Does taking caffeine with creatine cancel out its effect?

Short answer

No. Caffeine taken before training, after a period of creatine, added to the effect rather than cutting it. The canceled effect came from a 1996 study of 9 people who took caffeine daily for 6 days, and later studies found no loss in maximal strength.

Does taking caffeine with creatine cancel out its effect?
'Caffeine + creatine → effects cancel out' — does this formula hold?
Plenty of people take creatine with a pre-workout coffee. But there is a claim that caffeine wipes out creatine's effect. We checked where this came from and whether it holds.
Where it started: 9 people in 1996
Creatine's effect vanished with caffeine
When 9 people took creatine for 6 days (35 g a day for a 70 kg (154 lb) person), force in a repeated-effort test rose 10-23%. When they also took caffeine daily (about 350 mg for 70 kg), it did not rise. Creatine stores in muscle went up 4-6% either way.
The suspected reason
Muscle relaxation speed moved in opposite directions
In a study of 10 people, creatine cut the time a muscle takes to relax after contracting by about 5%, while caffeine taken for 3 days lengthened it by about 10%. Taken together, there was no change. Caffeine masked this creatine effect.
Later studies: maximal strength did not drop
Taken daily together, the weight lifted was the same
When 54 people took creatine for 5 days along with coffee or 300 mg of caffeine, maximal strength was no different from creatine alone. In a 6-week training study of 28 people, maximal strength did not differ either. The only difference was front-thigh muscle thickness in the creatine-only group.
The flip side: caffeine before training, after creatine
It pushed performance higher
When 12 people took caffeine (420 mg for 70 kg) after 5 days of creatine, their power in the first two cycling sprints was higher than without caffeine. 14 people took caffeine 1 hour before a run after 6 days of creatine, and their time to exhaustion rose from 198 to 222 seconds.
The fork in the road was how you take it
One dose before training, after creatine, added to the effect
A review of 10 studies found that among 5 studies where caffeine was taken before exercise after several days of creatine, 3 showed a bigger effect than creatine alone. Among 5 studies where caffeine was taken daily throughout the creatine period, only 1 did better.
A common side effect when combined
4 of 13 had an upset stomach
In the 54-person study, 4 of the 13 people taking creatine with caffeine reported mild stomach discomfort. No side effects were reported with creatine alone, creatine with coffee, or the dummy pill.
Summary: caffeine before training did not get in creatine's way
The vanished effect came from a 9-person study with daily caffeine
Caffeine taken before training, after a period of creatine, added to the effect instead of cutting it. The vanished effect came from a study of 9 people taking caffeine daily for 6 days. Even in the 54- and 28-person studies with daily caffeine, maximal strength did not drop.