2C-B: Difference between revisions
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MDElliottMD (talk | contribs) Populate 2C-B effects field: 60-effect subjective profile (parser-claude handoff), adapted from PsychonautWiki CC BY-SA 4.0, source approved by Mark; all 60 effect slugs verified in pcp_effects |
MDElliottMD (talk | contribs) home-claude: Erowid dosing (erowid-claude source; URLs verified; em-dash clean) |
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| bioavailability = Not well characterized | | bioavailability = Not well characterized | ||
| pregnancy = Not established | | pregnancy = Not established | ||
| legal = Schedule I (United States) | | legal = [[USLegal:DEA Schedule I|Schedule I]] (United States) | ||
| mechanism = 5-HT2A partial agonist | | mechanism = 5-HT2A partial agonist | ||
| intro = 2C-B, chemically 4-bromo-2,5-dimethoxyphenethylamine, is a synthetic psychedelic phenethylamine first prepared in 1974 by Alexander Shulgin at his home laboratory in Lafayette, California. It is the founding member of the 2C series, a family of 2,5-dimethoxy-4-substituted phenethylamines that Shulgin and his collaborators developed as variations on the mescaline skeleton. 2C-B occupies a distinctive position in the psychedelic medicine landscape: a compound with a mescaline-class structural lineage, a 5-HT2A pharmacology shared with the classical psychedelics, and a subjective character that has been described as bridging the entactogenic register of MDMA and the visionary register of the classical psychedelics. It had a brief legal-sale era in the late 1980s and early 1990s before being placed in Schedule I of the United States Controlled Substances Act, temporarily in 1994 and permanently in 1995, and in Schedule II of the United Nations Convention on Psychotropic Substances in 2001. | | intro = 2C-B, chemically 4-bromo-2,5-dimethoxyphenethylamine, is a synthetic psychedelic [[:Category:Phenethylamines|phenethylamine]] first prepared in 1974 by [[Alexander Shulgin]] at his home laboratory in Lafayette, California. It is the founding member of the [[:Category:2C-x series|2C series]], a family of 2,5-dimethoxy-4-substituted phenethylamines that Shulgin and his collaborators developed as variations on the [[Mescaline|mescaline]] skeleton. 2C-B occupies a distinctive position in the psychedelic medicine landscape: a compound with a mescaline-class structural lineage, a [[Receptor:5-HT2A|5-HT2A]] pharmacology shared with the [[:Category:Psychedelics|classical psychedelics]], and a subjective character that has been described as bridging the [[:Category:Empathogens|entactogenic]] register of [[MDMA]] and the visionary register of the classical psychedelics. It had a brief legal-sale era in the late 1980s and early 1990s before being placed in [[Schedule I]] of the United States [[Controlled Substances Act]], temporarily in 1994 and permanently in 1995, and in Schedule II of the [[Convention on Psychotropic Substances|United Nations Convention on Psychotropic Substances]] in 2001. | ||
| history = The compound that became 2C-B emerged from Shulgin's systematic exploration of the structure-activity relationships of mescaline analogs, a program he had begun in the mid-1960s. Shulgin's hypothesis was that modifications to the trimethoxyphenethylamine skeleton might yield compounds active at lower doses than mescaline's, with subjective profiles that varied in characteristic ways with the substituent at the 4-position of the phenyl ring. 2C-B, with bromine at the 4-position, was one of the most striking results. The first published description appeared in 1975 in Psychopharmacology Communications, the short-lived journal that was one of the few outlets willing to publish Shulgin's work in that era.<ref name="shulgin1975">Shulgin AT, Carter MF. Centrally active phenethylamines. Psychopharmacology Communications. 1975;1(1):93-98.</ref> | | history = The compound that became 2C-B emerged from Shulgin's systematic exploration of the structure-activity relationships of mescaline analogs, a program he had begun in the mid-1960s. Shulgin's hypothesis was that modifications to the trimethoxyphenethylamine skeleton might yield compounds active at lower doses than mescaline's, with subjective profiles that varied in characteristic ways with the substituent at the 4-position of the phenyl ring. 2C-B, with bromine at the 4-position, was one of the most striking results. The first published description appeared in 1975 in Psychopharmacology Communications, the short-lived journal that was one of the few outlets willing to publish Shulgin's work in that era.<ref name="shulgin1975">Shulgin AT, Carter MF. Centrally active phenethylamines. Psychopharmacology Communications. 1975;1(1):93-98.</ref> | ||
The compound entered psychotherapeutic underground practice in the late 1970s, where it gained a reputation as a potential adjunct to psychotherapy.<ref name="papaseit2018"/> Interest grew particularly after MDMA was placed in Schedule I, on an emergency basis in 1985 and permanently in 1988,<ref name="blok2020">Blok G. [From Adam to ecstacy; legal use of MDMA in the 1970s and 1980s]. Tijdschrift voor Psychiatrie. 2020;62(8):702-706. PMID 32816299.</ref> removing that medicine from the limited circle of therapists who had been using it adjunctively. 