Ghrelin dosage and evidence
Written by Aaron CuhaReviewed Sep 2026
The short answer
Ghrelin is the body's own hunger hormone. It is also the natural trigger for growth hormone, and every growth hormone peptide copies it.
Evidence grade for Ghrelin: Limited. The rule: people have taken it in a published study, but fewer than 100 of them. The sum on this page: 2 completed trials, 27 people given it. A grade counts how much has been done to people, not whether it works.
- People given it
- 27
- Human studies
- 2
- Found nothing
- 0
Dose
No human dose established
Amounts that were given in studies sit in Human evidence on this page. None of them is a personal dose.
2 completed trials, 27 people given it
1 effects reported, 1 wanted, by people using it, not a trial
Goal pages: Fat loss and metabolism
In plain English
In plain English, from Aaron
This is how I would explain it to a friend. The evidence, with the numbers, is further down the page.
Ghrelin is your hunger hormone. Your stomach makes most of it. It also tells your brain to release growth hormone. Every growth hormone peptide, like ipamorelin, copies it. It is a natural hormone, not a medicine you can get.
What people take it for
- People do not take ghrelin itself. They take drugs that copy it.
- Those copies are used to raise growth hormone.
What studies in people showed
The biggest human study had 18 young men. They got a drip of ghrelin at one of two doses, or a dummy drip. Both doses made growth hormone shoot up. The body cleared half the hormone in 9 to 13 minutes. Hunger went up a little with the dose, but not by enough to be sure. In another study, 9 healthy people got a ghrelin drip before a buffet. They ate about 28 percent more. In rats and mice, ghrelin made them eat more and gain fat.
What people report
Reports, not study results
The good
- In the studies on this page, people handled a single dose well.
The bad
- We have not collected user reports on this one, because nobody sells ghrelin itself.
Where these come from: The good line is from the human studies on this page. There are no user reports to collect, because ghrelin is not sold.
My bottom line
Ghrelin is the reason growth hormone peptides make you hungry. You cannot buy it, and you do not need to. Understand it, and you understand what those peptides do to you.
An opinion, not a finding. I am a coach, not a doctor.
What it has been measured to do
Measured in people
Goals Ghrelin has been tested for in people, biggest studies first. We count only what the studies on this page say, so the real numbers may be higher.
- Feeling less hungry27 people · 2 studies
Animal and lab work, not yet tested in people
Real results, but from animals or cells, not people. What works in a mouse often does not work the same way in a person. Nobody can patent this, so nobody would ever earn back the cost of a study in people. That is usually why there is none.
- Losing fat specifically1 animal or lab study
34 of the 36 indexed goals have no study of any kind behind Ghrelin
No study in people, animals or cells on this page reports a result for these. That does not prove Ghrelin does nothing for them. It does mean anything you have heard about Ghrelin and one of these did not come from a study cited here.
Show full evidence
What is Ghrelin?
Ghrelin is the body's own hunger hormone. It is also the natural trigger for growth hormone, and every growth hormone peptide copies it.
Ghrelin is a hormone made mostly in your stomach. It is 28 building blocks long and was found in 1999. It is the body's main natural trigger for growth hormone. It is also the only hormone in the blood known to make you hungry. Every lab-made growth hormone booster, from the GHRPs to ipamorelin, works by copying it. In people, a drip of ghrelin made nine healthy volunteers eat about 28% more at a buffet. In 18 young men, it set off a big rise in growth hormone, and the body cleared half of it in 9 to 13 minutes. In rats and mice, it made them eat more and gain fat. It is a well-known hormone, not an approved medicine.
How does Ghrelin work?
It switches on the ghrelin receptor in the pituitary gland and the brain. That releases growth hormone and makes you hungry.
The evidence, in charts
Fig. 1a · how many people
27people, across 2 studies in people cited here
| Study | People | Share |
|---|---|---|
| European Journal of Endocrinology 2004 | 18 | 67% |
| Journal of Clinical Endocrinology and Metabolism 2001 | 9 | 33% |
One study holds 67% of these people, so the total rests more on one study than its size suggests. Counts are the number of people each study on this page says it signed up. That includes studies that only watched people and gave nobody the compound. Studies still signing people up are left out, and only studies cited on this page are counted.
Fig. 1b · evidence mix
2 of 5 sources here are studies in people. The rest are not.
- Study in people · done in people240%
- Animal study · done in animals360%
Counted from the list of sources on this page. It counts only what we cite, so there may be more studies out there. A review counts once, however many studies it sums up.
