With the legalization of cannabis for medical use in almost the entire US (and for recreational use in half the states), an increasing number of people are trying to use it for the sole purpose of reducing their excessive sweating. Note that while cannabis is the botanical name of the actual plant, what people typically use is called marijuana. The latter is cannabis that contains a substantial amount of tetrahydrocannabinol (THC).
There is lots of research out there on cannabis and its effects on anxiety and stress levels, but very little on its impact on sweating. Below are several recent studies on the use of cannabis, cannabidiol (CBD) and cannabinoids to reduce hyperhidrosis.
In many cases, people use certain strains of marijuana (also called weed, hashish, ganja or pot) to reduce their anxiety levels, which in turn reduces their overall body sweating. However, some anecdotal reports on Reddit and other forums suggest that certain strains of weed can even increase your sweating. My guess is that sativa dominant strains can increase your heart rate and sweating, while indica dominant strains can calm you down and enable deep sleep (thereby stopping you from sweating to the point of whole body anhidrosis). Most people who use marijuana frequently tend to go for hybrid strains. The THC in marijuana also has anticholinergic effects, just like Robinul Forte.
It is hard to believe that I first ingested cannabis (albeit the plant's leaves) when I was around 7-10 years old. At the time, I used to visit a Hindu temple for the Holi festival of colors every year when they gave out a crushed cannabis leaf infused drink called bhang lassi to revelers. There was no age limit as to who could drink this concoction. It must have been very weak, since I do not ever remember being high after drinking the bhang, though I think I did get a mild buzz. At that age, I had no hyperhidrosis, so never had a chance to see if bhang lassi had any impact on my sweating. Thereafter, I never consumed cannabis (or marijuana) again till reaching college, where I tried it once. Then I did not consume it again for over a decade.
However, in my early 30s, I started using marijuana a few times a year after moving to the Seattle area, where recreational use became legal in 2012. Since this legalization, the number of stores selling weed proliferated rapidly (as did the number of strains and brands). I tried all kinds of methods in ingesting the product, including via joints, pre-rolls, chillums, edibles and tinctures. One thing I realized is that I have a very high tolerance to the effects of weed, more so than any of my friends. Half the time, I get almost no effect. The rest of the time, I need to ingest much larger quantities than others to get a decent reaction. During the few times that I did get the desired lengthy relaxation followed by deep sleep effect from marijuana (via indica or hybrid strains), my body could not sweat at all, including my bothersome feet. A great feeling to know for sure that the feet were guaranteed to be dry for hours on end. But I could never tell when I would get this deep sleep and calmness effect. Even the same strain of weed would have a different effect (including no effect) each time I tried it.
I do not think that cannabis is a legitimate long term solution to stop hyperhidrosis, especially since the long term effects of daily marijuana use are significant. The main reason I wrote this page is to perhaps collect some notes on various strains of weed that people have tried with the greatest chances at stopping the entire body from sweating. This type of solution can be helpful a few times a year when you are overly stressed and sweaty.