2C-B remained legal in the United States until 1994<ref name="fr1994"/> and, for a window of years, in much of Europe. [citation needed] During that period it was used by some therapists as an MDMA-adjacent option for couples and individual work. [citation needed] It was sold commercially as an aphrodisiac under the brand name Nexus<ref name="papaseit2018"/> and, in some accounts, the name Eroxan, with commercial sale dated to the late 1980s. [citation needed] As Nexus, 2C-B became particularly identified with South Africa, where it had a brief and conspicuous run as a legally sold aphrodisiac in the early 1990s before the South African Medicines Control Council scheduled it. [citation needed] | The compound entered psychotherapeutic underground practice in the late 1970s, where it gained a reputation as a potential adjunct to psychotherapy.<ref name="papaseit2018"/> Interest grew particularly after MDMA was placed in Schedule I, on an emergency basis in 1985 and permanently in 1988,<ref name="blok2020">Blok G. [From Adam to ecstacy; legal use of MDMA in the 1970s and 1980s]. Tijdschrift voor Psychiatrie. 2020;62(8):702-706. PMID 32816299.</ref> removing that medicine from the limited circle of therapists who had been using it adjunctively. 2C-B remained legal in the United States until 1994<ref name="fr1994"/> and, for a window of years, in much of Europe. [citation needed] During that period it was used by some therapists as an MDMA-adjacent option for couples and individual work. [citation needed] It was sold commercially as an aphrodisiac under the brand name Nexus<ref name="papaseit2018"/> and, in some accounts, the name Eroxan, with commercial sale dated to the late 1980s. [citation needed] As Nexus, 2C-B became particularly identified with South Africa, where it had a brief and conspicuous run as a legally sold aphrodisiac in the early 1990s before the South African [[Medicines Control Council]] scheduled it. [citation needed] | ||
{{ShulginsCorner | {{ShulginsCorner | ||
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}} | }} | ||
The full account of the synthesis, qualitative effects, and dose range was published in 1991 in Shulgin and Shulgin's PiHKAL: A Chemical Love Story, the first half of which is autobiographical and the second half of which is a methodical catalog of 179 phenethylamines that Shulgin and his collaborators synthesized and self-tested. The book included full experimental procedures and was published as a deliberate political act: Shulgin held a Drug Enforcement Administration analytical license to possess and study scheduled compounds, and chose to make the chemistry public knowledge in the conviction that the information should not be the property of governments. In 1994 a DEA inspection of his laboratory ended with Shulgin surrendering that license, an episode Ann Shulgin recounts in the opening chapter of the companion volume TiHKAL.<ref name="tihkal-invasion">Shulgin A, Shulgin A. TIHKAL: The Continuation. Berkeley, CA: Transform Press; 1997. Chapter 1, "Invasion".</ref> | The full account of the synthesis, qualitative effects, and dose range was published in 1991 in Shulgin and [[Ann Shulgin|Shulgin]]'s [[PiHKAL]]: A Chemical Love Story, the first half of which is autobiographical and the second half of which is a methodical catalog of 179 phenethylamines that Shulgin and his collaborators synthesized and self-tested. The book included full experimental procedures and was published as a deliberate political act: Shulgin held a [[Drug Enforcement Administration]] analytical license to possess and study scheduled compounds, and chose to make the chemistry public knowledge in the conviction that the information should not be the property of governments. In 1994 a DEA inspection of his laboratory ended with Shulgin surrendering that license, an episode Ann Shulgin recounts in the opening chapter of the companion volume TiHKAL.<ref name="tihkal-invasion">Shulgin A, Shulgin A. TIHKAL: The Continuation. Berkeley, CA: Transform Press; 1997. Chapter 1, "Invasion".</ref> | ||
The United States Drug Enforcement Administration placed 2C-B in Schedule I on a temporary, emergency basis in January 1994,<ref name="fr1994">Drug Enforcement Administration. Schedules of Controlled Substances: Temporary Placement of 4-Bromo-2,5-dimethoxyphenethylamine Into Schedule I. Final Rule. Federal Register. 1994 Jan 6;59:671.</ref> and made the placement permanent in 1995.<ref name="fr1995">Drug Enforcement Administration. Schedules of Controlled Substances; Placement of 4-Bromo-2,5-Dimethoxyphenethylamine Into Schedule I. Final Rule. Federal Register. 1995 Jun 2;60:28718.</ref> The United Nations Convention on Psychotropic Substances added it to Schedule II in 2001.<ref name="papaseit2018"/> Most other jurisdictions scheduled the compound on similar timelines. For roughly a decade after the US scheduling, 2C-B circulated as a clandestine product in European and South American party scenes, often sold as MDMA or under one of the brand names that survived the legal sale era. In the 2010s and 2020s a small body of formal clinical research has emerged: an observational study at the Universitat Autònoma de Barcelona reported the acute pharmacology of oral 2C-B in experienced users,<ref name="papaseit2018">Papaseit E, Farré M, Pérez-Mañá C, Torrens M, et al. Acute Pharmacological Effects of 2C-B in Humans: An Observational Study. Frontiers in Pharmacology. 2018;9:206. PMID 29593537.</ref> and groups at Maastricht University and the University of Basel have begun controlled comparisons of 2C-B with psilocybin and MDMA. | The United States Drug Enforcement Administration placed 2C-B in Schedule I on a temporary, emergency basis in January 1994,<ref name="fr1994">Drug Enforcement Administration. Schedules of Controlled Substances: Temporary Placement of 4-Bromo-2,5-dimethoxyphenethylamine Into Schedule I. Final Rule. Federal Register. 1994 Jan 6;59:671.</ref> and made the placement permanent in 1995.