Groeihormoonsecretagogen verhogen het eigen groeihormoon van het lichaam in plaats van synthetisch groeihormoon toe te voegen via injectie. De bekendste is ibutamoren, verkocht als MK-677; de injecteerbare peptiden sermorelin en ipamorelin werken op dezelfde as, maar met dunner menselijk data. Ze verhogen betrouwbaar groeihormoon en IGF-1, en in de sterkste proef voegde ibutamoren ongeveer een kilogram mager spierweefsel toe en verbeterde het bepaalde slaapmaten. Dezelfde proef vond geen toename in kracht of fysieke functie, hogere nuchter bloedsuikerspiegel, lagere insulinesensitiviteit, en meer honger en vochtretentie.
Bij mensen gaat een lager levenslang IGF-1 gepaard met langere overleving, dus het verhogen van IGF-1 gedurende decennia telt tegen veel van de levensduur-evidentie achter de anti-aging pitch in. Deze pagina behandelt het mechanisme, wat de proeven meetten, de metabole en bronrisico's, en waarom het educatief is. Het geeft geen dosering.
Findings & Outcomes
What It Is
A growth hormone secretagogue is a compound that prompts the body's own pituitary to release more growth hormone, instead of adding synthetic growth hormone by injection. Injected growth hormone, recombinant HGH, is a prescription drug with a flat, continuous action; a secretagogue works one level up and nudges the gland to fire its own pulses. Those pulses lift IGF-1, the downstream signal that carries most of the effect and most of the risk.
Three groups sit under the label. Ibutamoren, taken by mouth and sold as MK-677, is the only one with a two-year human trial behind it; the injectable peptides sermorelin and ipamorelin carry far thinner data.
Anatomy
1Ibutamoren (MK-677)
Ibutamoren is an oral, non-peptide compound that mimics ghrelin at the growth-hormone secretagogue receptor in the pituitary and hypothalamus. It is the most studied of the group and the one with a year-long trial behind it. It was developed as a drug candidate but is not an approved medicine, and it is sold widely as a research chemical.
2Sermorelin and the GHRH analogues
Sermorelin is a synthetic fragment of growth-hormone-releasing hormone, the natural signal the hypothalamus uses to tell the pituitary to release growth hormone. It was once available as a prescription product for diagnosing growth hormone deficiency and was withdrawn for commercial reasons, not safety ones. Human data on it for muscle or aging in healthy adults are thin.
3Ipamorelin and the injectable peptides
Ipamorelin, and relatives such as CJC-1295 and the GHRP compounds, act at the ghrelin receptor to trigger a growth hormone pulse. They are injected, sold as research peptides and not approved drugs, and their human evidence is mostly short studies that measured hormone levels in the blood without measuring any change in the body.
What It Does
In the strongest test, a two-year randomized study gave daily ibutamoren to 65 healthy adults aged 60 to 81. It raised their growth hormone and IGF-1 into the range of healthy young adults. Across the first year it added 2.4 lb (1.1 kg) of fat-free mass, while the placebo group lost a little. Much of that added mass was body water; the trial's authors read the rise in intracellular water as a real gain in cell mass.
The year of added lean mass came with no gain in strength or physical function. In separate crossover work, ibutamoren shifted sleep toward more deep and REM sleep in young adults. Against a hard clinical target, 12 months of ibutamoren in mild-to-moderate Alzheimer disease raised IGF-1 and failed to slow it.
The same trial logged a price. Fasting glucose climbed about 5 mg/dL, and the body's handling of insulin and glucose slipped over the year.
The Research & Studies
Everything here is based on the research we have collected and checked, sorted into groups and ordered with the strongest evidence first. Click any claim to open the studies behind it.
How it works
Secretagogues raise the body's own growth hormone and IGF-1 instead of injecting it
These compounds do not put growth hormone into the body. They stimulate the gland that makes it to release more, which then raises IGF-1, the downstream growth signal. Because they work through the body's own pulses, they keep the natural on-off pattern that a steady injection of growth hormone does not.
Ibutamoren (MK-677) is an orally active non-peptide ghrelin mimetic that acts at the growth-hormone secretagogue receptor to stimulate pituitary growth hormone release; sermorelin is a fragment of growth-hormone-releasing hormone acting at the GHRH receptor, and ipamorelin and the GHRP peptides act at the ghrelin receptor. All raise pulsatile growth hormone and, through it, hepatic IGF-1, and all remain subject to the body's negative feedback, which is the mechanistic argument advanced for them over recombinant growth hormone. The endpoint that carries the effects and the risks, a sustained rise in IGF-1, is shared with injected growth hormone.
