What Is GHRP-2? Dosage, Half-Life & How to Track It

What GHRP-2 is and how it works

GHRP-2 is a synthetic hexapeptide — six amino acids — that, like Ipamorelin and GHRP-6, activates the ghrelin receptor (GHS-R1a) in the pituitary and hypothalamus to trigger a pulse of growth-hormone release. It was originally studied under the code KP-102 and is sometimes called by its generic name, pralmorelin.

GHRP-2 sits in the middle of the GHRP family on selectivity: it produces a more potent GH pulse than Ipamorelin, but — unlike Ipamorelin — it also raises cortisol and prolactin somewhat and stimulates appetite, just less aggressively than GHRP-6. That trade-off — more GH output for more hormonal noise — is the central thing to understand when comparing it to its two siblings.

As with the other GHRPs, it stimulates the pituitary’s own release machinery rather than replacing GH directly, so the pulse still runs through the body’s normal feedback loop — which is why it is commonly stacked with a GHRH analog to produce a larger combined effect.

Typical dosing & reconstitution

GHRP-2 is reconstituted from a lyophilized powder with bacteriostatic water. Typical protocols run 100–300 mcg subcutaneously once daily, often introduced with a lower starting dose (around 100 mcg) for a few weeks before increasing.

Vial size and water volume set the concentration, and the concentration sets your syringe units:

At 1.67 mg/mL, a 200 mcg dose is 12 units. Below roughly 10 units, a 30- or 50-unit insulin syringe measures more precisely — one of the things the reconstitution calculator handles for any vial-and-water combination.

Half-life & what it means for frequency

GHRP-2 clears quickly — its half-life is on the order of ~55 minutes (about an hour) — which is why it is dosed once (occasionally twice) daily rather than weekly. Frequent dosing beyond that tends to blunt the pituitary’s response rather than improve it, so most protocols hold to once a day.

Timing follows the same logic as the other GHRPs: dosing before bed leans on the body’s largest natural nocturnal GH pulse, and dosing on an empty stomach avoids blunting the response — a recent meal, especially one with carbs or fat, dampens ghrelin-receptor signaling.

What to track & common side effects

The side effects that distinguish GHRP-2 from Ipamorelin are baked into its mechanism: a noticeable increase in appetite, some water retention, and mild, transient cortisol/prolactin elevation in a meaningful share of users. Injection-site irritation and occasional flushing or tingling right after the dose are also common.

Worth tracking alongside the daily dose: hunger level (if it works against your goals), sleep quality, and any labs you pull for IGF-1 or cortisol. Because the appetite effect is real, it is also worth noting whether your eating actually shifted — easy to lose track of without logging it next to the dose.

Frequently asked questions