Decoding Pre-Workout Supplements: What's on the Ingredient List, and What's Backed by Evidence

1The Truth About Ingredients in Market Pre-Workout Supplements

The study by Jagim et al., published in Nutrients in 2019, systematically analyzed the ingredient combinations of common pre-workout supplements on the market. The results revealed a key issue: products vary greatly, and almost half of the ingredients appear in "proprietary blends," without disclosing specific dosages.

This chart tells us two things: First, caffeine is the absolute star – nearly 90% of products contain it. Second, many ingredients have a high prevalence, but high prevalence does not equal effectiveness. Let's break them down one by one.

• Jagim et al., Nutrients 11(254), 2019

2Caffeine: The Most Well-Evidenced Pre-Workout Ingredient

Caffeine is one of the most widely researched ingredients in sports nutrition, and it's also a pre-workout ingredient with extensive evidence supporting its use in endurance sports.

Mechanism: As an adenosine receptor antagonist, caffeine reduces the brain's perception of fatigue — simply put, you'll feel "less tired" at the same physical state. It doesn't directly provide energy but allows you to push closer to your true physical limits.

Data: Meta-analyses indicate that caffeine intake of 3–6 mg/kg body weight can significantly improve endurance performance. For an athlete weighing 70 kg, this amounts to approximately 210–420 mg — equivalent to the caffeine content of 1–2 shots of espresso.

Practical Application:

• Ingest 30–60 minutes before exercise (blood concentration peaks 30–60 minutes after ingestion).
• Pay attention to individual tolerance: for those who already drink a lot of coffee daily, the effect may be weaker.
• SiS's GO Energy + Caffeine Gel provides 75–150 mg of caffeine (depending on flavor) + 22 g of carbohydrates, suitable as a caffeine + carbohydrate source before or during exercise.

• Strasser et al., J Int Soc Sports Nutr 2026; Liu et al., Front Nutr 2026

3Beta-Alanine: The Buffer for High-Intensity Training

Beta-alanine is the second most common ingredient (67% prevalence), but it works in a completely different way than caffeine.

Mechanism: Beta-alanine is converted to carnosine in the body — a buffering substance found in muscles that neutralizes hydrogen ions (the source of "muscle acidity") that accumulate during high-intensity exercise. Key point: Beta-alanine is not an "instant-effect" pre-workout ingredient; it requires 4–6 weeks of continuous supplementation (3–6 g daily) to effectively raise carnosine levels.

Data: Systematic reviews confirm that long-term beta-alanine supplementation can improve performance in high-intensity exercise lasting 1–4 minutes (e.g., sprints, the final sets of interval training). However, its direct benefit for pure endurance events (marathons, long-distance cycling) is limited.

Practical Application:

• If your training involves a lot of high-intensity intervals (HIIT, track repeats, 400m repeats), long-term supplementation is worth considering.
• As a single pre-workout dose? Essentially ineffective – carnosine stores need time to accumulate.
• Taking a pre-workout supplement containing beta-alanine might primarily result in a tingling sensation on the skin (paresthesia, harmless but potentially unsettling).
• SiS's BETA ALANINE capsules provide 3g of beta-alanine per 4 capsules, falling at the beginning of the evidence-based range of "3-6g daily for 4-6 consecutive weeks," making it suitable for quantitative long-term daily beta-alanine supplementation.

• Ong et al., J Int Soc Sports Nutr 2025; Hoffman et al., Adv Food Nutr Res 2018; Patel et al., J Sports Sci 2021

4Citrulline and Creatine: Each has its place, but not a "master key."

Citrulline (71% Prevalence)

Citrulline theoretically helps relax blood vessels and increase blood flow to muscles by converting to arginine and promoting nitric oxide (NO) production.

Reality: Review studies show that citrulline may offer minor benefits for repeated explosive performance (e.g., sets in strength training, short sprints), but the evidence for endurance sports is inconsistent. Effective doses in studies are typically 6–8 g — far higher than the likely content in many proprietary blends of supplements (and you simply don't know how much is there).

Creatine (49% Prevalence)

Creatine is one of the most well-evidenced supplements in sports science — but its role is for long-term strength and power, not an immediate pre-workout boost.

Mechanism: Creatine increases phosphocreatine stores in muscles, providing faster energy regeneration for the phosphagen system (ATP-PCr, responsible for seconds of explosive activity). It also requires a 3–4 week loading phase (3–5 g daily) to be effective.

Practical Application: Creatine is great, but putting it in a "pre-workout" supplement as a single-dose ingredient is misplaced. It should be part of your daily supplementation regimen, not a "secret weapon" to be taken only on race day.

• Gonzalez et al., J Strength Cond Res 2020; Wax et al., Nutrients 2021; Antonio et al., Nutrients 2024

5Tyrosine and Taurine: "Supporting" Ingredients with Weak Evidence

Tyrosine (63% Prevalence)

Tyrosine is a precursor to dopamine and adrenaline, theoretically aiding cognitive function under stress. However, actual research concludes that: in typical exercise scenarios, the performance-enhancing effects of tyrosine are limited and inconsistent. It may have some role in extreme environments (hypoxia, sleep deprivation, hot/cold stress), but for most training and competition situations — don't expect too much.