Who this may not transfer to:This is the shared mechanism of the class and not a measurement in people, so it describes how the compounds act, not an effect size that transfers to any group.
The study · 1
Thorner et al., Growth hormone-releasing hormone and growth hormone-releasing peptide as therapeutic agents to enhance growth hormone secretion in disease and aging · Recent Prog Horm Res 1997;52:215-244
Ibutamoren raises growth hormone and IGF-1 into the young-adult range
Ibutamoren reliably pushes growth hormone and IGF-1 back up toward youthful levels in older people. That the blood markers rise is well established; whether that makes someone healthier or stronger is a separate question these studies answer only in part.
Nass and colleagues (2008) gave 25 mg of oral ibutamoren daily to healthy adults aged 60 to 81 in a two-year double-blind placebo-controlled trial and found growth hormone and IGF-1 rose into the young-adult range without serious adverse effects over the study period. Chapman and colleagues (1996) had earlier shown that daily oral ibutamoren stimulates the growth hormone and IGF-1 axis in healthy elderly subjects. The biomarker effect is therefore robust; it is graded benefit here in the narrow sense of restoring a youthful hormone level, not as a demonstrated health outcome.
Who this may not transfer to:Measured in healthy older adults aged 60 to 81. The biomarker rise is the compound's most reliable effect and would be expected in other adults, but it is a lab marker, not a health outcome.
The studies · 2
Nass et al., Effects of an oral ghrelin mimetic on body composition and clinical outcomes in healthy older adults: a randomized trial · Ann Intern Med 2008;149(9):601-611
Chapman et al., Stimulation of the growth hormone (GH)-insulin-like growth factor I axis by daily oral administration of a GH secretagogue (MK-677) in healthy elderly subjects · J Clin Endocrinol Metab 1996;81(12):4249-4257
Counts once: this finding and 3 others here come from the same source, so they are one body of evidence, not separate confirmations.
Muscle And Strength
Ibutamoren adds about 2.4 lb (1.1 kg) of fat-free mass over a year, much of it fluid
Ibutamoren adds a modest amount of fat-free mass, roughly a kilogram over a year, while people on placebo tend to lose a little. Much of that gain is body water, not new muscle, though it is a small change in body composition.
In Nass and colleagues (2008), fat-free mass increased by about 2.4 lb (1.1 kg) (95% CI 0.7 to 1.5) in the ibutamoren group and fell by about 1.1 lb (0.5 kg) in the placebo group. Much of the gain reflects added body water, not contractile muscle: body cell mass measured as intracellular water rose about 1.8 lb (0.8 kg), body weight rose about 6 lb (2.7 kg) (more than the fat-free-mass gain), and the compound causes mild fluid retention. The change in lean tissue is the clearest body-composition effect of the compound, and its practical value is limited by the finding, in the same trial, that this lean mass did not increase strength or physical function.
Who this may not transfer to:Measured in healthy adults 60 to 81. The modest fat-free-mass gain, much of it body water, is what shows in this age group and has not been shown to build usable muscle at any age.
The study · 1
Nass et al., Effects of an oral ghrelin mimetic on body composition and clinical outcomes in healthy older adults: a randomized trial · Ann Intern Med 2008;149(9):601-611
Counts once: this finding and 3 others here come from the same source, so they are one body of evidence, not separate confirmations.
No gain in strength or physical function despite the added lean mass
The extra lean tissue ibutamoren produced did not make people stronger or more physically capable. The muscle showed up on the scan, but the strength and function tests did not move.
Nass and colleagues (2008) reported that the increase in fat-free mass with ibutamoren did not result in changes in strength or function, and noted that the study was not powered to fully evaluate functional endpoints in healthy elderly persons. This is the central limitation of the body-composition finding: the outcome most people are after, being stronger and more capable, was not demonstrated even as lean mass rose.
Who this may not transfer to:Measured in healthy adults 60 to 81 and underpowered for function. The absence of a strength or function gain despite more lean mass is the finding that carries; nothing suggests a larger functional payoff in younger users.
The study · 1
Nass et al., Effects of an oral ghrelin mimetic on body composition and clinical outcomes in healthy older adults: a randomized trial · Ann Intern Med 2008;149(9):601-611
Counts once: this finding and 3 others here come from the same source, so they are one body of evidence, not separate confirmations.
Blood Sugar
Ibutamoren raised fasting blood glucose about 5 mg/dL and lowered insulin sensitivity
Ibutamoren pushed fasting blood sugar up and made the body less sensitive to insulin. Because growth hormone naturally opposes insulin, this metabolic cost is expected from the way these compounds work.
