# Bretisilocin > Source: > Published: 2026-06-15 04:19:23+00:00 # Bretisilocin | Clinical data | | |---|---| | Other names | GM-2505; GM2505; 5-Fluoro-N-methyl-N-ethyltryptamine; 5F-MET; 5-F-MET; 5-Fluoro-MET | administration | [Intravenous](/wiki/Intravenous_administration),[[1]](#cite_note-AdisInsight-1)[[2]](#cite_note-MarekMakai-BölöniUmbricht2025-2)[[3]](#cite_note-HughesChristianDvorak2023-3)[[4]](#cite_note-UmbrichtChristianWinters2024-4)[intranasal](/wiki/Intranasal_administration)[[5]](#cite_note-Aipsin-5)[Drug class](/wiki/Drug_class) [Serotonergic psychedelic](/wiki/Serotonergic_psychedelic);[Hallucinogen](/wiki/Hallucinogen);[Serotonin](/wiki/Serotonin)[5-HT](/wiki/5-HT2A_receptor)and2A[5-HT](/wiki/5-HT2C_receptor)2Creceptor[agonist](/wiki/Agonist);[Serotonin](/wiki/Serotonin)[5-HT](/wiki/5-HT2B_receptor)2Breceptor[partial agonist](/wiki/Partial_agonist)or[antagonist](/wiki/Receptor_antagonist);[Serotonin releasing agent](/wiki/Serotonin_releasing_agent)[Legal status](/wiki/Regulation_of_therapeutic_goods) - Investigational [Pharmacokinetic](/wiki/Pharmacokinetics)data [Onset of action](/wiki/Onset_of_action) [IV](/wiki/Intravenous_injection): 10–20 minutes ([peak](/wiki/Tmax_(pharmacology)))[[2]](#cite_note-MarekMakai-BölöniUmbricht2025-2)[Elimination half-life](/wiki/Biological_half-life) [[2]](#cite_note-MarekMakai-BölöniUmbricht2025-2)[[3]](#cite_note-HughesChristianDvorak2023-3)[Duration of action](/wiki/Pharmacodynamics#Duration_of_action) [IV](/wiki/Intravenous_injection): 60–90 minutes[[2]](#cite_note-MarekMakai-BölöniUmbricht2025-2)[[6]](#cite_note-Peplow2024-6)*N*-ethyl-2-(5-fluoro-1*H*-indol-3-yl)-*N*-methylethanamine [CAS Number](/wiki/CAS_Registry_Number) [PubChem](/wiki/PubChem#CID)CID [ChemSpider](/wiki/ChemSpider) [ChEMBL](/wiki/ChEMBL) [Formula](/wiki/Chemical_formula) 13H17FN2[Molar mass](/wiki/Molar_mass) −1[JSmol](/wiki/JSmol)) - CCN(C)CCC1=CNC2=C1C=C(C=C2)F - InChI=1S/C13H17FN2/c1-3-16(2)7-6-10-9-15-13-5-4-11(14)8-12(10)13/h4-5,8-9,15H,3,6-7H2,1-2H3 - Key:XRWQULAXCLVBPP-UHFFFAOYSA-N **Bretisilocin**, also known by its developmental code name **GM-2505** and as **5-fluoro- N-methyl-N-ethyltryptamine** ( **5F-MET** or **5-fluoro-MET**), is a [serotonergic psychedelic](/wiki/Serotonergic_psychedelic)of the [tryptamine](/wiki/Substituted_tryptamine)family which is under development for the treatment of [major depressive disorder](/wiki/Major_depressive_disorder). [[1]](#cite_note-AdisInsight-1) [[7]](#cite_note-WitkinGolaniSmith2023-7) [[2]](#cite_note-MarekMakai-BölöniUmbricht2025-2)It is an [[3]](#cite_note-HughesChristianDvorak2023-3)[analogue](/wiki/Structural_analog)of [dimethyltryptamine](/wiki/Dimethyltryptamine)(DMT) and is the 5- [fluorinated](/wiki/Fluorine) [derivative](/wiki/Chemical_derivative)of [methylethyltryptamine](/wiki/Methylethyltryptamine)(MET). Bretisilocin's [[8]](#cite_note-US11440879B2-8)[route of administration](/wiki/Route_of_administration)is [intravenous infusion](/wiki/Intravenous_infusion). [[1]](#cite_note-AdisInsight-1) [[2]](#cite_note-MarekMakai-BölöniUmbricht2025-2) [[3]](#cite_note-HughesChristianDvorak2023-3) [[4]](#cite_note-UmbrichtChristianWinters2024-4)The drug acts as a [potent](/wiki/Potency_(pharmacology)) and well-balanced [serotonin](/wiki/Serotonin) [5-HT 2A](/wiki/5-HT2A_receptor) and [5-HT](/wiki/5-HT2C_receptor) 2Creceptor[agonist](/wiki/Agonist), serotonin [5-HT](/wiki/5-HT2B_receptor) 2Breceptor[partial agonist](/wiki/Partial_agonist)or [antagonist](/wiki/Receptor_antagonist), and [serotonin releasing agent](/wiki/Serotonin_releasing_agent). [[2]](#cite_note-MarekMakai-BölöniUmbricht2025-2) [[9]](#cite_note-HughesKleinAustin2022-9) [[8]](#cite_note-US11440879B2-8)It