Fig. 2 · evidence over time
The studies cover 4 different years, 1999 to 2004, counted from the list of sources on this page. The newest source on file is from 2004, more than five years ago. Research on it may have gone quiet.
Fig. 3 · legal status at a glance
US
Not approved
UK
Not approved
AU
Not approved
CA
Not approved
Not approved in any of the four countries shown. This is what the law says, not a verdict on the science. See Legal status below for the full text and any notes.
Fig. 4 · how much does what
Nobody has tested different amounts in people
This chart would show how the effect changes as the amount goes up. For this compound, nobody has measured that in people. So we leave it empty. We will not borrow an animal chart and pretend it works the same in people.
Fig. 5 · what the molecule is
- Kind of compound
- Peptide
- Molecule weight
- 3,370.9 Da
- Half-life
- About 30 minutesUltra-short, minutes
- Chain length
- None on file
No amino acid sequence is on file for Ghrelin, so none is drawn rather than guessed from a name.
The studies we cite
- Study in people2001Ghrelin enhances appetite and increases food intake in humans
Giving people ghrelin made them hungry, and they ate more. Nine healthy volunteers got the hormone through a drip, then sat down to a buffet. They ate roughly a quarter more food than they otherwise would. This was the first time a hormone circulating in the blood had been shown to drive eating in people. Nine is a very small group, and this was one meal in a laboratory, not a test of weight over time.
Intravenous ghrelin raised buffet energy intake by about 28% in nine healthy volunteers; first circulating hormone shown to stimulate food intake in man.
- Study in people2004Pharmacokinetics, safety, and endocrine and appetite effects of ghrelin administration in young healthy subjects
Put straight into the blood, the hormone set off a big release of growth hormone and people coped with it. 18 men got one of two doses or a dummy, and nobody involved knew which. Both doses drove growth hormone up strongly. The body cleared half of the active hormone in about 9 to 13 minutes, which is very fast. Hunger tended to rise as the dose rose, but not by enough to be sure of. 18 healthy young men and a single exposure is a small test.
Double-blind randomized placebo-controlled trial in 18 male volunteers given 1 or 5 micrograms per kilogram intravenously. Both doses strongly stimulated GH release and were well tolerated, with an elimination half-life of 9 to 13 minutes for acylated ghrelin; hunger tended to rise dose-dependently but not significantly.
- Animal study1999Ghrelin is a growth-hormone-releasing acylated peptide from stomach
In animals. This is the paper that found ghrelin. It showed ghrelin is the body's own key for the growth hormone booster switch, and that it is made mostly in the stomach.
Discovery paper: identified ghrelin as the endogenous ligand of the GH secretagogue receptor, produced mainly in the stomach.
- Animal study2000Ghrelin induces adiposity in rodents
In rats and mice. Ghrelin given into the body made them eat more and put on body fat.
Peripheral ghrelin increased food intake and body fat in rodents, establishing its role in energy balance.
- Animal study2001A role for ghrelin in the central regulation of feeding
In rats. Ghrelin in the brain made them eat a lot more. Blocking ghrelin made them eat less.
Central ghrelin strongly stimulated feeding in rats via hypothalamic NPY and AgRP neurons; anti-ghrelin antibody suppressed feeding.
Where to buy Ghrelin
No seller we track lists Ghrelin yet. We read sellers’ public product lists every week, and this section fills in as soon as one does. Every seller, graded
Common questions
Has Ghrelin been tested in people?
Yes. 27 people given it across 2 completed trials cited here, 0 of which found nothing. Ghrelin is the body's own hunger hormone. It is also the natural trigger for growth hormone, and every growth hormone peptide copies it.
What is the Ghrelin dosage?
No human dose established. Amounts that were given in studies sit in Human evidence on this page. None of them is a personal dose. 2 completed trials, 27 people given it
Is Ghrelin FDA-approved?
The hormone itself is not a medicine. No drug that switches on the ghrelin receptor is approved to boost appetite. The one approved drug that works this way is macimorelin (Macrilen, NDA 205598). It is a pill approved as a test for growth hormone deficiency, not as a treatment. The FDA's openFDA database now lists that product as discontinued.
Why does ghrelin matter for peptides?
It is the natural hormone that growth hormone peptides copy. If you understand ghrelin, you understand how ipamorelin and the GHRPs work.
Latest reading on Ghrelin
Blog posts about Ghrelin, newest first.