Muscle & performanceAnti-aging & longevity
GHRP-2
Pralmorelin · KP-102 · GHRP Kaken 100 (brand)
GHRP-2 is a synthetic hexapeptide that binds the ghrelin receptor and provokes the pituitary into releasing a pulse of growth hormone. It is a signal, not a hormone. That distinction matters more than anything else when comparing it to injected growth hormone.
It holds a real, if narrow, regulatory status: it is approved in Japan under the name pralmorelin as a single-dose diagnostic test for growth hormone deficiency. That is a genuine approval by a national regulator, and it pays to be precise about what it covers: one injection, to measure whether a pituitary responds. It is not an approval for repeated use to raise growth hormone over months, and nothing in that diagnostic programme speaks to the safety of doing so.
Among the three GHRPs, GHRP-2 is usually described as the middle option: more potent than GHRP-6 at releasing growth hormone, with markedly less of the hunger that makes GHRP-6 difficult to live with, and without hexarelin's desensitisation problem at the doses commonly discussed.
How it works
GHRP-2 binds the growth hormone secretagogue receptor, better known as the ghrelin receptor, in the pituitary and hypothalamus. Activating it produces a pulse of growth hormone release, and also suppresses somatostatin, the brake that normally limits those pulses. Releasing the accelerator and the brake at once is why the pulse is larger than a GHRH analogue alone produces.
Because the pulse comes from your own pituitary, it is self-limiting in a way exogenous growth hormone is not. This is the mechanistic argument people make for secretagogues over injected hGH, and it is a reasonable one. But "more physiological" describes the shape of the curve, not the long-term safety.
The same receptor sits on cells that release prolactin and cortisol. GHRP-2 raises both modestly, more than ipamorelin does and less than GHRP-6 or hexarelin. That is measurable in human studies rather than inferred.
Regulatory status — Japan and United States
Approved in Japan as pralmorelin, a single-dose diagnostic agent for growth hormone deficiency. Not approved anywhere for repeated use to raise growth hormone, and not approved in the United States for any indication. Material sold as a research chemical is not the approved product.
Last reviewed 16 Aug 2026. Regulatory positions in this category change frequently; we date this line so you can see how current it is.
What it is studied for
Each entry states the evidence behind it. We do not rank indications by effectiveness — for most compounds here, that would be a claim nobody can support.
Diagnosing growth hormone deficiency
Clinical trialThe approved use in Japan: a single injection to see whether the pituitary responds.
EvidenceApproved on the basis of a clinical programme establishing it as a reliable provocative test.
Raising growth hormone and IGF-1 over time
Clinical trialThe reason it is bought as a research chemical. Not what the approval covers.
EvidenceShort human studies confirm it raises growth hormone and, over weeks, IGF-1. No trial establishes what repeated use does over months, or what that means for body composition.
Body composition, recovery and sleep quality
Community practiceWhat people report using it for.
EvidenceNo controlled trial has measured these as endpoints for GHRP-2. What exists is community reporting.
Identity and clearance
Molecule
- Class
- Synthetic hexapeptide, growth hormone secretagogue
- Molecular weight
- 817.99 Da
- Length
- 6 amino acids
Sequence
D-Ala-D-2-Nal-Ala-Trp-D-Phe-Lys-NH2
The D-amino acids are what make it survive in circulation; the natural equivalents would be broken down almost immediately.
Pharmacokinetics
Clinical trialVery short-acting. The growth hormone pulse it produces peaks within about 30 minutes and is over within a couple of hours. That is why multiple daily doses are described rather than one.
Dose protocols reported in sources
Displayed for reference only. Every row says where it came from, and a trial protocol and a community convention are not the same kind of information. None of this is fed into the calculator, and none of it is a recommendation.
| Goal | Dose | Frequency | Route | Units, 5 mg vial | Source | Start this protocol |
|---|---|---|---|---|---|---|
| Diagnostic test, the approved use | 100 mcg | A single dose, once | SubcutaneousGiven intravenously in the approved diagnostic protocol, with growth hormone measured over the following hour. This is a test, not a treatment. | 10 u | Clinical trial | Start this |
| Repeated dosing, as studied | 100 mcg – 200 mcg | Twice daily | SubcutaneousThe range used in the short repeated-dose studies that measured IGF-1 response. | 10–20 u | Clinical trial | Start this |
| Commonly described community protocol | 100 mcg – 300 mcg | One to three times daily | SubcutaneousFrequently described alongside a GHRH analogue such as CJC-1295. Community sources converge on 100 mcg as a per-dose figure on the theory that higher doses saturate the receptor without releasing more growth hormone. That theory is plausible and untested. | 10–30 u | Community practice | Start this |
Start this copies a row into a protocol of your own, which you can then edit. Where a source gave a dose range or an ambiguous frequency, those fields arrive empty — we will not pick a number on your behalf.
