Ibogaine: History, Pharmacology and Safety

Table of Contents

1. The Iboga Plant
2. Traditional Use in Central Africa
3. Discovery and Western History
4. How Ibogaine Acts: Pharmacology in Plain Language
5. Noribogaine and the CYP2D6 Enzyme
6. The Research on Opioid Withdrawal
7. Other Research: Alcohol, Cocaine, PTSD and Brain Injury
8. The Heart: QT Prolongation and Arrhythmia
9. Deaths and Neurotoxicity Findings
10. Current Research Status and the 2026 FDA Notice
11. What Remains Unknown
12. Key Research Papers
13. Connections

1. The Iboga Plant

Tabernanthe iboga is a shrub of the dogbane family (Apocynaceae) native to the rainforests of West Central Africa. Its yellowish root bark is the part that carries the alkaloids. Ibogaine is the best known of these, but the root contains a family of related “iboga-type” alkaloids. A 2015 review of the cardiac literature gives the ibogaine content of the root bark as about 0.3% and notes a second route to the compound: semisynthesis from voacangine, a related alkaloid present at about 0.5% in Voacanga africana, another African plant of the same family.^[7]

The same family of alkaloids turns up in other dogbane-family plants. The site’s page on crape jasmine alkaloids describes coronaridine and voacangine in that plant and why their chemical closeness to ibogaine matters for safety.

Chemically, ibogaine is an indole alkaloid — it shares the indole ring found in serotonin and tryptophan — and it is fat-soluble. The 2015 review notes that it accumulates in fat tissue, where its levels become much higher than in plasma or brain.^[7]

Back to Table of Contents

2. Traditional Use in Central Africa

In West Central Africa, and most prominently in the Bwiti religious tradition of Gabon, iboga root has a long ceremonial history. Reviews describe two quite different traditional patterns. Small amounts of root were taken against fatigue, hunger and thirst. Much larger amounts are taken during initiation rites, where the intense, dream-like visionary state is the purpose of the ceremony.^[7]

Researchers describe that visionary state as a “waking dream”: intense visions with the eyes closed, often with vivid recall of autobiographical memories.^[7] This is one reason ibogaine is sometimes grouped with psychedelics, although a 2022 systematic review notes that its psychoactive and bodily effects set it apart from classic hallucinogens such as LSD, mescaline and psilocybin.^[21]

An ethnographic study published in 2008 separated the African religious use from what its authors called the “ibogaine medical subculture” that grew up elsewhere, and studied only the latter.^[2] The traditional ceremonial setting and the later use of purified ibogaine hydrochloride against drug dependence are different practices with different histories.

Back to Table of Contents

3. Discovery and Western History

Ibogaine was isolated from the root around the turn of the twentieth century; a 1995 review in Pharmacological Reviews marked roughly a century of study with the title “100 years of ibogaine.”^[1] Its Western medical history began in the early 1900s, when it was used as a stimulant, indicated for asthenia (weakness and fatigue) and as a neuromuscular stimulant. In the 1940s and 1950s it was studied as a possible cardiovascular drug.^[7]

From the 1960s it drew attention for a different reason: its possible use against drug dependence. People treated for dependence commonly reported that withdrawal faded within 12–18 hours and that craving fell for weeks. In the US it was classified as a Schedule I substance, as a hallucinogen with possible abuse potential.^[7]

Animal research followed. A 1991 rat study found that ibogaine reduced morphine self-administration in a dose-dependent way, both in the hour after dosing and, to a lesser extent, a day later — at a time when the drug would already have been cleared from the body. In some rats a single injection reduced morphine intake for days or weeks; a few rats showed no lasting effect.^[9]

The FDA’s own 2026 notice records that in 1993 its Drug Abuse Advisory Committee discussed an investigational application to study ibogaine for cocaine dependence, and that the risk of QTc prolongation and torsades de pointes was identified after that meeting. A 2015 review adds that the US National Institute on Drug Abuse decided in 1995 not to fund further human studies.^[7] With no approved route, use spread largely outside conventional medical settings — in a 2008 count, an estimated 3,414 people outside Africa had taken ibogaine by February 2006, a fourfold rise over five years; 68% had taken it for a substance-related disorder and 53% specifically for opioid withdrawal.^[2]

