I wonder if anyone has experience comparing the effects of eating san pedro with taking pure mescaline (apart from maybe the degree of nausea or emetic effects). Are the effects basically the same, somewhat different or very different in your opinion?

I can see that unprocessed san pedro contains:

mescaline (3,4,5-trimethoxy-B-phenethylamine)
3-methoxy-4-hydroxy-B-phenethylamine
3,5-dimethoxy-4-hydroxy-B-phenethylamine
tyramine
hordinenine

Obviously those additional substances must change the experience but I'd like to know if these make it a fundamentally different experience.

Also, do the normal extraction methods preserve those additional substances or are they mainly lost in the process?

Add to your list 3,4-dimethoxyphenethylamine, 3-hydroxy-4,5-dimethoxyphenethylamine, anhalonidine and anhalinine!

I don't get much nausea, and found slowly sipping hot cactus tea to be quite bearable. Lemon balm was one of the admixture plants used, though, which has been found to help against nausea.

Never tried pure mescaline (only crude extract) so maybe I just shut up at this point