Sermorelin + Ipamorelin Stack: Evidence, Mechanism Overlap, and Clinical Protocol

What evidence exists for each peptide?

Sermorelin's human data come largely from the years it was marketed as Geref. In a one-year, open-label, multicenter study, 110 previously untreated prepubertal children with growth hormone deficiency received GHRH(1-29) 30 micrograms/kg subcutaneously at bedtime; 86 were evaluable for efficacy, and mean height velocity rose from 4.1 cm/yr at baseline to 8.0 cm/yr at 6 months and 7.2 cm/yr at 12 months, with 74% classed as good responders at 6 months [10].

Adult data are small physiology studies. Ten healthy men with a mean age of 68 took GHRH(1-29) 0.5 mg and 1 mg subcutaneously twice daily for 14 days each, compared with nine men with a mean age of 26; at the higher dose, 24-hour GH and IGF-I rose to levels not significantly different from the young men [11]. A separate study of 11 men aged 64 to 76 given 2 mg nightly for 6 weeks found nocturnal GH release increased but IGF-I did not change; some strength measures improved, while body composition did not change [12]. These small studies do not establish lasting clinical benefit.

Ipamorelin's human record is thin: one published efficacy trial, in postoperative ileus, plus a volunteer study that measured drug levels and growth hormone release [4][5]. In the ileus trial, 117 adults were enrolled after bowel resection and 114 analyzed, receiving 0.03 mg/kg intravenously twice daily from postoperative day 1 to 7 or discharge. Median time to tolerate a standardized solid meal was 25.3 hours on ipamorelin versus 32.6 hours on placebo (p=0.15, not significant), secondary recovery endpoints did not differ, and the program was reportedly discontinued after disappointing phase 2 results [4][3].

A separate volunteer study gave healthy men single 15-minute intravenous infusions of 4.21 to 140.45 nmol/kg. Pharmacokinetics were dose-proportional, the terminal half-life was about 2 hours, and GH rose in a single peak about 0.67 hours after the infusion, then fell to negligible levels at every dose [5]. That study measured hormone levels, not any clinical benefit.

Do sermorelin and ipamorelin act on the same receptor?

No. Sermorelin is a 29-amino-acid analogue of human growth hormone-releasing hormone and the shortest synthetic peptide with full GHRH biological activity; it acts at the pituitary GHRH receptor to prompt release of the body's own growth hormone, and it is not growth hormone itself [1]. In a study of 30 healthy men given GHRH(1-29) intravenously or intranasally, the peptide was eliminated quickly after intravenous injection, yet GH stayed elevated for about 3 hours [13].

Ipamorelin is a five-amino-acid peptide (Aib-His-D-2-Nal-D-Phe-Lys-NH2) that releases GH through the ghrelin/GH-secretagogue receptor, not the GHRH receptor, and it contains unnatural amino acids [3][2]. In rats and pigs it released GH with potency similar to GHRP-6, and in swine it did not change FSH, LH, prolactin or TSH levels [2].

Sermorelin and ipamorelin act through different receptors, but whether combining them changes growth hormone release has not been established [1][2].

What doses were actually studied in humans?

Neither peptide has a current approved dose: sermorelin's approvals were withdrawn and ipamorelin was never approved [6][3]. The regimens below are study regimens, not recommended doses.

Sermorelin was studied at 30 micrograms/kg subcutaneously once daily at bedtime in children [10], at 0.5 mg or 1 mg subcutaneously twice daily for 14 days in older men [11], and at 2 mg nightly for 6 weeks in a separate group of 11 older men [12].

The human ipamorelin studies used intravenous dosing only: 0.03 mg/kg IV twice daily in the ileus trial [4] and single 15-minute infusions of 4.21 to 140.45 nmol/kg in healthy volunteers [5]. FDA found no human pharmacokinetic, safety or efficacy data for subcutaneous ipamorelin, so these findings do not establish a subcutaneous dose or its safety [3].

What are the safety concerns?

FDA's stated concerns about compounded ipamorelin acetate are possible immunogenicity for certain routes because of aggregation and impurities, unnatural amino acids that complicate characterization, and a published study that identified serious adverse events including death when ipamorelin was given intravenously to improve gastric motility. FDA said it has not identified safety-related information for other injectable routes [7].

In the ileus trial, per FDA's summary, low potassium occurred in 12.5% of ipamorelin patients versus 3.4% on placebo, insomnia in 10.7% versus 5.2%, high blood sugar at discharge in 14.3% versus 8.6%, and serious adverse events in 17.9% versus 15.5%. Two ipamorelin-treated patients died of surgical complications; FDA said it is unclear whether the deaths were related to ipamorelin but that they raise safety concerns [3][4].

Because ipamorelin stimulates the GH and IGF-1 axis, FDA said it may carry the risks listed on approved growth hormone labels — neoplasm, glucose intolerance and diabetes, intracranial hypertension, fluid retention, hypothyroidism and pancreatitis — and possibly QT prolongation, as with the approved GH stimulator macimorelin. FDA found no data showing it would not [3].

Claims that ipamorelin is selective rest on animal work and do not establish its effect on cortisol in people [2].

In the one-year study of children with growth hormone deficiency, sermorelin was well tolerated overall, with no adverse changes in general biochemistry or hormone tests, no change in fasting glucose, and no excessive IGF-I increase [10].

Are sermorelin and ipamorelin approved, and are they allowed in sport?

Sermorelin acetate was once FDA-approved as Geref under two applications: NDA 019863, the 0.05 mg/ampule product for testing the pituitary's ability to secrete growth hormone, approved December 28, 1990, and NDA 020443, the 0.5 mg and 1 mg vials for treating idiopathic growth hormone deficiency in children with growth failure, approved September 26, 1997 [6]. The manufacturer discontinued both in 2008 and asked FDA to withdraw the applications, which FDA did effective June 18, 2009. In March 2013 FDA determined that Geref was not withdrawn from sale for reasons of safety or effectiveness [6].

Geref's approved uses were only pediatric growth hormone deficiency treatment and a pituitary diagnostic test. It was never approved for adults, anti-aging, weight loss or athletic performance [6]. Sermorelin sold in the US today is compounded, and compounded drugs are not FDA-approved — FDA does not review their safety, effectiveness or quality before marketing [14]. HealthRX.com offers sermorelin by prescription.

On FDA's page of bulk substances that may present significant safety risks when compounded (content dated 04/22/2026), sermorelin is not listed [7]. Sermorelin acetate appears on FDA's nominated bulk list for outsourcing facilities in category 1, under evaluation, marked as a component of FDA-approved drugs [8].

Ipamorelin has never been approved. Ipamorelin acetate is in category 2 on FDA's significant-safety-risk list for outsourcing facilities, added September 29, 2023 and still listed on FDA's page dated 04/22/2026 and on the outsourcing-facility list updated March 21, 2025 [7][8]. On October 29, 2024, FDA's Pharmacy Compounding Advisory Committee voted 0 yes, 12 no, 1 abstention on ipamorelin free base, and the same on ipamorelin acetate, citing a lack of information supporting safety and efficacy [15]. It is not one of the six peptides in HHS's October 2026 draft enforcement-discretion policy [16].

In sport, WADA's 2026 Prohibited List names both sermorelin and ipamorelin in S2.2.4, prohibited at all times in and out of competition, and both are also named in the 2027 List in force January 1, 2027 [9][17].