Back to Table of Contents

4. How Ibogaine Acts: Pharmacology in Plain Language

Most drugs that act on the brain have one main target. Ibogaine is unusual because it touches many. Reviews list effects, at low micromolar concentrations, on:^[7][8]

• Opioid receptors — the kappa (κ) and mu (μ) receptors, the same family through which morphine and heroin act. Ibogaine is not a conventional opioid drug; in a phase 1 study of its metabolite noribogaine, no morphine-like effects on pupil size or pain tolerance were seen.^[12]
• NMDA glutamate receptors — the receptor blocked by ketamine; ibogaine has micromolar affinity for it.^[8]
• Neurotransmitter transporters for serotonin and dopamine, the pumps that clear these messengers from the gap between nerve cells.^[7][8]
• Sigma-2 receptor sites and nicotinic acetylcholine receptors.^[7][8]

A 2016 toxicology review adds that ibogaine changes the brain’s production of several proteins, including brain-derived neurotrophic factor (BDNF), substance P, c-fos and egr-1.^[8] A 2005 rodent study pointed to another growth factor: ibogaine reduced alcohol drinking in rats, raised levels of glial cell line-derived neurotrophic factor (GDNF) in a midbrain reward region (the ventral tegmental area), and the effect on drinking was blocked when that GDNF was neutralised with antibodies.^[10]

Which of these many actions explains the reported effect on withdrawal is not settled. The multiplicity cuts both ways: the same broad reach that interests researchers is, in the reviewers’ words, a considerable potential for adverse effects — above all on the heart (section 8).

Back to Table of Contents

5. Noribogaine and the CYP2D6 Enzyme

In the liver, ibogaine is converted to noribogaine (also called 12-hydroxyibogamine or 10-hydroxyibogamine, depending on the numbering system used). A 1998 study using human liver tissue showed that this conversion is carried out mainly by a single enzyme, cytochrome P450 2D6 (CYP2D6); liver tissue from a donor who appeared to be a CYP2D6 “poor metaboliser” lacked the main, efficient conversion activity, and quinidine, a drug that blocks CYP2D6, blocked it too.^[11]

CYP2D6 varies a great deal between people because of common genetic differences. Some people carry versions that work quickly, some slowly, and some barely at all. In 14 patients with opioid use disorder given a single dose in a Dutch hospital study, how fast ibogaine was cleared was strongly tied to each person’s CYP2D6 genotype.^[17] This is why the FDA’s 2026 notice lists CYP2D6 genotyping among the trial-design features on which it asks for comment.

The two compounds behave differently over time. A 2015 review gives the plasma half-life of ibogaine as about 4–7 hours, with most of it gone within 24 hours.^[7] Noribogaine lingers much longer: in a phase 1 study in 36 healthy men given single oral doses of 3 to 60 mg, its half-life was 28–49 hours, and no safety or tolerability problems were identified at those doses.^[12] Reviewers have suggested that this long-lived metabolite helps explain why reported effects outlast ibogaine itself.^[7][8]

Noribogaine has been studied as a drug in its own right. In 27 people on methadone treatment who had been switched to morphine, single doses of 60, 120 or 180 mg against placebo were described as well tolerated, with changes in light perception, headache and nausea the most frequent side effects. Noribogaine nonetheless lengthened the QT interval in proportion to its blood level, by about 16, 28 and 42 milliseconds at the three doses. Withdrawal scores showed a trend toward improvement that was not statistically significant.^[13] The FDA’s notice records that it has allowed an early-phase study of noribogaine hydrochloride for alcohol use disorder.