Nass and colleagues (2008) found that fasting blood glucose increased by an average of about 5 mg/dL (0.3 mmol/L) (P = 0.015) in the ibutamoren group and that insulin sensitivity decreased. Growth hormone is a counter-regulatory hormone that opposes insulin, so raising it chronically predictably degrades glucose handling. The size of the change was modest in a healthy population over the study period, but the direction is consistent and matters most for people with impaired glucose tolerance.
Who this may not transfer to:Measured in healthy adults 60 to 81. The glucose rise was modest here but follows from the mechanism and matters more for anyone with impaired glucose tolerance, in whom it has not been trialed at this dose.
The study · 1
Nass et al., Effects of an oral ghrelin mimetic on body composition and clinical outcomes in healthy older adults: a randomized trial · Ann Intern Med 2008;149(9):601-611
Counts once: this finding and 3 others here come from the same source, so they are one body of evidence, not separate confirmations.
Cognition
Ibutamoren raised IGF-1 but did not slow Alzheimer disease over twelve months
When ibutamoren was tested against a clinical outcome, it failed. It raised IGF-1 as expected in people with Alzheimer disease but did nothing to slow the disease over a year. The hormone moved and the outcome did not.
Sevigny and colleagues (2008) conducted a randomized placebo-controlled trial of the growth hormone secretagogue ibutamoren in patients with mild-to-moderate Alzheimer disease and found no clinical effect on disease progression despite the expected rise in IGF-1. This is one of the few settings where a secretagogue was measured against a functional clinical endpoint, not a biomarker, and it illustrates the gap between raising IGF-1 and changing an outcome a person would notice.
Who this may not transfer to:Measured against a clinical endpoint in Alzheimer patients. It shows that raising IGF-1 need not change an outcome, and it does not test muscle or aging endpoints.
The study · 1
Sevigny et al., Growth hormone secretagogue MK-677: no clinical effect on AD progression in a randomized trial · Neurology 2008;71(21):1702-1708
Longevity And Mortality
In people in their nineties, lower IGF-1 predicted longer survival
In very old people, having lower IGF-1 predicted living longer. Since these compounds are made to push IGF-1 up and keep it there, the longevity evidence points against using them for anti-aging.
Milman and colleagues (2014) followed 184 nonagenarians and found, in Kaplan-Meier and adjusted regression analyzes, that IGF-1 below the median predicted longer survival in women (P < 0.01) and in individuals with a history of cancer, though not in men overall. This human observation fits a large animal literature in which reduced growth-hormone and IGF-1 signaling extends lifespan. Because growth hormone secretagogues deliberately raise and sustain IGF-1, their intended effect runs against the direction associated with human longevity.
Who this may not transfer to:An observational cohort of people in their nineties. The survival advantage of lower IGF-1 was clearest in women and describes the direction of the association, not the effect of taking a drug.
The study · 1
Milman et al., Low insulin-like growth factor-1 level predicts survival in humans with exceptional longevity · Aging Cell 2014;13(4):769-771
Gene variants that dampen IGF-1 signaling are overrepresented in centenarians
People who live to a hundred are more likely to carry gene variants that turn IGF-1 signaling down. That genetic clue points the same way as the survival data: less growth signaling, not more, accompanies a very long life.
Suh and colleagues (2008) found that functionally significant mutations in the IGF-1 receptor, which reduce receptor activity, were enriched among centenarians relative to controls, with the signal notable in female centenarians. Together with the survival data and the animal literature, this genetic evidence points toward reduced IGF-1 signaling accompanying exceptional longevity, which is the opposite of what a growth hormone secretagogue is designed to do.
Who this may not transfer to:A genetic association in centenarians and controls. It describes naturally occurring receptor variants, not the effect of any secretagogue.
The study · 1
Suh et al., Functionally significant insulin-like growth factor I receptor mutations in centenarians · Proc Natl Acad Sci U S A 2008;105(9):3438-3442
Sleep
Ibutamoren raised deep sleep about 50% and REM sleep over 20% in young adults
Ibutamoren shifted sleep toward more deep and REM sleep in a small study. In young people the higher dose raised deep sleep by about half and REM sleep by more than a fifth, which fits the known link between growth hormone release and deep sleep.
Copinschi and colleagues (1997) used a placebo-controlled crossover design in eight healthy young adults (18 to 30) and six older adults (65 to 71). In the young group, high-dose ibutamoren increased stage IV sleep by about 50% and REM sleep by more than 20% versus placebo, and reduced deviations from normal sleep; in the older group it increased REM sleep and shortened REM latency. The finding is consistent with the physiological coupling of growth hormone secretion and slow-wave sleep.
