The 5 Best Supplements for Runners (Backed by Science)

Most of your running performance comes from consistent training, quality sleep, and smart nutrition. There’s no capsule that replaces hill repeats or a well-timed carbohydrate strategy. That said, research suggests certain evidence-based supplements can provide small but meaningful advantages for runners—particularly when the fundamentals are already in place. For those engaged in endurance running, the right supplements can help support stamina, maintain energy levels, and aid recovery during long-distance or sustained efforts.

This article covers five of the most researched supplements for runners: caffeine, creatine, dietary nitrates (beetroot juice), beta alanine, and electrolytes. The recommendations draw from peer-reviewed sports medicine research, including position stands from the International Society of Sports Nutrition (ISSN), American College of Sports Medicine (ACSM), and meta-analyses published between 2000 and 2025. These are general guidelines, not individual medical advice.

Set your expectations clearly: these supplements typically offer modest improvements in exercise performance or recovery. They work best as fine-tuning tools when your diet, training load, and hydration are already well-managed.

Safety, Testing & “Food First”: What to Know Before You Supplement

Before reaching for any supplement, embrace a “food first” philosophy. Whole foods deliver carbohydrates, complete protein, healthy fats, vitamins, and minerals in combinations that isolated powders cannot replicate. Meat provides natural creatine, beets and spinach offer dietary nitrates, and balanced meals supply electrolytes without any capsules required.

Most healthy adult runners may not need supplements at all. However, some can help fill nutritional gaps or support specific training demands—marathon blocks, high intensity interval training, or heat acclimatization phases. The key is knowing when supplementation adds value versus when it simply drains your wallet.

For competitive athletes subject to anti-doping rules, third-party testing is non-negotiable. Look for certifications like NSF Certified for Sport, Informed Sport, or BSCG Certified Drug Free. Studies show 10-15% of untested products contain banned substances or undeclared ingredients that could trigger positive tests.

Certain populations need extra caution: pregnant or breastfeeding women, adolescents, and people with cardiovascular, kidney, or liver conditions should consult a healthcare professional before using performance supplements. The doses mentioned throughout this article are typical research ranges, not prescriptions. Start at the lower end and test in training—never on race day.

1. Caffeine: The Most Researched Performance Booster for Runners

Caffeine stands as one of the most consistently supported ergogenic aids in endurance sports, with over 300 studies since 2000 confirming its benefits for distances from 5K to the marathon and beyond.

How caffeine works: It primarily blocks adenosine receptors in the brain, reducing perceived exertion and delaying the sensation of fatigue. This mechanism can improve alertness, concentration, and your ability to maintain race pace when things get uncomfortable. Research also shows caffeine may increase fat oxidation by up to 30% at moderate doses.

Evidence-based dosing: About 3-6 mg per kg of body weight, taken approximately 60 minutes before running. For a 70 kg runner, that’s roughly 210-420 mg—equivalent to 2-4 strong coffees or a standard caffeine capsule.

Common forms runners use:

• Coffee or tea (slower absorption, good gut tolerance)
• Caffeine pills (precise dosing, 99% bioavailability)
• Caffeinated gels or chews (25-100 mg with carbohydrates)
• Energy drinks (often contain added sugars and other stimulants)

Potential benefits: Research shows 1-4% improvements in time-trial performance, better ability to sustain high intensity efforts, and sharper focus during long runs or early-morning races. Elite marathoners like Eliud Kipchoge reportedly use 3-5 mg/kg strategically.

Side considerations: Individual variability matters significantly—about 10-20% of people are genetic non-responders due to CYP1A2 slow metabolism. Common negative effects include jitters, anxiety, gastrointestinal upset, and sleep disruption if used after mid-afternoon. Those prone to heart palpitations or insomnia should approach caffeine cautiously.

The ISSN and ACSM recognize caffeine as an effective endurance aid when used responsibly, though it’s not suitable for everyone. Medical guidance may be needed for certain conditions or pregnancy.

