Pre-workout
Works mostly through caffeine; the formula and doses are often undisclosed
What it is
A blend of several ingredients taken before training; the main one is usually caffeine. Makers often hide the amount of each ingredient behind a “proprietary blend” (JISSN review, NIH ODS).
Benefits
A single dose may improve muscular endurance and mood; results for force and power are mixed (JISSN review). The main driver is caffeine. The same review calls the research on the efficacy and safety of these blends preliminary at best. The effect of a particular blend can't be predicted until that blend has been tested in a trial (NIH ODS).
Dose
There is no recommended dose: formulas differ and ingredient amounts are often not listed. Some ingredients may be included far below an effective dose (JISSN review). AIS suggests taking the active ingredients as individual products, so that you control the dose and timing yourself.
When to take it
Before training. The sources give no separate guidance for these blends; for energy drinks ISSN cites 10–60 minutes before exercise. Beta-alanine in the blend works only if the product is taken for at least 4 weeks, not from a single serving (ISSN).
Who it's for
The JISSN review sees promise in these blends for active people, with a caveat: there is little data on long-term efficacy and safety. It makes sense only if you are healthy, tolerate caffeine well and know the exact formula.
Who can skip it
People for whom caffeine alone is enough: AIS suggests getting it from a source with an exact dose rather than a pre-workout, where the amount varies. With heart disease, ISSN advises avoiding products with stimulants. Competing athletes: formulas may contain banned substances (JISSN review, AIS).
Forms
There is no single formula. An analysis of the top 100 products (2019): 18.4 ingredients on average, and 44.3% of all ingredients were part of a proprietary blend with undisclosed amounts. The most common were beta-alanine (87% of products, 2.0 g on average), caffeine (86%, 254 mg), citrulline (71%, 4.0 g) and creatine (49%, 2.1 g). The average serving of beta-alanine was below the recommended efficacious dose.
Safety
In studies of up to 8 weeks they appear relatively safe; data on long-term use are scarce (JISSN). Risks: a large, unknown caffeine dose, other stimulants, untested combinations (AIS, NIH ODS). With diabetes, heart, liver, kidney or neurological disease or medication: only with a doctor's approval. Pregnancy: up to 200 mg of caffeine a day (EFSA).
This is a summary of public sources, not medical advice. If you have a health condition, are pregnant or take medication, talk to a doctor before taking a supplement.
Sources
- Multi-ingredient pre-workout supplements, safety implications, and performance outcomes: a brief review . Journal of the International Society of Sports Nutrition, 2018.
- Dietary Supplements for Exercise and Athletic Performance — Health Professional Fact Sheet . NIH ODS, 2024.
- AIS Sports Supplement Framework — Caffeine, Practitioner Fact Sheet . AIS, 2025.
- AIS Sports Supplement Framework — Isolated Protein Supplements, Practitioner Fact Sheet . AIS, 2025.
- ISSN position stand: energy drinks . ISSN, 2013.
- ISSN position stand: Beta-Alanine . ISSN, 2015.
- Caffeine (topic page, Scientific Opinion on the safety of caffeine) . EFSA, 2015.
- Common Ingredient Profiles of Multi-Ingredient Pre-Workout Supplements . Nutrients, 2019.
Other supplements
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