Tetrahydroharmine 🏆🥇 #

An Enigma #

Almost nothing is known about Tetrahydroharmine (THH). Shulgin reportedly took 300mg.¹ When sober, I can’t tell the difference between 5mg and 300mg.² There is optimism (not quite reaching mild euphoria) and a sense of well-being, but it’s barely noticeable.

Some say THH is a stimulant, but I doubt it. It can prevent sleep, but it doesn’t produce the jitteriness of coffee. I think it’s more accurate to say that it increases alertness, which can interfere with sleep.

Oh, and if you’re hoping it’ll spice things up in the bedroom—sorry, it won’t. THH is chaste as a monastery.

Pretty boring. Nothing to see here.

But Combined With Other Substances… #

The picture changes completely. I’d say its main effect is to create more psychological distance from your experience. It’s similar to MDMA, only more subtle and quiet. This is a drug that makes you feel sober! It helps keep you unblended (emotional distance).

Dosage Experiment #

Since it’s hard to tell 5mg from 300mg at baseline, judging THH’s intensity seems to require subjecting yourself to intense emotions and seeing whether THH pushes back. To explore this dose-response relationship, I took 300mg of THH on the morning of a day when I attended a Santo Daime work in the afternoon/evening. I’m not 100% certain I could discern the difference if blinded. The experience was not uncomfortable, but it created too much distance from the DMT effects.

“Not recommended."—Your Humble Guinea Pig

Tolerability #

No tolerability study of pure THH exists. However, harmine—a closely related beta-carboline—has been tested: Ables et al. (2024) found that healthy volunteers tolerated doses up to 300mg of harmine.³ Above that, nausea and other unpleasant effects can occur, but nothing life-threatening. THH and harmine are not identical molecules, so these results are suggestive rather than definitive for THH.

Notes #