Introduction
This is the first in a three-part series that explores supplements and their value for:
- Performance
- Body composition
- General health
In this article, we’ll focus on supplements with the strongest research backing for performance and discuss practical applications — all while keeping in mind the desire to keep negative side effects low.
Let’s dig in!
What defines a supplement?
Under the Dietary Supplement Health and Education Act (DSHEA) of 1994, a dietary supplement is a product designed to complement or augment your diet. It can contain one or more of the following ingredients:
- An amino acid
- An herb or other botanical
- A vitamin
- A mineral
- A dietary substance for use by people to supplement the diet by increasing the total dietary intake
- A concentrate, metabolite, constituent, extract, or combination of any of the above ingredients
Once an ingredient is classified as a dietary ingredient, it must comply with established DSHEA regulations (this includes proper labeling, ingredient listing, quantity, and intended use). However, the products themselves are not independently tested before reaching the market. Government agencies like the FDA and FTC oversee and regulate the products once they hit the shelves. They are responsible for determining whether a supplement contains banned substances, makes misleading claims, or is unsafe for consumption.
Understanding supplements for performance
In this article, I’m focusing on supplements that enhance physical performance; supplements that positively influence body composition or general health outcomes are a topic for another day.
Performance itself is also a broad category, encompassing not only the event itself (e.g., how well you run), but also recovery after these events. There is obviously some crossover with areas like muscle building that can enhance performance. However, muscle building also ties into body composition, which I’ll cover in the next article. For simplicity, this article will focus primarily on performance.
Understanding acute vs. chronic effects of supplements
When examining supplements, it’s important to distinguish between short-term and long-term effects.
| Considerations | Acute | Chronic |
|---|---|---|
| Time | Minutes or within a training session | Days, weeks, or months |
| Impact | Short-term may or may not influence long-term results | Long-term changes but likely require continued use |
| Example | Maintaining energy during a race | Sustained increase in progress or muscle growth |
Simply put, acute effects occur quickly, often within minutes to hours of supplementation, making them ideal for situations where immediate results are needed. Chronic effects develop over days, weeks, or months, with changes occurring gradually.
It’s also important to note that short-term benefits don’t necessarily lead to long-term improvements. For example, caffeine might help you power through a workout, but evidence doesn’t yet suggest that it increases your long-term progress on its own. However, by combining strategies that boost short-term performance while supporting long-term goals, you can potentially achieve the best of both worlds.
Selection of supplements: Evidence and effects
When evaluating performance supplements, the goal is to find a combination of strong evidence and notable results. Ideally the research should be solid, and the benefits should be clear, particularly in real-world training or performance settings. To keep things simple, I’ll break this down into two categories: top-tier and high mid-tier supplements.
| Tier | Characteristics |
|---|---|
| Top-tier | Has more robust evidence-consistent effects Works well across multiple populations |
| High mid-tier | Has promising evidence Smaller or less consistent effects on performance might be dependent on specific populations |
Top-tier supplements that are good for performance
Protein powder
Among the supplements discussed in this article, protein and carbohydrate supplements make the most sense, but can be a bit tricky regarding research. Why? Protein and carbohydrate supplements are sources of macronutrients and calories. This distinction is important because these supplements are essentially food and energy sources. While this may seem obvious to most, some people view protein supplements without fully grasping this concept.
Though protein supplements may contain additional ingredients, they are primarily a protein source — whether it’s whey, egg, soy, or another type — delivered in powder, ready-to-eat products, or shakes.
I’ve covered the importance of protein as an essential nutrient involved in nearly every function related to building and repair. If you’re unfamiliar with how much protein we need daily, this article provides a breakdown — but just to reiterate, protein is pretty important.
Ideally, the protein we consume comes from whole-food animal or plant sources, as these foods provide not just macronutrients but also valuable micronutrients and antioxidants.
That said, research shows that protein supplements can be useful for ensuring adequate intake, both for lifestyle and health needs and for performance. Where the research gets a bit more nuanced, particularly for performance, is in the balance between acute and chronic effects related to performance and recovery and the role of supplementation versus simply meeting your total daily protein needs.