2. Creatine Monohydrate: Strength, Speed, and Support for Hard Sessions

Creatine is naturally present in your body and in foods like meat and fish. It’s one of the most thoroughly studied sports supplements, with research primarily supporting its benefits for power and muscle strength rather than pure endurance. Creatine is one of the only legal supplements that is actually proven to work.

How creatine works: Supplementing creatine increases phosphocreatine stores in muscle by 20-40%, helping regenerate ATP quickly during short, intense efforts. This matters for hill repeats, sprint finishes, and the strength training that underpins running economy. Creatine can also help to improve glycogen storage in the muscles, which serves as an important fuel source during endurance activities like distance running.

Why runners benefit: Improved ability to perform high intensity exercise during intervals, better support for gym work that builds muscle endurance, and potential advantages in repeated surge efforts during 5K-10K races or cross-country with hills. A 2025 meta-analysis found creatine supplementation excels in 30-meter sprint speed acceleration. Supplementing creatine can benefit any athlete, particularly in speed and high-intensity sessions.

Standard dosing protocols:

• Loading phase: ~20 g/day (split into 4 doses of 5g) for five to seven days, then regular maintenance dosing of 3-5 g/day
• Maintenance phase: After the loading phase, the maintenance phase involves taking a lower, consistent dosage (typically 3-5 g/day) to sustain muscle creatine levels and maintain the benefits gained from loading. The duration and dosage of the maintenance phase can be tailored with advice from a healthcare professional based on individual goals.
• No-load approach: Simply 3-5 g/day from the start, which will quickly saturate stores over about 28 days with potentially less GI discomfort

Creatine monohydrate is the form most widely studied and recommended. Buffered or HCl versions are marketed as superior but show similar efficacy at higher cost.

Timeline and expectations: It may take 1-4 weeks to reach optimal levels and notice benefits during high intensity efforts. Don’t expect changes in easy-pace running or long runs directly—the gains show up in interval sessions and power output.

Common concerns: Mild water retention within muscle tissue, small increases in body weight (typically 1-2 kg of muscle water, not fat), and occasional digestive upset with large single doses. Long-term studies up to 5 years at 5 g/day show no harm to kidney or liver function in healthy adults. However, people with kidney disease or certain metabolic conditions should only use a creatine supplement under medical supervision.

Practical tips: Take with a meal or carbohydrate source for up to 60% better uptake. Split doses to reduce stomach issues. Test during a training cycle rather than starting immediately before a key race.

Benefits of Protein Powder for Runners

Protein powder has become a staple supplement for many endurance runners, offering a convenient way to boost daily protein intake and support muscle endurance—especially during periods of high intensity exercise or heavy training blocks. Research suggests that supplementing with protein powder can help reduce muscle damage and soreness after tough interval training sessions, making recovery faster and more effective.

For endurance runners who find it challenging to consume enough protein through whole foods alone, protein powder provides a concentrated source of complete protein. This is crucial for promoting muscle strength, maintaining muscle mass, and supporting muscle contractions during long runs and high intensity efforts. Choosing a protein powder that contains all essential amino acids—such as whey or casein—ensures you’re getting the building blocks needed for collagen synthesis and bone health, both of which are vital for reducing injury risk and supporting overall health.

Some protein powders are formulated with added ingredients like creatine monohydrate or beta alanine, which can further benefit athletes by increasing power output and delaying fatigue during high intensity exercise. These blends can be particularly useful for runners who incorporate regular interval training or strength work into their routines.

It’s important to be mindful of potential side effects, such as stomach discomfort or bloating, which can occur with some protein powders—especially those high in sugar or artificial additives. Opt for products with minimal ingredients and avoid using protein powder as a replacement for a balanced diet. Instead, use it to supplement your intake and aim for a daily protein target of 1.2-1.6 grams per kilogram of body weight to support muscle endurance, recovery, and running performance.

