Anti-Aging · Reference
Sermorelin vs Hexarelin: GHRH Analogue vs Ghrelin Mimetic, Compared
This page explains each peptide on its own terms, puts them side by side, covers what the research does and does not show, how each is dosed at Pepti, what each costs, the safety points that differ, and when a combination vial makes more sense than either alone.
Sermorelin and hexarelin both ask the pituitary to release its own growth hormone, but they knock on different doors. Sermorelin is the first 29 amino acids of GHRH, the hypothalamic hormone that signals growth hormone release, and it was once the active ingredient of an FDA-approved product for children. Hexarelin is a six-amino-acid synthetic peptide that imitates ghrelin; in the human studies it produced a larger single-dose growth hormone pulse than GHRH, along with a smaller rise in cortisol and prolactin, and its effect fades with continuous dosing. Sermorelin is the gentler, more selective option with controlled trials behind it; hexarelin is the stronger, less selective one that needs breaks. Both are compounded prescriptions, and neither is FDA approved.
This page explains each peptide on its own terms, puts them side by side, covers what the research does and does not show, how each is dosed at Pepti, what each costs, the safety points that differ, and when a combination vial makes more sense than either alone.
Sermorelin vs Hexarelin
The short answer
| If your main goal is | The usual prescription | What is in it | Price |
|---|---|---|---|
| A gentle, selective growth hormone signal with trial history | Sermorelin | 10 mg sermorelin in a 5 mL vial | $229/mo |
| The strongest single-agent ghrelin-receptor pulse, with breaks built in | Hexarelin | 12.5 mg hexarelin in a 5 mL vial | $209/mo |
| Both receptor types at once, without hexarelin's cortisol pulse | Ipamorelin + Sermorelin | Ipamorelin and sermorelin in one vial | $219/mo |
| A selective ghrelin-receptor peptide on its own | Ipamorelin | 5 mg ipamorelin in a 5 mL vial | $239/mo |
| A longer-acting GHRH analogue with a ghrelin-receptor peptide | CJC-1295 / Ipamorelin | CJC-1295 and ipamorelin in one vial | $239/mo |
Every figure is an all-in monthly price covering the medication, physician review, refill management and shipping. There is no separate membership fee, and Pepti is cash-pay and does not bill insurance. Current pricing always lives on each product page.
Sermorelin vs Hexarelin
Two doors into the same cell
The pituitary cells that make growth hormone, the somatotrophs, listen to two inputs. One is GHRH from the hypothalamus, acting on the GHRH receptor. The other is ghrelin-type signalling, acting on the growth hormone secretagogue receptor (GHS-R1a). Sermorelin uses the first door. Hexarelin uses the second. Neither contains growth hormone; both can only ask for what the gland is still able to give.
That one fact explains most of this comparison: why they behave differently, why they are often combined rather than chosen between, and why hexarelin brings extra hormones along with it.
Sermorelin vs Hexarelin
Sermorelin on its own terms
What it is
Sermorelin is GHRH(1-29)-NH2: the first 29 of the 44 amino acids of natural growth-hormone-releasing hormone, the shortest fragment that keeps full activity. It is supplied as an acetate salt. It acts on the same receptor the body's own GHRH uses every night. The full reference is what is sermorelin.
Its regulatory history
Sermorelin acetate was approved by the FDA in 1990 as a diagnostic test of whether a child's pituitary could release growth hormone, and in 1997 as a treatment for idiopathic growth hormone deficiency in children. The manufacturer discontinued it in 2008, the FDA withdrew approval in 2009, and in 2013 the FDA published a determination that it was not withdrawn for reasons of safety or effectiveness. No approved sermorelin product is on the US market today, and compounded sermorelin is not an FDA-approved product.
How sermorelin is described to work
- A pulse, not a plateau. National Institute on Aging work in 1992 described GHRH(1-29) in older men raising the amplitude of growth hormone peaks toward those of young men while keeping the pulsatile pattern intact.
- Feedback stays intact. Because the pituitary does the releasing, somatostatin still inhibits it and rising IGF-1 still feeds back. That is why a secretagogue is described as self-limiting in a way injected growth hormone is not.
- Selectivity. Sermorelin acts on the growth hormone axis and is not described as raising cortisol or prolactin.
