From USA Today:
News reports are mentioning AMP citrate, which some consider to be a close cousin of DMAA. AMP citrate is sometimes referred to as methylpentanamine. Scientists in the United States and the Netherlands testing several products found that the amount of the new synthetic stimulant varies widely, the dosage isn't disclosed on labels, there isn't much evidence that the chemical is natural and none that it's safe in humans.
Read more here: http://www.usatoday.com/story/news/nation/2014/10/08/amp-citrate-stimulant-dietary-supplements/16827669/