Tolerance? Slow Release version? You got to give us more information on your usage history and the form in which you used the drug.
Dont take a booster, even though yoiu are underwhelmed 1.2gr is quite a lot for your body to deal with.
If I would have to guess an abundant expression of CYP 450 enzymes or certain isomorphs that are involved in the DXM metabolism. Which basically means your body is built differently genetically and has different means to dispose of drugs (less or more of enzymes that help with drug conversion in the body to help with their excretion).
NSFW:
If DXM is mostly a pro-drug, DXO (dextrorphan) is the main psychoactive metabolite and 3-methoxy-morphinan (3-MM) turns out to be relatively impotent / inactive or at least generally irrelevant...
and
If you express large amounts of CYP3A(I wanna say -4..?) compared to CYP2D6 this would turn a person very tolerant to the effects of a dose of DXM.
The reverse is known to happen in 10% of caucasians (different for asians!), called enzyme deficiency given the context and is responsible for low tolerance / high sensitivity to DXM. However I have serious doubts that enough people who try DXM for the first time learned about this fact before trying, that may have something to do with a big part of DXM's audience. Anyway reacting strongly or weakly to a drug with potentially strong effects can obviously have serious consequences, mostly in the case of the former of course..
Anyway I figure another kind of enzyme defiency is in the realm of possibilities even if it is probably a little bit more rare than 10% - which frankly isn't rare at oll!
I edited the thread title to make it more descriptive - please always create descriptive thread titles yourself to make the message board / thread index a lot more transparent! Thnx.