<ref name="fr1995">Drug Enforcement Administration. Schedules of Controlled Substances; Placement of 4-Bromo-2,5-Dimethoxyphenethylamine Into Schedule I. Final Rule. Federal Register. 1995 Jun 2;60:28718.</ref> The United Nations Convention on Psychotropic Substances added it to Schedule II in 2001.<ref name="papaseit2018"/> Most other jurisdictions scheduled the compound on similar timelines. For roughly a decade after the US scheduling, 2C-B circulated as a clandestine product in European and South American party scenes, often sold as MDMA or under one of the brand names that survived the legal sale era. In the 2010s and 2020s a small body of formal clinical research has emerged: an observational study at the Universitat Autònoma de Barcelona reported the acute pharmacology of oral 2C-B in experienced users,<ref name="papaseit2018">Papaseit E, Farré M, Pérez-Mañá C, Torrens M, et al. Acute Pharmacological Effects of 2C-B in Humans: An Observational Study. Frontiers in Pharmacology. 2018;9:206. PMID 29593537.</ref> and groups at Maastricht University and the University of Basel have begun controlled comparisons of 2C-B with [[Psilocybin|psilocybin]] and MDMA. | ||
2C-B is not licensed as a medicine in any major jurisdiction. Formal clinical investigation is in early stages. Underground therapeutic use continues in the lineage that began with the late-1970s Shulgin circle. The compound's role in the modern psychedelic-medicine landscape is uncertain: its shorter duration and lower dose-response slope make it logistically tractable, but the limited modern clinical data and the absence of major-trial sponsorship have kept it on the margins of the renaissance that has gathered around psilocybin and MDMA. | 2C-B is not licensed as a medicine in any major jurisdiction. Formal clinical investigation is in early stages. Underground therapeutic use continues in the lineage that began with the late-1970s Shulgin circle. The compound's role in the modern psychedelic-medicine landscape is uncertain: its shorter duration and lower dose-response slope make it logistically tractable, but the limited modern clinical data and the absence of major-trial sponsorship have kept it on the margins of the renaissance that has gathered around psilocybin and MDMA. | ||
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<titration slug="harm-reduction" author="MDElliottMD" title="Harm reduction considerations"> | <titration slug="harm-reduction" author="MDElliottMD" title="Harm reduction considerations"> | ||
2C-B is a Schedule I controlled substance in the United States with no approved medical use and no legal supply chain that guarantees product identity or purity; in modern markets it is frequently misrepresented as MDMA or substituted with other compounds, including the structurally similar but pharmacologically distinct DOB. Onset after oral administration is typically 45-75 minutes; the long onset combined with the steep dose-response curve drives a common harm pattern in which inexperienced users redose during the onset window and overshoot the intended dose. Combinations with serotonergic medicines (SSRIs, SNRIs, MAOIs, tramadol, | 2C-B is a Schedule I controlled substance in the United States with no approved medical use and no legal supply chain that guarantees product identity or purity; in modern markets it is frequently misrepresented as MDMA or substituted with other compounds, including the structurally similar but pharmacologically distinct [[DOB]]. Onset after oral administration is typically 45-75 minutes; the long onset combined with the steep dose-response curve drives a common harm pattern in which inexperienced users redose during the onset window and overshoot the intended dose. Combinations with serotonergic medicines ([[:Category:Selective Serotonin Reuptake Inhibitors (SSRIs)|SSRIs]], [[:Category:Serotonin–Norepinephrine Reuptake Inhibitors (SNRIs)|SNRIs]], [[:Category:Monoamine Oxidase Inhibitors (MAOIs)|MAOIs]], [[Tramadol|tramadol]], [[Dextromethorphan|dextromethorphan]]) carry [[Serotonin syndrome|serotonin syndrome]] risk and should be avoided. [[Lithium]] is a separate concern: combined with psychedelics it is associated with a markedly increased risk of seizures and severe adverse reactions, and should likewise be avoided. Combinations with [[:Category:Psychostimulants|psychostimulants]] increase cardiovascular load. The general harm-reduction principles for psychedelic experiences (set, setting, sober companion, advance arrangement of supportive contacts) apply to 2C-B as they do to other 5-HT2A agonists. | ||
</titration> | </titration> | ||
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| voice = Commentary | | voice = Commentary | ||
}} | }} | ||
<titration slug="erowid-dose-oral" author="erowid-claude" | |||
title="Oral dose ladder (Erowid)"> | |||
Erowid's dosage documentation for oral 2C-B<ref name="erowid-2cb-dose"> | |||
Erowid. 2C-B Dosage. Erowid.org. | |||
https://www.erowid.org/chemicals/2cb/2cb_dose.shtml. | |||
Accessed 2026-05-25.</ref> reports the following tiers: | |||
* '''Threshold:''' 2-5 mg | |||
* '''Light:''' 5-15 mg | |||
* '''Common:''' 15-25 mg | |||
* '''Strong:''' 25-50 mg | |||
Timing data are not provided by Erowid for this substance. Nasal | |||
administration has been reported but Erowid does not provide separate | |||
insufflated dose tiers. Note that Erowid's common range (15-25 mg) | |||
approximates but is slightly broader than Shulgin's PiHKAL range | |||
(12-24 mg); both are consistent with the medicine's steep dose-response curve. | |||
</titration> | |||
| effects = | | effects = | ||
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| pk_metabolism = | | pk_metabolism = | ||
