Comparison
GHRP-2 vs Low-Dose Naltrexone
Side-by-side of GHRP-2 and Low-Dose Naltrexone. 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.
Low-Dose Naltrexone
Low dose naltrexone at 1.5 to 4.5 mg, one-tenth the 50 mg addiction dose. Compounded Rx. Small trials in fibromyalgia, Crohn's, Hashimoto's.
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
Low-Dose Naltrexone
- •Off-label use at 1.5 to 4.5 mg, roughly one-tenth the FDA-approved 50 mg addiction-treatment dose
- •Proposed mechanisms include brief opioid receptor blockade triggering rebound endogenous opioid release, plus TLR4 antagonism
- •Compounded prescription only; insurance rarely covers; cash prices 20 to 80 USD per month
- •Younger 2013 reported ~30% pain reduction in fibromyalgia at 4.5 mg in a small crossover trial
- •Smith 2011 reported endoscopic improvement in active Crohn's disease (n=40 placebo-controlled)
- •Vivid dreams affect 20 to 40% in first 2 weeks; manageable by switching to morning dosing
Side-by-side
| Attribute | GHRP-2 | Low-Dose Naltrexone |
|---|---|---|
| Category | peptide | pharmaceutical |
| Also known as | Growth Hormone Releasing Peptide 2, Pralmorelin, KP-102, GPA-748 | LDN, naltrexone (low dose) |
| Half-life (hr) ↗ | 0.5 | 4 |
| Typical dose (mg) ↗ | 0.1 | 4.5 |
| Dosing frequency | 2-3x daily | once daily, typically at bedtime |
| Routes | subcutaneous, intranasal, intravenous | oral |
| Onset (hr) | 0.25 | 1 |
| Peak (hr) | 0.5 | 1.5 |
| Molecular weight | 817.97 | 341.4 |
| Molecular formula | C45H55N9O6 | C20H23NO4 |
| 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. | Brief mu-opioid receptor antagonism proposed to trigger compensatory upregulation of endogenous opioids; secondary TLR4 antagonism on microglia and immune cells contributes to anti-inflammatory effect. |
| Legal status | Not FDA approved; approved in Japan as pralmorelin (diagnostic); research-use-only grey market in US/EU; banned by WADA | Off-label compounded prescription (naltrexone is FDA approved for opioid and alcohol use disorder at 50 mg) |
| WADA status | banned | allowed |
| DEA / Rx | Not scheduled in US (research chemical); approved diagnostic in Japan | Rx only (not a controlled substance) |
| Pregnancy | Insufficient data; not recommended | Insufficient data; not routinely recommended |
| CAS | 158861-67-7 | 16590-41-3 |
| PubChem CID | 9919072 | 5360515 |
| Wikidata | Q7235681 | Q426444 |
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)
Low-Dose Naltrexone
Common side effects
- vivid dreams
- sleep disruption
- headache
- mild GI upset
- fatigue (early)
Contraindications
- concurrent opioid use
- acute hepatitis or liver failure
- opioid dependence
- pregnancy (insufficient data)
Interactions
- opioid analgesics (oxycodone, morphine, codeine): blocks analgesic effect; precipitates withdrawal in dependent users(major)
- tramadol: blocks opioid component of analgesia(major)
- thyroid hormone replacement: may alter dose requirements after immune modulation; monitor TSH(minor)
Which Should You Take?
Low-Dose Naltrexone comes out ahead for most readers on the criteria we weight: 2 catalogued goals, prescription-only, 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 immune support, pick Low-Dose Naltrexone.
- → If your priority is pain modulation, pick Low-Dose Naltrexone.
Edge case: If you cannot self-administer injections, Low-Dose Naltrexone is the only oral option in this pair.
Default choice: Low-Dose Naltrexone. 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 Low-Dose Naltrexone?
GHRP-2 and Low-Dose Naltrexone differ in category (peptide vs pharmaceutical), mechanism, and typical dosing. See the side-by-side table for full details.
Which has a longer half-life, GHRP-2 or Low-Dose Naltrexone?
GHRP-2 half-life is 0.5 hours; Low-Dose Naltrexone half-life is 4 hours.
Can you stack GHRP-2 with Low-Dose Naltrexone?
Stack compatibility depends on mechanism overlap, legal status, and individual response. Check each compound page for specific interactions and contraindications before combining.
Go deeper