Who this may not transfer to:A small crossover study in young (18 to 30) and older (65 to 71) adults. The sleep-stage shift is an early signal, and its effect on next-day rest or daytime function was not measured.
The study · 1
Copinschi et al., Prolonged oral treatment with MK-677, a novel growth hormone secretagogue, improves sleep quality in man · Neuroendocrinology 1997;66(4):278-286
The Longevity Case Runs the Other Way
The anti-aging pitch runs into the human record. Among people in their nineties, those with IGF-1 below the median lived longer, an effect clearest in women. Gene variants that dampen IGF-1 signaling show up more often in women who live to a hundred.
These compounds are engineered to raise IGF-1 and hold it high, the direction this evidence points away from. Unlike rapamycin, which dials growth signaling down, they push it up, a pattern that runs through the biology of aging.
How It Works
Growth hormone leaves the pituitary in pulses, largely at night, and those pulses fall steadily with age. The hormone travels to the liver and other tissues, where it drives production of IGF-1, insulin-like growth factor 1. IGF-1 is the signal that reaches muscle, bone, and other tissue to promote growth and repair.
Secretagogues act one step above growth hormone. Ibutamoren and the ghrelin-receptor peptides imitate ghrelin to trigger a pulse; sermorelin imitates the hypothalamic releasing hormone, GHRH. Because they run through the body's own gland, they keep the natural pulsing pattern and stay under feedback control, the mechanistic case made for them over injected growth hormone. The endpoint is the same either way. Whether growth hormone is injected or released from the gland, the effect flows through a sustained rise in IGF-1. That rise also drives the metabolic and cancer concerns.
These compounds reliably raise IGF-1. What a raised IGF-1 does to a healthy person over years is the unanswered question, and it is the reason this page stops at education.
How To Think About It
There is no protocol here, this is education. The plainer levers below raise growth hormone naturally, and the few medical uses on this axis go through a clinician.
The largest natural pulse of growth hormone happens during deep sleep, and hard resistance and interval training raise it too. Protecting deep sleep and training regularly drive the same axis these compounds target, at no cost and with none of the metabolic downside. For most people this is the plainest answer to the goal behind the drugs.
Growth and repair need building blocks, not just a signal. Adequate daily protein, spread across meals, is what lets training and sleep translate into muscle. It is the best-evidenced lever for the body-composition goal that draws people to secretagogues in the first place.
Ibutamoren, sermorelin, ipamorelin and the other secretagogues are not approved drugs for muscle or aging, and most are sold as research chemicals from a gray market with no check on identity, dose, purity, or sterility. They are experimental substances sold ahead of the evidence.
Growth hormone deficiency is a medical diagnosis with established treatment, and a clinician can tell you whether anything on the growth axis fits your situation and monitor blood glucose if it does. That conversation, not a vial or a capsule from a website, is the practice here.
The Kidney, Jing, and the Limits of Forcing
Growth hormone secretagogues are products of modern endocrinology, synthesized within the last few decades. No classical Chinese text assigns a channel, a temperature, or a flavor to ibutamoren or MK-677, and no traditional formula contains one. Tradition works as a lens here, though it supplies no evidence; no herb or formula reproduces what these compounds do.
In Chinese medicine the Kidney stores Jing, the deep constitutional reserve that governs growth, development, and the vitality a body draws on across a lifetime. Jing is understood to thin with age. The anti-aging pitch appeals to the same intuition: topping up the growth and repair signals of youth, carried by IGF-1, as they fade.
Tonifying, building the body up, is held to suit only a true deficiency in someone who can assimilate what is given. Forcing a system harder than it can absorb is understood to deplete it. Driving the growth axis year after year in a body that is not deficient is that kind of forcing. It lines up with the finding that chronically raising IGF-1 counts against longevity. Placing a modern compound beside the Kidney and Jing connects it to a framework the tradition has long reasoned about; it makes no claim that Chinese medicine endorses or explains these compounds. The evidence for any secretagogue stands or falls on its trials.
Cautions
Everything to be aware of is here, in one place. This practice suits most healthy people; a few situations call for real care.
