Supplied ready in solution

Growth Hormone Axis

At a glance

Ten answers, each one line. Open any row for the detail behind it.

What it does A potent GH secretagogue with a genuine regulatory approval — but as a single-dose…

A potent GH secretagogue with a genuine regulatory approval — but as a single-dose pituitary function test, not as a therapy. Its therapeutic use is entirely off-label extrapolation.

How it works in detail

Half-life ~33 min (t1/2 0.55 h) after IV — measured in children, the… — Documented

~33 min (t1/2 0.55 h) after IV — measured in children, the only published human study; no adult figure exists.

Typical studied dose Set by the label of the regulator that approved it, which is not an FDA… — On the label

Set by the label of the regulator that approved it, which is not an FDA label and may not be in English. The approving country decides the dose, and it is not always the same as the dose studied elsewhere.

Read the prescribing information

How often it is used Set on the approved label. The interval follows the half-life above… — On the label

Set on the approved label. The interval follows the half-life above, which is why some of these are weekly and others daily.

How it is taken Subcutaneous or intravenous — Documented

Subcutaneous or intravenous

Main side effects No therapeutic approval · Unregulated supply outside Japan · Cortisol and prolactin elevation — Carries serious risk

No therapeutic approval — Approved only as a one-off diagnostic; chronic dosing has never been evaluated for safety.

Unregulated supply outside Japan — Sold as a research chemical with no quality assurance.

Cortisol and prolactin elevation — Less selective than ipamorelin; repeated dosing can push these hormones outside normal ranges.

All benefits and risks, weighed

Storage before mixing Supplied already in solution and kept refrigerated, not frozen. Freezing…

Supplied already in solution and kept refrigerated, not frozen. Freezing a protein solution can aggregate it, which is not always visible.

Shelf life after mixing Nothing to mix — it is not supplied as a powder. The relevant date is…

Nothing to mix — it is not supplied as a powder. The relevant date is the one printed on the product.

Evidence level 3/5 · Moderate — Depends on the study

Small or early-phase human trials, or good controlled topical human data.

How we rate evidence · What the studies found

Regulatory status Limited Approval — Documented

Approved in Japan as a diagnostic agent for GH deficiency. Not approved in the US or EU for therapeutic use. Diagnostic approval in Japan only. Not lawful for therapeutic sale in the US.

See the registered trials · The full legal position

Overview

A potent GH secretagogue with a genuine regulatory approval — but as a single-dose pituitary function test, not as a therapy. Its therapeutic use is entirely off-label extrapolation.

Limited or non-US approvalDiagnostic approval in Japan only. Not lawful for therapeutic sale in the US.

At a glance

Regulatory status	Approved in Japan as a diagnostic agent for GH deficiency. Not approved in the US or EU for therapeutic use.
Drug class	Growth hormone-releasing peptide — synthetic hexapeptide ghrelin mimetic
Route	Subcutaneous or intravenous
Half-life	~33 min (t1/2 0.55 h) after IV — measured in children, the only published human study; no adult figure exists.
Evidence rating	3/5 Moderate Evidence rating 3 out of 5: Moderate Small or early-phase human trials, or good controlled topical human data.
Studied in	Diagnostic validation studies in Japan; short-term GH secretion studies; small studies in cachexia.

GHRP-2 sequence & structure

GHRP-2 is a 6-residue linear peptide with a C-terminal amide, carrying D-amino acid substitutions, non-standard residues; molecular weight 817.99 Da.

Amino acid sequence (N-terminus → C-terminus)

H-a[d2Nal]AWfK-NH₂

lowercase = D-amino acid[bracketed] = non-standard residue

Three-letter	`H-D-Ala-D-2Nal-Ala-Trp-D-Phe-Lys-NH2`
Length	6 amino acid residues
Modifications	C-terminal amidation — C-terminal lysinamide (Lys-NH2) D-amino acid substitution — D-Ala1, D-2Nal2 and D-Phe5 Non-natural amino acid — 3-(2-naphthyl)-D-alanine (D-2Nal) at position 2
Molecular formula	C₄₅H₅₅N₉O₆
Molecular weight	817.99 Da (average, free base)
SMILES	`C[C@H](NC(=O)[C@@H](Cc1ccc2ccccc2c1)NC(=O)[C@@H](C)N)C(=O)N[C@@H](Cc1c[nH]c2ccccc12)C(=O)N[C@H](Cc1ccccc1)C(=O)N[C@@H](CCCCN)C(N)=O`
Identifiers	CAS 158861-67-7 · PubChem CID 6918245 · DrugBank DB18252
Sources	PubChem CID 6918245 (Pralmorelin) — properties and synonyms via PUG REST ChEMBL CHEMBL106593 (Pralmorelin) — HELM PEPTIDE1{[dA].[dNal].A.W.[dF].K.[am]}ChEBI CHEBI:135890 (pralmorelin, INN)KEGG DRUG D02040 (Pralmorelin dihydrochloride, JAN/USAN)Wikidata Q21098924 (pralmorelin) — DrugBank ID P715 and CAS P231 claims

INN pralmorelin; research codes KP-102, GPA-748; UNII E6S6E1F19M. Free-base formula and MW given (ChEBI 817.992, ChEMBL 817.99, PubChem 818.0); the Japanese diagnostic product (Kaken, GHRP) is the dihydrochloride C45H55N9O6·2HCl, MW 890.89, CAS 158827-34-0, while research vendors usually sell the acetate/TFA salt. PubChem CID 6852372, cited by Wikipedia, is the L-Phe5 stereoisomer, not pralmorelin. DrugBank DB18252 confirmed via Wikidata's DrugBank-ID claim; the DrugBank page itself returns 403 and was not read.

