People asking about ipamorelin side effects usually want a list. The honest list is short, because almost nobody has measured them. Two published human studies exist, and neither tested the drug the way it is sold today.
This page sets out what those studies recorded, what the FDA has said, and which effects come from related drugs rather than ipamorelin itself. The broader evidence, including what the trials were for, is in the ipamorelin evidence review.
The one controlled safety record
The only placebo-controlled record comes from a phase 2 trial in adults recovering from bowel surgery [1]. Patients received 0.03 mg/kg by intravenous infusion, or placebo, twice a day for up to 7 days.
Of 114 patients in the safety analysis, 87.5% on ipamorelin and 94.8% on placebo had at least one treatment-emergent adverse event [1]. The authors called the drug well tolerated. The published summary does not list the individual events.
Those rates say little about a healthy person. Nearly everyone recovering from bowel surgery has symptoms, so a high count in both groups is expected. The comparison with placebo is the useful part, and it showed no excess on ipamorelin in that setting.
A larger follow-up trial from the same sponsor enrolled 320 patients at doses up to 0.06 mg/kg three times a day. Its registry record lists it as completed in May 2014, with no results posted [6]. Its adverse-event data are not public.
What the healthy-volunteer study measured
The other human study gave 15-minute infusions to healthy men, eight at each of five dose levels [2]. It was built to measure blood levels and the growth hormone response, not side effects.
Each dose produced one pulse of growth hormone, peaking at 0.67 hours and then falling away. The published summary reports no adverse events either way. It is a pharmacology record, not a safety record.
Effects seen with related drugs
Ipamorelin works on the ghrelin receptor. Other drugs acting there have longer safety records, and they suggest what to watch for. These are findings about different molecules, not about ipamorelin.
The best-measured is MK-677, an oral ghrelin-receptor agonist. In 65 healthy adults aged 60 to 81, 25 mg a day for a year raised fasting glucose by an average of 0.3 mmol/L and lowered insulin sensitivity [3]. The most frequent side effects were increased appetite, mild leg swelling and muscle pain.
A 2026 review of growth hormone peptides used outside approved care lists a similar pattern across the class [4]. It names hormone changes such as prolactin and cortisol rises, appetite changes, blood sugar problems, fluid retention, joint and muscle aches, and injection-site reactions.
One animal finding points the other way for cortisol. In swine, ipamorelin did not raise ACTH or cortisol beyond growth-hormone-releasing hormone, even at doses over 200 times its effective dose [5]. That selectivity has not been confirmed in people.
| Signal | Source | In people? |
|---|---|---|
| Adverse events no higher than placebo after surgery | Phase 2 trial, by vein | Yes, 114 patients |
| Serious events including death, by vein | FDA summary of a published study | Yes, details not public |
| Immune reaction to impurities | FDA risk assessment | Not measured |
| Higher blood sugar, appetite, swelling | MK-677, a different drug | Not for ipamorelin |
| No cortisol rise | Swine study | Not confirmed |
Side effects in blends
Ipamorelin is often sold mixed with CJC-1295, a long-acting growth-hormone-releasing hormone analog. The FDA says it has identified serious adverse events with CJC-1295, including a raised heart rate and a systemic vasodilatory reaction [7]. No study has tested the two together in people. The evidence for that pairing is covered in CJC 1295 and ipamorelin.
What has never been recorded
Nobody has published side-effect data for ipamorelin injected under the skin, taken for weeks or months, or used by healthy adults for sleep or muscle. Those are the conditions under which it is marketed. For how it compares with a peptide that has an approved history, see sermorelin vs ipamorelin, and for the whole class, growth hormone peptides.
Two facts matter for anyone considering it. No human dose has been established for any use outside those two trials. And athletes should know the 2026 World Anti-Doping Agency list prohibits ipamorelin at all times [8].
The legal side of “research use only” labels is in are peptides legal. For approved options studied in people, the sleep goal page is the place to start.