What is this DMAA you speak of?
1, 3, dimethaylamine (probably spelt incorrectly)
It was used in pre workouts up until 2013/14 in the states: such as Jack3d etc. There are a few reported heart attacks, high profile one with a US marine, and the states subsequently banned it. Its relatively safe provided you use in moderation - people back then were double/triple scooping it.
It's a great ingredient for a pre workout, its essentially an amphetamine. You can still find it on the web and used resourcefully can be a great tool. Expect to feel wired for hours after your workout though, almost like a comedown from a party drug.
Don't use regularly or exceed 75mg (recommended serving for a lot of the pre workouts).