Ipamorelin vs Sermorelin: Two Growth Hormone Peptides With Opposite FDA Records

Ipamorelin and sermorelin are the two growth hormone peptides most often offered by telehealth clinics, and both make the pituitary release more of the body’s own growth hormone. They get there through different receptors. Sermorelin is the first 29 amino acids of growth hormone-releasing hormone (GHRH) and was once an FDA-approved drug for children, sold as Geref.^[1][2] Ipamorelin is a five-amino-acid peptide that acts on the ghrelin receptor and was never approved.^[5][6] Their regulatory records point in opposite directions: Geref was withdrawn for reasons other than safety, while FDA lists ipamorelin as a substance that may present significant safety risks in 503B compounding.^[2][7]

Ipamorelin vs sermorelin at a glance

What each peptide is

Sermorelin is the shortest synthetic piece of GHRH that keeps the full hormone’s activity. Given by IV or injection under the skin, it signals the anterior pituitary to release growth hormone.^[1]

Ipamorelin was developed in the 1990s from the growth hormone-releasing peptides (GHRPs), which act on what is now called the ghrelin receptor, separate from the GHRH receptor.^[5][6] It is described as “selective” because in pigs it raised growth hormone without raising ACTH or cortisol, even at very high doses.^[5] That selectivity was shown in animals, not people.

The human evidence for each

Sermorelin: children with growth hormone deficiency, and small adult studies

Sermorelin’s main human evidence comes from children. A single 1 microgram per kilogram IV dose was used as a test for growth hormone deficiency, and nightly injections under the skin increased height velocity in some prepubertal children with idiopathic growth hormone deficiency for 12 months, with data in a few children up to 36 months. The gains were smaller than with daily somatropin, the growth hormone drug, and the most common side effects were brief facial flushing and injection-site pain.^[1]

In adults, the evidence is small. In a 1997 trial, 19 men and women aged 55 to 71 injected placebo nightly for four weeks and then a close analog of sermorelin, [Nle27]GHRH(1-29), for 16 weeks. Growth hormone and IGF-1 rose, though IGF-1 drifted back toward baseline by week 16. Body weight and blood pressure did not change. Lean body mass rose in the men only, and insulin sensitivity improved in the men.^[3] That is a single-blind study of 19 people using a modified molecule, not a trial of the sermorelin sold today.

Ipamorelin: hormone modeling and one surgical trial

In healthy men given IV infusions at five dose levels, eight per level, ipamorelin caused a single growth hormone peak about 40 minutes later, and its half-life was about two hours.^[4] Its largest trial tested IV ipamorelin in 114 patients after bowel surgery. It did not significantly speed recovery: patients on ipamorelin reached a solid meal after a median of 25.3 hours, compared with 32.6 on placebo.^[6] No published trial has tested ipamorelin for body composition, sleep or recovery, the uses clinics sell it for.

Sermorelin has an old approval in children. Ipamorelin has a failed surgical trial. Neither has a trial in the healthy adults who are now offered them.

Regulatory status side by side

Sermorelin: approved once, withdrawn not for safety

FDA’s drug database lists Geref (sermorelin acetate, EMD Serono) as discontinued, with the note: “Federal Register determination that product was not discontinued or withdrawn for safety or effectiveness reasons.”^[2] Sermorelin is not on FDA’s safety-risk page and is not on any of its three 503A nomination lists.^[7][8]

That matters for compounding. Under section 503A, a pharmacy may compound from a bulk substance that meets a USP or National Formulary monograph if one exists; if none exists, from a substance that is a component of an FDA-approved drug; and otherwise only from one on FDA’s bulks list.^[9] Sermorelin was the active ingredient of an approved drug, which points to the second route rather than the bulks list. We found no FDA statement on sermorelin specifically, so a patient can fairly ask the pharmacy which route it relies on. Sermorelin is not in the October 28, 2026 HHS policy, which covers six other peptides.^[10]

Ipamorelin: an FDA safety flag

Ipamorelin acetate has been in FDA’s active Category 2 for 503B outsourcing facilities since September 29, 2023. FDA lists possible immune reactions and unnatural amino acids that make the peptide harder to characterize, and points to a published study of IV ipamorelin, given to speed stomach emptying, in which serious adverse events were reported, including deaths.^[7] It is not on the 503A nomination lists and not in the HHS policy.^[8][10] With no approval behind it, ipamorelin has no compounding route comparable to sermorelin’s.

Both are banned in sport at all times. WADA names sermorelin under S2.2.4 as a GHRH analog and ipamorelin in the same section as a growth hormone secretagogue.^[11]

Safety: what is known and what is not

• Sermorelin. In children it was well tolerated, with facial flushing and injection-site pain the most common side effects.^[1] Its adult record is a few small studies, and long-term safety in healthy adults is unknown.^[3]
• Ipamorelin. In the surgical trial, adverse events were about as common as with placebo over up to seven days of IV use.^[6] FDA nonetheless cites a published study with serious adverse events, including death, after IV use.^[7] There is no long-term human safety data.
• Both. A 2026 review of peptides that act on the growth hormone axis lists the effects reported with the class: rises in prolactin and cortisol, appetite changes, blood sugar problems, fluid retention, joint and muscle aches, and injection-site reactions.^[12] In the 1997 adult study, the sermorelin analog raised IGF-1, the hormone that growth hormone drives.^[3]

Why people combine them

A GHRH-type peptide such as sermorelin is often paired with a ghrelin-receptor peptide such as ipamorelin, because acting on both receptors releases more growth hormone than either alone. That synergy was shown in 1990 in 18 healthy men given single IV doses of GHRH and GHRP-6, an older relative of ipamorelin.^[13] No published study has given sermorelin and ipamorelin together, so whether the combination does anything useful over weeks or months, and whether it is safe, is untested.

The HHS policy’s single-ingredient rule does not decide this one, because neither peptide is in that policy. A blend of the two still combines a substance FDA has flagged for safety with one that has no adult approval. For the other common pairing, see CJC-1295 vs ipamorelin; for the GHRH analog that is still approved, see sermorelin vs tesamorelin.

To check where any other peptide stands, use our peptide status checker.