GHRP-2
Growth Hormone Releasing Peptide-2 · Pralmorelin · KP-102 · GPA-748 · GHRP Kaken 100
Potent, well-studied GHRP with a bigger pulse than ipamorelin and more cortisol.
Typical dose
100 mcg
2-3x daily
Range
100–300
mcg
Half-life
—
see Dosing
Evidence
Human trials
Subcutaneous · Intramuscular · Intranasal · Intravenous
What it is
GHRP-2, generic name pralmorelin, is a synthetic hexapeptide agonist at the ghrelin receptor and the only injectable GHRP anywhere with a regulatory approval. Japan licensed it as a single-dose diagnostic agent for growth hormone deficiency, sold as GHRP Kaken 100.
It sits in the middle of the GHRP range. It releases noticeably more GH per microgram than ipamorelin but it is not fully selective: past the saturation dose it pulls cortisol, ACTH and prolactin up along with GH. Appetite stimulation is real but milder and shorter-lived than GHRP-6, and it has been measured directly, with a subcutaneous infusion increasing ad libitum food intake by about 36 percent in lean men.
That combination, well characterised in humans and potent without being reckless, makes it the usual choice for someone who wants a bigger pulse than ipamorelin gives and is disciplined enough to keep the dose where the selectivity still holds.
How it works
GHRP-2 binds GHS-R1a on pituitary somatotrophs and in the arcuate nucleus of the hypothalamus. It releases GH by two routes at once, acting directly on the pituitary and suppressing somatostatin. Its effect also depends on your own GHRH: in human work where endogenous GHRH is blocked, most of the GH response to a GHRP disappears, which is why a GHRH analogue multiplies rather than merely adds to it.
Selectivity here is dose-dependent, not absolute. Around 100 mcg the GH response is close to maximal while cortisol and prolactin barely move. Push to 300 mcg and above and GH gains little while the adrenal and lactotroph responses climb steadily.
Dosing
Roughly 100 mcg, about 1 mcg/kg, is the saturation dose. Beyond it GH barely rises while cortisol and prolactin do, so extra doses per day beat extra micrograms per dose.
Reconstitution calculator
Pre-loaded with GHRP-2’s vial size, water volume and typical dose. Change anything.
Typical: 100 mcg · range 100–300
Draw to
4 u
0.04 mL · 100 mcg
Concentration
2.5 mg/mL
25 mcg per unit
Doses per vial
50
Vial lasts
2 weeks 3 days
Draw to 4 units on the barrel.
Once mixed
Keep at 2-8 C out of direct light and use within 3-4 weeks. Do not freeze once it is in solution.
Run the bacteriostatic water down the vial wall and swirl gently, never shake. A 5 mg vial in 2 mL gives 2,500 mcg/mL, so 100 mcg is only 4 units on an insulin syringe; if you dose in 100 mcg steps, using 5 mL instead gives a cleaner 1,000 mcg/mL where 100 mcg is exactly 10 units.
Storage
Before mixing
Stable sealed and dry for months at 2-8 C and for years at -20 C; short room-temperature shipping is tolerated.
After mixing
Keep at 2-8 C out of direct light and use within 3-4 weeks. Do not freeze once it is in solution.
Reported benefits
- ▪Large GH pulse per microgram, well above ipamorelin at the same dose
- ▪The best characterised GHRP in humans, with a licensed diagnostic use in Japan
- ▪Moderate, measurable appetite stimulation that is useful in a bulk
- ▪Strong synergy with GHRH analogues
- ▪Active by subcutaneous, intravenous and intranasal routes
- ▪Desensitises far less than hexarelin over an 8-12 week run
Side effects
- ▪Cortisol, ACTH and prolactin rise at doses above roughly 100 mcg
- ▪Hunger for 20-40 minutes after injection
- ▪Water retention with puffy hands and wrists
- ▪Tingling or numb fingers at higher doses
- ▪Head rush and facial flushing immediately after injecting
- ▪Reduced insulin sensitivity on long, high-dose use
- ▪Lethargy or flat mood in some users, most likely prolactin-driven
Do not use if
- ▪Active or suspected malignancy
- ▪Uncontrolled diabetes or significant insulin resistance
- ▪Existing hyperprolactinaemia
- ▪Active diabetic retinopathy
- ▪Untreated pituitary or hypothalamic disease
- ▪Pregnancy and breastfeeding
Evidence level — Human trials
Controlled human clinical data exists.
