Runners have long relied on ergogenic aids — a fancy term for performance enhancers — to achieve a mental or physical edge while training and competing. But not all ergogenic aids are created equal. From caffeine and carb-loading to illegal substances like anabolic steroids, these performance enhancers vary greatly in both their safety and effectiveness.
If you’re a runner looking for that cutting edge, these are the best ergogenic aids to consider, according to science.
What are ergogenic aids?
Ergogenic aids include training techniques, nutrition supplements, drugs, and devices that may help prepare you to exercise, improve exercise efficiency, enhance recovery or play a role in injury prevention during intense training 
The best ergogenic aids for runners
Love your morning coffee? Well, it might be useful for your running performance too. Found in everything from coffee to sports gels, caffeine has been used by athletes to improve performance for decades. Caffeine stimulates the nervous system by blocking the activity of adenosine, a compound found in cells that has sedative-like properties. Research shows caffeine can improve endurance by 7-9% when combined with carbohydrates, leg power by up to 7%, and shave up to 4.2 seconds off of a 1500m run [2, 3
According to board-certified sports dietitian, Leslie Bonci, MPH, RD, CSSD
: “Caffeine can improve exercise capacity and spare muscle glycogen,” she says, which “can be useful before and during exercise in combination with carbohydrate.”
Caffeine can benefit all competitive runners.
Caffeine is found naturally in coffee, tea, cacao (the main ingredient in chocolate), and various herbal and botanical sources including guarana and yerba mate. Caffeine is also available in capsule form and is often added to energy drinks, bars, and gels.
Studies show limiting caffeine intake to 50mg/day or cutting out caffeine altogether for 2-7 days before a race might maximize its effect 
A growing body of evidence also suggests that consumption of caffeine with fluid during exercise might extend its benefits for runners 
Good to know
When it comes to using caffeine to enhance performance, the key is figuring out how much your body can tolerate. “Caffeine at high levels can have a diuretic effect and can cause GI distress in some athletes,” says Bonci. To minimize the potential for any extra pre-race jitters and stomach upset on race day, Bonci recommends training with it since caffeine tolerance and sensitivity can vary greatly between individuals.
Carbohydrates are sugars, starches, and fiber found in food and beverages. Carbs receive a lot of criticism but the truth is that they are an important fuel source for runners, especially when improving performance is the goal.
Why? Carbohydrates are the preferred fuel source for muscles during moderate-to-intense exercise. Increased dietary carbohydrate intake before, during, and after exercise has been shown to enhance exercise performance and recovery for both prolonged and intermittent high-intensity exercise 
. (Interestingly, carbs are also the preferred fuel source of the brain).
Increasing carbohydrate intake days and even hours before a race has been shown to increase muscle glycogen (carbohydrate stores) and enhances performance in endurance events, particularly those lasting 90 minutes or more 
After exercise, adequate carbohydrate consumption promotes rapid repletion of liver and muscle glycogen stores to enhance recovery and minimize performance decline in the days that follow 
All runners, from sprinters to ultra-marathoners may benefit from carbohydrate consumption as an ergogenic aid.
Sources of carbohydrates
Foods like whole grains, vegetables, and fruits are excellent sources of carbohydrates and should make up the majority of dietary carbohydrate intake. Other sources of carbohydrates including refined sugars, starches, and engineered sports nutrition products (including sports drinks, gels, and chews) can be helpful when glucose or glycogen resynthesis needs are high (and digestive capacity is low), such as during or immediately after an endurance run 
Daily carbohydrate needs for runners
For recreational runners focused on general fitness, a normal diet comprised of 45-55% calories from carbohydrates, 15-20% calories from protein, and 25-35% calories from fat is typically adequate
Runners participating in more intense training (2-3 hours/day, 5-6 days/week) should aim to consume 5-8g carbohydrate/kg/day to maintain liver and muscle glycogen stores 
Before a run
For runs lasting 60 minutes or more, athletes should consume 1-4g carbohydrate/kg 1-4 hours before exercise 
. Light, rapidly absorbed choices like a banana or toast with jam are good options for topping-up carbohydrates pre-run. Skip high-fiber and high-fat options as these can lead to gastrointestinal distress mid-run (and no one has time for that).
During a run
For high-intensity races lasting roughly 1 hour:
small amounts of carbohydrate, including mouth-rinsing with sugar water, may enhance performance 
. Again, rapidly absorbed sources of carbohydrate like sports drinks, bananas, and gummy bears are preferable here to minimize gastrointestinal distress mid-run.
For running events lasting 1-2 ½ hours:
athletes should aim to consume 30-60g carbohydrates/hour 
For races lasting more than 2 ½ hours:
Runners may benefit from higher intakes up to 90g/hour 
After a run
For optimal muscle recovery and glycogen resynthesis, runners should consume at least 1-2g carbohydrates/kg as part of a post-workout meal.