| pk_elimination = | | pk_elimination = | ||
| pharmacodynamics = 2C-B is a partial agonist at the serotonin 5-HT2A receptor, with additional activity at 5-HT2C and 5-HT2B and weak inhibition of monoamine transporters.<ref name="nichols2016">Nichols DE. Psychedelics. Pharmacological Reviews. 2016;68(2):264-355. PMID 26841800.</ref> The pharmacological profile is intermediate between the classical 5-HT2A psychedelics such as LSD and psilocybin and the entactogens such as MDMA. The 5-HT2A action is the principal driver of the psychedelic component; the transporter activity may contribute to the entactogenic character at lower doses. Oral 2C-B has an onset of roughly 45 to 75 minutes and a duration of approximately four to eight hours, which is shorter than psilocybin and considerably shorter than LSD. The compound is structurally a phenethylamine in the mescaline lineage rather than a tryptamine; the 4-bromo substituent on the 2,5-dimethoxyphenethylamine scaffold confers substantially higher 5-HT2A affinity than mescaline's 3,4,5-trimethoxy parent compound, accounting for the dose-potency difference. | | pharmacodynamics = 2C-B is a partial agonist at the serotonin 5-HT2A receptor, with additional activity at [[Receptor:5-HT2C|5-HT2C]] and [[Receptor:5-HT2B|5-HT2B]] and weak inhibition of [[Monoamine transporter|monoamine transporters]].<ref name="nichols2016">Nichols DE. Psychedelics. Pharmacological Reviews. 2016;68(2):264-355. PMID 26841800.</ref> The pharmacological profile is intermediate between the classical 5-HT2A psychedelics such as [[LSD]] and psilocybin and the entactogens such as MDMA. The 5-HT2A action is the principal driver of the psychedelic component; the transporter activity may contribute to the entactogenic character at lower doses. Oral 2C-B has an onset of roughly 45 to 75 minutes and a duration of approximately four to eight hours, which is shorter than psilocybin and considerably shorter than LSD. The compound is structurally a phenethylamine in the mescaline lineage rather than a [[:Category:Tryptamines|tryptamine]]; the 4-bromo substituent on the 2,5-dimethoxyphenethylamine scaffold confers substantially higher 5-HT2A affinity than mescaline's 3,4,5-trimethoxy parent compound, accounting for the dose-potency difference. | ||
{{ShulginsCorner | {{ShulginsCorner | ||
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Key interaction concerns for 2C-B specifically: | Key interaction concerns for 2C-B specifically: | ||
* '''Serotonergic medicines: serotonin syndrome risk.''' Concurrent use of SSRIs, SNRIs, MAOIs, tramadol | * '''Serotonergic medicines: serotonin syndrome risk.''' Concurrent use of SSRIs, SNRIs, MAOIs, tramadol, dextromethorphan, or other strongly serotonergic agents carries serotonin syndrome risk and should be avoided. MAOI co-administration is particularly dangerous. | ||
* ''' | * '''Lithium: seizure and severe-reaction risk.''' Lithium combined with psychedelics including 2C-B is associated with a markedly increased risk of seizures and severe adverse reactions; the mechanism is distinct from serotonin syndrome. Avoid combination. | ||
* '''CYP interactions: not well characterized.''' Human metabolism of 2C-B has not been comprehensively studied. In vitro work suggests CYP2D6 and CYP3A4 involvement; strong inhibitors of these enzymes may increase 2C-B exposure. | * '''Psychostimulants: additive cardiovascular load.''' 2C-B itself produces modest sympathomimetic effects (elevated heart rate, mild blood pressure increase); concurrent psychostimulants compound the cardiovascular burden. | ||
* '''CYP interactions: not well characterized.''' Human metabolism of 2C-B has not been comprehensively studied. In vitro work suggests [[Enzyme:CYP2D6|CYP2D6]] and [[Enzyme:CYP3A4|CYP3A4]] involvement; strong inhibitors of these enzymes may increase 2C-B exposure. | |||
| pregnancy_details = Not characterized. 2C-B has not been studied in human pregnancy; no preclinical reproductive toxicology data are available in the public literature. The compound's Schedule I status precludes systematic study under conventional regulatory frameworks. Avoid in pregnancy on first-principles grounds. | | pregnancy_details = Not characterized. 2C-B has not been studied in human pregnancy; no preclinical reproductive toxicology data are available in the public literature. The compound's Schedule I status precludes systematic study under conventional regulatory frameworks. Avoid in pregnancy on first-principles grounds. | ||
Latest revision as of 16:10, 26 May 2026
Psychedelic, Phenethylamine, 2C-x series
2C-B
Nexus, Eroxan (historical, late-1980s through mid-1990s)
2C-B, chemically 4-bromo-2,5-dimethoxyphenethylamine, is a synthetic psychedelic phenethylamine first prepared in 1974 by Alexander Shulgin at his home laboratory in Lafayette, California. It is the founding member of the 2C series, a family of 2,5-dimethoxy-4-substituted phenethylamines that Shulgin and his collaborators developed as variations on the mescaline skeleton. 2C-B occupies a distinctive position in the psychedelic medicine landscape: a compound with a mescaline-class structural lineage, a 5-HT2A pharmacology shared with the classical psychedelics, and a subjective character that has been described as bridging the entactogenic register of MDMA and the visionary register of the classical psychedelics. It had a brief legal-sale era in the late 1980s and early 1990s before being placed in Schedule I of the United States Controlled Substances Act, temporarily in 1994 and permanently in 1995, and in Schedule II of the United Nations Convention on Psychotropic Substances in 2001.