Record confidence: high — two independent authoritative sources agree on the sequence and modifications. Every sequence on the site is listed with its sources on the peptide sequences index.

How it works

Ghrelin receptor agonism at the pituitary and hypothalamus. More potent than ipamorelin at releasing GH, but less selective: it produces measurable rises in ACTH, cortisol and prolactin.

Evidence base

Rated 3 of 5 — Moderate. Small or early-phase human trials, or good controlled topical human data.

Good acute pharmacology data; essentially no chronic-use safety data.

Benefits and risks, weighed against the evidence

Every entry below carries the strength of the evidence behind it — three bars for strong human data, two for moderate, one for preliminary or preclinical work. The two columns are not equal by design: where a compound has more documented risk than demonstrated benefit, the lists say so.

Reported benefits

3 entries · 1 on strong human evidence

Strong, reliable GH release

Robust and reproducible enough to serve as an approved diagnostic stimulus for pituitary function.
Evidence: Strong evidence
Appetite stimulation

Meaningful in cachexia and appetite-loss settings, where it has been studied in small trials.
Evidence: Preliminary
Oral and intranasal bioavailability studied

Alternative routes have been explored, unlike most peptides.
Evidence: Preliminary

Risks and cautions

6 entries · 2 serious or common

Cortisol and prolactin elevation

Less selective than ipamorelin; repeated dosing can push these hormones outside normal ranges.
Evidence: Moderate evidence
No therapeutic approval

Approved only as a one-off diagnostic; chronic dosing has never been evaluated for safety.
Evidence: Serious
Tachyphylaxis

GH response declines with continued use.
Evidence: Moderate evidence
Insulin resistance

GH-axis class effect.
Evidence: Moderate evidence
Unregulated supply outside Japan

Sold as a research chemical with no quality assurance.
Evidence: Serious
Banned in sport

Prohibited by WADA.
Evidence: Minor

Counts are not a score. A single serious risk can outweigh several well-supported benefits, and a long benefit list built on preclinical work outweighs nothing at all.

Opinion — what people actually report

5 themes · 1 reported benefit · 3 reported problems

This is the weakest tier on this site. These are themes drawn from public discussion — forums, subreddits and patient threads — not from trials. There is no control group, no denominator, and no way to confirm that what someone injected matched its label. People post when a result is dramatic and when something goes wrong, and rarely when nothing happens, so treat everything below as a description of the conversation rather than of the compound. The bars count how often a thing is said, not how well it is supported.

Stronger pulse than ipamorelin Reported benefit. Dominant theme: Comes up in most discussions of this compound.

The standard comparison. People describe a more pronounced effect, and choose it when ipamorelin has felt like nothing.
Hunger, though less than GHRP-6 Reported problem. Dominant theme: Comes up in most discussions of this compound.

Positioned in discussion as the middle option — noticeably appetite-stimulating but manageable.
Cortisol and prolactin are the standing worry Reported problem. Dominant theme: Comes up in most discussions of this compound.

The most-raised concern, often with people reporting water retention, mood changes or, occasionally, breast tenderness they attribute to prolactin.
Flushing and tingling after injection Reported problem. Recurring: Raised regularly, though not by everyone.

Facial warmth and tingling in the minutes after injection are described as routine rather than troubling, and pass quickly.
Desensitisation with continuous use Practical note. Recurring: Raised regularly, though not by everyone.

A widely held belief that the response fades, driving cycling schedules that are forum convention rather than evidence.

Where the reports and the evidence part ways

The receptor pharmacology is real: GHRP-2 is a ghrelin receptor agonist, it does release growth hormone, and it does raise cortisol and prolactin more than ipamorelin — the community ranking of these compounds by "cleanliness" is broadly accurate. What is absent is any efficacy evidence in humans for the outcomes people want. It was studied as a diagnostic agent and abandoned as a therapeutic, so there are no trials of body composition, recovery or ageing to check the reports against. The elaborate cycling protocols are inference from receptor theory, not findings.

Cheat sheet

The full sheet, all 77 compounds →

The community reference numbers for this compound — reconstitution, working dose, cycle and bloodwork. Research and education only, not medical advice, and not part of the evidence-rated monograph above. Doses assume a 1mL / 100-unit insulin syringe — the calculator does the units for you.

Protocol overview

GoalTrigger the body's own growth hormone secretion via the ghrelin receptor.

ScheduleDaily subcutaneous injections for 8 to 12 weeks (extend to 16 weeks if desired).