Athletes who experience stomach upset following carbohydrate ingestion post-exercise may benefit from pairing carbohydrates with a small amount of protein (0.2-0.4 g/kg/hr) as well as decreasing carb intake to 0.8 g/kg/hr 
Beta-alanine is an amino acid and a precursor to carnosine, a compound found in muscles that buffers lactic acid build-up in muscles. Lactic acid accumulates in muscles during moderate-to-high intensity activity and leads to reduced force and fatigue (as well as nausea).
Some research shows that beta-alanine supplementation can increase muscle carnosine levels, reduce lactic acid build-up, and thus improve certain aspects of performance, including anaerobic threshold, time to exhaustion, and muscle fatigue, particularly in older athletes 
Sprinters running short distances at max, or near-maximum speed 
Sources of beta-alanine
Beta-alanine is found in relatively low amounts in animal-based foods like meat, poultry, and fish. For runners seeking ergogenic benefits, beta-alanine is also available as a powder and in capsules as well.
For ergogenic benefits, the International Society of Sports Nutrition recommends a daily intake of 4-6g/day (taken in doses of 2 grams or less) for up to 8 weeks. This dosage of beta-alanine has been shown to significantly increase muscle carnosine after 4 weeks of supplementation 
Good to know
Evidence suggests that beta-alanine supplementation, even at the recommended dose, may leave you feeling a bit prickly. “Some athletes experience side effects, tingling in fingers and toes, and it is expensive,” says Bonci. This tingling, prickling, or burning sensation, also known as paresthesia, typically occurs in the upper body and can last anywhere from 60-90 minutes. Though uncomfortable, it is not a harmful reaction and can often be avoided by taking sustained-release beta-alanine supplements and/or dividing doses throughout the day 
Beet-stained hands may be worth it for runners. Beets are packed with nitrates and raise nitric oxide levels in the body. Nitric oxide is thought to enhance athletic performance in several ways including:
Research shows the combined effects of beetroot/nitrogen supplementation may improve aerobic exercise performance 
Chrissy Carroll, RD, and USAT Level I Triathlon Coach at Snacking in Sneakers
is a big fan of beet juice shots and says it’s one of her favorite ergogenic aids for runners. “They’re packed with dietary nitrates, which can increase levels of nitric oxide in the body. This helps increase blood flow and possibly enhances skeletal muscle contractions, both of which benefit performance,” says Carroll.
Nitrate supplementation seems to have the most ergogenic effect for exercise lasting 5-30 minutes, so short- to mid-distance runners will likely reap the most benefit. Limited evidence exists for performance improvement over longer durations 
Sources of nitrates
Nitrates are not sold as isolated dietary supplements due to concerns and regulations around ingesting high amounts of sodium nitrate, a food preservative. Instead, they are typically supplemented by consuming nitrate-rich foods, like beets and dark leafy greens 
Nitrate-rich foods :
Red beets, celery, and arugula contain approximately 250mg nitrate/100g
Raw spinach contains approximately 900mg nitrate/cup
Beet juice contains approximately 250mg nitrate /cup
Beetroot is also available in concentrated powders and juice “shots” which vary in potency and dosage.
Beet juice dosing
The International Society of Sports Nutrition recommends athletes consume 300-600mg nitrate/day (or 0.1mmol/kg/day), either in the form of beetroot juice or sodium nitrate, 2-3 hours before exercise, for ergogenic benefits 
Good to know
Consuming red beets or beetroot juice as an ergogenic aid can cause red urine and stools 
. While it might be alarming, red urine and stools from beet consumption are not harmful.
According to Carroll, mouthwash should also be avoided before consuming beet juice: “Don’t use mouthwash before drinking your beet juice shots! The bacteria in your mouth start metabolizing dietary nitrates. Mouthwash reduces that oral bacteria, potentially leading to lower levels of nitric oxide production and less chance of a performance boost.”
Creatine (creatine monohydrate)
One of the most popular sports dietary supplements on the market, creatine is a naturally occurring compound in muscles. Evidence suggests that creatine aids ATP (energy) production and may increase strength, power, and output from muscle contractions 
Sprinters running short distances at max, or near-maximum speed.
Creatine supplementation has been shown to enhance performance during short bursts of high-intensity activity like sprinting but seems to be of little value for mid-to-long distance runners 
. In fact, creatine supplementation may lead to weight gain which can hinder long-distance running performance 
Some research suggests that creatine supplementation paired with high carbohydrate intake post-run may enhance muscle glycogen stores, making it potentially beneficial for distance runners. However, the evidence to support this is limited 
Sources of creatine
Creatine is found naturally in food sources such as milk, red and white meat, and lesser amounts in fish and mollusks.
Creatine must be supplemented as food sources alone contain inadequate amounts for ergogenic benefits. Creatine monohydrate is the most common, affordable, and effective form of creatine on the market and typically comes in powder form that readily dissolves in liquids 
Creatine supplementation begins with a loading period before entering a maintenance phase.
The recommended loading dose is 0.3g creatine/kg/day (divided into 4 equal doses throughout the day) for 5-7 days 
. After the loading phase, the daily maintenance dose decreases to 0.03g/kg/day, with the maintenance phase lasting anywhere from 4-10 weeks (if cycling) to indefinitely [12
Good to know
Weight gain and water retention are common during the initial phases of creatine supplementation 
. Other commonly reported side-effects include stomach cramping (typically related to insufficient water intake) as well as diarrhea and nausea, which typically occurs when too much creatine is taken at once 
. These side effects can be mitigated with adequate hydration and splitting doses throughout the day.