Mescaline, MDMA, Psilocybin, LSD
History
The compound that became 2C-B emerged from Shulgin's systematic exploration of the structure-activity relationships of mescaline analogs, a program he had begun in the mid-1960s. Shulgin's hypothesis was that modifications to the trimethoxyphenethylamine skeleton might yield compounds active at lower doses than mescaline's, with subjective profiles that varied in characteristic ways with the substituent at the 4-position of the phenyl ring. 2C-B, with bromine at the 4-position, was one of the most striking results. The first published description appeared in 1975 in Psychopharmacology Communications, the short-lived journal that was one of the few outlets willing to publish Shulgin's work in that era.[1]
The compound entered psychotherapeutic underground practice in the late 1970s, where it gained a reputation as a potential adjunct to psychotherapy.[2] Interest grew particularly after MDMA was placed in Schedule I, on an emergency basis in 1985 and permanently in 1988,[3] removing that medicine from the limited circle of therapists who had been using it adjunctively. 2C-B remained legal in the United States until 1994[4] and, for a window of years, in much of Europe. [citation needed] During that period it was used by some therapists as an MDMA-adjacent option for couples and individual work. [citation needed] It was sold commercially as an aphrodisiac under the brand name Nexus[2] and, in some accounts, the name Eroxan, with commercial sale dated to the late 1980s. [citation needed] As Nexus, 2C-B became particularly identified with South Africa, where it had a brief and conspicuous run as a legally sold aphrodisiac in the early 1990s before the South African Medicines Control Council scheduled it. [citation needed]
Shulgin's Corner
If there is anything ever found to be an effective aphrodisiac, it will probably be patterned after 2C-B in structure.
Alexander Shulgin, PiHKAL, Recipe #20, pp. 503-506
Commentary
Commentary
The full account of the synthesis, qualitative effects, and dose range was published in 1991 in Shulgin and Shulgin's PiHKAL: A Chemical Love Story, the first half of which is autobiographical and the second half of which is a methodical catalog of 179 phenethylamines that Shulgin and his collaborators synthesized and self-tested. The book included full experimental procedures and was published as a deliberate political act: Shulgin held a Drug Enforcement Administration analytical license to possess and study scheduled compounds, and chose to make the chemistry public knowledge in the conviction that the information should not be the property of governments. In 1994 a DEA inspection of his laboratory ended with Shulgin surrendering that license, an episode Ann Shulgin recounts in the opening chapter of the companion volume TiHKAL.[5]
The United States Drug Enforcement Administration placed 2C-B in Schedule I on a temporary, emergency basis in January 1994,[4] and made the placement permanent in 1995.[6] The United Nations Convention on Psychotropic Substances added it to Schedule II in 2001.[2] Most other jurisdictions scheduled the compound on similar timelines. For roughly a decade after the US scheduling, 2C-B circulated as a clandestine product in European and South American party scenes, often sold as MDMA or under one of the brand names that survived the legal sale era. In the 2010s and 2020s a small body of formal clinical research has emerged: an observational study at the Universitat Autònoma de Barcelona reported the acute pharmacology of oral 2C-B in experienced users,[2] and groups at Maastricht University and the University of Basel have begun controlled comparisons of 2C-B with psilocybin and MDMA.
2C-B is not licensed as a medicine in any major jurisdiction. Formal clinical investigation is in early stages. Underground therapeutic use continues in the lineage that began with the late-1970s Shulgin circle. The compound's role in the modern psychedelic-medicine landscape is uncertain: its shorter duration and lower dose-response slope make it logistically tractable, but the limited modern clinical data and the absence of major-trial sponsorship have kept it on the margins of the renaissance that has gathered around psilocybin and MDMA.Experience
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+ Add a problemTitration strategies
Reported oral dose magnitudes0
PiHKAL #20 reports an oral dosage range of 12-24 mg with a duration of 4-8 hours. The dose-response curve is steep across this range; Shulgin's commentary observes that every 2 mg can make a profound change in response, and the practical implication is that 2C-B does not tolerate the kind of dose imprecision that is forgiving with longer-duration psychedelics such as psilocybin or LSD. Doses below 12 mg are described as threshold or "museum level" in the Shulgin literature, producing perceptual shifts subtle enough to allow ordinary public activity. The Papaseit 2018 observational study at the Universitat Autònoma de Barcelona characterized acute pharmacology in experienced users at doses comparable to the PiHKAL range and is the closest the modern clinical literature comes to a controlled human pharmacokinetic study; doses substantially above 24 mg are not characterized in the formal literature and the few case reports available describe adverse psychological events.
Shulgin's Corner
A day at the Stanford museum. Things were visually rich, yet I felt that I was reasonably inconspicuous. The Rodin sculptures were very personal and not terribly subtle. I saw Escher things in the ceiling design, when I decided to sit in a foyer somewhere and simply pretend to rest.
Anonymous (quoted in PiHKAL), Recipe #20, pp. 503-506
Narrative
Narrative
Harm reduction considerations0
2C-B is a Schedule I controlled substance in the United States with no approved medical use and no legal supply chain that guarantees product identity or purity; in modern markets it is frequently misrepresented as MDMA or substituted with other compounds, including the structurally similar but pharmacologically distinct DOB. Onset after oral administration is typically 45-75 minutes; the long onset combined with the steep dose-response curve drives a common harm pattern in which inexperienced users redose during the onset window and overshoot the intended dose. Combinations with serotonergic medicines (SSRIs, SNRIs, MAOIs, tramadol, dextromethorphan) carry serotonin syndrome risk and should be avoided. Lithium is a separate concern: combined with psychedelics it is associated with a markedly increased risk of seizures and severe adverse reactions, and should likewise be avoided. Combinations with psychostimulants increase cardiovascular load. The general harm-reduction principles for psychedelic experiences (set, setting, sober companion, advance arrangement of supportive contacts) apply to 2C-B as they do to other 5-HT2A agonists.
