Comparison
GHRP-2 vs Melatonin
Side-by-side of GHRP-2 and Melatonin. Every row below is pulled from the compound schema and will update as our data grows. For deeper reads, follow through to each compound page.
GHRP-2
GHRP-2 peptide (pralmorelin, KP-102) is a synthetic hexapeptide ghrelin-receptor agonist that triggers pulsatile growth hormone release via the pituitary.
Melatonin
Melatonin as a sleep supplement: 0.3-1 mg matches physiological output, 3-10 mg is pharmacological. Shifts circadian phase, shortens sleep latency.
Effects at a glance
GHRP-2
- •Hexapeptide ghrelin-receptor agonist that stimulates pulsatile GH release within 15 to 30 minutes
- •Strongest appetite signal among GHRPs at standard doses; centrally mediated via NPY/AgRP
- •Produces measurable cortisol and prolactin rise (more than ipamorelin, less than GHRP-6)
- •Approved in Japan as pralmorelin for GH-deficiency diagnostic provocation; not FDA approved
- •Anecdotal protocols use 100 to 300 mcg subcutaneously 2 to 3 times daily on an empty stomach
- •Banned by WADA under S2; detection methods validated in accredited labs
Melatonin
- •Shortens sleep onset latency by ~7 to 12 minutes at physiological 0.3 to 1 mg doses
- •Advances circadian phase when taken 30 to 60 minutes before target bedtime, useful for jet lag and shift work
- •Does not meaningfully increase total sleep time in healthy adults without circadian misalignment
- •Endogenous nighttime production is not suppressed by short-term exogenous supplementation
- •Higher doses (3 to 10 mg) raise plasma levels above physiological range and often increase morning grogginess
- •Effective for delayed sleep-wake phase disorder and reducing jet-lag severity in eastward travel
Side-by-side
| Attribute | GHRP-2 | Melatonin |
|---|---|---|
| Category | peptide | supplement |
| Also known as | Growth Hormone Releasing Peptide 2, Pralmorelin, KP-102, GPA-748 | N-acetyl-5-methoxytryptamine |
| Half-life (hr) ↗ | 0.5 | 0.75 |
| Typical dose (mg) ↗ | 0.1 | 0.5 |
| Dosing frequency | 2-3x daily | daily, 30 to 60 minutes before target sleep time |
| Routes | subcutaneous, intranasal, intravenous | oral, sublingual |
| Onset (hr) | 0.25 | 0.5 |
| Peak (hr) | 0.5 | 1 |
| Molecular weight | 817.97 | 232.28 |
| Molecular formula | C45H55N9O6 | C13H16N2O2 |
| Mechanism | Hexapeptide agonist of the growth-hormone secretagogue receptor (GHS-R1a). Suppresses hypothalamic somatostatin tone and stimulates pituitary somatotrophs, producing a pulsatile GH release with secondary cortisol, prolactin, and ACTH elevation. | Agonist at MT1 and MT2 receptors in the suprachiasmatic nucleus, signaling biological night and promoting sleep-onset gating plus circadian phase shifts. |
| Legal status | Not FDA approved; approved in Japan as pralmorelin (diagnostic); research-use-only grey market in US/EU; banned by WADA | OTC in US; prescription in UK, EU, Japan |
| WADA status | banned | allowed |
| DEA / Rx | Not scheduled in US (research chemical); approved diagnostic in Japan | OTC supplement in US; Rx in UK, EU, Japan, Australia |
| Pregnancy | Insufficient data; not recommended | Insufficient data; not routinely recommended |
| CAS | 158861-67-7 | 73-31-4 |
| PubChem CID | 9919072 | 896 |
| Wikidata | Q7235681 | Q179243 |
Safety profile
GHRP-2
Common side effects
- acute hunger
- head pressure or flushing
- water retention
- vivid dreams
- tingling at injection site
- transient lethargy
Contraindications
- pregnancy
- active malignancy
- history of pituitary tumor
- uncontrolled diabetes
- severe insulin resistance
Interactions
- CJC-1295: synergistic GH release; commonly co-administered for larger pulse(minor)
- sermorelin: additive GH release via parallel GHRH and ghrelin pathways(minor)
- insulin: sustained GH can blunt insulin sensitivity over weeks(moderate)
- corticosteroids: blunt GH response and amplify cortisol load(moderate)
Melatonin
Common side effects
- vivid dreams
- morning grogginess (higher doses)
- headache
- dizziness
Contraindications
- autoimmune disease (theoretical)
- concurrent anticoagulant therapy without monitoring
Interactions
- fluvoxamine: CYP1A2 inhibition raises melatonin levels substantially(major)
- warfarin: possible increased bleeding risk(moderate)
- benzodiazepines and alcohol: additive sedation(moderate)
- antihypertensives: may alter blood pressure response(minor)
Which Should You Take?
Melatonin comes out ahead for most readers on the criteria we weight: 2 catalogued goals, OTC, oral dosing, with a Tier-A outcome catalogued. GHRP-2 is the right call when one of the conditionals below applies.
- → If your priority is growth-hormone axis, pick GHRP-2.
- → If your priority is post-training recovery, pick GHRP-2.
- → If your priority is sleep onset or sleep quality, pick Melatonin.
- → If your priority is circadian regulation, pick Melatonin.
Edge case: If you want to avoid research-only / gray-market sourcing, Melatonin is the more accessible choice.
Default choice: Melatonin. Wider use case, a Tier-A evidence outcome catalogued, and broader goal coverage. Reach for GHRP-2 only if your priority sits squarely in the goals it owns above.
This verdict is generated from each compound's schema (goals, legal status, evidence outcomes, dosing route). It updates automatically as our compound data evolves; the deeper read sits on each individual compound page.
Common questions
What is the difference between GHRP-2 and Melatonin?
GHRP-2 and Melatonin differ in category (peptide vs supplement), mechanism, and typical dosing. See the side-by-side table for full details.
Which has a longer half-life, GHRP-2 or Melatonin?
GHRP-2 half-life is 0.5 hours; Melatonin half-life is 0.75 hours.
Can you stack GHRP-2 with Melatonin?
Stack compatibility depends on mechanism overlap, legal status, and individual response. Check each compound page for specific interactions and contraindications before combining.
Go deeper