CheckRows marked community practice describe what people commonly do, drawn from public discussion. They are not derived from any trial and are not evidence that a dose is safe or effective.
Calculator
Work out what to draw
Pre-filled with a 5 mg vial as a worked example. These are not recommended values — change them to match the vial in front of you.
Draw to 4 units on a 1 mL U-100 syringe. That is 0.04 mL, containing 100 mcg of GHRP-2.
4 units sits exactly on a printed line.
Bioalmanac performs arithmetic on values you enter. It does not recommend doses, schedules or compounds, and nothing here is medical advice. Confirm every calculation against your vial and syringe before drawing, and speak with a licensed healthcare provider.
Open this calculation in the full calculator
Units, concentration, bacteriostatic water — the glossary defines the vocabulary, and a unit is not a fixed volume.
Safety
Reported effects
- Increased hungerCommunity practice
Commonly reported
A ghrelin receptor effect. Present but substantially milder than with GHRP-6.
- Modest rise in prolactin and cortisolClinical trial
Measured in human studies
Real and dose-related. Larger than ipamorelin produces, smaller than GHRP-6 or hexarelin. Persistently raised prolactin can affect libido and menstrual cycles.
- Water retention, puffy hands and feetCommunity practice
Commonly reported
A growth hormone effect, not a peptide-specific one, and usually dose-related.
- Tingling or numbness in the handsCommunity practice
Occasionally reported
Consistent with carpal tunnel symptoms, which are a known effect of raised growth hormone. Worth taking seriously rather than tolerating.
- Flushing and light-headedness shortly after injectionCommunity practice
Occasionally reported
- Reduced insulin sensitivityPublished review
Expected from raised growth hormone
Growth hormone opposes insulin. Anyone with prediabetes or diabetes should treat this as the main concern rather than a footnote.
When to stop
- Numbness, tingling or persistent pain in the hands or wrists. This is a growth hormone effect and it can become carpal tunnel syndrome.
- Swelling that does not settle, particularly in the ankles or face.
- Rising fasting glucose, or new symptoms of high blood sugar: unusual thirst, frequent urination, blurred vision.
- Nipple tenderness or discharge, or a change in menstrual cycle. Possible signs of a prolactin effect.
- Any allergic response: rash, hives, facial swelling or difficulty breathing. Seek urgent care.
- Any new lump, unexplained weight loss or unexplained persistent pain. Growth hormone is a growth signal, and a new mass should be investigated before continuing.
Interactions and situations that need care
- Active or previous cancerAvoid
Growth hormone and the IGF-1 it raises are proliferative signals. There is no trial evidence that a secretagogue causes cancer, and equally none that it is safe in someone with malignancy. Deliberately raising a growth signal in that situation has no supporting evidence and an obvious mechanism for harm.
- Diabetes or impaired glucose toleranceUse caution
Growth hormone reduces insulin sensitivity, which is well established. Anyone managing blood glucose should expect their numbers to move and should be monitoring them rather than discovering it later.
- Competing in a tested sportAvoid
Growth hormone secretagogues are named explicitly in WADA's S2 category and are prohibited at all times, in and out of competition. Whether a current test detects this particular compound is beside the point. The prohibition is on the substance, not on being caught.
- Pregnancy and breastfeedingAvoid
No reproductive or developmental safety data, and no benefit to weigh against that.
- Untreated hypothyroidismUse caution
Growth hormone secretion and thyroid function interact, and raising growth hormone can unmask or worsen an existing thyroid problem. Thyroid function is worth establishing first.
SportProhibited by the World Anti-Doping Agency under S2: Peptide Hormones, Growth Factors, Related Substances, at all times, in and out of competition. Growth hormone secretagogues are named explicitly in S2. Prohibition applies whether or not a test can currently detect the specific compound.
What to expect
- It reliably produces a growth hormone pulse. That is measured, and it is the part that is not in doubt.
- What a growth hormone pulse several times a day does to body composition over months has not been measured for this compound. The step from 'raises growth hormone' to 'changes your body' is the step without evidence behind it.
- The effect is a pulse, not a plateau. It is over within a couple of hours. Which is why protocols describe multiple daily injections.
- Increased appetite is common and is the most frequent reason people stop. If you are using it while eating in a deficit, expect that to be harder.
- Water retention in the first weeks is common, and it is not fat loss reversing. It does make scale weight useless as a short-term signal.
Storage and handling
- Freeze-dried powder
- Refrigerated at 2–8 °C, protected from light.
- After mixing
- Refrigerated at 2–8 °C. Do not freeze once mixed.
- Long-term, frozen
- Unopened powder is stable at −20 °C or colder.
With other peptides
- CJC-1295synergistic
A GHRH analogue and a ghrelin-receptor agonist act on different pathways, and the combination produces a larger growth hormone pulse than either alone. This is the most commonly described pairing in the category and the mechanism behind it is sound.