What human data exists for sermorelin
Controlled trials in children with growth hormone deficiency, including a 1996 multicentre study of 110 children in the Journal of Clinical Endocrinology and Metabolism, plus several small trials in healthy older adults. The longest, a 1997 randomized, placebo-controlled sixteen-week trial in nineteen adults aged 55 to 71, reported nocturnal growth hormone rising and IGF-1 rising within two weeks, then drifting back toward baseline by sixteen weeks. A 1997 Johns Hopkins study of single nightly injections for six weeks found IGF-1 and body composition did not change. There is no large randomized trial of sermorelin in adults for body composition, recovery, sleep or anti-aging outcomes. Sermorelin benefits covers this in detail.
Sermorelin vs Hexarelin
Hexarelin on its own terms
What it is
Hexarelin is a hexapeptide, His-D-2-methyl-Trp-Ala-Trp-D-Phe-Lys-NH2. Two of its six amino acids are unnatural D-forms and one carries a methyl group not found in natural proteins, which lets it survive long enough to act. It was designed in the early 1990s as a more stable, more potent analogue of GHRP-6, the first growth hormone-releasing peptide. The full reference is what is hexarelin.
How hexarelin is described to work
- Ghrelin-receptor agonism. It binds GHS-R1a and triggers a growth hormone pulse. A 2001 study in the Journal of Clinical Endocrinology and Metabolism gave healthy young men ghrelin, hexarelin and GHRH on separate days: ghrelin released the most growth hormone, hexarelin the next most, and GHRH the least.
- Cortisol and prolactin too. Unlike the later selective peptides, hexarelin also stimulates the pituitary cells that make ACTH and prolactin. A 1997 study in Peptides reported rises in prolactin, ACTH and cortisol, the ACTH and cortisol response similar in size to that from corticotropin-releasing hormone.
- Heart receptors. Hexarelin also binds CD36 on heart muscle cells. Three small single-dose intravenous studies from Turin reported a short-lived rise in the heart's ejection fraction that growth hormone itself did not reproduce. Ongoing subcutaneous use in people has not been studied, and it is not a heart treatment.
Desensitisation: the key difference
The single most important hexarelin paper is a 1998 study in the Journal of Clinical Endocrinology and Metabolism. Healthy elderly volunteers took twice-daily subcutaneous hexarelin for sixteen weeks. The growth hormone response to a test dose fell by about a third by week one and by nearly half by week sixteen, and returned to baseline four weeks after stopping. Over the same sixteen weeks, IGF-1, total body fat, lean body mass and bone mineral density did not change significantly. Shorter intermittent schedules in older adults did not show desensitisation. That is why hexarelin is prescribed five nights on, two off.
What human data exists for hexarelin
A large body of 1990s single-dose pharmacology in hundreds of adults and children, two small open-label courses in short children, the sixteen-week study above, and the three single-dose cardiac studies. There are no randomized controlled trials of hexarelin for sleep, recovery, body composition, ageing or any wellness use.
Sermorelin vs Hexarelin
Head to head
| Sermorelin | Hexarelin | |
|---|---|---|
| Length | 29 amino acids | 6 amino acids |
| What it copies | GHRH, the hypothalamic releasing hormone | Ghrelin, the stomach hormone (via GHRP-6) |
| Receptor | GHRH receptor | Ghrelin receptor (GHS-R1a), plus CD36 in the heart |
| Single-dose growth hormone pulse | Smaller (GHRH ranked below hexarelin in the 2001 comparison) | Larger |
| Cortisol and prolactin | Not described as raised | Raised transiently with each dose |
| Desensitisation | IGF-1 drifted back toward baseline by week 16 in one trial | Growth hormone response fell by nearly half over 16 weeks of continuous dosing, reversible |
| Regulatory history | Active ingredient of a former FDA-approved product for children | Never approved; never categorized by the FDA |
| Strongest human evidence | Pediatric trials and small older-adult trials | Single-dose pharmacology and one 16-week study |
| Body composition in adults | No change in a six-week study | No change in the sixteen-week study |
| Vial at Pepti | 5 mL, 2 mg/mL (10 mg) | 5 mL, 2.5 mg/mL (12.5 mg) |
| Typical directions | 0.25 mL (25 units) Monday to Friday nights | 0.25 mL (25 units) Monday to Friday nights at bedtime |
| Amount per dose | 0.5 mg | 0.625 mg |
| Formats | Vial, or a pre-filled pepti Pen cartridge | Vial only |
| Price at Pepti | $229 a month | $209 a month |
"Stronger" is not the same as better
Hexarelin produces a bigger pulse per dose. It also brings cortisol and prolactin along, and continuous exposure turns its receptor down. Sermorelin's pulse is smaller and cleaner, with the body's feedback loops left in charge. Neither has a trial showing a body-composition, sleep or recovery outcome in adults, so the larger pulse has not been shown to translate into anything you would notice. The useful difference is the trade-off between potency and selectivity, not a ranking.