Back to Table of Contents

6. The Research on Opioid Withdrawal

Opioid withdrawal is the use most often studied, and the evidence for ibogaine itself consists mainly of case series and observational studies rather than large randomised, placebo-controlled trials. The main reports:

• 1999 case series (33 treatments). Treatments for opioid detoxification carried out in non-medical settings, open label, in people using on average 0.64 g of heroin a day. Withdrawal signs resolved without further drug seeking within 24 hours in 25 people and stayed resolved through 72 hours of observation; 4 sought drugs without withdrawal signs, 2 stayed abstinent with weaker withdrawal, 1 had continued withdrawal and drug seeking, and 1 died, possibly involving covert heroin use. The authors concluded that systematic study in a conventional clinical research setting was needed.^[3]
• 2018 observational study (30 people). Adults with opioid dependence (mean total dose 1,540 ± 920 mg ibogaine hydrochloride) who had averaged 3.1 previous treatment attempts. Withdrawal scores fell from 31.0 to 14.0 about three days after treatment. At one month, 15 of the 30 (50%) reported no opioid use in the previous 30 days; drug-use scores improved at every time point to 12 months, most at one month.^[4]
• 2018 observational study, New Zealand (14 people). A single treatment, followed for 12 months. Withdrawal scores dropped right after treatment; among the 8 who completed every interview, drug-use and depression scores were lower at 12 months. One enrolled patient died during treatment.^[5]
• 2018 review of an inpatient case series (191 people). Volunteers detoxifying from opioids or cocaine under medical monitoring; the authors reported diminished withdrawal and craving and no significant adverse events in the dose range they used. The analysis was a retrospective review of an open-label series.^[6]
• 2022 Dutch hospital study (14 people). Designed to measure safety rather than benefit: a single 10 mg/kg dose of ibogaine hydrochloride in people with opioid use disorder, with intensive heart monitoring. Its cardiac findings are in section 8.^[16]

A 2022 systematic review of clinical data found 24 studies with 705 people given ibogaine or noribogaine — two randomised double-blind controlled trials, one double-blind controlled trial, 17 open-label studies or case series, three case reports and one survey. Its authors read the data as suggesting reduced withdrawal and craving, and also recorded severe medical complications and deaths linked to ibogaine’s effects on the heart and nervous system.^[21]

The limits are the same across this literature: small numbers, no control group in most studies, people choosing treatment themselves, unstandardised products and doses, and loss to follow-up. The FDA’s 2026 notice states that the published literature lacks characterisation of the products used (dose, quality, purity, potency) and participant-level data.

Back to Table of Contents

7. Other Research: Alcohol, Cocaine, PTSD and Brain Injury

Alcohol. The 2005 rat work described above found reduced alcohol drinking, including in a relapse model, mediated by GDNF in the midbrain.^[10] Human evidence for alcohol use disorder is limited; the FDA’s notice mentions an early-phase noribogaine study in alcohol use disorder.

Cocaine. The 1993 investigational application discussed by the FDA’s advisory committee was for cocaine dependence, and the 191-person case series included people detoxifying from cocaine.^[6] No controlled trial in cocaine dependence has been published.

Traumatic brain injury, PTSD, depression and anxiety. A 2024 prospective observational study from Stanford enrolled 30 male Special Operations Forces veterans, mostly with mild traumatic brain injury, who received ibogaine together with magnesium (given because magnesium may reduce the heart risk) and other complementary treatments. Disability scores improved immediately after treatment and at one month, as did scores for PTSD, depression and anxiety at one month; there were no unexpected or serious adverse events. The authors wrote that controlled trials are needed to validate the open-label findings.^[15] The paper’s disclosures record that several authors held shares in, or patent applications connected with, an ibogaine treatment provider.

The FDA’s 2026 notice names adults with opioid use disorder and adults with PTSD as the populations for the first federally supported trials it expects. See the site’s pages on PTSD and addiction.

Back to Table of Contents

8. The Heart: QT Prolongation and Arrhythmia

Each heartbeat ends with a recharging phase, when heart muscle cells reset their electrical charge before the next beat. On an electrocardiogram (ECG) this shows up as the QT interval; corrected for heart rate it is called the QTc. Drugs that slow the recharging lengthen the QTc, and a very long QTc can tip the heart into torsades de pointes, a chaotic rhythm that can turn into ventricular fibrillation and sudden death. The site’s Long QT Syndrome page explains the inherited form of the same problem.

