What it is
Capromorelin is not a peptide. It is a small synthetic molecule — C28H35N5O4, molecular weight 505.6 (PubChem CID 216208) — that switches on the ghrelin receptor, the receptor the stomach hormone ghrelin uses to signal hunger. A drug designed to copy a peptide's action without being built from amino acids is called a peptidomimetic; capromorelin is one.
It is in this library for two reasons. Its job is a peptide hormone's job, and its name sits in the same searches as the peptide growth-hormone secretagogues — ipamorelin, GHRP-2 and the non-peptide MK-677. The difference matters: unlike those, capromorelin is an approved drug — for dogs and cats.
How it acts on the body
The Entyce label describes capromorelin as "a selective ghrelin receptor agonist" that works in two places:
- in the hypothalamus, where receptor signalling causes appetite stimulation;
- in the pituitary gland, where it binds the growth hormone secretagogue receptor to increase growth hormone secretion.
The Elura label adds that the ghrelin receptor "is found in many tissues in various species" and may affect the nervous system, gut, heart and energy balance — which is why both labels carry cardiovascular and glucose precautions.
In dogs the drug is short-lived: the Entyce label gives a peak within 0.83 hours and a terminal half-life of about 1.19 hours, with no build-up on daily dosing.
The animal trials behind the approvals
| Product | Study (label / paper) | Animals | Result |
|---|---|---|---|
| Entyce (dogs) | Randomised, masked, placebo-controlled field study (Zollers 2016, PMID 27859746) | 244 enrolled, 177 in the effectiveness analysis | Owner-rated appetite improved in 68.6% vs 44.6% on placebo (P = .008); weight +1.8% vs +0.1% |
| Entyce (dogs) | Laboratory study (label) | 24 healthy Beagles | Food intake significantly higher over 4 days than on vehicle (p < 0.001) |
| Elura (cats) | Masked, randomised, vehicle-controlled field study (label) | 176 enrolled cats with kidney disease and ≥5% weight loss; 112 evaluated | Weight +5.2% vs −1.6% at day 55 (p < 0.0001) |
Two caveats in the record itself. Four of the dog paper's five authors list the developer, Aratana Therapeutics, as their affiliation, and the endpoint was the owner's rating of appetite. And these are animal results; they say nothing about people.
The one human trial
Before its veterinary life, capromorelin was tested in older adults. A 2009 randomised, double-masked trial enrolled 395 men and women aged 65–84 with mild functional limitation for an intended two years (White et al., J Clin Endocrinol Metab, PMID 19174493). It was stopped early under pre-set criteria. At 6 months, pooled capromorelin groups gained 1.4 kg lean mass vs 0.3 kg on placebo and 1.4 kg body weight vs a 0.2 kg loss; the paper also reports fatigue, insomnia and small increases in fasting glucose, HbA1c and insulin resistance. No human product followed. That single trial is the whole human evidence base.
Safety on the labels
Reported from the labels, for reference — the decision belongs to the treating veterinarian.
- Heart and blood pressure: both labels warn of transient decreases in heart rate and blood pressure after dosing; the cat label says up to 4 hours.
- Blood glucose: the cat label warns that Elura "may increase serum glucose for several hours after dosing" and that use in diabetic cats has not been evaluated; the dog label cites post-approval reports of hyperglycaemia.
- Liver and kidneys: caution in hepatic dysfunction (the drug is metabolised by CYP3A4 and CYP3A5) and in renal insufficiency.
- People handling it: "Not for use in humans," keep away from children, and wash hands because "this product may be dermally absorbed."
Where it stands
- Dogs: Entyce, 30 mg/mL oral solution, approved 2016-05-16 (NADA 141-457).
- Cats: Elura, 20 mg/mL oral solution, approved 2020-10-16 (NADA 141-536), for weight loss in chronic kidney disease.
- People: not approved anywhere; both labels prohibit human use.
- Research record: 52 PubMed records, 24 in dogs or cats (2026-11-03).
Related reading
Capromorelin borrows its target from ghrelin, the 28-amino-acid hunger hormone. The peptide drugs that hit the same receptor in people are described in the ipamorelin entry and the GHRP-2 entry; the other well-known non-peptide in the family is MK-677 (ibutamoren). What separates a peptide from a mimic is set out in peptide vs protein.