- GHRP-6caution
Both act on the same receptor. Combining them stacks one mechanism, not two. The growth hormone response does not add up. The prolactin, cortisol and hunger effects do.
- Hexarelincaution
Same receptor again, with hexarelin's desensitisation added. There is no mechanistic reason to run two GHRPs together.
- Ipamorelincaution
Both are ghrelin receptor agonists, so the growth hormone effects overlap rather than add. Ipamorelin is usually chosen instead of GHRP-2 precisely because it avoids the prolactin and cortisol rise, and running both discards that advantage.
Checking your vial
Research chemicals carry no manufacturing standard, so what the vial looks like is often the only quality signal available before you use it. More on assessing quality and COAs.
White cake, clear solution
Standard for a short hexapeptide.
Collapsed, melted or fused cake
Heat exposure in transit. Refrigerating it afterwards does not undo the damage.
Cloudy solution or visible particles after gentle mixing
Degraded or contaminated. Do not use it.
Questions
- Is GHRP-2 approved?
- In Japan, as pralmorelin, for one specific purpose: a single injection used to diagnose growth hormone deficiency. That is a real approval and worth knowing about, but it covers a diagnostic test rather than repeated use, and it says nothing about the safety of injecting it twice a day for months.
- How is it different from ipamorelin?
- Both hit the same receptor. GHRP-2 produces a somewhat larger growth hormone pulse; ipamorelin is more selective and does not meaningfully raise prolactin or cortisol. Choosing between them is choosing between a bigger pulse and a cleaner one.
- Why do protocols say to inject on an empty stomach?
- Because raised insulin blunts growth hormone release, and eating raises insulin. The underlying relationship is well established. The specific twenty-minute window everyone repeats is convention rather than a measured figure.
- Does it work as well as injected growth hormone?
- No, and it is not trying to. Growth hormone raises the level directly and continuously; a secretagogue produces pulses from your own pituitary, bounded by whatever your pituitary can release. The effect is smaller by design.
References
Pralmorelin (GHRP-2) as a provocative test for growth hormone deficiency
Japanese regulatory approval and supporting clinical literature, 2006 · Clinical programme supporting a diagnostic approval
Humans, adults and children with suspected GH deficiency · 100 mcg, single intravenous dose · Single administration
Produced a reliable, measurable growth hormone response, supporting approval in Japan as a diagnostic agent for growth hormone deficiency.
Effects of repeated GHRP-2 administration on growth hormone and IGF-1 in healthy adults
Clinical endocrinology literature, 2004 · Short repeated-dose human study
Healthy adults · 100–200 mcg subcutaneous, twice daily · Weeks
Repeated dosing raised growth hormone and IGF-1, with modest concurrent increases in prolactin and cortisol. Study durations were too short to speak to body composition or to long-term safety.
Growth hormone secretagogues: pharmacology, clinical findings and open questions
Endocrine review literature, 2018 · Review
Humans
Summarises the GHRP class: reliable growth hormone release across the family, receptor-driven differences in prolactin and cortisol effects, reduced insulin sensitivity as a consistent consequence of raised growth hormone, and an absence of long-duration safety data for any member of the class.
Commonly reported community protocols
Bioalmanac editorial summary of public community sources, 2026 · Not a study
Records the dose and timing patterns described in public discussion, including the 100 mcg saturation convention and pairing with a GHRH analogue. Carries no evidential weight about safety or effect.
Related compounds
CJC-1295
A GHRH analogue that raises growth hormone by amplifying the body's own release signal. Sold in two forms whose durations differ by two orders of magnitude.
GHRP-6
The oldest of the growth hormone releasing peptides, and the one with the strongest effect on hunger. That appetite stimulation is the defining fact about it.
Hexarelin
The most potent growth hormone releasing peptide of the three, and the only one that reliably stops working. Its response fades within about two weeks of continuous use.
Ipamorelin
A selective growth hormone secretagogue that prompts a short pulse of GH release. Widely used, and supported almost entirely by early pharmacology rather than outcome trials.
Next
What to do with GHRP-2
- Keep a record of itTurn a dose and a schedule into a protocol, then log what you actually take. GHRP-2 is filled in for you.
- See what it costsPer-milligram prices read from vendor sites and confirmed by a person, so vial sizes compare.
- Check a combinationWhat our profiles record about GHRP-2 alongside each other compound — including the pairs where nothing is recorded.
Keep this page honest
If something here is wrong, out of date, or missing a source, tell us and we will fix it and say that we did.
This page is educational. It describes what published research reports, not what you should do. Peptides discussed here are largely not approved for human use, and nothing on Bioalmanac is medical advice. No clinician reviews these pages.
Page last updated 16 Aug 2026