or nitrates
  • For hydration, electrolytes are essential
  • Dietary deficiencies – Multivitamin/Mineral or specific letter vitamins
  • Injury avoidance – Vitamin D3, calcium, magnesium
  • Repair & Recovery – L-Glutamine, BCAAs, Protein

Cautions

We felt it important to address just a couple of potential issues or side effects based on the above information:

  • For hydration, we recommended fluids with added electrolytes. Rehydrating with water only during a long race could potentially lead to hyponatremia, a dangerous condition when blood sodium levels are too low.
  • Our macronutrient ratio called for 20% of calories from fat. Less than 20% of your caloric intake from fat could result in deficiencies in fat-soluble vitamins and essential fatty acids.
  • Several of our recommendations, such as creatine and amino acids, may cause gastrointestinal distress for endurance runners. Always test these products on non-race event days to determine your tolerance. Creatine HCL (creatine hydrochloride) versus monohydrate may be a safer option.

Best Nutrition Brands for Endurance Supplements

Listed below are several premier manufacturers in the sports nutrition and endurance space. 

brand for endurance athletes hammer nutrition

Hammer Nutrition

In the endurance/supplement space since 1987, Hammer has been one of the most respected brands for distance runners. From their beginning in fuels, they have expanded to a full line of supplements featuring many items in our Best of list.

NUUN

With a laser-like focus, NUUN markets electrolyte tablets to keep you hydrated. Our choice for the best electrolyte drink on the market – especially important for those runners who suffer leg cramps.

Cliff Bar

An early pioneer in the energy bar category, Cliff has expanded their offering to include gels, shots, blocks, cereals, and other condition-specific bars, such as Luna, Builder, and ZBar for kids.

Optimum Nutrition

For sports nutrition products, it’s challenging to do better than Optimum Nutrition. They market a complete line of supplements from protein powders to BCAAs, diet products, and virtually every one of the supplements in our review. 

Humann

A relative newcomer in the space, Humann’s main contribution to the endurance athlete is their nitrate products, BeetElite, SuperBeets, NEO 40, and more. 

In Summary

Long-distance runners and endurance athletes, in general, are some of the most dedicated and disciplined individuals on the planet. Since their events place unique demands on the body, adequate training, proper nutrition, and hydration are essential. The nutritional supplements highlighted in this review will benefit endurance athletes in addressing dietary deficiencies, meeting nutritional requirements, and improving performance. 

We’ve addressed supplements to increase energy, enhance stamina, speed recovery, and avoid injuries; in short, aids to improve your times and keep you on the track or road.