Sermorelin vs Hexarelin
Who suits which
Sermorelin
Sermorelin is the usual starting point for someone who wants a growth hormone axis peptide with the longest regulatory and trial history, a selective action, and an uninterrupted course. It also comes as a pre-filled pepti Pen cartridge for people who would rather dial a dose than draw one.
Hexarelin
Hexarelin is a choice when a stronger single-agent ghrelin-receptor pulse is the priority, and the person is comfortable with a course structured around breaks. Its five-nights-on schedule is the practical answer to the desensitisation data.
A combination vial
The two signals add together. A 1996 study in Clinical Endocrinology found hexarelin given with GHRH produced a peak greater than the sum of the two alone, though the synergy faded on repeat dosing. Pepti does not supply a hexarelin and sermorelin vial. Ipamorelin + Sermorelin pairs sermorelin with ipamorelin, a ghrelin-receptor peptide designed to release growth hormone without hexarelin's cortisol and prolactin response, and is the more usual way to get both doors in one injection. Sermorelin vs tesamorelin vs ipamorelin and CJC-1295 vs sermorelin cover the wider family.
Sermorelin vs Hexarelin
When neither is the right first step
| Situation | What makes more sense |
|---|---|
| Weight loss is the main goal | Semaglutide or tirzepatide, which have large randomized trials |
| Sleep is the only goal | DSIP or the SERENITY Blend, aimed at sleep more directly |
| A specific soft-tissue injury | BPC-157 or TB-500, the recovery peptides |
| You want a GHRH analogue with adult trial data | Tesamorelin, which has randomized adult trials |
| Diabetes, impaired glucose tolerance or a cortisol-sensitive condition | A conversation with your physician first; anything that raises growth hormone can raise blood glucose, and hexarelin adds a cortisol pulse |
Sermorelin vs Hexarelin
Where each stands with the FDA
Neither is on the FDA's 503A category lists. Neither was in Category 2, so neither was among the peptides removed from it on 15 April 2026, and neither was reviewed at the July 2026 advisory committee meeting.
| Sermorelin | Hexarelin | |
|---|---|---|
| Approval history | Approved 1990 and 1997 for children, discontinued 2008, withdrawn 2009 | None |
| FDA determination | 2013: withdrawal was not for safety or effectiveness | None either way |
| 503A Category 1, 2 or 3 | Not listed | Not listed |
| Advisory committee review | None | None |
| Basis for compounding | History as the active ingredient of an approved drug | Prescribed by physicians and compounded by licensed pharmacies to those prescriptions |
Both are compounded medications, and compounded medications are not FDA approved. Are peptides FDA approved explains the difference between not approved and not legal.
Sermorelin vs Hexarelin
Dosing, side by side
Both are injected under the skin (subcutaneously) into the abdomen or thigh, rotating sites, at night, five nights a week with weekends off. Night dosing lands the pulse on top of the body's natural nocturnal release. The draw is the same, 0.25 mL, which is 25 units on a U-100 insulin syringe. The vials differ in strength, so the amounts differ. This is math only, for reading a label:
| Sermorelin | Hexarelin | |
|---|---|---|
| Directions printed on the vial | Inject 0.25 mL (25 units) subcutaneously Monday through Friday nights | Inject 0.25 mL (25 units) subcutaneously Monday through Friday nights at bedtime |
| Concentration | 2 mg/mL | 2.5 mg/mL |
| Amount in 25 units | 0.5 mg | 0.625 mg |
| Total in the vial | 10 mg in 5 mL | 12.5 mg in 5 mL |
| Doses per vial | 20 | 20 |
| Time per vial | 4 weeks at 5 nights a week | 4 weeks at 5 nights a week |
Your physician sets your directions after reviewing your intake, and they are printed on the vial. Never carry a units number from one product to another. Twenty doses covers about four weeks, which is why refills run every 28 days, one vial per fill. Both ship refrigerated with ice packs, sterile syringes and alcohol prep pads, as ready-to-use multi-dose solutions. The sermorelin pen is dosed by its dial rather than syringe units, so the table does not apply to it. More in sermorelin dosage and how long does a peptide vial last.
