What is the difference between Sermorelin and Ipamorelin?

Sermorelin: Sermorelin is a synthetic analog of growth hormone-releasing hormone (GHRH) consisting of the first 29 amino acids of the 44-aa native hormone — the shortest fragment that retains full biological acti... Ipamorelin: Ipamorelin is a synthetic pentapeptide (Aib-His-D-2-Nal-D-Phe-Lys-NH2) originally developed by Novo Nordisk and later advanced by Helsinn/Nycomed. It is a selective ghrelin receptor agonist / growth h...

Sermorelin vs Ipamorelin

Q: Can you stack Sermorelin and Ipamorelin?

Sermorelin (performance) and Ipamorelin (performance) are in the same category and may have overlapping mechanisms — researchers should review both profiles carefully before combining. Consult a licensed provider before combining any compounds.

Head-to-head comparison of Sermorelin and Ipamorelin — mechanism, dosing, side effects, legal status, and pricing.

Sermorelin

Sermorelin is a synthetic analog of growth hormone-releasing hormone (GHRH) consisting of the first 29 amino acids of the 44-aa native hormone — the shortest fragment that retains full biological activity. It was FDA-approved in the 1990s as Geref (EMD Serono) for diagnostic testing of pituitary GH reserve and later for pediatric idiopathic GH deficiency, but was withdrawn from the US market in 2008–2009 at the manufacturer's request for commercial reasons (not safety or efficacy). It remains on the FDA Category 1 list of bulk substances nominated for use in 503A compounding, where it is now widely prescribed off-label for adult GH insufficiency and "anti-aging" indications.

Profile Prices Calculator

Ipamorelin

Ipamorelin is a synthetic pentapeptide (Aib-His-D-2-Nal-D-Phe-Lys-NH2) originally developed by Novo Nordisk and later advanced by Helsinn/Nycomed. It is a selective ghrelin receptor agonist / growth hormone secretagogue (GHRP). Its defining feature versus older GHRPs (GHRP-2, GHRP-6, hexarelin) is that in preclinical and early clinical studies it raised GH without meaningfully increasing ACTH, cortisol, or prolactin. It is not FDA-approved for any indication; a Phase 2 trial for postoperative ileus failed to meet its primary endpoint and clinical development was discontinued. In the wellness/grey market it is sold as a research chemical and used off-label for anti-aging and body-composition goals despite no clinically validated human dose for those uses.

Profile Prices Calculator

Sermorelin

Ipamorelin

Category

Performance

Legal Status

Category 1 — Legally Compoundable

Mechanism

Sermorelin binds GHRH receptors on anterior pituitary somatotrophs, activating Gs-adenylyl cyclase-cAMP-PKA signaling to stimulate both GH gene transcription and pulsatile GH vesicle release. Because GH release remains subject to somatostatin feedback, sermorelin preserves physiologic pulsatility and avoids the continuous supraphysiologic exposure seen with exogenous recombinant GH. Plasma half-life is short (~11–12 min), which is why bedtime subcutaneous dosing is used to augment the natural nocturnal GH pulse.

Ipamorelin binds the growth hormone secretagogue receptor 1a (GHSR-1a) on pituitary somatotrophs and in the arcuate nucleus of the hypothalamus, mimicking endogenous ghrelin. GHSR-1a is a Gq-coupled GPCR; activation triggers phospholipase C, IP3, and intracellular calcium release, driving pulsatile GH secretion. Ipamorelin's selectivity appears to come from its distinct binding profile at the GHSR compared with GHRP-2/GHRP-6, producing GH release without substantial ACTH/cortisol or prolactin co-release at therapeutic doses. It is pharmacologically complementary to GHRH analogs (sermorelin, CJC-1295) because the two receptor systems converge on somatotroph GH release through different second messengers, producing additive-to-synergistic GH pulses when co-administered.

Dose Range

100–500 mcg

200–300 mcg per dose (grey-market range)

Route

SubQ

Frequency

Once daily at bedtime

1–3 times daily

Dosing Notes

Typical compounded adult dosing is 100–500 mcg SubQ at bedtime to coincide with the nocturnal GH pulse; the historical Geref pediatric dose was 0.3 mg (300 mcg) SubQ nightly. Diagnostic GHRH stimulation testing used a 1 mcg/kg IV bolus. A 2+ hour fast before injection is conventionally recommended because post-prandial hyperglycemia and free fatty acids blunt the GH response. Effects on body composition and IGF-1 typically take 3–6 months.

