Ipamorelin

Also called ipamorelin acetate, Aib-His-D-2Nal-D-Phe-Lys-NH2¹

Ipamorelin is a small lab-made peptide that copies the hunger hormone ghrelin's signal to release growth hormone. Its developers described it in 1998 as unusually selective: in animals it raised growth hormone without raising the stress hormone cortisol.⁴ In people, the main trial tested it for gut recovery after bowel surgery, and it missed its goal.⁶ No study has tested it for muscle, fat loss, sleep or aging.¹ FDA's advisers rejected it for compounding in 2024, so there is no legal US source.²

See every peptide's status in the regulatory tracker

At a glance

Where to get it

MoveWell sells no peptides and links only to legal options. All options

Molecular structure

A short chain of 5 building blocks. Three are not standard amino acids: Aib at the start, and the "mirror-image" D forms of naphthylalanine and phenylalanine in the middle. The end is capped as an amide.

The two D-amino acids (positions 3 and 4)

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AibAibHHis2NalD-2NalfD-PheKLys-NH2

Sequence

H-Aib-His-D-2Nal-D-Phe-Lys-NH2

Length

5 building blocks

Formula

C38H49N9O5

Weight

711.9 g/mol

CAS

170851-70-4 (free base)

FDA UNII

Y9M3S784Z6 (free base)

Drawn from the sequence in FDA's 2024 review. Formula and weight are for the free base.¹

What it is

Ghrelin is a hormone made mostly in the stomach. Besides hunger, it signals the pituitary to release growth hormone through a receptor called the growth hormone secretagogue receptor. Ipamorelin is a synthetic peptide built to switch on that receptor.^{1, 4}

It was first reported in 1998.^{1, 4} Earlier peptides of this type, such as GHRP-6 and GHRP-2, also raised the stress hormones ACTH and cortisol. In pig studies, ipamorelin did not, even at more than 200 times the dose needed to release growth hormone.⁴

It was later tested as an IV drug to restart the gut after bowel surgery. Development stopped after a phase 2 trial found no significant benefit.^{1, 6} Today it is sold online and by some clinics for muscle, fat loss and anti-aging.¹

How it works

• Ghrelin receptor. In rat pituitary cells and live animals, it released growth hormone with about the same potency as GHRP-6, an older peptide that acts on the same receptor.⁴
• Selective in animals. In pigs it didn't raise ACTH or cortisol above what natural GHRH does, and it didn't change prolactin or the pituitary hormones that control the thyroid and reproduction (TSH, LH and FSH).⁴
• One pulse per dose. In healthy men given an IV infusion, each dose produced one burst of growth hormone, peaking about 40 minutes later. Ipamorelin itself had a half-life of about 2 hours.⁵

FDA found no human study of ipamorelin injected under the skin, the way it is usually sold.¹

Evidence map

Each claimed use is graded separately, because the evidence differs by use.

Scale: 5 FDA-approved, 4 strong human, 3 limited human, 2 animal or lab only, 1 anecdotal

Key studies

FDA found no human studies of the under-the-skin route and no data for growth hormone deficiency. It also cites a 2020 review reporting that development stopped "due to these disappointing results."¹

By goal and route

Pick your goal to see what the evidence supports.

Sources: FDA review,¹ FDA advisory minutes,² FDA safety list,³ WADA.⁷

How it's used

We don't give a dose. No approved product or trial to US standards has set one.

The human studies gave it by IV, in a research unit or hospital.^{5, 6} Clinics and online sellers offer it as an injection under the skin, and FDA's database includes a compounded nasal spray.¹ We report this as information, not instruction.