produces psychedelic-like effects in animals and similarly produces robust [[10]](#cite_note-WO2022256554-10)[hallucinogenic](/wiki/Hallucinogen)effects in humans. [[9]](#cite_note-HughesKleinAustin2022-9)The [[3]](#cite_note-HughesChristianDvorak2023-3)[duration](/wiki/Duration_of_action)of bretisilocin is 60 to 90 minutes and is intermediate between the durations of DMT and [psilocybin](/wiki/Psilocybin). [[6]](#cite_note-Peplow2024-6) [[11]](#cite_note-HughesKleinDvorak2023-11) [[4]](#cite_note-UmbrichtChristianWinters2024-4) [[12]](#cite_note-Gunther2023-12) [[8]](#cite_note-US11440879B2-8)It has been regarded by its developer as an "improved version of DMT". [[2]](#cite_note-MarekMakai-BölöniUmbricht2025-2) [[12]](#cite_note-Gunther2023-12)Bretisilocin was invented by Andrew Kruegel at [Gilgamesh Pharmaceuticals](/wiki/Gilgamesh_Pharmaceuticals) and was [patented](/wiki/Patented) in 2021.[[9]](#cite_note-HughesKleinAustin2022-9) [10] It is under development by Gilgamesh Pharmaceuticals. As of June 2025, the drug is in [[1]](#cite_note-AdisInsight-1)[phase 2](/wiki/Phases_of_clinical_research#Phase_II) [clinical trials](/wiki/Clinical_trial)for the treatment of [major depressive disorder](/wiki/Major_depressive_disorder). Bretisilocin was acquired from Gilgamesh Pharmaceuticals by [[1]](#cite_note-AdisInsight-1)[AbbVie](/wiki/AbbVie)in a deal worth up to $1.2 billion in August 2025. [[13]](#cite_note-Taylor2025b-13)It was encountered as a novel [[14]](#cite_note-PsychedelicAlpha2025b-14)[recreational](/wiki/Recreational_drug) [designer drug](/wiki/Designer_drug)in 2026. [[5]](#cite_note-Aipsin-5)## Use and effects [[edit](/w/index.php?title=Bretisilocin&action=edit§ion=1)] Bretisilocin, given by [intravenous injection](/wiki/Intravenous_injection), produces threshold [psychedelic](/wiki/Psychedelic) effects at doses of 1 mg and 3.3 mg, has an optimal dose range of 10 to 15 mg, and produces particularly intense effects at a dose of 20 mg. [2] The drug's effects at doses of 15 to 20 mg intravenously were described as equivalent to or greater than those of 30 mg [psilocybin](/wiki/Psilocybin) [orally](/wiki/Oral_administration)or 100 to 200 μg [LSD](/wiki/LSD)orally based on [hallucinogen rating scales](/wiki/Hallucinogen_rating_scale). The 20 mg dose of bretisilocin was associated with more [[2]](#cite_note-MarekMakai-BölöniUmbricht2025-2)[challenging experiences](/wiki/Challenging_experience)including [anxiety](/wiki/Anxiety), [cognitive impairment](/wiki/Cognitive_impairment), and dread of [ego dissolution](/wiki/Ego_dissolution), which led to selection of a lower optimal dose range of 10 to 15 mg intravenously. Compared to other psychedelics like psilocybin and LSD, bretisilocin has a much shorter [[2]](#cite_note-MarekMakai-BölöniUmbricht2025-2)[duration](/wiki/Duration_of_action), but is longer-lasting than [dimethyltryptamine](/wiki/Dimethyltryptamine)(DMT). [[2]](#cite_note-MarekMakai-BölöniUmbricht2025-2) [[11]](#cite_note-HughesKleinDvorak2023-11) [[4]](#cite_note-UmbrichtChristianWinters2024-4)Its duration is about 60 to 90 minutes, whereas psilocybin has a duration of multiple hours and DMT has a duration of as short as 10 minutes. [[8]](#cite_note-US11440879B2-8) [[2]](#cite_note-MarekMakai-BölöniUmbricht2025-2) [[6]](#cite_note-Peplow2024-6)The psychedelic effects of bretisilocin are generally resolved by approximately 2 hours after administration, but have been found to last up to 4 to 6 hours in some individuals. [[12]](#cite_note-Gunther2023-12)Peak effects occur about 10 to 20 