There is no FDA-approved dose. Grey-market protocols typically inject 200–300 mcg subcutaneously 1–3 times per day (commonly pre-bed, pre-workout, and/or post-workout), often stacked with a GHRH analog such as CJC-1295 (no DAC) / modified GRF(1-29) to exploit GHRH+GHRP synergy. Administration on an empty stomach is favored because nutrients (especially carbohydrate and fat) blunt the ghrelin-axis GH response. None of these regimens have been validated in controlled human trials for body-composition or anti-aging endpoints.

Side Effects

Injection site reactions — redness, pain, or swelling (most common; ~16% in Geref trials)
Facial flushing
Headache
Nausea
Dizziness
Transient dysgeusia (altered taste)

Injection-site reactions (erythema, itching, transient welt)
Transient mild water retention / peripheral edema
Increased appetite (ghrelin-class effect)
Headache and flushing shortly after injection
Paresthesias (tingling or numbness in hands or feet)
Transient post-dose fatigue or lightheadedness
Reduced insulin sensitivity / elevated fasting glucose with sustained GH elevation, of particular concern when stacked with long-acting GHRH analogs in predisposed individuals

Contraindications

Known hypersensitivity to sermorelin or excipients (mannitol)
Pregnancy (former FDA pregnancy category C) and breastfeeding
Active malignancy (theoretical concern from IGF-1 elevation)
Untreated hypothyroidism (blunts GH response; correct first)
Disruption of the hypothalamic-pituitary axis (surgery, radiation, trauma)

Active or suspected malignancy (theoretical risk via GH/IGF-1 signaling on occult neoplasm)
Pregnancy and breastfeeding (no safety data)
Uncontrolled or poorly controlled diabetes mellitus, including type 2 diabetes with significant insulin resistance
Active acute or critical illness (GH-axis manipulation is associated with worse outcomes in ICU-level illness)
Known hypersensitivity to ipamorelin or excipients

Sermorelin Research Summary

Geref received FDA approval in the 1990s based on pediatric GHD trials and was used for the GHRH stimulation test of pituitary function. Vittone et al. (1997) showed nightly sermorelin in healthy elderly men raised IGF-1 and modestly increased lean mass. Khorram, Laughlin & Yen (1997) demonstrated that 16 weeks of nightly GHRH(1-29) in adults aged 55–71 restored GH/IGF-1 toward young-adult levels with small gains in lean mass and skin thickness. Walker (2006) reviewed sermorelin's rationale as a more physiologic alternative to rhGH in adult-onset GH insufficiency. EMD Serono discontinued Geref in 2008; FDA withdrew approval of NDAs 19-863 and 20-443 in 2009 and later (2013) affirmed the withdrawal was not for reasons of safety or effectiveness.

Key references

Ipamorelin Research Summary

The seminal preclinical characterization (Raun et al., 1998) established ipamorelin as the first GHRP-receptor agonist with a GH-release selectivity comparable to GHRH, without raising ACTH or cortisol even at doses more than 200-fold above the ED50 for GH. Pharmacokinetic-pharmacodynamic modeling in healthy male volunteers (Gobburu et al., 1999) confirmed a roughly 2-hour half-life and dose-dependent GH response following IV infusion. The most advanced human study is Beck et al. (2014), a Phase 2, randomized, double-blind, placebo-controlled trial in 114 patients after bowel resection evaluating IV ipamorelin 0.03 mg/kg twice daily for postoperative ileus; the drug was well tolerated but did not separate from placebo on the primary endpoint (time to tolerance of solid food), and the sponsor discontinued development. There are no completed registrational trials in adult growth hormone deficiency, frailty, or body-composition indications. Use in wellness medicine for anti-aging, fat loss, or muscle gain is extrapolated from short-term GH/IGF-1 pharmacodynamic data and is not clinically validated.

Key references

Can you stack Sermorelin and Ipamorelin?

Sermorelin and Ipamorelin are both in the Performance category and may have overlapping mechanisms. Researchers should review both profiles carefully, understand the mechanisms of action, and monitor the relevant biomarkers when combining compounds in the same class. As always, consult a licensed healthcare provider before making any decisions about combining research compounds.

Other comparisons

BPC-157 vs TB-500 Semaglutide vs Tirzepatide Ipamorelin vs CJC-1295 CJC-1295 vs Sermorelin Semaglutide vs Liraglutide Selank vs Semax BPC-157 vs GHK-Cu MK-677 vs Ipamorelin

This platform provides informational tools only, not medical advice. This comparison is for educational purposes only. Consult a licensed provider.

Sermorelin

Ipamorelin

Sermorelin Research Summary

Ipamorelin Research Summary

Can you stack Sermorelin and Ipamorelin?