Taurine (51% Prevalence)

Taurine is involved in various physiological functions (bile synthesis, cell membrane stabilization, antioxidant), but independent evidence for its effect on athletic performance is very limited. Most pre-workout supplements containing taurine often have levels below the dosages observed to be effective in research — coupled with the opacity of proprietary blends, the actual effects are difficult to assess.

6Proprietary Blend Pitfall: "More is Better" is a Misconception

Returning to Jagim's 2019 study's core finding: 44.3% of ingredients are categorized as proprietary blends, without specific quantities disclosed. The following three common misconceptions are worth noting:

• Misconception 1: Believing "proprietary blend" means professional secrecy – in reality, not disclosing quantities means you can't verify effectiveness, and you might be taking ineffective doses.
• Misconception 2: Believing more ingredients mean greater effectiveness – a few evidence-backed ingredients are better than ten fillers.
• Misconception 3: Believing pre-workout supplements are essential – in most cases, sufficient carbohydrates, hydration, and caffeine are enough.

What does this mean?

1. You don't know how much of each ingredient you're consuming – it could be an effective dose, or it could be "label dressing" (just to make the ingredient list look good).
2. You cannot attribute effects to any specific ingredient – if the product has no effect (or has side effects), you cannot determine which ingredient is responsible.
3. "More does not mean better" – more ingredients don't mean better results; dosage is key.

Conclusion: When choosing supplements, prioritize products that disclose full ingredients and dosages, and avoid black boxes that only state "proprietary blend XXX mg" without breaking it down.

• Jagim et al., Nutrients 11(254), 2019; Bella et al., J Cardiovasc Dev Dis 2025

7Practical Advice for Endurance Athletes

Based on the evidence above, for athletes primarily engaged in endurance sports like running, cycling, and triathlons:

• Antonio et al., Nutrients 2024; Strasser et al., J Int Soc Sports Nutr 2026

Conclusion

Pre-workout supplements are not magic potions. Caffeine has strong endurance performance data to support it, β-alanine and creatine have value in their respective roles (but neither is for "immediate pre-workout" effects), while evidence for other ingredients varies. The most practical approach: understand the ingredient list, pay attention to dosages, don't be fooled by "proprietary blends," and focus your energy on what truly makes a difference – sufficient carbohydrate intake, appropriate caffeine timing, and testing everything in training.

Action Checklist:

1. Check the ingredient list of your pre-workout supplement – are there proprietary blends that don't disclose individual component amounts?
2. If you primarily do endurance sports, caffeine + carbohydrates is the most evidence-backed pre-workout combination.
3. Always test any new product or dosage in training first, never try it for the first time on race day.

1. Jagim AW, et al. Prevalence of Ingredients Included in Pre-Workout Supplements. Nutrients 2019;11(1):254. DOI:10.3390/nu11010254
2. Strasser B, et al. Dietary interventions interact with the perception of effort and enhance endurance performance. J Int Soc Sports Nutr 2026;23(1):2692003. DOI:10.1080/15502783.2026.2692003
3. Liu J, et al. Effects of caffeine intake on exercise performance in basketball players: a systematic review and meta-analysis. Front Nutr 2026;13:1837912. DOI:10.3389/fnut.2024.1837912
4. Ong SW, et al. Dosing strategies for β-alanine supplementation in strength and power performance: a systematic review. J Int Soc Sports Nutr 2025;22(1):2566368. DOI:10.1080/15502783.2025.2566368
5. Hoffman JR, et al. Effects of β-Alanine Supplementation on Carnosine Elevation and Physiological Performance. Adv Food Nutr Res 2018;84:183-206. DOI:10.1016/bs.afnr.2017.12.003
6. Patel KA, et al. The effect of β-alanine supplementation on high intensity cycling capacity in normoxia and hypoxia. J Sports Sci 2021;39(11):1295-1301. DOI:10.1080/02640414.2020.1867416
7. Gonzalez AM, et al. Effects of Citrulline Supplementation on Exercise Performance in Humans: A Review. J Strength Cond Res 2020;34(5):1480-1495. DOI:10.1519/JSC.0000000000003426
8. Wax B, et al. Creatine for Exercise and Sports Performance, with Recovery Considerations. Nutrients 2021;13(6):1915. DOI:10.3390/nu13061915
9. Antonio J, et al. The Top 5 Can't-Miss Sport Supplements. Nutrients 2024;16(19):3247. DOI:10.3390/nu16193247
10. Bella YF, et al. Pre-Workout Supplements and Their Effects on Cardiovascular Health: An Integrative Review. J Cardiovasc Dev Dis 2025;12(4):112. DOI:10.3390/jcdd12040112