minutes following injection. [[2]](#cite_note-MarekMakai-BölöniUmbricht2025-2) [[2]](#cite_note-MarekMakai-BölöniUmbricht2025-2)The drug, administered intravenously in clinical studies, produces effects in humans including "[altered states of consciousness](/wiki/Altered_states_of_consciousness), altered visual [depth perception](/wiki/Depth_perception), [abnormal thinking](/wiki/Abnormal_thinking), [euphoric mood](/wiki/Euphoric_mood), [feeling drunk](/wiki/Feeling_drunk), feeling of [body temperature](/wiki/Body_temperature) changes, [relaxation](/wiki/Relaxation_(psychology)), [sensory processing disorder](/wiki/Sensory_processing_disorder) (including intense visual effects with color changes), [sensory overload](/wiki/Sensory_overload), and [time perception altered](/wiki/Time_dilation)".[[2]](#cite_note-MarekMakai-BölöniUmbricht2025-2)[[3]](#cite_note-HughesChristianDvorak2023-3) [4] The subjective effects of bretisilocin were described as very robust and consistent in strength with the effects of other psychedelics including LSD, DMT, and psilocybin as have been reported in clinical studies. [[2]](#cite_note-MarekMakai-BölöniUmbricht2025-2) [[3]](#cite_note-HughesChristianDvorak2023-3)In addition to intravenous administration, bretisilocin has been [[4]](#cite_note-UmbrichtChristianWinters2024-4)[anecdotally reported](/wiki/Anecdotal_report)by recreational users to be active [intranasally](/wiki/Intranasal_administration). [[5]](#cite_note-Aipsin-5)## Side effects [[edit](/w/index.php?title=Bretisilocin&action=edit§ion=2)] [Side effects](/wiki/Side_effect) of bretisilocin include acute [sensory processing disorder](/wiki/Sensory_processing_disorder), [altered state of consciousness](/wiki/Altered_state_of_consciousness), [abnormal thinking](/wiki/Abnormal_thinking), [euphoric mood](/wiki/Euphoric_mood), [fatigue](/wiki/Fatigue), and small increases in [heart rate](/wiki/Heart_rate) and [blood pressure](/wiki/Blood_pressure), among others.[[2]](#cite_note-MarekMakai-BölöniUmbricht2025-2)[[3]](#cite_note-HughesChristianDvorak2023-3) [4] Adverse effects like fatigue and [headache](/wiki/Headache)occur after the [psychedelic experience](/wiki/Psychedelic_experience)and can persist for up to 24 hours after administration. [[2]](#cite_note-MarekMakai-BölöniUmbricht2025-2)## Interactions [[edit](/w/index.php?title=Bretisilocin&action=edit§ion=3)] ## Pharmacology [[edit](/w/index.php?title=Bretisilocin&action=edit§ion=4)] ### Pharmacodynamics [[edit](/w/index.php?title=Bretisilocin&action=edit§ion=5)] Bretisilocin acts as a [potent](/wiki/Potency_(pharmacology)) and well-balanced [serotonin](/wiki/Serotonin) [5-HT 2A](/wiki/5-HT2A_receptor) and [5-HT](/wiki/5-HT2C_receptor) 2Creceptor[agonist](/wiki/Agonist), serotonin [5-HT](/wiki/5-HT2B_receptor) 2Breceptor[antagonist](/wiki/Receptor_antagonist), and [serotonin releasing agent](/wiki/Serotonin_releasing_agent). [[2]](#cite_note-MarekMakai-BölöniUmbricht2025-2) [[9]](#cite_note-HughesKleinAustin2022-9)In another study however, it was a moderate- [[10]](#cite_note-WO2022256554-10)[efficacy](/wiki/Maximal_efficacy) [partial agonist](/wiki/Partial_agonist)of the serotonin 5-HT 2Breceptor. The drug appears to have negligible activity as a serotonin [[10]](#cite_note-WO2022256554-10)[5-HT](/wiki/5-HT1A_receptor)agonist. 1AreceptorHowever, another study found that it was a serotonin 5-HT [[9]](#cite_note-HughesKleinAustin2022-9)1Areceptor [full agonist](/wiki/Full_agonist), with an [EC](/wiki/Half-maximal_effective_concentration)at this receptor that was about 44-fold less 50[potent](/wiki/Potency_(pharmacology))than at the serotonin 5-HT 2Areceptor. [[10]](#cite_note-WO2022256554-10)The [affinity](/wiki/Affinity_(pharmacology)) (Ki) of bretisilocin for the serotonin 5-HT2A receptor was 4.9 nM with [DOI](/wiki/DOI_(drug)) as the [radioligand](/wiki/Radioligand) and 140–191 nM with [ketanserin](/wiki/Ketanserin) as the radioligand.