Iron supplements, including iron bisglycinate and ferrous sulfate, are also worth considering for endurance runners—particularly those at higher risk of iron deficiency, such as menstruating women or those training for distance running events. Iron is essential for the production of red blood cells and the efficient transport of oxygen to working muscles, directly impacting endurance performance and helping runners avoid feeling tired or sluggish during training.

By strategically incorporating protein powder and iron supplements into your diet, you can help maintain optimal levels of muscle mass, support bone health, and reduce your risk of injury. These supplements, when used alongside a well-rounded diet and consistent training, can make a big difference in your ability to recover, perform at higher exercise intensity, and achieve your running goals.

3. Dietary Nitrates (Beetroot Juice): Supporting Oxygen Efficiency

Beetroot juice and nitrate-rich foods like spinach, arugula, and lettuce have become popular among endurance athletes aiming to improve oxygen efficiency.

The mechanism: Dietary nitrates convert in the body to nitric oxide, which helps blood vessels widen (vasodilation). This can improve blood flow and reduce the oxygen cost of submaximal exercise by 3-5% at 60-80% VO2max. The result? Better endurance performance at tempo paces.

Best applications: Time trials and races from 5K to half marathon, tempo runs, and steady efforts where small economy gains translate into faster times. Meta-analyses show 1-2% time-trial improvements—meaningful at competitive levels.

Research-informed protocols:

• Acute dosing: 400-800 mg nitrate (70-140 ml concentrated beetroot shots) taken 2-3 hours before exercise
• Chronic loading: Daily intake for 3-7 days before a key event for potentially greater economy gains

Individual variability: Response varies widely—up to 50% of runners may be non-responders, influenced by training status, diet, and gut microbiome. Trained endurance runners sometimes show smaller benefits than recreational athletes.

Potential side effects: Harmless “beeturia” (red urine) affects about 14% of users. Some experience temporary stomach discomfort or bloating. Those taking blood pressure medications should consult a healthcare professional, as nitrates can affect blood vessels and lower blood pressure.

Food-first approach: Include nitrate-rich vegetables regularly for overall health—arugula tops the charts at 480 mg per 100g. Reserve concentrated beetroot products for specific races or training blocks.

4. Beta-Alanine: Buffering the Burn in High-Intensity Efforts

Beta alanine is a non-essential amino acid that increases muscle carnosine levels by 40-80% over 4-10 weeks of supplementation. Carnosine helps buffer hydrogen ions (lactic acid byproducts) during hard efforts.

Where it helps: Research supports benefits for efforts lasting about 1-10 minutes at very high intensity exercise levels—think 800m to 3K races, VO2max intervals, and uphill repeats. Effects on long, steady distance running are less clear. A 2025 meta-analysis confirmed improvements in jump performance and interval capacity.

Typical dosing: About 3.2-6.4 g per day, divided into smaller doses (800-1600 mg, 3-4 times daily) over at least 4 weeks to build muscle carnosine stores. This is a loading-style supplement—you won’t “feel” it immediately like caffeine.

The tingling sensation: The most common side effect is paresthesia—tingling or “pins and needles” in the skin, especially with larger single doses. Smaller divided doses or sustained-release forms reduce this by about 70%.

Important limitations: Beta-alanine doesn’t increase muscle mass or strength by itself. Performance effects are usually modest (1.5-2% overall). It’s primarily relevant for runners who regularly compete or train in events with significant high intensity efforts.

Safety has not been well established for children, adolescents, pregnant women, or people with certain medical conditions. The ISSN classifies beta-alanine as having good evidence for specific applications, while noting it’s optional for most runners focused on distance running.

5. Electrolytes & Hydration: Essential for Longer and Hot-Weather Runs

Electrolytes—especially sodium, but also potassium, magnesium, and calcium—regulate fluid balance, nerve signals, and muscle contractions. You lose them in sweat during every run.

When supplementation matters: For short, easy runs under 60 minutes in cool conditions, water and normal meals cover most needs. But long runs, back-to-back training days, hot weather, and heavy sweating create situations where targeted electrolyte intake can make a big difference.

