Supergreen. It could be argued that this type of Kratom (sun dried pure green) incites the most opioid activity, more so than any red.
It's dried outdoors in the open air in the sun.
This means that conditions are ideal for photooxidation to occur, which converts Mitragynine into 7ohm. According to a recent study, 7ohm has about 10 times stronger Mu Opioid Activity than Mitragynine.
What is photooxidation?
Dissolved oxygen in the plant matter interacts with the sunlight and phytochemicals in the leaf causing an organic chemical process called photooxidation. This oxidation is responsible for converting Mitragynine which is not that strong of an opioid, into 7 Hydroxymitragnine, an opioid stronger than Morphine. In a lab, Mitragynine extract in an aqueous solution was converted to 7ohm simply by exposing it to sunlight. However, because of the lack of control in photooxidation, only 8% yield was observed.
Supergreen is dried outside in direct sunlight for several hours before moving into the shade. This is a pure, unmixed strain. Kratom leaf only takes hours to dry outdoors in the sun. Lab tests show that leaf dried indoor in the dark has only trace amounts of 7ohm, and high concentrations of Mitragynine. The presumption here is that most of the oxidation that occurs with Mitragynine is done with light: (photooxidation). The degree to which the leaf is oxidized ultimately determines the alkaloid profile.
Heavily oxidized leaf is presumed to be red. However, when they cure red leaf, they put it in a plastic bag, then in the sun for 5 days. During this time, fermentation is alleged to occur. However, Given that there are not many sugars in the Kratom leaf, and there's no addition of yeast or natural bacteria, fermentation must be minimal. Instead, the assumption is made that 7 ohm is maximized through photooxidation, turning the yellowish Mitragynine into the orangish 7ohm. Oxidation from the air alone seems minimal as can be seen by the minimal amounts of 7ohm found in the leaf dried by air only. The amount of dissolved oxygen in the plant material varies by how much oxygen is present in the air. So, while traditional reds are cured in an anaerobic setting, the sun dried green is exposed to greater amounts of oxygen, yielding greater amounts of 7ohm, and having a greater opioid effect.