Tetrahydroharmine (Harmala Beta-Carboline · MAO / Serotonin Modulation)
Compiled from published pharmacological and botanical literature. Not independently verified by Herbuno. Spotted an error or have a correction? Flag it below →
| Compound | Tetrahydroharmine (THH; Leptaflorine) |
| Chemical class | Alkaloid — Beta-carboline (fully reduced harmala indole alkaloid) |
| CAS | 7629-35-8 |
| Primary source | Peganum harmala (Syrian rue) seeds; Banisteriopsis caapi stem |
| Key applications | Weak MAO-A inhibition; serotonin-reuptake modulation; antioxidant; research context |
| Claim strength | Emerging |
| Typical form | Harmal (Peganum harmala) seed extract — THH as minor beta-carboline (~0.1% of seed) |
| Buy from Herbuno |
Harmal Seed Extract Powder - Peganum harmala → Harmal Oil Soluble Extract - Peganum harmala → |
Name origin: Tetrahydroharmine (THH) is the fully reduced, or tetrahydro, member of the harmala beta-carboline series, related to the aromatic harmine by saturation of the pyridine ring; its older name, leptaflorine, records an early independent isolation. Traditional use: Peganum harmala (Syrian rue, harmal, Isband) carries extensive Unani, Persian, and Central Asian medicinal and ritual use — the seeds burned as a fumigant and incense, taken for a range of complaints, and used as a source of red dye. The plant also supplies the beta-carbolines of ayahuasca-analogue preparations, a role otherwise filled by Banisteriopsis caapi, which shares the same alkaloids; THH occurs as a minor constituent in both botanical sources. Research trajectory: THH has been identified and quantified as one of the five principal beta-carbolines of Peganum harmala, present at low seed levels, in analytical work that simultaneously mapped the plant's monoamine-oxidase-inhibitory profile and showed that seed extracts are potent, reversible, competitive inhibitors of human MAO-A Herraiz 2010. Within that profile THH is a weaker MAO inhibitor than harmine or harmaline, and preclinical studies additionally attribute serotonin-reuptake-modulating activity to it. Commercial source: Tetrahydroharmine is delivered as a minor beta-carboline within Harmal Seed Extract Powder (Peganum harmala) from Herbuno, alongside the dominant harmine and harmaline, with an oil-soluble format also available.
Evidence for Tetrahydroharmine Applications
Beta-carboline / MAO context: THH is one of the five main beta-carbolines quantified in Peganum harmala, and within the harmala alkaloid complex the MAO-A inhibition is dominated by harmine and harmaline, with THH contributing more weakly; the same analytical study established seed extracts as potent reversible competitive MAO-A inhibitors with a defined potency for the fraction Herraiz 2010. Claim strength: Emerging.
Serotonergic modulation: Preclinical studies attribute weak serotonin-reuptake-modulating activity to THH, a property that distinguishes it pharmacologically from the more strongly MAO-inhibitory aromatic beta-carbolines and that is often invoked to explain its particular contribution within the alkaloid mixture. Claim strength: Emerging.
Antioxidant activity: Like other beta-carbolines, THH exhibits radical-scavenging activity in vitro, consistent with the electron-rich indole core shared across the class; this contributes to the general antioxidant capacity attributed to harmala alkaloid preparations. Claim strength: Emerging.
Whole-extract context: THH's practical relevance is as a co-constituent of the harmala beta-carboline complex; its individual effects in humans have not been isolated in clinical study, so its behaviour is best understood in the context of the full seed alkaloid profile rather than as a standalone agent. Claim strength: Emerging.
Distribution and abundance: Analytical profiling places THH at roughly 0.1% of Peganum harmala seed by weight — a genuinely minor fraction relative to harmine and harmaline, which accumulate at several percent — so realistic material delivers THH as a trace component of a harmine/harmaline-dominated extract. Claim strength: Emerging.
Harmal Seed Extract Powder - Peganum harmala →
Harmal Oil Soluble Extract - Peganum harmala →
Browse Standardised Extract Powders →
Dosage & Formulator Specification
No isolated tetrahydroharmine human dosing data exist, and the compound is not offered or studied as a standalone dose. THH is present at roughly 0.1% of seed weight in Peganum harmala, so it is delivered as a minor co-alkaloid rather than a standardised single ingredient; formulators working with Harmal seed extract should specify total beta-carboline content by HPLC, within which harmine and harmaline dominate and THH is a small fraction.
The most important formulation consideration is a class-level one. Because the harmala beta-carbolines include reversible MAO-A inhibitors, Peganum harmala preparations carry the interaction cautions of MAO inhibition — notably with tyramine-rich foods and with serotonergic drugs — and this governs responsible labelling of any Harmal-derived ingredient even though THH itself is a weaker MAO inhibitor than harmine or harmaline. The relevant safety profile is that of the whole extract, not the trace constituent.
Harmal Seed Extract Powder and Harmal Oil Soluble Extract both provide THH within the full beta-carboline spectrum, with the oil-soluble format suited to lipid-phase applications such as softgels or emulsions. Standardisation to total beta-carbolines by HPLC, with a specified harmine/harmaline ratio where the application demands it, is the appropriate commercial specification, and batch-level assay is advisable given the natural variability of alkaloid content between seed lots.
For the formulator, THH is best positioned as a characterising minor constituent of a Harmal beta-carboline ingredient rather than as an active in its own right, and marketing or labelling should reflect the early, preclinical nature of its individual evidence while relying on the whole-extract safety framework.
Frequently Asked Questions — Tetrahydroharmine
What is tetrahydroharmine?
Tetrahydroharmine (THH) is a beta-carboline alkaloid found in Peganum harmala (Syrian rue) and Banisteriopsis caapi. It is the fully reduced member of the harmala beta-carboline series and occurs as a minor constituent alongside the dominant harmine and harmaline.
How does tetrahydroharmine differ from harmine and harmaline?
THH is the fully reduced (tetrahydro) member of the series, whereas harmine is fully aromatic and harmaline is the dihydro intermediate. Functionally, harmine and harmaline are the strong reversible MAO-A inhibitors of the group, while THH inhibits MAO more weakly and shows additional serotonin-reuptake-modulating activity in preclinical work.
Which Herbuno product contains tetrahydroharmine?
Harmal Seed Extract Powder (Peganum harmala) delivers tetrahydroharmine as a minor beta-carboline within the full alkaloid spectrum, dominated by harmine and harmaline. Harmal Oil Soluble Extract is a lipid-phase alternative for formulations requiring an oil-dispersible input.
Is tetrahydroharmine well characterised?
THH has been identified and quantified as one of the five principal beta-carbolines of Peganum harmala, present at low levels (around 0.1% of seed weight). Most of its pharmacology is preclinical, and it is best understood as a co-constituent of the whole harmala alkaloid complex rather than as an isolated, clinically studied agent.
Related compounds: Harmine, Harmaline, Harmalol, Harmol
Claim-strength scale – High = multiple human RCTs; Moderate = limited trials or strong preclinical convergence; Emerging = early-stage lab or animal data.
← HerbIQ Compound Index · HerbIQ P02: Extraction · HerbIQ P03: Delivery