Sermorelin vs Hexarelin
Side effects
Sermorelin. Its adverse-event profile was collected during its years as an approved drug. The most common reactions were at the injection site (redness, swelling, pain), with headache, flushing and a transient warm feeling after injection also reported. The older-adult trials reported no significant adverse effects at the doses studied. More in is sermorelin safe.
Hexarelin. Single doses were consistently reported as well tolerated in the 1990s studies, and the sixteen-week study reported no significant adverse effects. Reported clinically: warmth or flushing after the injection, hunger, a transient headache, light-headedness and injection-site redness or soreness. Each dose also raises cortisol and prolactin for an hour or two, and a single dose produced a short-lived rise in the heart's contractility in every human study that looked, so a cardiac diagnosis belongs on the intake.
Both. Anything that raises growth hormone and IGF-1 carries the class concerns of glucose intolerance and fluid retention, and a personal history of cancer is a reason to discuss it first. Message your care team about anything that persists or worries you. Call 911 for facial or throat swelling or difficulty breathing.
Sermorelin vs Hexarelin
Who should not take either, or should discuss it first
| Situation | Why |
|---|---|
| Personal history of cancer | Both raise a growth signal |
| Diabetes or impaired glucose tolerance | Growth hormone reduces insulin sensitivity |
| A condition affected by cortisol or prolactin | Especially for hexarelin, which raises both transiently |
| A cardiac diagnosis | Especially for hexarelin, because of its direct effect on heart contractility |
| Pregnancy or breastfeeding | Not used; safety data is absent |
| Tested athletes | The 2026 WADA Prohibited List bans GHRH analogues including sermorelin and ghrelin mimetics including hexarelin at all times |
Sermorelin vs Hexarelin
What the evidence shows, honestly
Both peptides have more human pharmacology behind them than most compounded peptides. Sermorelin has controlled pediatric trials that supported an approval and small older-adult trials showing it raises a person's own growth hormone and IGF-1. Hexarelin has a large body of 1990s single-dose work showing a strong pulse, plus one sixteen-week study showing that pulse fading with continuous use and no change in body fat, lean mass or bone density. Neither has a randomized trial in adults showing a body-composition, sleep, recovery or anti-aging outcome. Any provider presenting either as shown to change how you look or feel is overstating it.
Sermorelin vs Hexarelin
Where to get sermorelin or hexarelin prescribed
Neither can be bought legitimately without a prescription. Sites selling them "for research use only" are not accountable for what is in the vial. The prescription route:
- Complete a free online intake covering your history, medications and what you want help with.
- A physician licensed in your state reviews it, usually within 24 hours.
- If it is appropriate, a PCAB-accredited, FDA-registered US 503A compounding pharmacy prepares it to that prescription. Lot test results are published at /quality/lab-results.
- It ships refrigerated with your directions printed on the vial.
- Your physician stays reachable for questions and dose changes.
Step-by-step pages: how to get sermorelin prescribed online and how to get hexarelin prescribed online.
References
What this is based on.
