How much caffeine is in pre-workout?
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About 254 mg a serving, on average, across the top 100 pre-workout products in a 2019 count. That’s close to three 8 oz coffees in one scoop. The amount changes a lot from one product to the next, so the label on your tub is the only number that counts.
A scoop of powder doesn’t look like much. If you train after work, the scoop at 5 or 6pm can be the biggest dose of caffeine in your day, taken at the latest hour. Of those 100 products, 86% had caffeine at all, so a caffeine-free one exists if you look.
We’d read the label, keep the full scoop for morning and lunchtime sessions, and use half a scoop or a caffeine-free product for evening ones.
How much do you need for training?
The International Society of Sports Nutrition’s 2021 review found 3 to 6 mg per kg of body weight consistently improves performance, and as little as 2 mg per kg may work. Very high doses, around 9 mg per kg, bring a lot of side effects. The usual timing is about 60 minutes before you start.
| Body weight | 2 mg per kg | 3 to 6 mg per kg |
|---|---|---|
| 150 lb (68 kg) | about 135 mg | about 205 to 410 mg |
| 180 lb (82 kg) | about 165 mg | about 245 to 490 mg |
The researchers who counted the 100 products noted that the average scoop sits near the low end of an effective dose for a 70 kg (154 lb) person. Half a scoop, about 127 mg, is 2 mg per kg for a 140 lb (64 kg) person.
What an evening scoop does to your night
A full scoop at 5pm, for a 6pm session, still leaves about 123 mg at 11pm, about half the scoop and more than an 8 oz coffee’s worth. Half a scoop leaves about 61 mg. A 2023 review of 24 sleep studies worked out that a standard pre-workout serving (217.5 mg) should be had at least 13.2 hours before bed.
| Scoop | Taken at | Left at 11pm |
|---|---|---|
| Full, 254 mg | 7am | about 31 mg |
| Full | noon | about 61 mg |
| Full | 5pm | about 123 mg |
| Half, 127 mg | 5pm | about 61 mg |
| Full | 6pm | about 141 mg |
These use the average half-life of 5 hours. For an 11pm bedtime, a full scoop by about 8:55am keeps you under 40 mg when you fall asleep, the lower of our two bedtime lines. Half a scoop by about 1:55pm does the same.
Who it’s not for
A full scoop is more than the 200 mg line for a whole day in pregnancy, and more than twice the 100 mg pediatricians suggest for ages 12 to 18. If you take a stimulant medicine, ask your prescriber before adding a pre-workout.
Work out your scoop
The pre-workout window takes your weight, your session time and your bedtime, and gives you the dose for your weight and the latest start for a full scoop or a half. The training chapter has the rest. If a scoop is how you get through short nights, the tiredness is still there under it, and how to have more energy without caffeine starts with sleep.
254 mg
Pre-workout, 1 scoop. Jagim 2019: the top 100 products averaged 254 mg a serving. Check your label. One at 3pm still leaves about 93 mg at an 11pm bedtime.
When should I stop?
When you fall asleep at 11:00pm
83 mgA measured cost
You'll fall asleep with about a cup of coffee in you.
- Brewed coffee, 8 oz95 mg
Brewed coffee, 16 oz190 mg
Your last drink, a 16 oz coffee at 3:00pm
- Under 40 mg at sleep
- by 8:10am
- Under 80 mg
- by 2:45pm
The full clock, with the band, 3am and the table by drink.
7 sources
- Jagim AR, Harty PS, Camic CL, Common Ingredient Profiles of Multi-Ingredient Pre-Workout Supplements, Nutrients, 2019doi.org
- Guest NS and others, International society of sports nutrition position stand: caffeine and exercise performance, Journal of the International Society of Sports Nutrition, 2021doi.org
- Gardiner C and others, The effect of caffeine on subsequent sleep: a systematic review and meta-analysis, Sleep Medicine Reviews, 2023doi.org
- USDA FoodData Central, SR Legacy: brewed coffee (171890), espresso (171891), brewed black tea (173227) and brewed green tea (171917)fdc.nal.usda.gov
- American Academy of Child and Adolescent Psychiatry, Facts for Families No. 131: Caffeine and Children, April 2026aacap.org
- American College of Obstetricians and Gynecologists, Committee Opinion No. 462: Moderate Caffeine Consumption During Pregnancy, August 2010, reaffirmed 2026acog.org
- Antonio J and others, Common questions and misconceptions about caffeine supplementation: what does the scientific evidence really show? Journal of the International Society of Sports Nutrition, 2024doi.org