[[2]](#cite_note-MarekMakai-BölöniUmbricht2025-2) [9] Its [EC](/wiki/Half-maximal_effective_concentration)( 50[E](/wiki/Maximal_efficacy)) values were 15.0–20.6 nM (80.6–87.6%) at the serotonin 5-HT max2Areceptor and 9.5 nM (85.1%) at the serotonin 5-HT 2Creceptor, whereas its [IC](/wiki/Half-maximal_inhibitory_concentration)at the serotonin 5-HT 502Breceptor was 5.8 nM. [[2]](#cite_note-MarekMakai-BölöniUmbricht2025-2)It showed much higher [[9]](#cite_note-HughesKleinAustin2022-9)[efficacy](/wiki/Maximal_efficacy)at the serotonin 5-HT 2Areceptor than its [parent compound](/wiki/Parent_compound) [MET](/wiki/Methylethyltryptamine)(E max= 87.6% vs. 36.2%, respectively). Bretisilocin showed very weak activity at the serotonin 5-HT [[8]](#cite_note-US11440879B2-8)1Areceptor (EC 50= 16,918 nM, E max= 83.0%). [[2]](#cite_note-MarekMakai-BölöniUmbricht2025-2) [[9]](#cite_note-HughesKleinAustin2022-9)In addition to its actions at the serotonin [[8]](#cite_note-US11440879B2-8)[5-HT](/wiki/5-HT2_receptor), it is a 2receptors[partial](/wiki/Partial_monoamine_releasing_agent)serotonin releasing agent in rat brain [synaptosomes](/wiki/Synaptosome), with an EC 50of 8.4–15.7 nM and an E maxof 66.8–71.4%. [[2]](#cite_note-MarekMakai-BölöniUmbricht2025-2) [[9]](#cite_note-HughesKleinAustin2022-9)Bretisilocin is also a [[8]](#cite_note-US11440879B2-8)[serotonin reuptake inhibitor](/wiki/Serotonin_reuptake_inhibitor)to a much weaker extent (IC 50= 418.9 nM). Additional values have also been published. [[8]](#cite_note-US11440879B2-8) [[2]](#cite_note-MarekMakai-BölöniUmbricht2025-2) [[10]](#cite_note-WO2022256554-10)Bretisilocin is related to [DMT](/wiki/Dimethyltryptamine) and is considered by its developer to be an "improved version of DMT".[[2]](#cite_note-MarekMakai-BölöniUmbricht2025-2) [12] It also induces more serotonin release than DMT, which may provide it with more [entactogen](/wiki/Entactogen)-like qualities compared to DMT. [[2]](#cite_note-MarekMakai-BölöniUmbricht2025-2)Bretisilocin produces the [[12]](#cite_note-Gunther2023-12)[head-twitch response](/wiki/Head-twitch_response), a behavioral proxy of psychedelic effects, in rodents. [[2]](#cite_note-MarekMakai-BölöniUmbricht2025-2) [[9]](#cite_note-HughesKleinAustin2022-9) [[3]](#cite_note-HughesChristianDvorak2023-3)It shows [[8]](#cite_note-US11440879B2-8)[antidepressant](/wiki/Antidepressant)-like effects in rodents. [[9]](#cite_note-HughesKleinAustin2022-9)The drug [[11]](#cite_note-HughesKleinDvorak2023-11)[dose-dependently](/wiki/Dose_dependence)produces [hypolocomotion](/wiki/Hypolocomotion)in rodents similarly to many other serotonergic psychedelics. [[8]](#cite_note-US11440879B2-8)Likewise, it produces [[15]](#cite_note-HalberstadtGeyer2018-15)[anti-obsessional](/wiki/Anti-obsessional)effects in the form of reduced [marble burying](/wiki/Marble_burying)in rodents. Bretisilocin does not produce [[8]](#cite_note-US11440879B2-8)[conditioned place preference](/wiki/Conditioned_place_preference)(CPP) in rodents, suggesting lack of [reinforcing](/wiki/Positive_reinforcement)properties. [[8]](#cite_note-US11440879B2-8)### Pharmacokinetics [[edit](/w/index.php?title=Bretisilocin&action=edit§ion=6)] The [pharmacokinetics](/wiki/Pharmacokinetics) of bretisilocin have been studied.