Oh boy, this is one of my favourite threads. I've absolutely, 100% noticed that many of the major metabolic and psychological benefits of cannabis are dramatically reduced with smoking vs vaping. I've spoken to quite a few patients who have found the same experience. Typically I find that after several years of use most patients who have given vaporization a fair chance only return to smoking (other than out of necessity or convenience) if they have significant pain or gastro issues that make it difficult to deal with escalating tolerance levels.
Other observations to add to what's already in this thread: I spent about a year only using dabs because I couldn't afford bud anymore, but I figured it would be just as good because it's still vaporization. I started gaining weight again, and my depression got so much worse I had to go onto an SSRI.
I've talked to quite a few professionals in the industry about this, including several of the doctors at our clinics, and this is the best hypothesis we've come up with:
This has less to do with the negative effects of combustion than it has to do with the synergistic effects of whole plant medication that are lost to the combustion reaction. While there are many plant compounds that are important for this, terpenes have become more or less commonplace in popular cannabis literature lately so I'll use them as the first example for my explanation.
Cannabinoids are relatively complex molecules that can withstand a combustion reaction with very little degradation other than decarboxylation. If the imbalance in your own endocannabinoid system can be adequately stayed with THC or CBD -say your gut is just a little shy pumping out anandamide or you've got inflammation or nerve pain- smoking might work just fine. But suppose you're responding better to high limonene & caryophyllene strains because of fatigue or depression related symptoms. Will smoking provide the same or similar results? Terpenes are hydrocarbons, which theoretically makes them more readily available as fuel for that combustion reaction*. Additionally, many terpenes degrade significantly at temperatures much lower than where we start to see combustion. So taking the exact same bud and smoking it might give you a dramatically different ratio of terpenes to cannabinoids, where as someone who's responding more to the ratios of CBD and THC might perceive very little difference. Right now we know that terpenes modulate the way our body absorbs cannabinoids (like how myrcene increases THC receptivity at the CB1 site) but I also strongly suspect that in time we will discover endogenous analogues that the human endocannabinoid system uses in a similar manner as terpenes to help regulate mood, metabolism, etc.
So terpenes are my favourite example, but what about them gooood dabs? Those PHO or CO2 concentrates that smell like an actual candy forest? Distilled! Solventless! Anti-gravity! Having extraction methods with better terpene preservation definitely helps, but just like THC wasn't the whole story like we once thought, terpenes are simply the next piece of the puzzle that's progressing our understanding of the plant. What about flavonoids and other pigments, phenols, esters, ketones, etc etc etc. Many of these things have been demonstrated to affect the way our body utilizes other forms of nutrition, and cannabis is basically a nutritive supplement for your endocannabinoid system. Many of these things are also not extracted in a significant capacity with even the most sophisticated methods currently popular for dabbables.
*I'm no chemist so citation needed on this point
There's so much more I'd like to say on this and the undiscovered potential of whole plant cannabis, but that's beginning to get away from the topic of the thread (health benefits of vaporization vs smoking) and more into cool stuff that I never would have discovered without vaporization here to illuminate the differences