In a systematic review, meta-analysis, and metaregression of 49 randomized controlled trials, adding protein supplements increased muscle mass and strength in resistance-trained subjects. Specifically, protein supplementation improved participants’ one-repetition maximum (1RM) strength by an average of 2.49kg (about a 9% improvement). However, the study also noted that supplementation isn’t necessary if you’re already meeting your daily protein needs.
There are plenty of successful protein supplement studies (examples can be found here, here, and here) that highlight performance benefits. The more important question is whether you need supplements to meet your overall protein intake.
The simple take home? If supplements make it easier to hit your daily protein targets or meet your workout nutrition needs, they could be your most valuable supplement, and they have a great track record with helping performance. However, if you already consume enough protein from your diet, there’s no need to take a protein supplement.
Creatine
Creatine takes us into the realm of pure “supplement” territory. It’s widely regarded as the gold standard for performance supplements, with strong research-supported effects. It’s the go-to supplement for performance, and its popularity is well deserved.
Creatine is a compound made from three amino acids: arginine, glycine, and methionine. We naturally produce creatine in the body, so it’s present even without supplementation. However, your diet can influence how much creatine you get daily. For example, omnivores typically consume about 1–2 grams of creatine per day, while vegetarians may have lower creatine stores since it’s predominantly found in animal products. The exact amount also depends on the specific animal products included in an omnivorous diet.
There are two common approaches to creatine supplementation: loading and steady-state. The loading phase involves taking 20-25 grams per day for 5-7 days to quickly “saturate” the muscles with creatine. Afterward, a lower dose of 3-5 grams per day is maintained. Note, loading like this can lead to digestive discomfort, but some people are happy to hit their saturation level faster. The steady-state method skips the loading phase. Although it takes about a month to reach full saturation, many find it easier on the digestive system. Ultimately, the choice comes down to personal preference.
Creatine aids performance through several pathways, the most commonly discussed being its ability to increase phosphocreatine availability, which helps regenerate ATP, the body’s “energy currency.” Without diving too deeply into biochemistry, creatine essentially allows us to “spend more” energy during short, intense efforts, potentially leading to more reps or work within a training session.
There are other possible pathways in which creatine helps aid performance, such as reducing oxidative acidosis (which can be simplified as a burning feeling or weakness/fatigue during training).
Strength-wise, we can see positives in both upper and lower limbs. There is also evidence for recovery from workouts. While I’ll cover more on muscle building in the body composition article, it is fair to say that preserving or increasing muscle mass can also be good for performance.
| Possible performance benefits of creatine supplementation |
|---|
| Increased single and repetitive sprint performance |
| Increased work during maximal effort muscle contractions |
| Increased muscle mass & strength adaptations during training |
| Enhanced glycogen synthesis |
| Increased anaerobic threshold |
| Possible aerobic capacity enhancement (ATP shuttling) |
| Increased work capacity |
| Enhanced recovery |
| Greater training tolerance |
| Pathways and activities that may benefit from creatine | |
| Pathway | Activity examples |
| Increased PCr | Track sprints (60–200 m), Swim sprints (50 m), Pursuit cycling |
| Increased PCr Resynthesis | Basketball, Field hockey, American Football, Ice hockey, Lacrosse, Volleyball |
| Reduced Muscle Acidosis | Downhill skiing, Water sports, Swim events (100, 200 m), Track events (400, 800 m), Combat sports |
| Oxidative Metabolism | Basketball, Soccer, Team handball, Tennis, Volleyball, Endurance athletes (interval training) |
| Increased Body Mass/Muscle Mass | American Football, Bodybuilding, Combat sports, Powerlifting, Rugby, Track/Field, Olympic Weightlifting |
Now, I want to note that not everyone responds to creatine supplementation in the same way, and there are a few reasons for this. One of the most intuitive explanations is that some individuals are already “loaded” with creatine, meaning they naturally have higher creatine stores. People can have higher or lower muscle creatine levels before starting supplementation, and supplementation is most likely to benefit the people who are starting with low muscle creatine concentrations.
Overall, creatine is a well-researched, safe, and widely tested supplement with minimal negative side effects. Some side effects, like digestive discomfort, can often be avoided by taking a slower approach to reaching full saturation. In the end, it’s a supplement worth considering.
Carbohydrate supplements
Carbohydrate supplements, like protein supplements, are sources of Calories. In a recent article, I explored the ideal carbohydrate intake levels for different styles of training.
