Be warned.
I'm serious-- use this as a cautionary lesson.
I can no longer experience DMT-- I have become completely immune.
It started last month for me--it was sudden.
Following a couple weeks of pretty heavy Rue harmalas and DMT vaping without any incident-- I had some kind of severe interaction with a protein/supplement shake that I stupidly put an unmeasured amount of 5-HTP powder and other supplements into while I was using the rue harmalas at heavy dose.
I then experienced what I am guessing was serotonin syndrome-- extreme panic, dangerous heart palpitations, extreme confusion, auditory hallucinations and other nightmarish symptoms. Nothing I've ever experienced before. I thought I was going to die-- I thought I had done neurological damage. I only avoided 911 because I didn't want to go to jail.
In the following almost 2 months I have not been able to feel anything from either Harmalas or DMT in any amount, aside from the mildest hint of effects. I was able to trip on cactus as usual last week, but towards the end of the experience I felt physically awful.
I know I over-did it. I know it's my fault. I'm devastated. Two weeks ago I tried 50mg in my GVG-- nothing. I waited until yesterday to see if anything changed, and again-- NOTHING but the barest, almost imperceptible effects.
I feel like I've done permanent damage to my brain's wiring--
I am locked out... ruined one of the best things in my life.
UPDATE 4/2021
Just thought I'd post a long-term follow up in the OP for reference.
After over a year I can report that I have only been able to regain some of the effects of DMT when vaped.
It's not close to what it once was.
I've also tested ground (baked) rue powder in low doses a couple times over the past couple months since the crisis event, with no unusual effect.
Mushrooms are extremely mild in effect as well--just like the DMT-- maybe 10-20% of normal. Fuck.
Cactus/mescaline does still work as before the crisis.
The lesson remains-- be careful my friends-- it's just too dangerous to ever mix this otherwise harmless stuff with 5HTP or anything like it-- hypertensive crisis and/or serotonin syndrome can kill you. Please stay safe!
Man, bummer.

That's OK-- it's all well-meant and received.