References
- Ghigo E, Arvat E, Gianotti L et al.. Growth hormone-releasing activity of hexarelin, a new synthetic hexapeptide, after intravenous, subcutaneous, intranasal, and oral administration in man · J Clin Endocrinol Metab (1994) · PMID 8126144
- Rahim A, O'Neill PA, Shalet SM. Growth hormone status during long-term hexarelin therapy · J Clin Endocrinol Metab (1998) · PMID 9589671
- Rahim A, Shalet SM. Does desensitization to hexarelin occur? · Growth Horm IGF Res (1998) · PMID 10990150
- Ghigo E, Arvat E, Gianotti L et al.. Short-term administration of intranasal or oral Hexarelin, a synthetic hexapeptide, does not desensitize the growth hormone responsiveness in human aging · Eur J Endocrinol (1996) · PMID 8921821
- Klinger B, Silbergeld A, Deghenghi R et al.. Desensitization from long-term intranasal treatment with hexarelin does not interfere with the biological effects of this growth hormone-releasing peptide in short children · Eur J Endocrinol (1996) · PMID 8766941
- Laron Z, Frenkel J, Deghenghi R et al.. Intranasal administration of the GHRP hexarelin accelerates growth in short children · Clin Endocrinol (Oxf) (1995) · PMID 8548949
- Loche S, Cambiaso P, Carta D et al.. The growth hormone-releasing activity of hexarelin, a new synthetic hexapeptide, in short normal and obese children and in hypopituitary subjects · J Clin Endocrinol Metab (1995) · PMID 7852535
- Massoud AF, Hindmarsh PC, Matthews DR, Brook CG. The effect of repeated administration of hexarelin, a growth hormone releasing peptide, and growth hormone releasing hormone on growth hormone responsivity · Clin Endocrinol (Oxf) (1996) · PMID 8762732
- Maccario M, Veldhuis JD, Broglio F et al.. Impact of two or three daily subcutaneous injections of hexarelin, a synthetic growth hormone (GH) secretagogue, on 24-h GH, prolactin, adrenocorticotropin and cortisol secretion in humans · Eur J Endocrinol (2002) · PMID 11888836
- Arvat E, di Vito L, Maccagno B et al.. Effects of GHRP-2 and hexarelin, two synthetic GH-releasing peptides, on GH, prolactin, ACTH and cortisol levels in man. Comparison with the effects of GHRH, TRH and hCRH · Peptides (1997) · PMID 9285939
- Ghigo E, Arvat E, Ramunni J et al.. Adrenocorticotropin- and cortisol-releasing effect of hexarelin, a synthetic growth hormone-releasing peptide, in normal subjects and patients with Cushing's syndrome · J Clin Endocrinol Metab (1997) · PMID 9253314
- Arvat E, Ramunni J, Bellone J et al.. The GH, prolactin, ACTH and cortisol responses to Hexarelin, a synthetic hexapeptide, undergo different age-related variations · Eur J Endocrinol (1997) · PMID 9437229
Citations are provided for educational purposes. They do not constitute medical advice. Always discuss any peptide protocol with your prescribing physician.
Common questions
Sermorelin vs Hexarelin, answered.
Per dose, hexarelin releases more growth hormone. In a 2001 human comparison, hexarelin produced a larger pulse than GHRH, the hormone sermorelin copies. It also raises cortisol and prolactin and loses some effect with continuous use, so stronger does not mean better.
Sermorelin is a fragment of GHRH and acts on the GHRH receptor. Hexarelin is a synthetic ghrelin mimetic and acts on the ghrelin receptor. Both act on the same pituitary cells, through different doors.
The human data show a ghrelin-type peptide and a GHRH analogue producing more growth hormone together than either alone, though the synergy faded on repeat dosing. Pepti does not supply them in one vial; Ipamorelin + Sermorelin is the usual combination. Whether any combination fits you is set by your physician after reviewing your intake.
Partly, and reversibly. In a sixteen-week study of twice-daily dosing, the growth hormone response fell by nearly half and returned to baseline four weeks after stopping. Intermittent schedules did not show the same effect, which is why it is prescribed five nights on, two off.
Sermorelin is not described as raising cortisol or prolactin. Hexarelin raises both transiently with each dose; in a 24-hour study, two or three daily injections did not change total daily cortisol or prolactin.
Neither is a sleep medication. Growth hormone release is concentrated in deep sleep, and some people report sleeping more deeply on sermorelin, but no trial has measured sleep as an outcome for either. DSIP is aimed at sleep more directly.
Neither has shown it in adults. The six-week sermorelin study found no body-composition change, and the sixteen-week hexarelin study found no change in body fat or lean mass. Both are described as part of a plan that depends on training and diet.
At Pepti, sermorelin is $229 a month and hexarelin is $209 a month, all-in, including medication, physician review, refill management and shipping. Ipamorelin + Sermorelin is $219 a month.
Sermorelin acetate was the active ingredient of an FDA-approved product for children, approved in 1990 and 1997 and discontinued in 2008 for commercial reasons. Compounded sermorelin is not FDA approved, and no approved sermorelin product is currently marketed in the US.
Yes. The 2026 WADA Prohibited List bans GHRH analogues, including sermorelin, and ghrelin mimetics, including hexarelin, at all times. Tested athletes should not use either and should tell their physician.
Bloodwork is not required for any Pepti treatment. If your physician wants labs for your care, they'll ask through your account. The free assessment goes to a physician licensed in your state. A consultation does not guarantee a prescription.
Next step
See what a physician recommends for you.
A licensed physician in your state reviews your intake and decides what is appropriate. A consultation does not guarantee a prescription.