Supplements for Performance – The Big Five

Summary: The article reviews which supplements can truly boost performance for healthy endurance athletes, based on a scientific overview and the guidelines of the International Olympic Committee. The primary question is which supplements are worth prioritizing to enhance performance in training and competitions – not just to improve well-being. The conclusion is that only a few supplements have clear support for direct performance enhancement, with the most relevant being nitrate/beetroot juice, caffeine, creatine, bicarbonate, and beta-alanine. Vitamins and minerals are generally justified when there's a confirmed deficiency.

Introduction – part two: supplements

In the first part of this two-part article series, we explored research and new guidelines regarding dietary practices aimed at optimizing training and competition results. It is a useful review for those looking to excel in their sport, reach their peak performance, and not just train for health or weight management.

Now it's time for part two. Drawing from the same scientific article and the International Olympic Committee's (IOC) guidelines, we delve into supplements that might be worthwhile to have at home for better performance.

Basis – the study and IOC's guidelines

The study is titled: Energy Availability, Macronutrient Intake, and Nutritional Supplementation for Improving Exercise Performance in Endurance Athletes.

The studies included were published in 2017, placebo-controlled, and utilized a crossover design where all participants acted as their own control group (meaning they underwent tests both with and without the supplement). The subjects were healthy, competing athletes tested at normal sea level and under standard temperature conditions. The studies included physical tests lasting from approximately 2 minutes to extended durations, covering interval times to long-distance.

The study also serves as the foundation for the IOC's new guidelines on which supplements are effective and which are not (see table 3 in their report).

Overview – the supplements examined

The researchers evaluated evidence for the following supplements:

• Vitamin C
• Vitamin E
• Coenzyme Q10
• L-Arginine
• Beetroot
• Beta-Alanine
• Beta-hydroxy-beta-methylbutyrate (HMB)
• Betaine
• BCAA 
• Caffeine
• L-Citrulline
• Creatine
• Deer antler
• Dehydroepiandrosterone (DHEA)
• Ginseng
• Glutamine
• Iron
• Protein
• Quercetin
• Ribose
• Bicarbonate
• Tart Cherry Juice
• Tribulus terrestris

We will not cover all the supplements here but focus on those with demonstrated performance-enhancing effects. You can find these in table 1 here next to/below.

Supplements with Direct Performance-Enhancing Effects

Here we have nitrate/beet juice, caffeine, creatine, bicarbonate, and beta-alanine, all of which are scientifically proven to directly enhance performance. There are many other supplements that affect the body in different ways—for example, iron supplements can help restore normal iron levels if you're deficient, thereby improving your performance. However, this study focuses on individuals without any deficiencies; the participants are healthy, fit athletes.

When it comes to vitamins and minerals with scientifically proven performance-enhancing effects in cases of deficiency, it's iron, calcium, and vitamin D that work. Therefore, these three nutrients make sense to supplement if your blood values show low levels, as the levels of these substances correlate with sports performance.

If you're interested in more details, we recommend reading the tables in the IOC report. There are also substances that can help with tendon health, injury prevention, recovery, and more.

Beetroot Juice / Nitrate – Performance Increase 1–3%

The benefits include reduced oxygen consumption at a given workload and improved performance during time trials on both treadmill and bicycle. These are due to the nitrate in beetroot juice (or pure nitrate), which is converted into nitric oxide. Nitric oxide dilates blood vessels, enhancing blood flow and oxygen delivery to working muscles.

Most studies note an effect with an intake of 6–8 millimoles (mmol), but well-trained athletes with an oxygen uptake of around 60 milliliters per kilo per minute (ml/kg/min) or more seem to require higher doses acutely and/or buffering with intake over 3 days before competition. Studies measuring performance-enhancing effects in these well-trained individuals have used 12.5–19.5 mmol as an acute intake or 3–7 days of buffering. This is not unreasonable: well-trained individuals often already have an extensive network of blood vessels with good oxygen transport, so to achieve additional effects requires more nitric oxide signaling — meaning a higher dose of nitrate.

The intake should occur 2–3 hours before activity for acute use. For exceptionally well-trained athletes, buffering is recommended, with intake occurring during the day for 3–7 days before competition, plus an intake 2–3 hours before the start.

We have a previous article on the subject if you want to geek out more.

Caffeine – Performance Increase 1.5–3.5%

No doubt here: caffeine enhances performance (as long as you don't have a specific genetic setup that affects your response). More about that in our previous article on caffeine.