Ibutamoren increased appetite and caused mild leg edema and muscle pain
In Nass and colleagues (2008) the most frequent side effects of ibutamoren were an increase in appetite that subsided after a few months and transient, mild lower-extremity edema and muscle pain; cortisol rose by about 47 nmol/L (P = 0.020) and there were changes in bone mineral density consistent with increased bone remodeling. Body weight rose by about 6 lb (2.7 kg) in the treated group, more than the lean-mass gain alone, reflecting the appetite and fluid effects.Nass et al., Effects of an oral ghrelin mimetic on body composition and clinical outcomes in healthy older adults: a randomized trial
Higher IGF-1 tracks with more prostate and premenopausal breast cancer
Renehan and colleagues (2004) pooled case-control studies, including some nested within cohorts, in a systematic review and meta-regression and found that higher circulating IGF-1 was associated with increased risk of prostate cancer and premenopausal breast cancer. The data are observational, so they show association, not proof that raising IGF-1 causes cancer, and no long trial of growth hormone secretagogues has measured cancer outcomes. Because these compounds are used precisely to elevate IGF-1, the association is a substantive safety concern.Renehan et al., Insulin-like growth factor (IGF)-I, IGF binding protein-3, and cancer risk: systematic review and meta-regression analysis
Raised blood glucose and lower insulin sensitivity
The best trial of ibutamoren found it raised fasting blood glucose and lowered insulin sensitivity over a year. Because these compounds work by raising growth hormone, which opposes insulin, this metabolic cost is expected. Anyone with prediabetes, diabetes, or a family history of it has particular reason to weigh this, and it is a change a clinician would want to monitor.
Appetite, fluid retention, and other effects
In the same trial the most common effects were an increase in appetite, which subsided over a few months, and transient mild swelling in the lower legs along with muscle pain. Cortisol rose modestly and there were changes in bone remodeling. These are the effects people report, and they belong to the package.
The IGF-1 and cancer concern
These compounds are designed to raise IGF-1, and across large observational studies higher IGF-1 is associated with a higher risk of some cancers, including prostate and premenopausal breast cancer. No long trial has measured cancer outcomes for secretagogues, so deliberately raising IGF-1 over years is an untested concern. Anyone with a personal or family history of cancer has extra reason for caution.
Not approved, and mostly gray market
Ibutamoren, ipamorelin and the other secretagogues are not approved medicines for muscle or aging. Most are sold as research chemicals outside pharmaceutical controls, and testing of such products has found wrong doses, missing active ingredient, and contamination. What is in a given capsule or vial is uncertain, and the injectable peptides add the separate risks of self-injecting a non-sterile product. Ibutamoren is also a banned substance in competitive sport.
The anti-aging rationale may be backwards
In people, lower lifelong IGF-1 tracks with longer survival, and reduced growth-hormone signaling extends lifespan in animals. Taking a compound specifically to raise IGF-1 for anti-aging runs against that evidence. This is a serious reason to be skeptical of the longevity claim.
A conversation for a clinician
Growth hormone deficiency is a medical diagnosis with established treatment, and whether anything on the growth axis fits a given person is a clinical judgment. If these compounds interest you, the step is a knowledgeable clinician who can assess your situation and monitor the metabolic effects, not a purchase and a self-designed schedule. This page gives no dose because there is no trial that would tell a healthy person a safe and effective one.
Start slow, be smart, read the research, and consult a professional if you have any concerns. This is here to inform your choice, not make it for you.
Common Questions
Is raising my own growth hormone safer than injected HGH?
The theoretical edge, keeping the natural night-time pulse and the feedback brakes, is laid out above. No head-to-head trial has tested that edge for safety over years, and both routes converge on the same downstream signal, IGF-1, as the mechanism above shows. Injected HGH is at least a regulated prescription drug; the secretagogues sold online have no such approval.
Will it slow aging?
No trial has shown any secretagogue extends healthspan or lifespan in a person. The human and animal evidence, covered above, leans the other way. Raising IGF-1 for decades is the bet, and no long study has scored whether that bet pays off in either direction.
How do sermorelin and ipamorelin compare with ibutamoren?
Their human evidence is thinner. Sermorelin has a past as a diagnostic product but little controlled data for muscle or aging in healthy adults. Ipamorelin and related injectable peptides mostly show a bump in growth hormone and IGF-1 on a blood draw, with no measured change in the body. All are sold as research chemicals; injecting a gray-market vial stacks unknown identity, dose, and sterility on top of evidence that only tracked IGF-1 in a blood tube.
Explore Related
Other pages this one connects to, by the evidence they share, the outcomes they touch, and the ground they cover.
All 12 sources on this page independently checked and cross-referenced.
Thomas Dehli, Founder & Editor, Sacred Lotus
Sacred Lotus has published Chinese medicine reference material since 2001. Integrative pages are held to the same standard as the herb and formula library: cite the source, grade the claim at its real strength, and say where the research has not looked. This page is educational and it is not medical advice. Last reviewed and updated August 9, 2026.
Evidence strength
How confidently the research supports a claim. Strength describes the evidence, not our endorsement.