Recognize this one? Often used in baking and household cleaning, sodium bicarbonate (aka baking soda), might also improve athletic performance in runners.
Known as bicarbonate loading, ingesting baking soda as an ergogenic aid can be an effective way to buffer the buildup of lactic acid in muscles during high-intensity exercise (typically lasting 1-3 minutes) 
Short-distance runners that feel the effects of lactic acid build-up 
Sources of sodium bicarbonate
Sodium bicarbonate supplements are available in capsules though store-bought baking soda is equally effective and less expensive 
Sodium bicarbonate dosing
For ergogenic benefits, sodium bicarbonate should be supplemented in a single dose of 0.3g sodium bicarbonate/kg, 60-90 minutes before exercise 
Good to know
Gastrointestinal distress is a common side effect of consuming too much sodium bicarbonate too quickly and supplementation should be approached cautiously at first.
Also, it’s important to know that sodium bicarbonate contains a lot of sodium — 1,259 mg per teaspoon — and can cause temporary fluid retention when consumed in high doses. High sodium intake over time is also associated with high blood pressure, heart attack, and stroke and studies have not evaluated the safety of long-term use of sodium bicarbonate as an ergogenic aid 
Sodium phosphate is a supplement and compound composed of salt and phosphate. Sodium phosphate is thought to improve oxygen transport and buffer the effect of lactic acid buildup, both of which impact aerobic and anaerobic capacity, power output, and cardiovascular response 
All runners may benefit from sodium phosphate supplementation due to the potential impact on both aerobic and anaerobic performance.
Sources of sodium phosphate
Sodium phosphate is found in common food sources like red meat, dairy, fish, and cereal, however oral supplementation (capsule form) is necessary to produce ergogenic benefits.
Sodium phosphate dosing
For use as an ergogenic aid, the recommended dosage for sodium phosphate is 3–5g/day for 3-6 days 
Good to know
The majority of studies evaluating the ergogenic potential of sodium phosphate have been conducted in men and the studies including females have returned varying results 
. Thus, more research is needed to determine the potential impact of gender on the ergogenic potential of sodium phosphate supplementation.
Water and sports drinks
Water and sports drink might not be the first thing that comes to mind when you think about performance enhancement, however, they are safe, legal, and highly substantiated ergogenic aid. Adequate fluid before, during, and after a run helps regulate body temperature, reduce cardiovascular strain and improve post-run recovery 
Sports drinks are typically used as ergogenic aids during and after longer endurance activities and contain a combination of water for hydration, carbohydrate (glucose) which provides muscles with quick-burning fuel, and electrolytes to offset those lost in sweat.
All runners and athletes can benefit from proper hydration. For long-distance runners running for one hour or more, sports drinks can offer added benefits by providing carbohydrates for sustained energy and replenishing lost electrolytes.
When it comes to hydration, filtered tap water, and bottled water are equally effective though filtered tap water is significantly less expensive.
Dissolvable electrolyte tablets and powders may be beneficial if you sweat heavily during exercise or are exercising in hot and humid conditions but do not need the additional carbohydrate from a traditional sports drink 
Sports drinks are available in ready-to-drink bottles, as well as tablets and powders that are easily dissolved in water.
Before a run, athletes should aim to consume 5-10mL fluid/kg (preferably water) 2-4 hours before exercise, to achieve urine output lemonade or lighter 
For runs lasting less than one hour, small amounts of water, as needed, are typically adequate to sustain optimal performance during the event.
For runs lasting one hour or more, runners should aim to consume 0.4-0.8L (13 ½ to 27 oz) of fluid from water and/or sports drinks per hour, though individual needs and tolerance vary 
. For prolonged runs lasting two hours or more, electrolyte-containing fluids like sports drinks should be consumed to keep runners hydrated and replace sodium lost in sweat.
The International Society of Sports Nutrition also recommends athletes consume 12-16 oz (0.35-0.47L) every 10-15 minutes of intense exercise in hot conditions 
Since most athletes finish exercising with a fluid deficit, many runners benefit from consuming enough water (and sodium, if needed) to achieve urine output that is lemonade or lighter. Rehydrating at a modest rate will help retain fluids ingested and minimize urinary losses of both fluid and electrolytes 
Good to know
Sports gels and bars have become increasingly popular among athletes. While the carbohydrates and electrolytes they contain offer similar ergogenic benefits as those found in sports drinks, these products do not provide fluids and thus should be consumed with water for optimal digestion, absorption, and hydration.
When it comes to ergogenic aids, these are the safest and most effective options for runners according to science. However, experimenting in training is important to develop a routine that works best for you. As always, check with your doctor before starting supplements if you have a pre-existing condition.
Disclaimer: The text, images, videos, and other media on this page are provided for informational purposes only and are not intended to treat, diagnose or replace personalized medical care.