Ipamorelin

Key points

• Ipamorelin is a five amino acid peptide in the growth hormone releasing peptide class, also called a growth hormone secretagogue.
• It works through the ghrelin receptor to trigger a pulse of growth hormone, and is valued for being fairly selective.
• Most human data is a single early study of how it behaves in the body, not a trial of real world benefit.
• It has no UK marketing authorisation, and growth hormone secretagogues are prohibited in sport.

Quick facts

What it is

Growth hormone secretagogue, 5 amino acids

Studied for

Raising the body's own growth hormone

UK status

Not a licensed medicine; sold for research use

Human evidence

Very limited; one early study of hormone release

In sport

On the WADA Prohibited List

How it works

Ipamorelin binds to the ghrelin receptor on pituitary cells, which triggers a pulse of growth hormone, and that in turn raises IGF-1. Its appeal is selectivity: unlike some older peptides in the same class, it is reported to raise growth hormone without much effect on hormones such as cortisol and prolactin. The body's own brake, somatostatin, still applies, which is the argument for it being gentler than injected growth hormone. It is often paired with a GHRH analogue such as CJC-1295, which acts through a different route.

What the evidence shows

The human evidence is thin. There is an early study in healthy volunteers showing it raises growth hormone in a dose dependent way, along with animal work on bone. What is missing is any controlled trial in people on the outcomes it is marketed for, such as muscle, fat or ageing, and any long term safety or head to head data.

What it does not settle

• There are no controlled human trials on body composition or ageing.
• There is no established human dose from proper trials.
• Long term safety and heart outcomes are not known.

Side effects

Common

• Headache, flushing or warmth after injecting, mild fluid retention and injection site reactions, usually early on.
• A mild increase in appetite, less than with some related peptides.

Less common but serious

• Signs of too much growth hormone, such as joint pain, hand numbness or raised blood sugar, are possible but poorly characterised in people.
• Because there is no licensed product, the dose, purity and contents of material bought online cannot be verified.

Report any suspected side effect through the MHRA Yellow Card scheme.

UK legal status and access

Ipamorelin has no UK marketing authorisation, so it is not a licensed medicine and is not offered by registered clinics or pharmacies. It is sold online labelled for research use. Genuine growth hormone deficiency is diagnosed and treated with licensed medicines under specialist care.

Common questions