Again, it depends on the extract. The alkaloids that cause the nasty sides (chills, etc) are NOT the same as the yohimbinoids. Yohimbinoids create anxiety and such in prone users, but that applies to the whole class, including yohimbine. No two extracts are the same. Two that I know standardize for yohimbinoids are our products (obviously I know this one lol) and muscletech (from talking to a lead rep). The issues arise with things like "8% yohimbe bark extracts," which are typically sold by ingredient suppliers as the extract of choice. These are typically loaded with sides.
Also, Lyle is a great source on many things, but I've read his work on yohimbine, and many of his posts, especially those posted on his forum, are blatantly incorrect. He's a great source for nutrition/training. Biochemistry, not so much
I'm a big fan of Lyle's work and when he said that, I felt like he was telling me his father was tougher then my own. Fight words. haha, kidding. I always enjoy learning more and Coop is a great source to correct some of my misinformation.
Current Log- http://anabolicminds.com/forum/supplement-reviews-logs/240979-bruiser-shreds-lecheeks.html (AMPilean+HyperT2)