Shulgin's Corner
The 2C-B experience is one of the shortest of any major psychedelic drug. Wherever you might be, hang on. In an hour or so you will be approaching familiar territory again.
Alexander Shulgin, PiHKAL, Recipe #20, pp. 503-506
Commentary
Commentary
Oral dose ladder (Erowid)0
Erowid's dosage documentation for oral 2C-B[7] reports the following tiers:
- Threshold: 2-5 mg
- Light: 5-15 mg
- Common: 15-25 mg
- Strong: 25-50 mg
Timing data are not provided by Erowid for this substance. Nasal administration has been reported but Erowid does not provide separate insufflated dose tiers. Note that Erowid's common range (15-25 mg) approximates but is slightly broader than Shulgin's PiHKAL range
(12-24 mg); both are consistent with the medicine's steep dose-response curve.Effects
Physical
- Stimulation 100% -47.0 (n=1) no reports yetDid you experience this?How often have you seen this?How was it? (-100 worst, +100 best)How was it? (-100 worst, +100 best)
- Spontaneous bodily sensations 100% +0.0 (n=1) ~0% -62.0 (n=1)Did you experience this?How often have you seen this?How was it? (-100 worst, +100 best)How was it? (-100 worst, +100 best)
- Physical euphoria 100% +45.0 (n=1) no reports yetDid you experience this?How often have you seen this?How was it? (-100 worst, +100 best)How was it? (-100 worst, +100 best)
- Tactile intensification 100% +38.0 (n=1) no reports yetDid you experience this?How often have you seen this?How was it? (-100 worst, +100 best)How was it? (-100 worst, +100 best)
- Nausea 100% -25.0 (n=1) no reports yetDid you experience this?How often have you seen this?How was it? (-100 worst, +100 best)How was it? (-100 worst, +100 best)
- Appetite Suppression 100% +20.0 (n=1) no reports yetDid you experience this?How often have you seen this?How was it? (-100 worst, +100 best)How was it? (-100 worst, +100 best)
- Bodily control enhancement 0% — (n=1) no reports yetDid you experience this?How often have you seen this?How was it? (-100 worst, +100 best)How was it? (-100 worst, +100 best)
- Increased heart rate 0% — (n=1) no reports yetDid you experience this?How often have you seen this?How was it? (-100 worst, +100 best)How was it? (-100 worst, +100 best)
- Increased blood pressure 0% — (n=1) no reports yetDid you experience this?How often have you seen this?How was it? (-100 worst, +100 best)How was it? (-100 worst, +100 best)
- Increased bodily temperature 100% -10.0 (n=1) no reports yetDid you experience this?How often have you seen this?How was it? (-100 worst, +100 best)How was it? (-100 worst, +100 best)
- Increased perspiration 100% -10.0 (n=1) no reports yetDid you experience this?How often have you seen this?How was it? (-100 worst, +100 best)How was it? (-100 worst, +100 best)
- Dehydration 0% — (n=1) no reports yetDid you experience this?How often have you seen this?How was it? (-100 worst, +100 best)How was it? (-100 worst, +100 best)
- Pupil dilation no reports yet no reports yetDid you experience this?How often have you seen this?How was it? (-100 worst, +100 best)How was it? (-100 worst, +100 best)
- Jaw clenching / bruxism 0% — (n=1) no reports yetDid you experience this?How often have you seen this?How was it? (-100 worst, +100 best)How was it? (-100 worst, +100 best)
Visual
- Color enhancement no reports yet no reports yetDid you experience this?How often have you seen this?How was it? (-100 worst, +100 best)How was it? (-100 worst, +100 best)
- Magnification no reports yet no reports yetDid you experience this?How often have you seen this?How was it? (-100 worst, +100 best)How was it? (-100 worst, +100 best)
- Pattern recognition enhancement no reports yet no reports yetDid you experience this?How often have you seen this?How was it? (-100 worst, +100 best)How was it? (-100 worst, +100 best)
- Visual acuity enhancement no reports yet no reports yetDid you experience this?How often have you seen this?How was it? (-100 worst, +100 best)How was it? (-100 worst, +100 best)
- Drifting no reports yet no reports yetDid you experience this?How often have you seen this?How was it? (-100 worst, +100 best)How was it? (-100 worst, +100 best)
- After images no reports yet no reports yetDid you experience this?How often have you seen this?How was it? (-100 worst, +100 best)How was it? (-100 worst, +100 best)
- Color shifting no reports yet no reports yetDid you experience this?How often have you seen this?How was it? (-100 worst, +100 best)How was it? (-100 worst, +100 best)
- Depth perception distortions no reports yet no reports yetDid you experience this?How often have you seen this?How was it? (-100 worst, +100 best)How was it? (-100 worst, +100 best)
- Recursion no reports yet no reports yetDid you experience this?How often have you seen this?How was it? (-100 worst, +100 best)How was it? (-100 worst, +100 best)
- Scenery slicing no reports yet no reports yetDid you experience this?How often have you seen this?How was it? (-100 worst, +100 best)How was it? (-100 worst, +100 best)
- Symmetrical texture repetition no reports yet no reports yetDid you experience this?How often have you seen this?How was it? (-100 worst, +100 best)How was it? (-100 worst, +100 best)
- Tracers no reports yet no reports yetDid you experience this?How often have you seen this?How was it? (-100 worst, +100 best)How was it? (-100 worst, +100 best)
- Geometry no reports yet no reports yetDid you experience this?How often have you seen this?How was it? (-100 worst, +100 best)How was it? (-100 worst, +100 best)
- Transformations no reports yet no reports yetDid you experience this?How often have you seen this?How was it? (-100 worst, +100 best)How was it? (-100 worst, +100 best)
