Pralmorelin (GHRP-2) dosing & administration
A powerful hexapeptide that stimulates growth hormone release—used clinically in Japan for GH testing and studied for healing and anti-inflammatory effects.
Written by Michael Carroll — Owner, Director of Research · Reviewed by the Peptide Initiative Research Team · Editorial standards
Dosing
How much do I take?
Subcutaneous: A small injection into the fatty layer just under the skin — the same way insulin is given.
Bioavailability High — most of the dose reaches your bloodstream, just more gradually than an IV.
1 mcg/kg/hour (continuous infusion) in research settings
Frequency
Continuous infusion
Duration
Study-defined (e.g. ~270 minutes in published trials)
Subcutaneous infusion dose used in controlled human GH-release/appetite studies; not an approved therapeutic regimen. [4]
Timing
Best time to take
Administer on an empty stomach (2+ hours after meals, 30+ minutes before eating) to maximize GH response. [5][7] Fasting state enhances peptide efficacy.
With food?
Food intake, especially carbohydrates and amino acids, blunts the GH response. Maintain a gap of at least 2 hours post-meal for optimal effect.
If stacking
If combining with CJC-1295, space injections 15-30 minutes apart for synergistic effect. [10] Avoid injecting into the same body site within 48 hours.
Adjusting your dose
Increase if
- No observable GH response (elevated fasting glucose, minimal flush sensation)
- Baseline GH-deficient and diagnostic testing shows poor response
- Recovery progress is slower than expected after 2 weeks
- Individual has significant peptide experience and tolerates well
Decrease if
- Experiencing persistent headaches, dizziness, or flushing
- Blood pressure spikes during dosing windows
- Carpal tunnel symptoms develop
- Excessive appetite stimulation interferes with diet adherence
Signs of right dose
- Mild to moderate flush 5-15 minutes post-injection (indicates GH release)
- Improved energy and stamina during training or daily activities
- Faster recovery from soreness and improved sleep quality
- Visible improvements in muscle tone or injury healing within 4 weeks
Administration
How do I use it?
Reconstitution
What you need
Injection
Route
Subcutaneous injection into fatty tissue (adipose layer between skin and muscle)
Best sites
Storage
Before reconstitution
Keep lyophilized powder in freezer at -20°C or refrigerator at 4°C. Avoid repeated temperature fluctuations. Store in original vial protected from light and moisture.
After reconstitution
Refrigerate reconstituted solution at 2-8°C (36-46°F). Do NOT freeze reconstituted peptide. Use within 28 days of reconstitution. Keep vial capped and protected from light.
Signs of degradation — discard the vial
Sample daily schedule
Morning (upon waking, fasted)
100-200 mcg injection
Site: Lower abdomen
Administer after 8+ hours of fasting for maximum GH response. Eat 30+ minutes after injection.
Pre-workout (if using twice daily)
100-200 mcg injection
Site: Outer thigh
Inject 30-60 minutes before resistance training on non-fasting days for enhanced muscle protein synthesis during workout.
Evening (optional third dose)
100-200 mcg injection
Site: Back of upper arm
Some advanced users inject before bed on fasted stomachs to capitalize on natural nighttime GH peaks. Not typical—reserve for intensive protocols.
Safety
Is it safe?
Side effects
Commonly reported: Facial flushing, Transient headache, Increased appetite, Temporary dizziness or lightheadedness
Less common: Carpal tunnel-like sensations, Joint or muscle aches, Sleep quality changes
Stop and seek help if
- Severe or persistent headaches that worsen despite dose reduction
- Uncontrolled blood pressure elevation during dosing windows
- Development of new joint pain or swelling that interferes with daily function
- Signs of allergic reaction (rash, swelling, difficulty breathing)
- Any signs of infection at injection site (increasing redness, warmth, drainage)
- Planned surgery or acute hospitalization (discuss with medical team first)
This list is for educational purposes only and does not replace medical judgment. Always consult with a healthcare provider before starting, modifying, or stopping any peptide protocol. Pralmorelin is not FDA approved and should only be used under qualified medical supervision or within approved research settings.
Flagged pairings
- Ipamorelin — Both GHRPs work through similar mechanism. Combining offers minimal additional benefit and increases side effects. Avoid stacking.
- GHRP-6 — Both are GHRPs with overlapping function. GHRP-2 is more potent; stacking with GHRP-6 is redundant and increases appetite effects unnecessarily.
Published research
What the studies show
Suzuki S, Ruike Y, Ishiwata K, et al. · 2022
This study investigated the properties and effects of Pralmorelin (GHRP-2), contributing to our understanding of its mechanism of action and potential therapeutic applications.
Onuki T, Hiroaki T, Sawano K, et al. · 2024
This study investigated the properties and effects of Pralmorelin (GHRP-2), contributing to our understanding of its mechanism of action and potential therapeutic applications.