The mechanism. The key channel in the recharging phase is the hERG potassium channel. A 2012 laboratory study found that ibogaine at concentrations reached in human blood after use reduces hERG currents, giving a mechanism for life-threatening arrhythmias.^[19] A 2016 review adds that noribogaine appears at least as harmful to heart function as ibogaine — important because it stays in the body for days.^[8]

Measured in patients. The 2022 Dutch hospital study is the most detailed measurement. In 14 people with opioid use disorder given a single 10 mg/kg dose of ibogaine hydrochloride:^[16]

• the mean maximum lengthening of the QTc (Fridericia correction) was 95 milliseconds, ranging from 29 to 146;
• half of the participants exceeded a QTc of 500 milliseconds, a level widely treated as a danger threshold;
• 6 of the 14 still had a QTc above 450 milliseconds more than 24 hours after dosing;
• no torsades de pointes occurred; and
• every participant had severe, temporary ataxia (loss of coordination).

A follow-up analysis of the same 14 patients found that QTc lengthening and the cerebellar effects tracked blood levels of ibogaine rather than noribogaine.^[17]

The wider literature. A systematic review of reports from 2015 to 2020 (18 studies) found QTc prolongation to be the most common acute adverse event and called for phase I trials with standardised products.^[18] A 2026 review in Addiction noted that torsades case reports occur at doses used therapeutically and in people with no prior heart disease, and pointed to CYP2D6 variability as one source of unpredictability.^[22] A 2016 toxicology review presented 8 case reports suggesting ibogaine caused ventricular arrhythmias and QT prolongation in people without any known heart condition or family history.^[8]

The FDA’s 2026 notice summarises the clinical data in its own words: ibogaine “commonly causes substantial QTc interval prolongation, which has been associated with life-threatening ventricular arrhythmias and death.” The notice also names intravenous magnesium pretreatment as one approach that trial sponsors could study to reduce QTc prolongation; the site’s magnesium page covers the mineral.

Back to Table of Contents

9. Deaths and Neurotoxicity Findings

Deaths. The most detailed forensic study, published in 2012, collected 19 known deaths between 1990 and 2008 that were temporally associated with taking ibogaine outside West Central Africa. Deaths occurred between 1.5 and 76 hours after ingestion. Of the 14 cases with adequate post-mortem data, pre-existing medical conditions — mainly cardiovascular disease — and/or other substances explained or contributed to the death in 12.^[14] A 2016 review counted 27 reported fatalities.^[8] The 76-hour upper figure matters: it falls well after ibogaine itself has cleared, in the window when noribogaine is still present.

Deaths have also occurred within the published studies: one in the 1999 case series (possibly involving covert heroin use) and one during treatment in the 2018 New Zealand study.^[3][5] Other substances, including opioids, recur among the contributing factors in these reports; the site’s opioid overdose page covers opioid toxicity itself.

Neurotoxicity in animals. A 1993 rat study found that ibogaine (and the related alkaloid harmaline) caused degeneration of a subset of Purkinje cells — the large output neurons of the cerebellum, the brain region that coordinates movement — in narrow stripes of the cerebellar vermis. The authors proposed over-stimulation by excitatory signals from the brainstem as the cause.^[20] A 2016 review notes that no signs of neurotoxicity were found in rats at doses below 25 mg/kg given by injection into the abdomen, and that noribogaine might be less neurotoxic than ibogaine.^[8] The FDA’s 2026 notice describes dose-dependent neurotoxicity in animals ranging from tremor and ataxia to neuronal degeneration, convulsions and death, with injury to the cerebellum, and lists it, alongside QTc prolongation and uncertainty about a human starting dose, as one of the main safety risks.

Back to Table of Contents

10. Current Research Status and the 2026 FDA Notice

On 5 October 2026 the FDA announced, and on 6 October published in the Federal Register (91 FR 63563, docket FDA-2026-N-10429), a request for information titled “Design and Safety Considerations for Clinical Trials Involving Ibogaine Drug Products.” It sets out the agency’s preliminary thinking on how a first early-phase ibogaine trial could be designed — dose selection, inpatient cardiac monitoring, stopping rules, eligibility and the first populations — and invites comments until 20 November 2026. The notice approves no trial, makes no finding about effectiveness, and states that it does not establish legally enforceable requirements.

