GHRP-2: Dosage, Effects and How It Compares to GHRP-6

GHRP-2 is the growth hormone secretagogue that people land on once they have decided GHRP-6 makes them too hungry and ipamorelin does not push hard enough. It sits between the two, and that middle position is the whole reason it is still in catalogues twenty five years after it was first synthesised.

It is also the only compound in this class with a regulatory approval attached to it anywhere in the world, which makes its pharmacology unusually well characterised for a grey market peptide. This page covers the doses that actually appear in protocols, how it differs from GHRP-6 and ipamorelin, what the cortisol question is really about, and the arithmetic for getting a consistent draw out of a vial.

What GHRP-2 Actually Is

GHRP-2 is a synthetic hexapeptide, six amino acids, with a molecular weight around 818 daltons. Its other names are pralmorelin and KP-102, and you will see it sold as GHRP-2 acetate because the acetate salt is the stable storable form. Six amino acids makes it a small peptide by any standard, roughly a quarter the mass of sermorelin.

It is a growth hormone releasing peptide, not a growth hormone releasing hormone analogue, and that distinction drives everything below. Sermorelin, tesamorelin and CJC-1295 are GHRH analogues: they copy the hypothalamic signal that tells the pituitary to release growth hormone. GHRP-2 copies ghrelin instead, binding the growth hormone secretagogue receptor GHS-R1a. Two different doors into the same room.

The regulatory footnote matters. In Japan, pralmorelin is approved as a diagnostic agent for assessing growth hormone deficiency, given as a single intravenous bolus in a stimulation test. That means the acute pharmacology was studied properly in humans. It does not mean repeated subcutaneous dosing over months has been. A diagnostic single dose and a sixteen week protocol are different questions, and only the first has an answer.

How GHRP-2 Works

Binding GHS-R1a does three things at once. It triggers growth hormone release from pituitary somatotrophs. It amplifies the natural GH pulse rather than creating a flat elevation, which is the argument for secretagogues over exogenous growth hormone. And it suppresses somatostatin, the brake the hypothalamus applies to GH release, which is why combining a GHRP with a GHRH analogue beats either one alone.

The half life is short, on the order of thirty minutes. That is not a flaw, it is the design. A short pulse that clears quickly mimics physiological GH secretion, which is itself pulsatile. It is also why dosing frequency, not dose size, is the lever that actually moves anything in these protocols.

Because it is a ghrelin mimetic, GHRP-2 does what ghrelin does beyond growth hormone: it stimulates appetite and it nudges cortisol and prolactin upward. The degree to which it does each of those is the entire basis for choosing between the compounds in this family.

GHRP-2 Dosage: The Numbers That Appear in Protocols

The organising concept here is the saturation dose. Roughly 100mcg, or about 1mcg per kilogram of body weight, produces close to the maximal growth hormone response this receptor can deliver. Past that point the GH curve flattens while cortisol and prolactin keep climbing. Doubling the dose does not double the result, it buys a worse side effect profile for a marginal gain. This is the single most useful thing to understand about dosing any GHRP.

Timing is not optional detail. Growth hormone release is blunted by circulating glucose and by dietary fat, so administrations are placed on an empty stomach, conventionally twenty minutes clear of food in either direction. The pre sleep dose is the one people keep when they drop to a single administration, because it lands on the largest natural GH pulse of the day. Administration is subcutaneous, and the dose is small enough that an insulin syringe is the only sensible instrument.

GHRP-2 vs GHRP-6: The Comparison That Decides Most Purchases

These two are separated by one variable that dominates everything else: appetite.

GHRP-6 produces hunger frequently described as overwhelming, arriving within twenty minutes and difficult to ignore. GHRP-2 produces hunger that is noticeable and manageable. For someone in a deficit trying to preserve tissue that difference is the entire decision, and it is why GHRP-2 is the default pick for anyone whose goal involves not eating more. For someone struggling to hit a surplus, GHRP-6 turns the same property into a feature.

On growth hormone release the two are close, with GHRP-2 generally reported as slightly the stronger of the pair at equivalent doses. On cortisol and prolactin, GHRP-2 is the cleaner one, though neither is clean in the way ipamorelin is. Our GHRP-6 guide works through the other side of this comparison, and sermorelin versus GHRP-6 covers the GHRH analogue contrast.

GHRP-2 vs Ipamorelin

Ipamorelin is the selective member of the family. It hits GHS-R1a with essentially no measurable effect on cortisol, prolactin or appetite at standard doses, which is why it became the default recommendation for long protocols. The trade is potency: the GH pulse it produces is smaller than the one GHRP-2 produces.

So the choice reduces to what you are optimising. If the protocol runs for months and tolerability compounds, ipamorelin is the sensible default, and the ipamorelin guide sets out why. If you want a larger pulse and can accept a modest hormonal cost, GHRP-2 is the stronger tool. Hexarelin sits at the far end of the same axis: most potent, fastest to desensitise, rarely run continuously.

Stacking GHRP-2 With a GHRH Analogue

This is the standard use rather than an advanced variation. A GHRP and a GHRH analogue given together produce a response larger than the two added separately, because they solve different halves of the same problem. The GHRH analogue supplies the release signal, the GHRP lifts the somatostatin brake and adds its own signal on top.

CJC-1295 without DAC, sometimes sold as mod GRF 1-29, is the usual partner because its duration roughly matches the GHRP pulse. The DAC version instead produces a sustained elevation rather than a pulse, which works against the reason for using a secretagogue at all. Typical descriptions pair 100mcg of each, given together, two or three times daily. The CJC-1295 and ipamorelin stack page covers the same logic with the selective GHRP in place of this one.

