Head-to-head
Ipamorelin vs Semaglutide
A field-by-field comparison of Ipamorelin and Semaglutide drawn from the PeptideIndex database: mechanism, evidence grade, half-life, administration route, reported dosing, side effects, storage and legal status. They belong to different categories — growth hormone and metabolic — so this page focuses on what each one actually does rather than which is "better".
Ipamorelin vs Semaglutide at a glance
| Attribute | Ipamorelin | Semaglutide |
|---|---|---|
| Category | Growth hormone | Metabolic |
| Evidence grade | Moderate | Strong |
| Also known as | NNC 26-0161 | Ozempic, Wegovy |
| Chain | Pentapeptide (Aib-His-D-2-Nal-D-Phe-Lys-NH2) | GLP-1 analogue, 94% homology to human GLP-1 |
| Mechanism | Acts as a ghrelin receptor (GHS-R1a) agonist on the pituitary, triggering a clean GH pulse. Its selectivity avoids the appetite and cortisol effects seen with older secretagogues like GHRP-6. | Mimics GLP-1 to enhance glucose-dependent insulin secretion, suppress glucagon, slow gastric emptying and act on hypothalamic appetite centres. Fatty-acid acylation extends its half-life to once-weekly dosing. |
| Reported benefits | Clean GH pulse without hunger spikes · Better sleep quality and recovery · Mild fat-loss and body-composition support | ~15% mean body-weight reduction over 68 weeks in STEP-1 · Improved HbA1c and cardiovascular outcomes · Marked reduction in appetite and food noise |
| Reported side effects | Mild headache · Injection-site redness · Light-headedness shortly after dosing | Nausea and vomiting · Constipation or diarrhoea · Gallbladder issues · Contraindicated with medullary thyroid carcinoma history |
| Half-life | About 2 hours | About 7 days |
| Administration | Subcutaneous injection, 1–3 times daily | Once-weekly subcutaneous injection (oral tablet also approved) |
| Dosing overview | 200–300 mcg per dose, often 100–300 mcg before bed | Label titration from 0.25 mg weekly up to 2.4 mg over 16+ weeks |
| Storage | Reconstituted vials refrigerated 2–8 °C, stable ~4 weeks | Refrigerate 2–8 °C; in-use pens may be kept at room temperature per label |
| Legal status | Not FDA-approved; compounding restrictions apply in the US. Banned in sport. | FDA-approved and prescription-only. |
Key differences between Ipamorelin and Semaglutide
Different categories, different goals
Ipamorelin is indexed under growth hormone, while Semaglutide sits under metabolic. They are not substitutes for one another: Ipamorelin is described as "The most selective of the growth-hormone secretagogues, valued because it lifts GH without meaningfully raising cortisol or prolactin." and Semaglutide as "A long-acting GLP-1 receptor agonist with the strongest clinical weight-loss evidence of any peptide on the market."
Mechanism of action
Ipamorelin: Acts as a ghrelin receptor (GHS-R1a) agonist on the pituitary, triggering a clean GH pulse. Its selectivity avoids the appetite and cortisol effects seen with older secretagogues like GHRP-6. Semaglutide: Mimics GLP-1 to enhance glucose-dependent insulin secretion, suppress glucagon, slow gastric emptying and act on hypothalamic appetite centres. Fatty-acid acylation extends its half-life to once-weekly dosing.
Evidence quality is not equal
Ipamorelin carries a Moderate evidence grade and Semaglutide a Strong grade on this index. The grade describes the quality of published human data, not how well a compound works — Semaglutide has the better-documented record of the two, and claims made about Ipamorelin rest on thinner human evidence.
Half-life and dosing frequency
Ipamorelin is listed at about 2 hours; Semaglutide at about 7 days. That difference is what drives the reported schedules: 200–300 mcg per dose, often 100–300 mcg before bed versus Label titration from 0.25 mg weekly up to 2.4 mg over 16+ weeks
Route of administration
Ipamorelin is administered by subcutaneous injection, 1–3 times daily. Semaglutide is administered by once-weekly subcutaneous injection (oral tablet also approved).
Legal and regulatory status differs
Ipamorelin: Not FDA-approved; compounding restrictions apply in the US. Banned in sport. Semaglutide: FDA-approved and prescription-only. This is usually the most practical difference between two compounds, because it determines whether a supply chain is labelled and regulated at all.
Handling and storage
Ipamorelin is stored reconstituted vials refrigerated 2–8 °c, stable ~4 weeks. Semaglutide is stored refrigerate 2–8 °c; in-use pens may be kept at room temperature per label.
What Ipamorelin and Semaglutide have in common
On the attributes tracked in this database — category, evidence grade, mechanism, half-life, administration, dosing overview, storage and legal status — Ipamorelin and Semaglutide share no identical values. They are compared here because they come up together in the same searches, not because they overlap.
Each compound in brief
Ipamorelin
Growth hormone · Moderate evidence
The most selective of the growth-hormone secretagogues, valued because it lifts GH without meaningfully raising cortisol or prolactin.
Considerations: Weakest GH release of the GHRPs — usually stacked with CJC-1295 · Effects build over weeks, not days · Dose ceiling: more than ~300 mcg per pulse gives diminishing returns
Semaglutide
Metabolic · Strong evidence
A long-acting GLP-1 receptor agonist with the strongest clinical weight-loss evidence of any peptide on the market.
Considerations: Muscle loss can account for a meaningful share of weight lost — resistance training and protein intake matter · GI side effects are dose-dependent; titrate slowly · Weight regain is common after stopping
Related comparisons and reading
Every figure on this page is reproduced from the compound profiles in this database and reflects published literature and commonly reported protocols. It is educational information, not medical advice, and not a recommendation to use either compound. See the medical disclaimer.