Across 98 first-hand reports, people mentioned a side effect 12 times (about 12 per 100 reports). The most common: jitteriness, chest pain, erectile dysfunction. User reports show what people notice — they can't tell you whether Dmaa is safe for you.
“DMAA - tried 4 times. Feel jittery for a little while and it's hard to concentrate... then I crash and just want to nap.”
“The DMAA can certainly give you energy for your workouts but it can also cause a pretty nasty crash that isn't quite worth the energy for me personally.”
“I've experimented with DMAA as well, but that seems to have some unwanted side effects.”
“Our DMAA bottles use a 25mg dosage for focus.”
“I nearly passed out while driving and experienced crazy heart palpitations, violent/uncontrollable shaking in my limbs and light headedness.”
“I'm not a huge fan of DMAA because there's not enough evidence behind it's safety (and a few reports of recreational overdoses in Oceania)”
Conclusion: Memantine is a safe drug and may be useful for treating Alzheimer's, vascular,and mixed dementia of all severities. Most of the trials so far reported have been small and not long enough to detect clinically important benefits. However there is a possible benefit on cognition and global measures, and an early improvement in behaviour in people with dementia. More studies are needed.