The notice also records federal research funding: an ARPA-H programme of early-phase trials and NIDA-funded ibogaine research in opioid use disorder, with the data to be made publicly available to investigators. The full explanation — what is asked, the proposed safety parameters, and what the notice does not cover — is on the site’s regulatory page: FDA Ibogaine Research Notice (2026), part of the new FDA and Regulation section. The 11 October 2026 news roundup reported the notice alongside five other findings.

Back to Table of Contents

11. What Remains Unknown

• Whether it works, under controlled conditions. The opioid-withdrawal evidence for ibogaine is almost entirely open-label and observational; the few controlled trials in the 2022 systematic review are small.^[21]
• A safe human starting dose. The FDA’s notice states that the 5–20 mg/kg doses in published clinical reports lack adequate safety margins based on the animal data, and lists uncertainty about a starting dose as a core risk.
• Who is most at risk. CYP2D6 genotype, existing heart disease, other medicines and blood mineral levels all appear to matter, but how much each contributes is not well measured.
• The role of noribogaine. Whether the long-lived metabolite drives the reported benefits, the late cardiac risk, or both, is still debated; the Dutch data tied QTc changes to ibogaine, while laboratory work finds noribogaine also blocks hERG.^[17][8]
• The mechanism. With effects on opioid, glutamate, serotonin, dopamine, sigma and nicotinic systems and on growth factors such as GDNF and BDNF, no single explanation for the withdrawal effect has been established.
• Long-term effects on the brain, heart and drug use, beyond one year.

The 1995 review’s title, “a putative anti-addictive drug,” still describes the state of the evidence three decades later.^[1]