[[2]](#cite_note-MarekMakai-BölöniUmbricht2025-2) [3] The [time to peak](/wiki/Tmax_(pharmacology))concentrations with [intravenous injection](/wiki/Intravenous_injection)is 10 to 20 minutes. Its [[2]](#cite_note-MarekMakai-BölöniUmbricht2025-2)[elimination half-life](/wiki/Elimination_half-life)is approximately 45 minutes (range 40 to 50 minutes). [[2]](#cite_note-MarekMakai-BölöniUmbricht2025-2) [[3]](#cite_note-HughesChristianDvorak2023-3)## Chemistry [[edit](/w/index.php?title=Bretisilocin&action=edit§ion=7)] Bretisilocin, also known as 5-fluoro-*N*-methyl*-N*-ethyltryptamine, is a [substituted tryptamine](/wiki/Substituted_tryptamine) [derivative](/wiki/Chemical_derivative). [8] It is a derivative of [dimethyltryptamine](/wiki/Dimethyltryptamine)(DMT) and [methylethyltryptamine](/wiki/Methylethyltryptamine)(MET) as well as of [5-fluorotryptamine](/wiki/5-fluorotryptamine)(5-FT). [[6]](#cite_note-Peplow2024-6) [[8]](#cite_note-US11440879B2-8)### Synthesis [[edit](/w/index.php?title=Bretisilocin&action=edit§ion=8)] The [chemical synthesis](/wiki/Chemical_synthesis) of bretisilocin has been described.[[10]](#cite_note-WO2022256554-10) ### Analogues [[edit](/w/index.php?title=Bretisilocin&action=edit§ion=9)] Some [analogues](/wiki/Structural_analog) of bretisilocin include [5-fluoro-DMT](/wiki/5-fluoro-DMT), [5-fluoro-DET](/wiki/5-fluoro-DET), [5-fluoro-EPT](/wiki/5-fluoro-EPT), [5-chloro-DMT](/wiki/5-chloro-DMT), [5-bromo-DMT](/wiki/5-bromo-DMT), [5-fluoro-AMT](/wiki/5-fluoro-AMT), [5-fluoro-AET](/wiki/5-fluoro-AET), [5-MeO-MET](/wiki/5-MeO-MET), and [7-F-5-MeO-MET](/wiki/7-F-5-MeO-MET), among others. ## History [[edit](/w/index.php?title=Bretisilocin&action=edit§ion=10)] Bretisilocin was first described in the literature in 2021.[[9]](#cite_note-HughesKleinAustin2022-9) [10] It was [patented](/wiki/Patent)by Andrew Kruegel at [Gilgamesh Pharmaceuticals](/wiki/Gilgamesh_Pharmaceuticals). The drug was encountered as a novel [[10]](#cite_note-WO2022256554-10)[recreational](/wiki/Recreational_drug) [designer drug](/wiki/Designer_drug)in March 2026. [[5]](#cite_note-Aipsin-5)## Society and culture [[edit](/w/index.php?title=Bretisilocin&action=edit§ion=11)] ### Names [[edit](/w/index.php?title=Bretisilocin&action=edit§ion=12)] *Bretisilocin* is the [generic name](/wiki/Generic_term) of the drug and its [INN](/wiki/International_Nonproprietary_Name) . [16] It is also known by its developmental code name *GM-2505*. [[1]](#cite_note-AdisInsight-1) [[9]](#cite_note-HughesKleinAustin2022-9) [[3]](#cite_note-HughesChristianDvorak2023-3)### Legal status [[edit](/w/index.php?title=Bretisilocin&action=edit§ion=13)] #### Canada [[edit](/w/index.php?title=Bretisilocin&action=edit§ion=14)] Bretisilocin is not a [controlled substance](/wiki/Controlled_substance) in [Canada](/wiki/Canada) as of 2025.[[17]](#cite_note-CDSA-17) #### United States [[edit](/w/index.php?title=Bretisilocin&action=edit§ion=15)] Bretislocin is not an explicitly [controlled substance](/wiki/Controlled_substance) in the [United States](/wiki/United_States). [18] However, it could be considered a [controlled substance](/wiki/Controlled_substance)under the [Federal Analogue Act](/wiki/Federal_Analogue_Act)if intended for human consumption. ## Research [[edit](/w/index.php?title=Bretisilocin&action=edit§ion=16)] Bretisilocin is under development as a potential [pharmaceutical drug](/wiki/Pharmaceutical_drug) by [Gilgamesh Pharmaceuticals](/wiki/Gilgamesh_Pharmaceuticals). [1] As of June 2025, it is in [phase 2](/wiki/Phases_of_clinical_research#Phase_II) [clinical trials](/wiki/Clinical_trial)for the treatment of [major depressive disorder](/wiki/Major_depressive_disorder). A [[1]](#cite_note-AdisInsight-1)[phase 2a](/wiki/Phases_of_clinical_research#Phase_II)trial of bretisilocin for major depressive disorder has been completed and the [efficacy](/wiki/Efficacy)and [safety](/wiki/Drug_safety)data for the trial have been released. [[1]](#cite_note-AdisInsight-1) [[19]](#cite_note-PsychedelicAlpha2025-19) [[20]](#cite_note-Taylor2025-20)The drug has since been acquired from Gilgamesh Pharmaceuticals by [[21]](#cite_note-Dunne2025-21)[AbbVie](/wiki/AbbVie)in a deal worth up to $1.2 billion. [[13]](#cite_note-Taylor2025b-13)In 2026 bretisilocin entered [[14]](#cite_note-PsychedelicAlpha2025b-14)[European Medicines Agency](/wiki/European_Medicines_Agency)’s priority medicines (PRIME) scheme for major depressive disorder. [[22]](#cite_note-22) [[23]](#cite_note-23)## See also [[edit](/w/index.php?title=Bretisilocin&action=edit§ion=17)] [Substituted tryptamine](/wiki/Substituted_tryptamine)[List of investigational hallucinogens and entactogens](/wiki/List_of_investigational_hallucinogens_and_entactogens)[List of investigational antidepressants](/wiki/List_of_investigational_antidepressants)[Luvesilocin](/wiki/Luvesilocin)(RE104; FT-104; 4-GO-DiPT) ## References [[edit](/w/index.php?title=Bretisilocin&action=edit§ion=18)] - ^ **a****b****c****d****e****f****g****h****i**["GM 2505"](https://adisinsight.springer.com/drugs/800067965).*AdisInsight*. 5 June 2025. Retrieved 29 July 2025. - ^ **a****b****c****d****e****f****g****h****i****j****k****l****m****n****o****p****q****r****s****t****u****v****w****x****y****z****aa****ab****ac****ad****ae** Marek GJ, Makai-Bölöni S, Umbricht D, Christian EP, Winters J, Dvorak D, et al. (2025). "A novel psychedelic 5-HT**af** 2Areceptor agonist GM-2505: The pharmacokinetic, safety, and pharmacodynamic profile from a randomized trial healthy volunteer".*Journal of Psychopharmacology*02698811251378512.[doi](/wiki/Doi_(identifier)):[10.1177/02698811251378512](https://doi.org/10.1177%2F02698811251378512).[hdl](/wiki/Hdl_(identifier)):[1887/4298848](https://hdl.handle.net/1887%2F4298848).[PMID](/wiki/PMID_(identifier))[41099491](https://pubmed.ncbi.nlm.nih.gov/41099491). - ^ **a****b****c****d****e****f****g****h****i****j****k** Hughes Z, Christian E, Dvorak D, Umbricht D, Winters J, Raines S, et al. (December 2023).**l**["ACNP 62nd Annual Meeting: Poster Abstracts P1 - P250: P238. Subjective and Pharmacodynamic Effects of the Novel 5-HT2A Receptor Agonist GM-2505 in Healthy Volunteers Show High Translatability From Rodent Data and Hold Promise for Future Development in Patients With Depression"](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10729595).*Neuropsychopharmacology*.**48**(Suppl 1). Springer Science and Business Media LLC: 63–210 (202–203).[doi](/wiki/Doi_(identifier)):[10.1038/s41386-023-01755-5](https://doi.org/10.1038%2Fs41386-023-01755-5).[PMC](/wiki/PMC_(identifier))[10729595](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10729595).[PMID](/wiki/PMID_(identifier))[38040809](https://pubmed.ncbi.nlm.nih.gov/38040809). - ^ **a****b****c****d****e****f** Umbricht D, Christian E, Winters J, Raines S, Hughes ZA, Leong W, et al. (2024).**g**["Pharmacokinetic, pharmacodynamic and subjective and effects of the novel 5-HT2A receptor agonist GM-2505 in healthy volunteers"](https://doi.org/10.1016%2Fj.nsa.2024.104845).*Neuroscience Applied*.**3** 104845.[doi](/wiki/Doi_(identifier)):[10.1016/j.nsa.2024.104845](https://doi.org/10.1016%2Fj.nsa.2024.104845). - ^ **a****b****c****d**["Бретисилоцин (5F-MET)"](https://aipsin.com/newsubstance/1924/).*АИПСИН*(in Russian). Retrieved 18 March 2026. - ^ **a****b****c** Peplow M (22 June 2024).