Sweat sodium variability: Losses range from 460-1840 mg per liter of sweat depending on the individual. Signs you might need more: salt crusts on clothing, frequent cramping, or unusually high sweat rates. Some endurance athletes lose over 1,000 mg sodium per hour.

Common options: | Product Type | Sodium Content | Carbohydrates | |————–|—————-|—————| | Sports drinks | 200-400 mg/L | Yes | | Electrolyte tablets | 300-500 mg/tablet | Usually no | | Salt capsules | 200-400 mg/capsule | No | | Homemade mixes | Variable | Optional |

General guidance: Aim to replace a portion of losses during long runs, starting around 300-600 mg sodium per hour and adjusting based on climate, exercise intensity, and personal response.

A critical warning: Overhydration without adequate electrolytes can cause low blood sodium (hyponatremia), which affects up to 13% of ultra participants. Listen to thirst, have a plan, and avoid forcing excessive fluid intake.

Magnesium supports muscle function but high-dose supplementation without professional guidance can cause GI issues or interact with medications affecting bone health and heart rhythm. Meet the recommended dietary allowance through food first.

Other Evidence-Informed Options Runners Often Ask About

Beyond the core five, several supplements frequently come up in runner conversations:

Protein powder: Convenient for meeting daily needs—especially for busy athletes or those needing higher intake. However, many runners get enough protein through whole foods like dairy, eggs, fish, and legumes. Aim for complete protein sources providing all essential amino acids.

Collagen: When taken with vitamin c, emerging research suggests it may support collagen synthesis and tendon health. Early findings show potential for connective tissue support, but data remain preliminary. It shouldn’t replace complete proteins.

Iron supplements: Critical for red blood cells and oxygen transport. Endurance runners face higher risk of iron deficiency—especially menstruating women who may feel tired despite adequate training. Only supplement after blood testing confirms low ferritin (typically <30 mcg/L). Forms like iron bisglycinate or ferrous sulfate each have tradeoffs. Iron overload poses real risks.

Magnesium: Supports muscle and nerve function. Some runners with low dietary intake benefit from supplementation, but doses above 400-500 mg often cause GI distress.

Sodium bicarbonate: Can buffer acidity during short, all-out efforts but causes significant gastrointestinal distress in about 30% of users. Better suited for track events under professional supervision.

Prioritize the core five before exploring these situational options. Blood work and nutrition consultation help if you suspect deficiencies affecting overall health or glycogen storage.

Practical Tips: Building a Supplement Plan Around Your Running Goals

The most effective supplement plan matches your specific goals, training phase, and health history. Here’s a simple decision framework:

Change one variable at a time. Introduce one supplement at a conservative dose, test for several weeks, and track perceived exertion, GI comfort, and running performance before adding another.

Keep a simple log: Record date, session type, supplement, dose, timing, and how the run felt. This low-tech approach reveals patterns over time and helps you spot what truly helps versus what’s placebo.

Take periodic breaks during lighter training phases. This controls costs and lets you reassess whether each product delivers value. Consulting a sports dietitian can help tailor choices to lab results (like insulin sensitivity or ferrous status) and dietary patterns—especially for vegetarian or vegan endurance athletes who may face higher risk of certain deficiencies.

Conclusion: Small Edges, Big Picture

Caffeine, creatine monohydrate, dietary nitrates, beta alanine, and electrolytes represent the best supplements for runners when we follow the evidence. Each offers potential benefits for specific training demands—from race day focus to interval power to reduce injury risk during longer training blocks.

But supplements cannot replace consistent training, adequate carbohydrate and protein intake, quality sleep, and smart recovery. They’re fine-tuning tools, not foundations. Approach them as experiments: start conservatively, choose third-party tested products to avoid banned substances, and focus on how you feel and perform over weeks and months.

The best “supplement” for most runners remains patience and consistency. Evidence-based products play a supporting role when chosen thoughtfully—helping competitive athletes and recreational runners alike benefit athletes pursuit of their goals, one well-planned training block at a time.

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