20g is a very large dose..Personally I could never hold that much leaf down. I would throw it up for sure. Extracts are expensive yes..but you can easily buy in bulk, say 1000 grams for 60 bucks I have gotten online before. And with this, you could make your own extracts. It could possibly involve using crude chemicals like acetone or butane and such, but if you get the process down right, this could save you a lot of money and gut ache..and because it is concentrated, you can take up the dose much easier..the only downside is of course rapid tolerance spikes. 7-OH, one of the primary opioid alkaloids in kratom is considered 17 times more potent than oral morphine, but it is a partial agonist so it may have a ceiling effect where taking any more at a certain point may not have any larger affect. Mitragynine, I'm not sure if it is a full agonist or partial agonist..but mitragynine is much more abundant and is 1/3 the potency of oral morphine..still strong.