**d**["Should Next-Generation Psychedelics Skip the Trip?"](https://www.scientificamerican.com/article/should-next-generation-psychedelics-skip-the-trip/).*Scientific American*. Retrieved 20 February 2025.Gilgamesh is also working on GM-2505, a 5-HT2A agonist that is structurally related to psilocybin and DMT. GM-2505 completed a phase 1 trial late last year and should enter phase 2 for major depressive disorder this year. Its psychedelic effect lasts 60 to 90 minutes — long enough for patients to "explore the altered state of consciousness that might be needed for long-term durable efficacy," Krugel says, yet within a timeframe that is manageable for healthcare systems. "Personally, I believe that the hallucinogenic effects are an important component, as multiple hallucinogenic compounds have demonstrated durable, transformational changes from a single dose in human studies," he adds. `{{` : CS1 maint: deprecated archival service ([cite web](/wiki/Template:Cite_web)}}[link](/wiki/Category:CS1_maint:_deprecated_archival_service)) Witkin JM, Golani LK, Smith JL (April 2023).[^](#cite_ref-WitkinGolaniSmith2023_7-0)["Clinical pharmacological innovation in the treatment of depression"](https://figshare.com/articles/journal_contribution/22567705).*Expert Review of Clinical Pharmacology*.**16**(4): 349–362.[doi](/wiki/Doi_(identifier)):[10.1080/17512433.2023.2198703](https://doi.org/10.1080%2F17512433.2023.2198703).[PMID](/wiki/PMID_(identifier))[37000975](https://pubmed.ncbi.nlm.nih.gov/37000975).GM-2505 is a dual-acting compound with both agonist activity at 5-HT 2A receptors and a releaser of 5-HT. [...] - ^ **a****b****c****d****e****f****g****h****i****j****k****l****m****n**["Methods of treating mood disorders"](https://patents.google.com/patent/US11440879B2).*Google Patents*. 2022. Retrieved 14 November 2024. - ^ **a****b****c****d****e****f****g****h****i****j****k****l** Hughes Z, Klein A, Austin E, Dvorak D, Gatti S, Kiss L, et al. (December 2022).**m**["ACNP 61st Annual Meeting: Poster Abstracts P1 - P270: P254. Gm-2505 is a Novel 5-Ht2a Receptor Agonist and 5-Ht Releaser That Induces Rapid, Robust, and Durable Antidepressant Effects at Doses Associated With Decreased Power in Low Frequency EEG Bands in Rats"](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9714397).*Neuropsychopharmacology*.**47**(Suppl 1): 63–219 (209–209).[doi](/wiki/Doi_(identifier)):[10.1038/s41386-022-01484-1](https://doi.org/10.1038%2Fs41386-022-01484-1).[PMC](/wiki/PMC_(identifier))[9714397](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9714397).[PMID](/wiki/PMID_(identifier))[36456693](https://pubmed.ncbi.nlm.nih.gov/36456693). - ^ **a****b****c****d****e****f****g****h****i**[WO application 2021168082](https://patentscope.wipo.int/search/en/detail.jsf?docId=WO2021168082&_cid=P12-MOBKAX-21125-1), Kruegel, Andrew, "Specific tryptamines for use in the treatment of mood disorders", published 2021-08-26, assigned to Gilgamesh PharmaceuticalsExample 2 - ^ **a****b** Hughes Z, Klein A, Dvorak D, Austin E, Kiss L, Marek G, et al. (2023). "22. GM-2505 has Rapid Onset Antidepressant Activity and Causes Dose-Dependent Changes in qEEG With Increasing 5-HT2A Receptor Occupancy".**c*** Biological Psychiatry*.**93**(9): S102–S103.[doi](/wiki/Doi_(identifier)):[10.1016/j.biopsych.2023.02.262](https://doi.org/10.1016%2Fj.biopsych.2023.02.262). - ^ **a****b****c****d** Gunther M (31 January 2023).**e**["Gilgamesh Tweaks Known Psychedelics To Improve Therapies"](https://www.lucid.news/gilgamesh-tweaks-psychedelics/).