Pre-Workout side effects
Across 98 first-hand reports, people mentioned a side effect 13 times (about 13 per 100 reports). The most common: insomnia, diarrhea, heart palpitations. User reports show what people notice — they can't tell you whether Pre-Workout is safe for you.
Reported side effects
insomnia4
diarrhea2
heart palpitations2
dependence1
itchiness1
burnout1
jitteriness1
kidney pain1
What got worse for some people
In their own words
“I had a terribly tough time falling asleep. A couple times I couldn't sleep at all. I may be stimulant sensitive.”
“two scoops of C4 has almost no effect on me. I notice almost no difference except maybe the C4 gives me fruit punch flavored burps.”
“when i took c4, after 2 scoops i would get nauseas and light headed but only certain times.. some days id feel great, others id feel like i was about to pass out.”
“I started off with one scoop and ended up with 5 scoops and 5 scoops didn't do anything”
“cut the stim pre-workout around the same time and honestly that probably did more for my sleep than any supplement i've ever taken. 350mg caffeine at 4pm, what was i thinking”
“PUMP: 2/10 (I did not get any pump)”
Is Pre-Workout safe? What the research covers
BResearch: Moderate1 meta-analyses · 38 randomized trials on PubMed
None of the top reviews we found focus on safety. All research on Pre-Workout.