When you consume carbohydrates, your body breaks them down into glucose, which fuels your training. Carbohydrates are particularly efficient because they produce more ATP per unit of oxygen in aerobic metabolism. When glucose isn’t circulating, your body taps into glycogen stores to fuel exercise. Consuming carbs before or during a workout helps maintain glycogen levels and circulating glucose, which keeps performance steadier during higher volume or longer training sessions.
A pretty large meta-analysis (45+ years, 96 studies, and 142 trials) examined the impact of carbohydrate solutions on exercise performance and found that the longer the exercise duration, the more effective carbohydrate supplementation became. Additionally, consuming carbohydrates during exercise was more beneficial than taking them beforehand, particularly for longer efforts.
While there’s no single protocol that all studies follow, popular carbohydrate sources include hydrogels and sports drinks. The meta-analysis included an assortment of sugar-type ratios, but the most common is a glucose-to-fructose ratio of 2:1.
It’s also worth noting that cyclists saw larger effects in similar studies than runners. However, your specific type of training and performance goals should influence how much attention you should give to carbohydrate supplementation. For example, strength lifters are less likely to rely on carbohydrate intake for performance, so they may not see as much benefit from carbohydrate supplementation.
Could you argue about where one draws the line between what’s food and what’s supplements? Sure. I’d argue that choosing supplements versus whole foods depends on context and need. In some situations, supplementation is more practical for performance, while whole foods may be a better fit in others. As always, context and individual needs are key.
Honorable mention: Caffeine
Caffeine deserves an honorable mention because, while it’s classified as a natural drug and regulated differently than dietary supplements, it’s commonly found in performance supplements.
Caffeine is part of the methylxanthine family, a group of alkaloids known for their stimulatory effects. It primarily works by blocking adenosine receptors. While there are other possible contributors to caffeine’s impact on performance, blocking adenosine receptors seems to be the most significant factor. This can lead to reduced pain perception, stronger muscle contractions during anaerobic performance, and improved cognitive function during exercise.
Beyond adenosine receptors, caffeine might also enhance performance by increasing calcium release in muscle cells, aiding in muscle contraction. Some studies also suggest caffeine may boost nitric oxide and dopamine activity, further enhancing performance.
An umbrella review of 21 meta-analyses found that caffeine tends to have a larger impact on aerobic exercises than anaerobic ones, though it showed performance improvements across the board.
Most studies in this meta used decent doses, around 6mg per kilogram of body weight. The general range seems to be 3-6 mg/bw, with some studies showing little benefit for lower intakes and increasing risk of negative side effects at higher doses.
Let’s quickly break down how caffeine intake plays out in the real world. If we pick a moderate intake of 4mg per kilogram of body weight, here’s what that looks like:
For a 70kg (154lb) person, 70kg × 4 mg/kg = 280mg of caffeine.
In practical terms, that’s about 2-3 good-sized cups of coffee. This amount of caffeine might be too much (or too little) depending on your sensitivity to caffeine. For example, I’m highly sensitive to caffeine and need very little to see results. In contrast, others in the MacroFactor family (not naming names) could probably handle an IV drip of caffeine and still fall asleep easily.
Ultimately, caffeine is proven to enhance performance. I recommend experimenting with slow increases and trying different sources — whether it’s coffee, green tea, or caffeine in supplement powders — to find what works best for you.
High mid-tier, but perhaps smaller effects or more niche (smaller side effects)
As you can see, there is substantial support for the previously discussed supplements. In this next section, we’ll discuss supplements that fall into a few different buckets:
- Supplements that seem to warrant more investigation
- Supplements that are not as powerful in effects, not as supported by the research, or both
But if you like supplements and are looking for relatively safe performance enhancement, you will find this section interesting as well.
Beta-alanine
Beta-alanine is a non-essential amino acid, so we don’t technically need to obtain it through diet. Mechanistically, beta-alanine supplementation increases muscle carnosine concentrations (a dipeptide molecule found in high concentrations in muscle tissue). Increased carnosine levels enhance our muscle’s ability to buffer acids, particularly during high-intensity exercise. This reduction in acid buildup could delay muscle fatigue, allowing for longer and harder effort.
