Ghrelin: what it is and what the evidence says
A hormone produced mainly in the stomach that rises before eating and falls afterwards. It acts on appetite in the hypothalamus and on GH release in the pituitary.
Last reviewed: August 16, 2026 · How we verify this
The ground it plays on
Hormones work in axes: a signal from the brain tells a gland to release another hormone, and so on down the chain, with brakes that shut the process off. Intervening at one point has consequences both upstream and downstream. That is why this is the group where professional assessment stops being a recommendation and becomes essential.
What it is studied for
Appetite, GH signalling.
There is a distinction that almost always gets lost. A compound being studied for something is not the same as achieving it. And even where it works in a dish or in a mouse, that says little about whether it works in a person or whether the benefit is worth the risk. The section below therefore carries more weight than everything above it.
What the human evidence says
There is real evidence here: intravenous ghrelin acutely increases appetite and food intake in healthy volunteers, its levels are reduced in obesity, and in malnourished dialysis patients a randomised trial showed greater acute intake. In cancer cachexia, the oral agonist anamorelin increased weight and lean mass in two phase 3 trials, but did NOT improve handgrip strength.
The limitation that matters most
The key point is the dissociation between the scale and function: it adds weight and lean mass without adding strength or improving functional capacity. It is also not GH-selective: it stimulates ACTH and cortisol as well.
Regulatory status
Ghrelin itself is not approved. The agonist anamorelin was approved only in Japan, for cancer cachexia.
Status can change and varies by country. Always verify the rules in force where you live before drawing conclusions.
Cautions and context
Not a marketable product. The secretagogues that mimic it are not selective.
Appetite that runs out of control or vanishes without explanation deserves a medical workup, since a digestive, endocrine or drug-related cause is far likelier than anything to do with ghrelin.
What this page cannot give you
A reference page can take you this far. You know what Ghrelin is and where its research stands, which already puts you ahead of most readers. Four questions remain that no encyclopedia can answer for you, because the answers depend on your own situation:
- What would you measure beforehand, so that later you could tell whether anything actually changed?
- What would you watch along the way, and how consistently?
- What would you ask a professional, and in how much detail, so you do not walk out with a textbook answer?
- What would make you stop?
That is what the course is for
PeptiXtreme is ${CIF.LECCIONES} lessons that hand out no numbers. Each one ends with your starting point, what to watch along the way, the specific questions you take to a professional and the signals that mean stop. It includes per-module exams, a diploma with a verifiable folio, a record to track how you progress, and a human advisor you can actually write to.
See the course → Or measure your judgment, freeReferences
Every entry links to its record on PubMed, the US National Library of Medicine database. Open them and check. We would rather have a reader who verifies than one who takes our word for it.
- Ghrelin is a growth-hormone-releasing acylated peptide from stomachpreclinical Nature · 1999 · PMID 10604470 →
- Ghrelin enhances appetite and increases food intake in humanshuman J Clin Endocrinol Metab · 2001 · PMID 11739476 →
- Circulating ghrelin levels are decreased in human obesityhuman Diabetes · 2001 · PMID 11289032 →
- Subcutaneous ghrelin enhances acute food intake in malnourished patients who receive maintenance peritoneal dialysis: a randomized, placebo-controlled trialhuman J Am Soc Nephrol · 2005 · PMID 15888560 →
- Anamorelin in patients with non-small-cell lung cancer and cachexia (ROMANA 1 and ROMANA 2): results from two randomised, double-blind, phase 3 trialshuman Lancet Oncol · 2016 · PMID 26906526 →
- Anamorelin for cancer anorexia-cachexia syndrome: a systematic review and meta-analysis Support Care Cancer · 2017 · PMID 28074289 →
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Frequently asked questions
What is Ghrelin?
A hormone produced mainly in the stomach that rises before eating and falls afterwards. It acts on appetite in the hypothalamus and on GH release in the pituitary. It is studied within the area of hormonal/sexual.
Is there human evidence for Ghrelin?
There is real evidence here: intravenous ghrelin acutely increases appetite and food intake in healthy volunteers, its levels are reduced in obesity, and in malnourished dialysis patients a randomised trial showed greater acute intake. In cancer cachexia, the oral agonist anamorelin increased weight and lean mass in two phase 3 trials, but did NOT improve handgrip strength.
Is it approved by any health agency?
Ghrelin itself is not approved. The agonist anamorelin was approved only in Japan, for cancer cachexia.
What is the dose of Ghrelin?
We do not publish dosages. This is not an oversight. No single figure works for everyone: the regimen depends on a person's medical history, on whatever medication they already take, and on the goal they are chasing, which is something a professional weighs with the case in front of them. What you can build is the ability to walk into that appointment knowing what to ask.
Where can I learn to evaluate this properly?
This page tells you what Ghrelin is and what the evidence says. The PeptiXtreme course teaches the other half: what you would measure before considering anything, what you would watch, the specific questions you would take to a professional and when you would stop.