The Three Most Popular GHRPs
Growth Hormone Releasing Peptides (GHRPs) stimulate GH release by mimicking ghrelin at the GHSR-1a receptor. Ipamorelin, GHRP-2, and GHRP-6 are the three most studied — each with a distinct balance of potency vs side effects.
For the most potent GHRP of all, see our Hexarelin deep dive.
How GHRPs Work
All three bind the GHSR-1a receptor (ghrelin receptor) in the pituitary gland, triggering a GH pulse. The key differences are in selectivity — how much they activate other pathways beyond GH release.
- More selective = fewer side effects (hunger, cortisol, prolactin)
- Less selective = stronger GH pulse but more off-target effects
Quick Comparison Table
| Feature |
Ipamorelin |
GHRP-2 |
GHRP-6 |
| GH release potency |
Moderate |
High |
Moderate-High |
| Selectivity |
Highest |
Moderate |
Lowest |
| Hunger stimulation |
Minimal |
Moderate |
Strong |
| Cortisol increase |
None |
Mild |
Moderate |
| Prolactin increase |
None |
Mild |
Mild-Moderate |
| Typical dose |
200–300 mcg |
150–300 mcg |
100–300 mcg |
| Best for |
Clean GH pulse, beginners |
Maximum GH output |
Appetite stimulation + GH |
| Side effect profile |
Mildest |
Moderate |
Most side effects |
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Detailed Mechanism Comparison
Ipamorelin — The Selective Option
Ipamorelin is the most selective GHRP available. It triggers a clean GH pulse without significantly raising cortisol, prolactin, or appetite.
Key properties:
- Does not increase cortisol — important for avoiding stress hormone elevation
- Does not increase prolactin — no hormonal disruption
- Minimal ghrelin-like hunger — suitable when appetite stimulation is unwanted
- Dose-dependent GH release — predictable, linear response
This selectivity makes Ipamorelin the go-to choice when a clean GH pulse is the primary goal without metabolic side effects.
GHRP-2 — The Potency Pick
GHRP-2 produces the strongest GH release among commonly used GHRPs (excluding Hexarelin, which is even more potent but desensitizes).
Key properties:
- Highest sustained GH output — greater peak amplitude than Ipamorelin
- Mild cortisol elevation — generally considered clinically insignificant at standard doses
- Moderate appetite increase — noticeable but manageable
- No desensitization — unlike Hexarelin, GHRP-2 maintains efficacy with continued use
GHRP-2 is the choice when maximizing GH release is the priority and mild side effects are acceptable. See the full GHRP-2 Benefits Guide for a deeper look at its research-backed effects.
GHRP-6 — The Appetite Stimulator
GHRP-6 is the original GHRP and the least selective. Its strong ghrelin mimicry produces significant hunger alongside GH release.
Key properties:
- Strong appetite stimulation — the most pronounced of any GHRP (can be a benefit or drawback)
- Moderate cortisol increase — higher than GHRP-2
- Good GH release — effective but not as potent per mcg as GHRP-2
- Strongest ghrelin mimicry — most activation of non-GH ghrelin pathways
GHRP-6 is studied when appetite stimulation is a desired effect (e.g., recovery from illness, muscle gain phases) alongside GH release. See the full GHRP-6 Benefits Guide for its cytoprotective and appetite-related research.
GH Release Comparison
Approximate GH pulse amplitude at standard doses (from published research):
| Peptide |
Dose |
GH Peak (approximate) |
| Ipamorelin |
200 mcg |
20–35 ng/mL |
| GHRP-2 |
200 mcg |
35–60 ng/mL |
| GHRP-6 |
200 mcg |
25–45 ng/mL |
| Hexarelin |
200 mcg |
50–80+ ng/mL |
Note: Individual response varies significantly. These are approximate ranges from research literature.
Stacking with GHRH
All GHRPs work synergistically with GHRH analogs. Combining a GHRP with a GHRH produces a much larger GH pulse than either alone:
- CJC-1295 + Ipamorelin — the most popular combination, clean and predictable
- CJC-1295 DAC + GHRP-2 — sustained baseline elevation + strong pulses
- Sermorelin + Ipamorelin — natural GHRH analog + selective GHRP
For a detailed breakdown of GHRH vs GHRP mechanics, see our GHRH vs GHRP guide.
Dosing Comparison
For research and educational discussion only.
| Peptide |
Standard Dose |
Frequency |
Timing |
| Ipamorelin |
200–300 mcg |
2–3x daily |
Pre-bed, morning, post-workout |
| GHRP-2 |
150–300 mcg |
2–3x daily |
Same timing |
| GHRP-6 |
100–300 mcg |
2–3x daily |
30 min before meals (hunger effect) |
Timing Notes
- GH release is blunted by elevated blood sugar — administer on an empty stomach or 2+ hours after eating
- Pre-bed dosing takes advantage of natural nocturnal GH pulse
- Wait 15–30 minutes after injection before eating
Side Effects Comparison
| Side Effect |
Ipamorelin |
GHRP-2 |
GHRP-6 |
| Hunger |
Rare |
Moderate |
Strong (30–60 min) |
| Water retention |
Minimal |
Mild |
Mild |
| Cortisol |
No increase |
Small increase |
Moderate increase |
| Prolactin |
No increase |
Small increase |
Moderate increase |
| Numbness/tingling |
Rare |
Occasional |
Occasional |
| Desensitization |
No |
No |
No |
The Bottom Line
| If your research goal is... |
Best choice |
| Clean GH pulse, minimal sides |
Ipamorelin |
| Maximum GH release |
GHRP-2 (or Hexarelin short-term) |
| Appetite stimulation + GH |
GHRP-6 |
| Beginner-friendly |
Ipamorelin |
| Stacking with CJC-1295 |
Ipamorelin (most popular combo) |
| Long-term use |
Ipamorelin or GHRP-2 (no desensitization) |
| Budget-conscious |
Check live pricing above |
For most research contexts, Ipamorelin is the safest starting point due to its selectivity. GHRP-2 is the step up when more GH output is needed. GHRP-6 is best when appetite stimulation is a desired effect.
This article is for educational and research purposes only. It is not medical advice.