- Machinescapes no reports yet no reports yetDid you experience this?How often have you seen this?How was it? (-100 worst, +100 best)How was it? (-100 worst, +100 best)
- Internal hallucination no reports yet no reports yetDid you experience this?How often have you seen this?How was it? (-100 worst, +100 best)How was it? (-100 worst, +100 best)
- Peripheral information misinterpretation no reports yet no reports yetDid you experience this?How often have you seen this?How was it? (-100 worst, +100 best)How was it? (-100 worst, +100 best)
Cognitive
- Empathy, affection and sociability enhancement no reports yet no reports yetDid you experience this?How often have you seen this?How was it? (-100 worst, +100 best)How was it? (-100 worst, +100 best)
- Analysis enhancement no reports yet no reports yetDid you experience this?How often have you seen this?How was it? (-100 worst, +100 best)How was it? (-100 worst, +100 best)
- Conceptual thinking no reports yet no reports yetDid you experience this?How often have you seen this?How was it? (-100 worst, +100 best)How was it? (-100 worst, +100 best)
- Creativity enhancement no reports yet no reports yetDid you experience this?How often have you seen this?How was it? (-100 worst, +100 best)How was it? (-100 worst, +100 best)
- Emotion intensification no reports yet no reports yetDid you experience this?How often have you seen this?How was it? (-100 worst, +100 best)How was it? (-100 worst, +100 best)
- Immersion intensification no reports yet no reports yetDid you experience this?How often have you seen this?How was it? (-100 worst, +100 best)How was it? (-100 worst, +100 best)
- Novelty enhancement no reports yet no reports yetDid you experience this?How often have you seen this?How was it? (-100 worst, +100 best)How was it? (-100 worst, +100 best)
- Increased music appreciation no reports yet no reports yetDid you experience this?How often have you seen this?How was it? (-100 worst, +100 best)How was it? (-100 worst, +100 best)
- Increased sense of humor no reports yet no reports yetDid you experience this?How often have you seen this?How was it? (-100 worst, +100 best)How was it? (-100 worst, +100 best)
- Increased libido no reports yet no reports yetDid you experience this?How often have you seen this?How was it? (-100 worst, +100 best)How was it? (-100 worst, +100 best)
- Laughter fits no reports yet no reports yetDid you experience this?How often have you seen this?How was it? (-100 worst, +100 best)How was it? (-100 worst, +100 best)
- Thought acceleration no reports yet no reports yetDid you experience this?How often have you seen this?How was it? (-100 worst, +100 best)How was it? (-100 worst, +100 best)
- Thought connectivity no reports yet no reports yetDid you experience this?How often have you seen this?How was it? (-100 worst, +100 best)How was it? (-100 worst, +100 best)
- Time distortion no reports yet no reports yetDid you experience this?How often have you seen this?How was it? (-100 worst, +100 best)How was it? (-100 worst, +100 best)
- Wakefulness no reports yet no reports yetDid you experience this?How often have you seen this?How was it? (-100 worst, +100 best)How was it? (-100 worst, +100 best)
- Memory suppression no reports yet no reports yetDid you experience this?How often have you seen this?How was it? (-100 worst, +100 best)How was it? (-100 worst, +100 best)
- Personal bias suppression no reports yet no reports yetDid you experience this?How often have you seen this?How was it? (-100 worst, +100 best)How was it? (-100 worst, +100 best)
- Rejuvenation no reports yet no reports yetDid you experience this?How often have you seen this?How was it? (-100 worst, +100 best)How was it? (-100 worst, +100 best)
- Ego death no reports yet no reports yetDid you experience this?How often have you seen this?How was it? (-100 worst, +100 best)How was it? (-100 worst, +100 best)
- Anxiety no reports yet no reports yetDid you experience this?How often have you seen this?How was it? (-100 worst, +100 best)How was it? (-100 worst, +100 best)
- Paranoia no reports yet no reports yetDid you experience this?How often have you seen this?How was it? (-100 worst, +100 best)How was it? (-100 worst, +100 best)
- Delusion no reports yet no reports yetDid you experience this?How often have you seen this?How was it? (-100 worst, +100 best)How was it? (-100 worst, +100 best)
Auditory
- Auditory acuity enhancement no reports yet no reports yetDid you experience this?How often have you seen this?How was it? (-100 worst, +100 best)How was it? (-100 worst, +100 best)
- Auditory distortion no reports yet no reports yetDid you experience this?How often have you seen this?How was it? (-100 worst, +100 best)How was it? (-100 worst, +100 best)
- Auditory hallucination no reports yet no reports yetDid you experience this?How often have you seen this?How was it? (-100 worst, +100 best)How was it? (-100 worst, +100 best)
Multi-sensory
- Synaesthesia no reports yet no reports yetDid you experience this?How often have you seen this?How was it? (-100 worst, +100 best)How was it? (-100 worst, +100 best)
Transpersonal
- Existential self-realization no reports yet no reports yetDid you experience this?How often have you seen this?How was it? (-100 worst, +100 best)How was it? (-100 worst, +100 best)
- Spirituality intensification no reports yet no reports yetDid you experience this?How often have you seen this?How was it? (-100 worst, +100 best)How was it? (-100 worst, +100 best)
- Unity and interconnectedness no reports yet no reports yetDid you experience this?How often have you seen this?How was it? (-100 worst, +100 best)How was it? (-100 worst, +100 best)
Subjective-effect profile adapted from PsychonautWiki, CC BY-SA 4.0.