And if you’re thinking, why not just take the carnosine itself? You can, but there could be bioavailability and side effect issues. So, for ease, the thought is to use the precursor that can lead to increased saturation and performance over time. It’s worth noting that some people only take beta-alanine through pre-workout supplements rather than using it regularly. If that’s your approach, you’re probably not getting the benefit. However, chronic use of beta-alanine has been shown to reduce muscle fatigue during high-intensity exercise, making it more effective when taken consistently over time.
Research shows that muscle carnosine concentrations increase with the total cumulative dosage of beta-alanine you consume, with a cumulative dose of around 1500g being necessary to maximize muscle carnosine levels. So, if you only take the standard ~6g dose before your workouts, it’ll take ages for your muscles to reach maximal carnosine concentrations. However, if you take approximately 10g per day, every day, you’ll maximize your muscle carnosine concentrations much faster.
A meta-analysis from Rezende et al found that beta-alanine succeeded overall at raising carnosine levels and that almost all individuals (99.3%) in the study responded to beta-alanine regardless of sex. Another meta-analysis found that supplementation with beta-alanine had a minor impact on performance during activities that fall between aerobic and anaerobic effort levels. Lastly, a study by Yamaguchi et al looked at increasing muscle carnosine with beta-alanine and then watched for depleting levels after supplementation ceased. They found that after stopping supplementation, levels returned to baseline by the 16-week mark.
It’s safe to say that supplementing with beta-alanine can increase carnosine levels, which may lead to small but consistent performance benefits across various populations, especially during bouts of exertion lasting between 30 seconds and 10 minutes. So, beta-alanine probably won’t help endurance athletes that specialize in longer events, and it probably won’t improve your performance in heavy, low-rep sets of resistance exercise. Furthermore, it requires chronic dosing rather than intermittent, small pre-workout doses to be most effective. Beta-alanine also appears to be relatively safe with minimal side effects. Lastly, there is interest in trying to combine carnosine with anserine to decrease the unenjoyable side effects of carnosine alone. But for now, beta-alanine offers a simple and effective option.
Sodium bicarbonate
Following beta-alanine, sodium bicarbonate is another supplement that helps buffer pH levels and reduce exercise fatigue, though it works a bit differently. You might already be more familiar with sodium bicarbonate than you realize, as it’s commonly known as baking soda.
Unlike beta-alanine, sodium bicarbonate acts acutely, meaning its effects are immediate. It raises pH levels in the blood or cellular fluids, neutralizing excess acid produced during exercise. The result is often a reduced fatigue, allowing you to extend your effort or squeeze out a few more reps.
A meta-analysis of 20 studies found that sodium bicarbonate improved muscular endurance. The typical dose across most studies was 0.3 grams per kilogram of body weight with the timing for intake ranging from 60 to 180 minutes before exercise. However, it’s important to note that the same research showed little impact on strength training, so as with other supplements, the type of training you’re doing should guide your use of sodium bicarbonate.
Something else to consider with sodium bicarbonate is that gastrointestinal distress can be far more common and an issue with more effective dosing. However, some of that can be avoided by ingesting multiple smaller doses for almost a day prior to your specific performance event (for example, using 0.1g/kg three times per day, instead of taking 0.3g/kg in a single dose). Note that GI distress does not happen to everyone, but it is common enough to warrant consideration.
So, it would appear that sodium bicarbonate can be good in a pinch to slightly increase muscle endurance for some individuals. Just take it slow, or you could be running to the bathroom.
Citrulline malate
Citrulline malate (CitMal) combines L-citrulline, a non-essential amino acid, and malic acid, typically in a 2:1 ratio. Malic acid might sound familiar if you’ve ever studied the Krebs cycle (how we release energy). From a performance perspective, CitMal is studied for its potential to boost nitric oxide levels, improve circulation, and reduce perceived exertion during exercise. While L-citrulline alone has shown potential for increasing blood flow, citrulline malate may offer additional benefits by reducing muscle fatigue and aiding recovery, thanks to malic acid’s role in energy production and reducing lactic acid buildup.
With CitMal, the evidence is promising, but the total body of evidence is still fairly small. Also, when looking at research, some studies don’t always differentiate between L-citrulline and CitMal. For example, this meta-analysis from Rhim et al allows for the inclusion of both and found a small but promising improvement in the perceived rate of exertion. Looking at only CitMal on strength endurance, Vårvik et al looked at eight studies and dosing roughly 40-60 minutes before training. They found CitMal had a modest improvement in strength endurance. In a recent 2024 study looking at short-duration, high-intensity performance, taking 8g of citrulline malate for three days reduced the drop in performance between repeated sprints.
