So, if genetics doesn't determine the alkaloid profile of Kra8om leaf, what does? (Metabolism)
It turns out that how it's dried determines the level of oxidation, which in turn determines the levels of Mitragynine. This level of Mitragynine seems to be what single handedly determines the effects of leaf. It seems that when a large amount of Mitragynine is involved like in extract, it is void of any opioid effect. Instead, the effect seems much more stimulating, presumably from Mitragynine and cyp inhibition. Additionally, when this occurs there is often wobbles associated with it. This also happens with some indoor dried leaf (as high as 2.1), which has a high concentration of Mitragynine. MItragynine has been called the great neuromuscular blockade by researchers and is most likely the cause of this eye muscle weakening phenomenon. It is important to know that Mitragynine is also a cyp3a4 inhibitor.
However, when the levels are lower, like in sun dried leaf (reds)(about 1.2%), the effects is much more opioid like. This could explain why reds are perceived as having this effect. When reds are dried for a long period of time like they are with bentuangie, the levels drop to levels as low as .3%. Additionally, if you take a poll of any vendors' most popular leaf, it is almost always a moderate level. One of the strongest strains that I've had only tested at 1.6%. So, what seems to be happening is that High levels of MG inhibit the cyp enzyme to a point where this conversion is not happening. There seems to be a threshold level where this happens, meaning that it continues to convert to 7ohm until it reaches this level. So, anything below this, and you continue to get conversion, increasing 7ohm and the opioid effect.
How do we know that the stim effect comes from Mitragynine? A recent study by Boyer et al. showed the binding affinities of other target central nervous system receptors. This recent study quantitatively demonstrated Mitragynine's affinity to the a2a adenosine receptor, a neuromodulator responsible for facilitating sleep. These receptors" are responsible for the effect of caffeine on wakefulness." The Adenosine antagonism produced by Mitragynine, is not unlike that of coffee. So, it is a safe to assume that Mitragynine might largely be responsible for the stimulant effect of Kra8om, especially given the high level of inhibition of adenosine found in the posted study and lack of a competing theory. It is also interesting to note that this effect has a ceiling, as you can't inhibit this mediator more than 100%, which means zero adenosine production in the brain. You can't have negative adenosine.
Mitragynine is maximized by minimizing the level of oxidation, and by inhibiting the cyp3a4 enzyme, preventing the conversion into 7ohm. Since MG oxidizes from sun, drying the leaf in a dark room would prevent photooxidation. Therefore, the most stimulating leaf would have to be green leaf dried in the dark. "White vein" in Indonesia is made with 60% indoor green, 30% outdoor red, and 10% stem and vein. It is widely believed by Indonesians that stem and vein is what causes the stimulating effect. Having assayed and sold large amounts of stem and vein myself, this kratomite would beg to differ. I have some if you want to try it. It was believed that photo-oxidaton of Mitragynine inside the leaf converted it into 7ohm. The reason I say it doesn't is because 7ohm levels in 50 lab tests, all showed similar levels averaging around .03%. It is believed by researchers that this amount is too low to cause the Opioid effect.
The perceived stimulating effects of "White Vein" Kratom appear to be purely placebo effect. Leaf with high MG would inhibit said enzyme and theoretically be less sedating, and conceivably more stimulating. A considerable amount of the Psychoactive effects that comes from Kratom seems to come from MG, while the Opioid effect seems to be from 7ohm. So, why would you mix a red (or stem and vein) in with a green when looking for cognitive alertness? Hence, the belief that "White" Kratom is the most stimulating has no scientific foundation. Instead, an indoor dried (high mitragynine) leaf is most likely the most stimulating. This also disproves the theory that more equals opioid and less equals stim. We've established that more mg, that which crosses the threshold levels, inhibits cyp3a4 and prevents conversion, thereby antagonizing adenosine, and creating a stimulating effect.