Li Y, Yao L, Zhang C, et al. · 2025
This study investigated the properties and effects of Pralmorelin (GHRP-2), contributing to our understanding of its mechanism of action and potential therapeutic applications.
Laferrere B, Abraham C, Russell CD, Bowers CY · 2005
Kaken Pharmaceutical Co., Ltd.; Pharmaceuticals and Medical Devices Agency (PMDA) · 2025
Approved in Japan for the diagnosis of growth hormone deficiency as a single intravenous dose given in the fasting state — 2 mcg/kg for ages 4 to under 18 (100 mcg if body weight exceeds 50 kg), 100 mcg from age 18 — with serum GH sampled to 60 minutes. Listed adverse reactions include heat sensation (16.0%) and, at 0.1-5%, dizziness, facial flushing and headache. Contraindicated in pregnant women or women who may be pregnant; breastfeeding to be weighed against diagnostic benefit.
Fukuda I, Hizuka N, Muraoka T, Ichihara A · 2014
In Japan the GHRP-2 test is available and is recommended as a convenient and safe GH-stimulating test for diagnosing adult growth hormone deficiency, with a peak GH cut-off of 9 microg/L for severe deficiency.
Ghigo E, Arvat E, Muccioli G, Camanni F · 1997
Review of the GHRP class: GHRPs act via specific pituitary and hypothalamic receptors distinct from GHRH, counteract somatostatinergic activity, and release GH synergistically with GHRH. GHRP-6 was the first hexapeptide studied in humans, with GHRP-2 and hexarelin synthesised later. The GH-releasing effect does not depend on sex, is blunted by glucose and free fatty acids, and undergoes partial desensitization — more during continuous infusion, less during intermittent administration.
Root AW, Root MJ · 2002
Ghrelin and the synthetic GH secretagogues act through a G-protein-coupled receptor that stimulates phospholipase C, producing inositol 1,4,5-trisphosphate and diacylglycerol, raising cytosolic calcium and releasing GH; GHRH acts through a separate receptor via adenylyl cyclase/cAMP, and the two act synergistically in vivo. Secretagogues stimulate endogenous GH secretion, in contrast to recombinant human GH which supplies the hormone directly.
Bowers CY · 1993
GHRP-6, GHRP-1 and GHRP-2 are 6-7 amino-acid synthetic peptides; in humans the three were found to be increasingly more effective at releasing GH in that order, and all release GH more efficaciously than GHRH 1-44 NH2. Combined GHRP and GHRH administration releases GH synergistically.
Pihoker C, Middleton R, Reynolds GA, Bowers CY, Badger TM · 1995
GHRP-2 acts directly on pituitary somatotrophs to stimulate GH release. In 12 children given GHRH and GHRP-2 simultaneously the GH response was synergistic, matching observations previously reported in adults.
Pihoker C, Badger TM, Reynolds GA, Bowers CY · 1997
Fifteen short-stature children received intranasal GHRP-2 two to three times daily for 6 months, six of them for 18-24 months; administration was well tolerated and height velocity rose from 3.7 to 6.1 cm/year at 6 months.
Furuta S, Shimada O, Doi N, et al. · 2004
KP-102 / GHRP-2 / pralmorelin (CAS 158861-67-7) is the hexapeptide D-alanyl-3-(2-naphthyl)-D-alanyl-L-alanyl-L-tryptophyl-D-phenylalanyl-L-lysinamide dihydrochloride, which promotes GH release at both hypothalamic and pituitary sites. Across animal models it showed no serious general pharmacological effects on the central nervous, autonomic, respiratory, cardiovascular, digestive, renal or blood systems at GH-releasing doses.
Anderson SM, Shah N, Evans WS, Patrie JT, Bowers CY, Veldhuis JD · 2001
After bolus intravenous GHRP-2 the deconvolved GH secretory burst peaked within 8-13 minutes, and mean endogenous GH half-life was 17-18 minutes.
Higham CE, Jostel A, Trainer PJ · 2007
Weight-based GH replacement regimens led to significant side effects related to excess GH — arthralgias, headaches and peripheral edema — alongside IGF-I levels above the upper limit of the reference range.
Yuen KCJ, Heaney AP, Popovic V · 2016
GH and IGF-I may enhance tumorigenesis, metastasis and cell proliferation; studies of GH therapy in GH-deficient adults and childhood cancer survivors have not convincingly demonstrated an increased cancer risk, and the authors recommend individualised consideration, initiation no sooner than 2 years after remission, and close oncological surveillance.
Cohn L, Feller AG, Draper MW, Rudman IW, Rudman D · 1993
In elderly men treated with human growth hormone, carpal tunnel syndrome occurred in 10 of 62 treated men and gynaecomastia in 4, against 21 untreated controls. Both were associated with mean plasma IGF-I rising above 1.0 units/ml during treatment.
Head to head
Pralmorelin (GHRP-2) compared
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The complete Pralmorelin (GHRP-2) research profile: mechanism of action, clinical studies, effectiveness timeline, and FAQ.