Back to Table of Contents

Key Research Papers

1. Popik P, Layer RT, Skolnick P (1995). 100 years of ibogaine: neurochemical and pharmacological actions of a putative anti-addictive drug. Pharmacological Reviews 47(2):235–253 — PubMed PMID: 7568327
2. Alper KR, Lotsof HS, Kaplan CD (2008). The ibogaine medical subculture. Journal of Ethnopharmacology 115(1):9–24 — PubMed PMID: 18029124
3. Alper KR, Lotsof HS, Frenken GM, Luciano DJ, Bastiaans J (1999). Treatment of acute opioid withdrawal with ibogaine. American Journal on Addictions 8(3):234–242 — PubMed PMID: 10506904
4. Brown TK, Alper K (2018). Treatment of opioid use disorder with ibogaine: detoxification and drug use outcomes. American Journal of Drug and Alcohol Abuse 44(1):24–36 — PubMed PMID: 28541119
5. Noller GE, Frampton CM, Yazar-Klosinski B (2018). Ibogaine treatment outcomes for opioid dependence from a twelve-month follow-up observational study. American Journal of Drug and Alcohol Abuse 44(1):37–46 — PubMed PMID: 28402682
6. Mash DC, Duque L, Page B, Allen-Ferdinand K (2018). Ibogaine detoxification transitions opioid and cocaine abusers between dependence and abstinence: clinical observations and treatment outcomes. Frontiers in Pharmacology 9:529 — PubMed PMID: 29922156
7. Koenig X, Hilber K (2015). The anti-addiction drug ibogaine and the heart: a delicate relation. Molecules 20(2):2208–2228 — PubMed PMID: 25642835
8. Litjens RP, Brunt TM (2016). How toxic is ibogaine? Clinical Toxicology 54(4):297–302 — PubMed PMID: 26807959
9. Glick SD, Rossman K, Steindorf S, Maisonneuve IM, Carlson JN (1991). Effects and aftereffects of ibogaine on morphine self-administration in rats. European Journal of Pharmacology 195(3):341–345 — PubMed PMID: 1868880
10. He DY, McGough NN, Ravindranathan A, Jeanblanc J, Logrip ML, Phamluong K, et al. (2005). Glial cell line-derived neurotrophic factor mediates the desirable actions of the anti-addiction drug ibogaine against alcohol consumption. Journal of Neuroscience 25(3):619–628 — PubMed PMID: 15659598
11. Obach RS, Pablo J, Mash DC (1998). Cytochrome P4502D6 catalyzes the O-demethylation of the psychoactive alkaloid ibogaine to 12-hydroxyibogamine. Drug Metabolism and Disposition 26(8):764–768 — PubMed PMID: 9698290
12. Glue P, Lockhart M, Lam F, Hung N, Hung CT, Friedhoff L (2015). Ascending-dose study of noribogaine in healthy volunteers: pharmacokinetics, pharmacodynamics, safety, and tolerability. Journal of Clinical Pharmacology 55(2):189–194 — PubMed PMID: 25279818
13. Glue P, Cape G, Tunnicliff D, Lockhart M, Lam F, Hung N, et al. (2016). Ascending single-dose, double-blind, placebo-controlled safety study of noribogaine in opioid-dependent patients. Clinical Pharmacology in Drug Development 5(6):460–468 — PubMed PMID: 27870477
14. Alper KR, Stajić M, Gill JR (2012). Fatalities temporally associated with the ingestion of ibogaine. Journal of Forensic Sciences 57(2):398–412 — PubMed PMID: 22268458
15. Cherian KN, Keynan JN, Anker L, Faerman A, Brown RE, Shamma A, et al. (2024). Magnesium–ibogaine therapy in veterans with traumatic brain injuries. Nature Medicine 30(2):373–381 — PubMed PMID: 38182784
16. Knuijver T, Schellekens A, Belgers M, Donders R, van Oosteren T, Kramers K, et al. (2022). Safety of ibogaine administration in detoxification of opioid-dependent individuals: a descriptive open-label observational study. Addiction 117(1):118–128 — PubMed PMID: 33620733
17. Knuijver T, ter Heine R, Schellekens AFA, Heydari P, Lucas L, Westra S, et al. (2024). The pharmacokinetics and pharmacodynamics of ibogaine in opioid use disorder patients. Journal of Psychopharmacology 38(5):481–488 — PubMed PMID: 38519421
18. Ona G, Rocha JM, Bouso JC, Hallak JEC, Borràs T, Colomina MT, et al. (2022). The adverse events of ibogaine in humans: an updated systematic review of the literature (2015–2020). Psychopharmacology 239(6):1977–1987 — PubMed PMID: 34406452
19. Koenig X, Kovar M, Boehm S, Sandtner W, Hilber K (2014). Anti-addiction drug ibogaine inhibits hERG channels: a cardiac arrhythmia risk. Addiction Biology 19(2):237–239 — PubMed PMID: 22458604
20. O’Hearn E, Molliver ME (1993). Degeneration of Purkinje cells in parasagittal zones of the cerebellar vermis after treatment with ibogaine or harmaline. Neuroscience 55(2):303–310 — PubMed PMID: 8377927
21. Köck P, Froelich K, Walter M, Lang U, Dürsteler KM (2022). A systematic literature review of clinical trials and therapeutic applications of ibogaine. Journal of Substance Abuse Treatment 138:108717 — PubMed PMID: 35012793
22. Brunt TM (2026). Rare but relevant: ibogaine and cardiovascular complications — prolonged QT interval and ventricular arrhythmias. Addiction 121(6):1616–1621 — PubMed PMID: 41560340

Note: the Koenig 2014 hERG paper (no. 19) was first published online in 2012; the text above refers to it by that year.

PubMed Topic Searches

1. Ibogaine and opioid withdrawal — PubMed search
2. Ibogaine and QT prolongation — PubMed search
3. Noribogaine — PubMed search
4. Ibogaine and CYP2D6 — PubMed search
5. Tabernanthe iboga — PubMed search

Back to Table of Contents

Connections

• Medicines and Oils
• All Remedies
• FDA Ibogaine Research Notice (2026)
• FDA and Regulation
• News: October 11, 2026
• Nicotine: The Research
• Aspirin
• Addiction
• Opioid Overdose
• Post-Traumatic Stress Disorder (PTSD)
• Long QT Syndrome
• Magnesium
• Crape Jasmine: Alkaloid Pharmacology and Toxicity
• Albert Hofmann