Side effects and who should avoid it

• Serious events with IV use. FDA's safety list says "a study published in literature identified serious adverse events including death when ipamorelin was administered intravenously" for gut movement.³ FDA's review describes two deaths in ipamorelin-treated patients after colon cancer surgery, and says it is unclear whether they were related to the drug.¹
• The surgery trial. Side effects were common in both groups after bowel surgery: 87.5% on ipamorelin and 94.8% on placebo.⁶
• Reports to FDA. Two non-serious reports through Sep 2023: headache and watery eyes with a compounded nasal spray, and joint pain with an ipamorelin-sermorelin injection.¹
• Heart rhythm. The approved ghrelin-receptor drug macimorelin can prolong the QT interval. FDA says it is "concerned that similar potential risks" apply to ipamorelin.^{1, 12}
• Immune reactions and impurities. FDA "cannot rule out the potential for immunogenicity," especially for injected products, and found little impurity, aggregate or endotoxin data.¹
• Missing safety studies. FDA found no repeat-dose, genetic-damage or cancer studies. It also notes ghrelin-receptor drugs may have reward or addiction potential, and that it is unknown whether ipamorelin affects fertility or pregnancy. The mouse data FDA cites are for ghrelin itself, not ipamorelin.¹
• Who should avoid it. Anyone tested for sport, anyone pregnant or trying to conceive, and anyone with a heart rhythm problem or on drugs that prolong QT.^{1, 7, 12}

Compared with

Sources: FDA advisory minutes,^{2, 14} Macrilen label,¹² WADA.⁷ See our MK-677 and CJC-1295 guides.

CJC/ipamorelin blends

Ipamorelin is most often sold premixed with CJC-1295, usually the no-DAC version. The idea comes from 1990 research: in 18 healthy men, a GHRH-type hormone and a ghrelin-type peptide given together released more growth hormone than either alone.¹³ That study used neither CJC-1295 nor ipamorelin, and we found no study of the blend.

FDA's advisers voted against both ingredients in 2024, so the blend has no legal US source.^{2, 14} Some clinics pair ipamorelin with sermorelin instead. Sermorelin was once FDA-approved, but adding ipamorelin still puts the product outside any legal pathway.^{2, 17}

Myths vs evidence

All options

MoveWell sells no peptides. Checked November 1, 2026

Licensed compounding, with a prescription

None. FDA's advisers voted 0–12 against both the free base and the acetate, and the HHS policy doesn't include it.^{2, 8} FDA still lists ipamorelin acetate as a safety risk for outsourcing facilities.³ Outsourcing facilities last reported making it in 2020.¹ Telehealth pages offering "ipamorelin prescriptions" have no lawful product to fill them with, so we don't link them.

Legal alternatives for low growth hormone

Adults with suspected growth hormone deficiency can be tested by an endocrinologist, and approved growth hormone is the treatment.^{1, 12} Sermorelin is sold by licensed compounding pharmacies; see our sermorelin guide for what that means.

Research use only products

We don't list sellers. In August 2026 FDA warned five peptide sellers that a "research use only" label doesn't excuse products clearly meant for people.¹⁵

Legal status history

Newest first.

1. Current statusNov 1, 2026Not approved in the US. Not on the 503A bulks list and not in the HHS policy, so US pharmacies can't compound it. Banned in sport.^{1, 7, 8}
2. Next · no dateNo FDA review or rule is scheduled that we could find.
3. Oct 28, 2026HHS enforcement policy covers six peptides: BPC-157, TB-500, KPV, MOTS-c, semax and epitalon. Ipamorelin is not included.^{8, 9}
4. Apr 16, 2026FDA's July 2026 advisory meeting notice lists seven peptides. Ipamorelin is not among them.¹⁰
5. Jan 7, 2025FDA's revised interim policy: only Category 1 substances keep enforcement discretion while FDA builds the list.¹¹
6. Oct 29, 2024FDA's compounding advisory committee votes 0–12, with 1 abstention, against both the free base and the acetate. Members said the data didn't show safety or benefit.²
7. Aug 19, 2024FDA staff review says the criteria "weigh against" listing either form.¹
8. Sep 27, 2024Removed from 503A Category 2 after the nominators withdrew. FDA lists it as "nominated but withdrawn," which does not permit compounding, and sends it to its advisers anyway.^{3, 11, 18}
9. Sep 2023Ipamorelin acetate placed in Category 2 for pharmacies (503A) and, on Sep 29, 2023, for outsourcing facilities (503B), over immune-reaction risk.^{3, 18}
10. 2014Phase 2 bowel-surgery trial published. No significant benefit, and development was discontinued.^{1, 6}
11. 1998First described in a published study.⁴

See every peptide's status in the regulatory tracker.

FAQ

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References