Approved in Japan only as a single-use diagnostic agent for GH deficiency; not FDA-approved, sold elsewhere as a research chemical, and prohibited by WADA at all times.
Commonly run with
CJC-1295 no-DAC
Short-acting GHRH fragment that sharpens one GH pulse, almost always run with a GHRP.
100 mcg · 1-3x daily
CJC-1295 with DAC
Albumin-binding GHRH analogue that lifts GH and IGF-1 for days from one injection.
1000 mcg · 1-2x weekly
Sermorelin
The first 29 amino acids of human GHRH, once approved as Geref and now compounded.
300 mcg · once nightly, 5-7 nights per week
Tesamorelin
The only FDA-approved GHRH analogue, proven to shrink visceral abdominal fat.
2 mg · once daily
GHRP-2 FAQ
Is 300 mcg per shot better than 100 mcg?+
Not for GH. The pituitary response is close to saturated around 1 mcg/kg, so tripling the dose adds little GH while cortisol and prolactin keep climbing. If you want more total GH exposure, add a third or fourth pulse in the day rather than raising the dose.
How much does it raise prolactin and cortisol in practice?+
At 100 mcg the rise is usually small enough to be clinically unimportant in healthy people. It becomes noticeable at 200-300 mcg and above, especially when repeated three times daily for months. If you get nipple sensitivity, low libido or persistent lethargy, drop the dose before adding anything to counter it.
GHRP-2 or GHRP-6 if I want the appetite effect?+
GHRP-6 is considerably hungrier and lasts longer. GHRP-2 gives a shorter, more manageable appetite bump alongside a bigger GH pulse. Pick GHRP-6 if eating is the actual problem you are solving, GHRP-2 if GH is the goal and the hunger is incidental.
Does it need a GHRH analogue alongside it?+
It works alone but you leave a lot on the table. The GH response to a GHRP depends heavily on endogenous GHRH, so adding CJC-1295 no-DAC or sermorelin produces a pulse larger than the two effects added together. Most established protocols dose them in the same syringe.
Will it test positive?+
Yes. GHRP-2 and its metabolites are detectable in urine by LC-MS/MS and anti-doping labs have screened for them routinely for over a decade. It is prohibited in and out of competition.
References
- 1.Growth hormone releasing peptide-2 (GHRP-2), like ghrelin, increases food intake in healthy men — The Journal of Clinical Endocrinology and Metabolism (2005) PMID 15699539
- 2.Pralmorelin: GHRP 2, GPA 748, growth hormone-releasing peptide 2, KP-102 D, KP-102 LN — Drugs in R&D (2004) PMID 15230633
- 3.Determination of growth hormone releasing peptides metabolites in human urine after nasal administration of GHRP-1, GHRP-2, GHRP-6, Hexarelin, and Ipamorelin — Drug Testing and Analysis (2015) PMID 25869809
More gh secretagogues
CJC-1295 no-DAC
Short-acting GHRH fragment that sharpens one GH pulse, almost always run with a GHRP.
100 mcg · 1-3x daily
CJC-1295 with DAC
Albumin-binding GHRH analogue that lifts GH and IGF-1 for days from one injection.
1000 mcg · 1-2x weekly
GHRP-6
The original GHRP: solid GH release and the strongest hunger response of the group.
100 mcg · 2-3x daily
Hexarelin
The most potent GHRP, and the fastest to stop working if you run it continuously.
100 mcg · 1-2x daily