Pentylone
Pentylone is a stimulant developed in the 1960s. It is a substituted cathinone that has been identified in some samples of powders sold as "NRG-1", along with varying blends of other cathinone derivatives including flephedrone, MDPBP, MDPV, and 4-MePPP.
It was also found in combination with 4-MePPP being sold as "NRG-3". Reports indicate side effects include paranoia, agitation, and insomnia, with effects lasting for several days at high doses.