Dose Range100 to 300 mcg daily with gradual titration; higher doses show dose-dependent responses but may offer limited added benefit with routine use.

Reconstitution0.5 mL per 5 mg vial (10 mg/mL).

StorageLyophilized frozen; reconstituted refrigerated (use within 2 to 3 weeks for optimal integrity).

Half-life~33 min (t1/2 0.55 h) after IV — measured in children, the only published human study; no adult figure exists.

Dosing & reconstitution 5 mg vial

WEEK	DAILY DOSE	UNITS PER INJECTION
Weeks 1 to 2	100 mcg	1 units (0.01 mL)
Weeks 3 to 4	150 mcg	1.5 units (0.02 mL)
Weeks 5 to 8	200 mcg	2 units (0.02 mL)
Weeks 9 to 12	200 mcg	2 units (0.02 mL)
Weeks 13 to 16	200 mcg	2 units (0.02 mL)

Frequency: Inject once daily subcutaneously. This once-daily schedule balances efficacy with receptor recovery time, avoiding the rapid attenuation seen with frequent dosing. Administering in the evening may capitalize on nocturnal GH rhythms. For 10 unit (0.10 mL) or smaller administrations, consider 30- or 50-unit insulin syringes for improved readability.

On the master sheet

03 Growth Hormone & Recovery · GHRP-2

Vial: 5mg
BAC: 2mL
Dose: 100–300mcg 1–3x daily
Route: SubQ
Cycle: 6–12 wks
Time Off: 3–4 wks
Bloodwork: IGF-1, prolactin, cortisol

Side-effect family — GH Secretagogues (CJC, Ipa, GHRP): Water retention and bloat · Carpal tunnel or tingling hands · Increased hunger (GHRP-6) · Drowsiness. What helps, and the red flags →

Questions & answers

Readers on GHRP-2

Questions and answers from readers, under generated names. Nothing here has been checked or reviewed by the site and none of it is medical advice. It is the least verified thing on this page — and it is here because people ask each other these things anyway, and most of the other places they can ask are run by sellers.

0 questions · 0 answers

Other readers answer these. Ask about GHRP-2 and the people who have actually looked into it can reply. You post under a generated name — two ordinary words — and that is the only thing anyone else sees. Your address is never shown on the page, never sold and never used for marketing. What we keep, and why.

No questions yet. Ask the first one above — it takes one box and an email address.

How names work, and the house rules

Names. Every verified address is given one generated name — two ordinary words — and keeps it. Nobody chooses a name and nobody can take another's. Posts marked desk were written by the site's own editorial desk, usually to open a thread; they carry a generated name like everyone else's and are held to the site's rules, which means they never state an amount.

What is not allowed. Selling, sourcing, vendor names, coupon codes and "message me" — posts that read that way are held and usually removed. Personal medical details you would not want public. Abuse. Instructions framed as what someone else should do.

What this is not. A reader's report of what happened to them is a report, not a finding, and an answer here is one person's view. Nothing in this section changes the evidence rating above it. If something you read here would change what you take, take it to a pharmacist or physician first.

Your data. Delete any post of yours at any time, or remove everything you have written together with your name. Details in the privacy notice.

Who should avoid it

Active malignancy
Pregnancy
Hyperprolactinemia
Cushing syndrome or adrenal disorder

If used under medical supervision, monitor

IGF-1, prolactin, morning cortisol
Fasting glucose

Regulatory & legal status

Diagnostic approval in Japan only. Not lawful for therapeutic sale in the US.

Infographic

GHRP-2 — benefits & risks at a glance Download SVG

Where to read further

We link to live literature searches rather than a frozen citation list, so you always see current results — including anything published after our last review.

growth hormoneghrelindiagnosticappetite

Related peptides in Growth Hormone Axis

Terms used on this page

Growth Hormone Secretagogue (GHS): A growth hormone secretagogue is any compound that stimulates endogenous GH release, a class spanning GHRH analogues and ghrelin-mimetic agents acting at the GHS receptor.
Growth Hormone Secretagogue Receptor (GHS-R1a): GHS-R1a is the G protein-coupled ghrelin receptor mediating growth hormone release and appetite, notable for unusually high constitutive activity in the complete absence of any ligand.
Potency vs Efficacy: Potency is the concentration a drug needs to produce a given effect, while efficacy is the largest effect it can produce at any concentration; the two are independent properties.
Prolactin: Prolactin is a 199-amino-acid anterior pituitary hormone held under tonic dopamine inhibition, central to lactation and the marker of prolactinomas and drug-induced hyperprolactinaemia.
Cortisol: Cortisol is the principal human glucocorticoid, secreted by the adrenal cortex under ACTH control on a pronounced daily rhythm and carried in plasma largely bound to corticosteroid-binding globulin.
Agonist: An agonist is a ligand that binds a receptor and stabilises its active conformation, producing a biological response rather than merely occupying the binding site.

This page is educational information, not medical advice. It cannot account for your medical history, medications, or risk factors. Do not start, stop or change any treatment based on it. Speak to a qualified healthcare professional who knows your case.