CJC-1295 at Pantheon

Reconstitution and the Arithmetic Problem

GHRP-2 arrives as a lyophilised powder, commonly in 5mg or 10mg vials, and is reconstituted with bacteriostatic water. The practical difficulty is that 100mcg is a very small volume, and under dilution makes it unmeasurable.

Reconstitute a 10mg vial with 2ml and the concentration is 5mg/ml, putting a 100mcg dose at 0.02ml, or 2 units on a standard 100 unit insulin syringe. At two units the difference between a careful draw and a sloppy one is a large percentage of the dose. Use 5ml instead and the concentration falls to 2mg/ml, putting the same dose at 5 units, far easier to hit repeatably. The total peptide is identical either way, so there is no reason to choose the harder number.

Bacteriostatic water, not sterile water, because the benzyl alcohol is what allows repeated entry into the vial across the weeks a protocol runs. How to reconstitute peptides covers the procedure, this page covers the diluent itself, and peptide storage covers keeping the reconstituted vial intact once it is open.

Bacteriostatic water at Amino Club

GHRP-2 Side Effects

The reported effects cluster into three groups. The ghrelin effects are appetite increase, and occasionally a head rush or brief lethargy after administration. The growth hormone effects are water retention, tingling or numbness in the hands, and joint discomfort, all dose dependent and usually resolving when the dose comes down. The endocrine effects are the rises in cortisol and prolactin, which stay modest at saturation dosing and stop being modest above it.

Two longer horizon considerations are worth stating plainly. Growth hormone reduces insulin sensitivity, so anyone with a glucose handling problem is in a different risk category with any compound in this class. And receptor desensitisation is real across the GHRP family, which is why protocols are described in blocks of eight to twelve weeks with a break rather than run indefinitely. Peptide cycles covers how that break is usually structured.

Sourcing Notes

GHRP-2 is an inconsistently stocked compound. Of the vendors the Bureau scores, Pantheon Peptides carries GHRP-2 acetate as a standing catalogue item with a batch certificate of analysis attached, which is the reason it is the pick here rather than a price argument. Availability that survives a restock cycle matters more than a few dollars a vial across a twelve week protocol.

The Pantheon review sets out how the scorecard treats them. How to spot a fake peptide vendor covers what a real certificate of analysis looks like, which is worth reading before a first order anywhere. If the conclusion after all of this is that the injection frequency is the dealbreaker, MK-677 is the orally active compound that targets the same receptor, and natural GH boosters covers the further end of that spectrum.

Key Takeaways

• GHRP-2 is a six amino acid ghrelin mimetic, approved in Japan as pralmorelin for diagnostic growth hormone testing
• The saturation dose is around 100mcg, and exceeding it adds cortisol and prolactin rather than growth hormone
• Escalate by adding pulses, typically to two or three daily, not by raising the dose per administration
• Administer on an empty stomach, twenty minutes clear of food, with the pre sleep dose the one to keep if only one is run
• It sits between GHRP-6 and ipamorelin: less hunger than the former, more potency and more hormonal cost than the latter
• Pairing with a GHRH analogue such as CJC-1295 without DAC produces more than the sum of the two
• Reconstitute to a concentration that puts your dose at five units or more, because two unit draws are not repeatable
• Protocols are described in eight to twelve week blocks because receptor desensitisation is real

Frequently Asked Questions

What is the correct GHRP-2 dosage?

Protocol descriptions cluster at 100mcg per administration, which is approximately the saturation dose for this receptor at around 1mcg per kilogram of body weight. Frequency is usually one to three times daily, giving a daily total of 100 to 300mcg. Escalation is handled by adding an administration rather than by increasing the amount per administration, because the growth hormone response flattens above saturation while cortisol and prolactin do not.

Is GHRP-2 better than GHRP-6?

It depends entirely on whether you want to be hungry. GHRP-6 produces pronounced appetite stimulation, GHRP-2 produces a noticeably milder version of the same effect. Growth hormone release is comparable with GHRP-2 usually described as marginally stronger, and GHRP-2 raises cortisol and prolactin somewhat less. For a fat loss protocol GHRP-2 is the obvious choice. For someone trying to eat more, GHRP-6 turns its main drawback into its main feature.

Does GHRP-2 raise cortisol and prolactin?

Yes, modestly, and the size of the effect is dose dependent. At saturation dosing around 100mcg the rise is small. The reason the saturation concept matters is that above that dose growth hormone release plateaus while these two continue to climb, so a larger dose shifts the ratio of what you want to what you do not. Ipamorelin is the compound in this family with essentially no effect on either, at the cost of a smaller growth hormone pulse.

Can GHRP-2 be stacked with CJC-1295?

That is the standard use rather than an unusual one. A GHRP and a GHRH analogue act on different mechanisms and produce a combined response larger than the two administered separately. CJC-1295 without DAC is the usual partner because its duration matches the GHRP pulse. The DAC version produces a sustained elevation instead, which is a different strategy and works against the pulsatile logic that makes secretagogues attractive in the first place.

How should GHRP-2 be reconstituted?

With bacteriostatic water, in a volume chosen so the dose is easy to measure. A 10mg vial reconstituted with 5ml gives 2mg/ml, putting a 100mcg dose at 5 units on an insulin syringe. The same vial with 2ml gives 5mg/ml and a 2 unit dose, which is harder to draw consistently. The peptide quantity is unchanged by the choice, so pick the dilution that makes the measurement readable.

How long does GHRP-2 take to work?

The growth hormone pulse itself is immediate, peaking within roughly thirty minutes of a subcutaneous administration. Downstream effects are slower because they are mediated by IGF-1, which takes time to rise and longer still to produce changes in tissue. Protocol descriptions generally treat the first four weeks as the point where sleep quality and recovery changes become noticeable, with anything structural belonging to a longer horizon.