There’s definitely potential with CitMal. It appears to have minimal side effects and mixes easily into drinks, making it convenient for most people. That said, it’s still early in the research, so while the initial findings are promising, more studies are needed to fully understand its long-term impact.
Beetroot juice
Boosting nitric oxide levels can also be achieved through a different pathway by adding beetroot juice to your supplement routine. Beetroot juice carries nitrate, which the body converts into nitric oxide after consumption.
From a benefit perspective, nitric oxide can widen blood vessels, increasing blood flow and oxygen supply to muscles. This could enhance muscle efficiency and potentially improve muscle contraction, providing decent evidence for boosting aerobic performance and endurance.
A systematic review of beetroot juice examined 23 studies, mostly involving trained athletes. The authors found promising effects for endurance athletes, with potential added benefits for high-altitude sports. This may be due to beetroot’s ability to convert to nitric oxide, which works more effectively when oxygen is limited — making it particularly useful in low-oxygen environments.
The typical amount of beetroot juice needed to improve performance is about 500 mL, which can provide approximately 6-8 mmol of nitrate. Nitric oxide levels tend to peak 2-3 hours after ingestion, so consuming beetroot juice 90 to 150 minutes before exercise is ideal.
Interestingly, beetroot juice can interact with other products. Caffeine, for example, might counteract some of its effects. Another less obvious interaction is that using mouthwash could reduce the effectiveness of beetroot juice by lowering the bacteria in your mouth needed to convert nitrate into nitrite (which is then converted to nitric oxide). Despite these nuances, beetroot juice generally has minimal side effects and is considered a well-tolerated, low-risk supplement.
| Supplement | Effect Type | Explanation |
|---|---|---|
| Protein supplements | Mix of both (mostly chronic) | Helps with muscle repair and growth. Great if you struggle to get enough protein from food alone. |
| Creatine | Mix of both (mostly chronic) | Quick energy boost during workouts and improves strength and muscle over time. |
| Carbohydrate supplements | Mostly acute | Keeps energy levels up during long or intense training sessions. Good for endurance athletes. |
| Caffeine | Mostly acute | Sharpens focus and reduces fatigue. Ideal for boosting immediate workout performance. |
| Beta-alanine | Mostly chronic | Buffers acid buildup and delays fatigue, but you need to use it consistently for the best results. |
| Sodium bicarbonate | Mostly acute | Works fast to reduce fatigue in short, intense efforts, but if dosed too high, it can cause stomach issues for some people. |
| Citrulline Malate | Mix of both | Boosts blood flow and reduces fatigue quickly. Consistent use might improve endurance over time. |
| Beetroot juice | Mostly acute | Boosts nitric oxide for better blood flow and oxygen delivery. Might be better for endurance. |
Recap
Here’s a quick TL;DR summary for those seeking the basics on performance supplements.
Top-tier supplements with solid research and effects:
Protein supplements: Vital for recovery and muscle growth, especially when you can’t hit your daily protein target through food alone. While whole food should be the priority, supplement use can be beneficial to hit your targets or simplify intake.
Creatine: Creatine has been studied extensively and still yields notable performance results. It helps with high-intensity efforts and reduces muscle fatigue, making it a no-brainer if you’re training hard.
Carbohydrate supplements: Simple and effective fuel for various styles of training. Supplemental forms may make continuous energy easier and make sense, depending on your training style.
Honorable mention: Caffeine: While not technically a supplement, it’s often used in supplement products to improve endurance and reduce perceived effort.
High mid-tier supplements with strong promise:
Beta-alanine: It can help increase carnosine levels in the muscle and may help buffer acid buildup during intense exercise, which delays fatigue.
Sodium bicarbonate: It can boost endurance by buffering pH levels, but if you take too much, you may experience stomach issues, so pacing is important with this one.
Citrulline Malate: It may improve blood flow and reduce fatigue. The research is promising but still early, and the effects might be more noticeable in specific types of training.
Beetroot juice: Boosts nitric oxide levels, improving endurance and possibly aerobic performance. It’s especially good for longer efforts, but the research is still growing.
