What these drugs are
GLP-1 receptor agonists imitate a gut hormone released after a meal. They tell the pancreas to release insulin when sugar is high, tell the brain that you are full, and slow the stomach so food leaves it more slowly. Semaglutide (Ozempic, Wegovy, and the tablet Rybelsus), liraglutide (Victoza, Saxenda) and dulaglutide (Trulicity) work on that one receptor. Tirzepatide (Mounjaro, Zepbound) adds a second hormone, GIP, and produces more weight loss. Most are a weekly injection, and one injection stays in the body for about a week: semaglutide has a half-life of around seven days, tirzepatide around five.
They were built for type 2 diabetes and are now prescribed mostly for weight. The common side effects are the ones you would expect from a slowed stomach: nausea, vomiting, constipation or diarrhea, reflux, and a smaller appetite that often extends to drinking less. Resting heart rate rises by a few beats per minute on average. Less common are dehydration severe enough to hurt the kidneys, gallbladder problems, pancreatitis, and a stomach that stops emptying properly.
Retatrutide is a different case
Retatrutide adds a third target, the glucagon receptor, on top of GLP-1 and GIP. In its phase 2 trial, published in 2023, the highest dose produced about a quarter of body weight lost in under a year, more than anything approved. At the time of writing it is still in phase 3 trials. No regulator has approved it, there is no approved dose, and nobody has published long-term safety data. Almost everyone using it is buying a vial labeled "for research use only" from an online vendor and drawing up their own dose.
Two things follow. The glucagon action raises heart rate and energy expenditure more than the older drugs, and it tends to bring more nausea in the first weeks. And a vial from an unregulated source carries its own uncertainties: how much is actually in it, whether it is sterile, and what else is in there. When you tell us you take retatrutide, we take you at your word about the dose, and we still treat the drug as an unknown. That is not a judgment. It is the only honest way to screen for it.
Why they matter for an iboga night
Iboga is taken by mouth over a long night. The medicine itself makes most people nauseous, many vomit, everyone loses coordination and lies down for twelve hours or more, and it lengthens the QT interval of the heart and slows the pulse. Everything in the medical protocol exists to hold that night safely. GLP-1 drugs push against several of those safeguards at once.
- GLP-1
- GIP
- Glucagon
Your own baselineAbout +2 to 4 beats per minuteAbout +2 to 5 beats per minuteAbout +6 beats per minute, more in the first weeks
What iboga does. The root bark is swallowed, sits in the stomach for a short while, moves into the small intestine and is absorbed into the blood from there. The practitioner watches this onset, usually one to two hours, to pace the next dose.
What Ozempic and Wegovy do. Semaglutide acts on one receptor, GLP-1. It tells the brain you are full and holds the stomach shut for hours. Iboga reaches the blood later and more slowly, and the stomach is still full when the vomiting starts.
What Mounjaro and Zepbound do. Tirzepatide adds a second receptor, GIP, which brings more weight loss and often more nausea. The stomach is just as slow. The same onset problem, the same full stomach.
What retatrutide does. Three receptors: GLP-1, GIP and glucagon. Glucagon raises the resting pulse and the energy burn. The stomach empties slowly all the same. No approved dose, no safety data outside its own trials.
- A stomach that does not empty. Iboga is absorbed from the gut. A slowed stomach makes onset later and less predictable, so the practitioner, who paces doses by what they see, has less to go on. It also means food and liquid are still sitting in the stomach hours after a meal. Anesthesia societies now warn about this before sedation, because vomiting with a full stomach while unable to protect your own airway is how aspiration happens. An iboga night involves both vomiting and lying down unable to move well.
- Electrolytes. Weeks of nausea, loose stools and drinking less leave many people short of potassium and magnesium without feeling it. Low potassium and low magnesium are exactly what turns iboga's effect on the QT interval from a monitored curiosity into a dangerous one. Every death in the ibogaine literature involves the heart, an unscreened condition, an interaction, or an unsupervised setting. Read Can iboga kill you?
- The heart rate baseline. These drugs raise the resting pulse, retatrutide more so. That is not dangerous by itself. It does mean the ECG we read before travel is not quite your own, and the monitor on the night is comparing against a moved baseline.
- Blood sugar. On a GLP-1 drug alone, low blood sugar is rare. Add the fasting before a ceremony, a day of eating little, a long night of exertion and vomiting, and, for people with diabetes, insulin or a sulfonylurea, and it stops being rare. Sweating, shaking and confusion look like the medicine when they are actually hypoglycemia, which is why glucose is on the panel and the physician checks it.
