Do pre-workout supplements really make your workout better?

Short answer

Only a little, and only on the day. On the day you take it, you get a few more reps. But it did not beat the same amount of caffeine, and 6 to 8 weeks of use did not add extra muscle or strength.

Do pre-workout supplements really make your workout better?
'18 ingredients in one scoop → a better workout' — is that true?
Pre-workout powders mix caffeine, beta-alanine, citrulline, creatine and more in one tub. More ingredients, bigger effect? We checked the day you take it, the weeks after, and what is actually inside the tub.
What happens on the day?
You get a few more reps
When 20 people did bench presses and rows, they completed 96.9 total reps after the pre-workout versus 89.5 after a placebo, about 7 more. Effort felt lower too: 7.6 instead of 8.3 out of 10. In a study of 12 people, the last bench set went from 9.1 to 9.8 reps.
So where did that boost come from?
It did not beat the same amount of caffeine
12 people rotated through a pre-workout, the same amount of caffeine, and a placebo. Arm work output showed no difference among the three. In a study of 18 people, a creatine-based product did no better than the same amount of creatine alone. No extra benefit from the other ingredients was found.
Do weeks of use build more muscle?
No difference after 6 to 8 weeks
When 19 people trained for 7 weeks and 80 people for 8 weeks while taking it, lean mass (muscle and everything except fat) and max strength did not differ from placebo. In a 2025 study of 43 people, lean mass rose by 0.9 kg and 0.8 kg after 6 weeks, no different from a carbohydrate-only drink.
What if both drinks have the same caffeine?
Only the 'feeling' changed
43 people trained for 6 weeks with either a pre-workout or a comparison drink with exactly the same caffeine. The pre-workout group reported more energy and focus. But strength results and body composition did not improve.
Why so little effect from so many ingredients?
Doses were hidden or too low
The 100 top-selling products had 18.4 ingredients on average, but 44.3% of them were hidden in 'proprietary blends' with no amounts listed. Beta-alanine averaged 2.0 g, below the amount that works. Caffeine averaged 254 mg, just above the minimum effective amount for a 70 kg (154 lb) person (210 mg).
Can you trust the caffeine on the label?
6 in 10 products did not match
Of 36 products that listed caffeine, 15 (42%) had less than 80% of the label amount and 7 (19%) had more than 120%. 6 products had caffeine that was not on the label at all. Taken as directed, 5 products went over 400 mg a day.
Bottom line: most of the effect was caffeine
A few more reps that day, no difference weeks later
On pre-workout days people did a few more reps and felt less tired. But it did not beat the same caffeine dose, and 6 to 8 weeks of use did not add muscle or strength. When choosing one, it is enough to check that caffeine is listed and that, with your coffee, it stays under 400 mg a day.