*Lucid News - Psychedelics, Consciousness Technology, and the Future of Wellness*. Retrieved 20 February 2025. - ^ **a** Taylor NP (25 August 2025).**b**["AbbVie tunes in to Gilgamesh's story, inking $1.2B deal for psychedelic program"](https://www.fiercebiotech.com/biotech/abbvie-tunes-gilgameshs-story-inking-12b-deal-psychedelic-program).*Fierce Biotech*. Retrieved 15 October 2025. - ^ **a** Psychedelic Alpha (25 August 2025).**b**["AbbVie to Acquire Gilgamesh's Bretisilocin for Up to $1.2B"](https://psychedelicalpha.com/news/abbvie-to-acquire-gilgameshs-bretisilocin-for-up-to-1-2b).*Psychedelic Alpha*. Retrieved 15 October 2025. Halberstadt AL, Geyer MA (2018). "Effect of Hallucinogens on Unconditioned Behavior".[^](#cite_ref-HalberstadtGeyer2018_15-0)*Behavioral Neurobiology of Psychedelic Drugs*. Curr Top Behav Neurosci. Vol. 36. pp. 159–199.[doi](/wiki/Doi_(identifier)):[10.1007/7854_2016_466](https://doi.org/10.1007%2F7854_2016_466).[ISBN](/wiki/ISBN_(identifier))[978-3-662-55878-2](/wiki/Special:BookSources/978-3-662-55878-2).[PMC](/wiki/PMC_(identifier))[5787039](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5787039).[PMID](/wiki/PMID_(identifier))[28224459](https://pubmed.ncbi.nlm.nih.gov/28224459).[^](#cite_ref-WHO2024_16-0)[https://iris.who.int/bitstream/handle/10665/380497/9789240107038-eng.pdf](https://iris.who.int/bitstream/handle/10665/380497/9789240107038-eng.pdf)"bretisilocinum bretisilocin N-ethyl-2-(5-fluoro-1H-indol-3-yl)-N-methylethan-1-amine serotonin (5-HT2A) receptor agonist"[^](#cite_ref-CDSA_17-0)["Controlled Drugs and Substances Act"](https://laws-lois.justice.gc.ca/eng/acts/c-38.8/FullText.html).*Department of Justice Canada*. Retrieved 19 January 2026.[^](#cite_ref-OrangeBook2026_18-0)(PDF),*Orange Book: List of Controlled Substances and Regulated Chemicals (January 2026)*[United States](/wiki/United_States): U.S.[Department of Justice](/wiki/Department_of_Justice):[Drug Enforcement Administration](/wiki/Drug_Enforcement_Administration)(DEA): Diversion Control Division, January 2026Psychedelic Alpha (27 May 2025).[^](#cite_ref-PsychedelicAlpha2025_19-0)["Gilgamesh's Next-Gen Psychedelic GM-2505 Prints Impressive Results in Phase 2a Major Depressive Disorder Study"](https://psychedelicalpha.com/news/gilgameshs-next-gen-psychedelic-gm-2505-prints-impressive-results-in-phase-2a-major-depressive-disorder-study).*Psychedelic Alpha*. Retrieved 29 July 2025.Taylor NP (27 May 2025).[^](#cite_ref-Taylor2025_20-0)["Gilgamesh links psychedelic to 94% remission rate in midphase depression trial"](https://www.fiercebiotech.com/biotech/gilgamesh-links-psychedelic-90-remission-rate-midphase-depression-trial).*Fierce Biotech*. Retrieved 29 July 2025.Dunne R (31 May 2025).[^](#cite_ref-Dunne2025_21-0)["Gilgamesh's psychedelic drug demonstrates exceptional efficacy for treating depression"](https://mugglehead.com/gilgameshs-psychedelic-drug-demonstrates-remarkable-efficacy-for-treating-depression/).*Mugglehead Investment Magazine*. Retrieved 29 July 2025.Psychedelic Access and Research European Alliance (2026-03-19).[^](#cite_ref-22)["Bretisilocin Becomes First Psychedelic in EMA PRIME Scheme for Depression"](https://www.drugpolicywatch.com/news/2026-03-19-bretisilocin-becomes-first-psychedelic-in-ema-prime-scheme-for-depression).*Drug Policy Tracker*. Retrieved 2026-03-29.European Medicines Agency (EMA) (2026-03-18).[^](#cite_ref-23)["New PRIME tools to accelerate development of medicines in the EU"](https://www.ema.europa.eu/en/news/new-prime-tools-accelerate-development-medicines-eu).*www.ema.europa.eu*. Retrieved 2026-03-19. ## External links [[edit](/w/index.php?title=Bretisilocin&action=edit§ion=19)]