I have problem with cross tolerance after taking 5-meo-mipt and 2cd with redosing, problem occured for 2 persons. We are resistant to all serotoninergic psychedelics from almost year (but never had break longer than 1 month, so now we have longer break) - we've tried shrooms, up to 8grams, lsd (up to 2 good blotters), mescaline. also MAL not working.
Now I'm taking some supplements: ALCAR (up-regulates mglu2 receptors, forming hetorodimers with 5ht2a , that's mechanysm of working of common serotoninergic psychedelics), Inositol,, B12/folate/b6 and magnesium occasionally.
BTW. Long-term tolerance may be connected with insulin resistance, that's my observations - based on fact, that I know some person with natural high tolerance (4g of shrooms without serious visuals) - have insulin resistance from previous obesity (now he's in good shape). Also I know two other persons with unusual high tolerance after too much amount of psychedelics.
Next in queue are some other substances: NAC, hypericum. Last in queue I'll try maybe q10, oleamide, quietapine. I know that up-regulatiung or recovery of neurons could lasts i.e. for half a year, so I'm trying to not take all in one turn.
If you want some more info, don't afraid to ask. I.e. ALCAR seems to bring back my HPPD, which disapearred completely after such issue with 5-meo-mipt. Now I have it in my level before that.