Caffeine pills & powder are far more dangerous. It is very easy to overdose on them, and death is not out of the question. It still isn't common.
With marijuana, it is virtually impossible to have an overdose that kills you (It's very difficult to find sources on CBD/THC overdose):
> An overdose on marijuana is dissimilar to overdoses on other drugs because marijuana consumption, in and of itself, is not life-threatening. But using too much of the drug can have hazardous results, which may increase the risk of death.
> For instance, someone who consumed a lot of marijuana may be unaware of their environment, which can lead to accidents or falls. Furthermore, marijuana intoxication has been linked, in some studies, with psychosis,3 a condition in which the individual is disconnected with reality, typically resulting in hallucinations, delusions, or extreme paranoia. A person who is having a psychotic episode may put him or herself in dangerous situations due to confusion or detachment. [0]
Synthetic MJ (K2) is far more dangerous, though.
[0]: https://www.projectknow.com/research/marijuana-overdose/
Caffeine pills usually come in 200mg. Caffeine has an LD50 of about 200mg/kg of body mass. In US units a 150lb person would have to consume 68 caffeine pills to reach LD50 levels.
From this page:
https://www.westword.com/news/dear-stoner-how-much-thc-equal...
> For THC, there are varying figures, ranging from 1,260 milligrams of THC per kilogram of body weight down to 666 mg/kg. Even going with the lowest figure, a 175-pound man would have to consume more than 53 whole grams of pure THC all at once. [...] Need more perspective? Caffeine has an LD50 of 192 mg/kg, and nicotine is around 60 mg/kg.