Pharmacodynamics
2C-B is a partial agonist at the serotonin 5-HT2A receptor, with additional activity at 5-HT2C and 5-HT2B and weak inhibition of monoamine transporters.[8] The pharmacological profile is intermediate between the classical 5-HT2A psychedelics such as LSD and psilocybin and the entactogens such as MDMA. The 5-HT2A action is the principal driver of the psychedelic component; the transporter activity may contribute to the entactogenic character at lower doses. Oral 2C-B has an onset of roughly 45 to 75 minutes and a duration of approximately four to eight hours, which is shorter than psilocybin and considerably shorter than LSD. The compound is structurally a phenethylamine in the mescaline lineage rather than a tryptamine; the 4-bromo substituent on the 2,5-dimethoxyphenethylamine scaffold confers substantially higher 5-HT2A affinity than mescaline's 3,4,5-trimethoxy parent compound, accounting for the dose-potency difference.
Shulgin's Corner
The drug effect first became known to me as a shift of colors toward golden and rose tones. Pigments in the room became intensified. Shapes became rounder, more organic. A sensation of lightness and rivulets of warmth began seeping through my body.
Anonymous (quoted in PiHKAL), Recipe #20, pp. 503-506
Narrative
Narrative
Shulgin's Corner
I am totally into my body. I am aware of every muscle and nerve in my body. The night is extraordinary — moon full. Unbelievably erotic, quiet and exquisite, almost unbearable.
Anonymous (quoted in PiHKAL), Recipe #20, pp. 503-506
Narrative
Narrative
Interactions
MDMA exp 5.0/5 outcome n/a (n=1) no reports yet
How much experience do you have with this combination (1 a little, 5 a lot)?
How did it go? (-100 worst, +100 best)
Key interaction concerns for 2C-B specifically:
- Serotonergic medicines: serotonin syndrome risk. Concurrent use of SSRIs, SNRIs, MAOIs, tramadol, dextromethorphan, or other strongly serotonergic agents carries serotonin syndrome risk and should be avoided. MAOI co-administration is particularly dangerous.
- Lithium: seizure and severe-reaction risk. Lithium combined with psychedelics including 2C-B is associated with a markedly increased risk of seizures and severe adverse reactions; the mechanism is distinct from serotonin syndrome. Avoid combination.
- Psychostimulants: additive cardiovascular load. 2C-B itself produces modest sympathomimetic effects (elevated heart rate, mild blood pressure increase); concurrent psychostimulants compound the cardiovascular burden.
- CYP interactions: not well characterized. Human metabolism of 2C-B has not been comprehensively studied. In vitro work suggests CYP2D6 and CYP3A4 involvement; strong inhibitors of these enzymes may increase 2C-B exposure.
Pregnancy and lactation
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See also
References
- ↑ Shulgin AT, Carter MF. Centrally active phenethylamines. Psychopharmacology Communications. 1975;1(1):93-98.
- ↑ 2.0 2.1 2.2 2.3 Papaseit E, Farré M, Pérez-Mañá C, Torrens M, et al. Acute Pharmacological Effects of 2C-B in Humans: An Observational Study. Frontiers in Pharmacology. 2018;9:206. PMID 29593537.
- ↑ Blok G. [From Adam to ecstacy; legal use of MDMA in the 1970s and 1980s]. Tijdschrift voor Psychiatrie. 2020;62(8):702-706. PMID 32816299.
- ↑ 4.0 4.1 Drug Enforcement Administration. Schedules of Controlled Substances: Temporary Placement of 4-Bromo-2,5-dimethoxyphenethylamine Into Schedule I. Final Rule. Federal Register. 1994 Jan 6;59:671.
- ↑ Shulgin A, Shulgin A. TIHKAL: The Continuation. Berkeley, CA: Transform Press; 1997. Chapter 1, "Invasion".
- ↑ Drug Enforcement Administration. Schedules of Controlled Substances; Placement of 4-Bromo-2,5-Dimethoxyphenethylamine Into Schedule I. Final Rule. Federal Register. 1995 Jun 2;60:28718.
- ↑ Erowid. 2C-B Dosage. Erowid.org. https://www.erowid.org/chemicals/2cb/2cb_dose.shtml. Accessed 2026-05-25.
- ↑ Nichols DE. Psychedelics. Pharmacological Reviews. 2016;68(2):264-355. PMID 26841800.
Summary
Classes
Psychedelic, Phenethylamine, 2C-x series
Common uses
Pharmacy
Pharmacology
Routes
Oral, insufflated, PR
Onset
45-75 min (oral)
Duration
4-8 h
Half-life
Not well characterized
Bioavailability
Not well characterized
Pregnancy
Not established
Legal status
Schedule I (United States)
Purported mechanism
5-HT2A partial agonist