- Kidneys. Dehydration plus vomiting is the usual road to acute kidney injury on these drugs. A ceremony adds more of both, which is why kidney function is in the blood work and IV fluids are placed before any dose.
No study has combined them
There is no published research on ibogaine or iboga given to people on a GLP-1 drug, and none on retatrutide with anything at all outside its own trials. What we do know is reassuring on one point: these are peptides, cleared by the body without the liver enzyme, CYP2D6, that turns ibogaine into noribogaine, so there is no reason to expect the drugs to change each other's levels. Everything above is indirect, through the stomach, the fluids, the salts and the pulse. Indirect is not the same as minor. Most of what has gone wrong with ibogaine historically was indirect too.
The craving connection
Some applicants are on semaglutide for a reason other than weight. Since 2024, observational studies and a small randomized trial have reported that people on GLP-1 drugs drink less alcohol and show less craving, and several trials are now testing them for alcohol and other substance use. Iboga, through noribogaine, is known for the same thing: a marked drop in craving that lasts weeks. The two seem to touch the same reward circuits from different sides. Nobody has studied them together, and we do not treat a GLP-1 drug as part of the medicine. But if you started it hoping it would help with drinking, tell the physician. It changes how we read your history, and how we plan the taper, which is the part that actually needs to be right.
What we ask of you
- List it on the application. Brand name, dose, how often, and where it comes from. "Research peptides" count. So do compounded versions from a telehealth service. A drug that is not disclosed cannot be planned for, and the plan is what keeps you safe.
- Expect a pause before you travel. The physician sets it case by case, and it is measured in weeks, not days. One injection lasts about a week, and the slowing of the stomach outlasts the drug in the blood. For retatrutide, for anyone with ongoing nausea or reflux, and for anyone who has been on a high dose for a long time, expect longer. If you take the drug for diabetes, the pause is planned together with your prescriber, because your blood sugar needs a plan too.
- Eat and drink normally in the meantime. Appetite comes back when the drug fades. Let it. The weeks before a retreat are for rebuilding potassium and magnesium, not for holding a deficit.
- Do the blood work after the pause, not before. The panel we ask for, with electrolytes, magnesium, kidney function, glucose and an ECG, is meant to show the body you will bring to the mat. Results from a week when the drug was still active are of limited use.
About one applicant in five is declined or postponed after screening, for all reasons combined. A GLP-1 drug on its own is rarely one of them. An undisclosed one, found late, often is.
After the retreat
Appetite is low for a day or two after a ceremony and then returns strongly. That is the moment most guests ask whether to restart. Our answer is to wait until the integration weeks are underway and the body has recovered, then decide with your own doctor. Iboga is not a weight treatment, and we make no claim about it. What guests do describe is a different relationship with food and with the drinking or eating that a GLP-1 drug was suppressing, which is worth knowing before you reach for the pen again. If you restart, start low, as the drug's own labeling says, because tolerance to the nausea is lost within weeks.
Questions people ask
Do I have to stop Ozempic or Mounjaro before an iboga retreat?
In almost every case, yes, for a period the physician sets after seeing your application and blood work. The reasons are the stomach, the electrolytes and the heart rate baseline, not the drug reacting with iboga directly. Stopping for a few weeks is safe for people taking it for weight. People taking it for diabetes plan the pause with their prescriber.
I bought retatrutide online. Does that count as a medication?
Yes. It is an active drug in phase 3 trials, with stronger effects on the heart rate and the stomach than the approved ones, and no safety data outside those trials. List it with the dose you use and where it came from. Nobody will lecture you. The physician needs it to plan.
Will iboga help me lose weight?
There is no evidence that it does, and we do not offer it for that. What the retreat can change is the pattern underneath, the drinking, the sugar, the eating at night, and the reasons for them. Weight follows patterns, slowly. Anyone promising more is selling.
Can I take my injection during the retreat and skip the ceremony days?
No. A weekly injection is active for the whole week and the stomach effect lasts longer than that. The pause runs through the last ceremony, and the physician will tell you when it is reasonable to restart.
What about the tablet, Rybelsus?
Same drug, same effects, a daily dose instead of a weekly one. It is easier to pause and clears faster, but the stomach and electrolyte questions are the same, and the same rules apply.