The recommendation is 3–6 mg of caffeine per kg of body weight 1 hour before activity. If you're used to caffeine through, for example, coffee, you might need to go up towards 6 mg/kg, while an inexperienced user can manage with 3 mg/kg, and some may even experience negative effects at doses up to 6 mg/kg.

Research also shows interest in Yerba Mate — a plant containing two xanthines, caffeine and theobromine, as well as other bioactive compounds like chlorogenic acids. These can act synergistically with caffeine, potentially providing even higher performance boosts. The research is still young, and caffeine remains the standard for comparison, but we are closely following Yerba Mate research.

Caffeine is effective across a wide spectrum — from short, intense sprints to longer endurance sessions.

Creatine – Performance Increase 3–45%

Creatine is especially beneficial during strength training or high-intensity intervals (10–20 seconds) with short rest periods. It enhances your "muscle endurance" for this type of effort once you've buffered creatine levels in the muscles.

Common plan:

• Loading phase: 5–7 days with 20–25 g of creatine per day, spread over 4–5 intakes.
• Maintenance dose: 3–5 g/day to maintain levels.

The percentage increases in performance might seem significant, but it's logical — if someone could previously manage 9 repetitions and after loading can do 10, that's about a 10% increase. For endurance athletes, creatine is smart during the base period, especially if you do strength training 1–2 sessions per week. If you get 10% more effect per strength session, winter training becomes significantly more valuable ahead of cycling or running races with hills, breakaways, or sprints.

As a bonus, creatine has shown positive effects on the immune system in some studies, and research in the area is ongoing (link). There is also research suggesting intake based on body weight where 0.1 g/kg before training can provide performance-enhancing effects at the cellular level during strength training (link).

Anecdotally, some may experience some water retention and feel a bit "bloated." Find your level if you think it affects performance during short intervals. But based on what research knows today, there's no reason to fear creatine.

“No study has reported any adverse effects from up to 30 g/day for 5 years of creatine supplementation”

More nerdy info about creatine in our previous article.

Bicarbonate – Performance boost 2–12%

Bicarbonate, or sodium bicarbonate, is something we've discussed before. In short: it works by increasing the blood's pH, allowing more "acid" produced in the muscles to leave the muscles and be processed in the blood. This enables us to work longer or push harder above the threshold during intervals and threshold sessions.

The dose is 0.2–0.4 g/kg body weight and should be taken 1–3 hours before activity.

Admittedly, it doesn't taste great, but it is effective as long as you avoid stomach issues. A well-known side effect is stomach discomfort due to gas production when something very basic meets the acidic environment in the stomach. It's not exactly a warm summer feeling in the gut—more like a small volcanic eruption—which has made many hesitate.

A lot of research is ongoing on how to encapsulate bicarbonate in acid-resistant capsules to avoid negative effects in the stomach. We are involved in some of this research and hope to present new results shortly.

Performance enhancements range from 2–12% depending on distance and intensity. The greatest effect is achieved when the intensity is high and "lactic acid" is really present in every step or pedal stroke.

Beta-Alanine – Performance Increase 2–3%

Almost a bit embarrassed that we don't have a longer article on beta-alanine yet — it's on our "to-do" list (the one on the fridge until you don't see it anymore). But here are the basics.

Beta-alanine works similarly to bicarbonate but in a different spot: bicarbonate buffers the blood's pH so that more acidic ions can leave the muscle. However, beta-alanine buffers inside the muscle cell by increasing the amount of carnosine by about 50–60%, which helps manage the "acid" locally.

The recommended intake is 4–6 g/day over 4–12 weeks, which provides performance-enhancing effects for high-intensity intervals with work durations of about 1–4 minutes. Beta-alanine seems to have a greater effect the older the test subject is, as studies have shown it to be more pronounced in older than younger subjects. A possible explanation (Tommy hypothesis) is that the ability to handle hydrogen ions and acidic environments in muscles decreases with age.

Beta-alanine can cause a tingling sensation in the skin; it is harmless and can be reduced by taking lower doses (1–2 g) several times a day during the buffering phase.

Once you've buffed up the levels, they diminish slowly (about 2% per week according to study), so the effect lasts long. The average performance increase is about 2.85%.

Conclusion

Great supplement – use, push hard, go home, rest, repeat. Nuff said.