Which GHRP is most selective?

Ipamorelin is the most selective ghrelin receptor agonist — minimal cortisol/prolactin elevation and no significant hunger stimulation. GHRP-2 has moderate cortisol/prolactin effects. GHRP-6 has the highest hunger-stimulating effect.

Do GHRPs stack with tesamorelin?

Yes — GHRH (tesamorelin, CJC-1295, sermorelin) and GHRPs work synergistically because they stimulate GH release through different receptor systems (GHRH-R vs ghrelin-R). Combined, they produce larger GH pulses than either alone.

Which GHRP for fat loss research?

Ipamorelin is preferred for fat-loss research protocols because the cortisol/prolactin neutrality avoids stress-related fat retention. GHRP-2 is sometimes selected for higher GH pulse amplitude when cortisol elevation is acceptable.

GHRP-2 vs GHRP-6 vs Ipamorelin: Complete UAE Research Comparison 2026

Published 23 June 2026 · REVIVE Peptides Research Desk · 9 min read

TL;DR. All three are ghrelin receptor agonists (GHRPs) that trigger GH release. Ipamorelin is the cleanest — minimal cortisol, prolactin, or hunger. GHRP-2 has the strongest GH pulse but raises cortisol/prolactin. GHRP-6 produces a moderate GH pulse plus pronounced hunger stimulation. For most research, ipamorelin is the default; GHRP-2 for max pulse research; GHRP-6 niche.

How GHRPs Work

GHRPs (growth hormone releasing peptides) are synthetic agonists of the ghrelin receptor (GHS-R1a). They mimic the natural hunger/GH-release hormone ghrelin but with different selectivity profiles. Each binds the same primary receptor but with varying affinity for downstream pathways that drive secondary effects:

ACTH/cortisol axis — varying activation
Prolactin release — varying activation
Appetite/hunger signalling — varying activation

The "cleanest" GHRP is the one that drives the GH pulse with minimal off-target activation. Howard 1996 and later Bowers 2001 reviewed the selectivity comparisons that established ipamorelin's clean profile.

Head-to-Head Comparison

Property	Ipamorelin	GHRP-2	GHRP-6
GH pulse amplitude	Moderate	Highest	Moderate
Cortisol elevation	None/minimal	Mild	Mild
Prolactin elevation	None/minimal	Mild	Mild
Hunger stimulation	None/minimal	Mild	Strong
Half-life	~2 hours	~1 hour	~1 hour
Typical research dose	200–300 µg SC	100–300 µg SC	100–300 µg SC
Frequency	2–3x daily	2–3x daily	2–3x daily

When to Choose Each

Ipamorelin — default for most research

Selective ghrelin agonism without cortisol or prolactin spikes
Best for long-term protocols where off-target effects compound
Best for fat-loss research (cortisol neutrality)
Best for stacking with GHRH (tesamorelin/CJC-1295) — clean synergy

GHRP-2 — when max pulse matters

Highest GH amplitude in published comparisons
Useful for research questions about maximal GH output
Accept mild cortisol/prolactin trade-off

GHRP-6 — niche, hunger-positive research

Pronounced appetite stimulation — useful for cachexia research
Less popular for general GH research because of the hunger side effect
Effective in low-appetite research populations

The GHRH + GHRP Stack Concept

GHRH analogues (tesamorelin, sermorelin, CJC-1295) and GHRPs activate different receptors on the same pituitary cells. Combined, they produce synergistic GH release — not just additive.

Stack	Mechanism	Research positioning
Tesamorelin + ipamorelin	GHRH-R + ghrelin-R synergy, clean profile	Long-term, low side effect
CJC-1295 + ipamorelin	Same synergy, longer half-life GHRH	Twice-daily simpler dosing
Tesamorelin + GHRP-2	Same synergy, higher pulse	Max GH research

For deep stack research see our tesamorelin + ipamorelin protocol.

Why REVIVE Stocks Tesamorelin Not Ipamorelin

Tesamorelin has the strongest published clinical trial portfolio (Stanley 2014 JAMA, Stanley 2019 Lancet HIV, Falutz 2010). GHRPs including ipamorelin have substantial mechanistic and animal data but fewer large human RCTs. For research-grade supply, REVIVE prioritises peptides with published human dose ranges and outcome data.

Researching GH-axis peptides in the UAE?
REVIVE supplies tesamorelin 5 mg and 10 mg vials, with HPLC certificates and cold-chain delivery.
View tesamorelin vials →

Practical Research Protocol Considerations

Timing: All GHRPs work best on empty stomach. Carbs blunt GH response; fat to a lesser extent.
Frequency: Pulsatile GH biology favours 2–3 daily injections rather than once.
Stacking with GHRH: Mix in same syringe is acceptable (peptides are chemically compatible).
Monitoring: IGF-1 every 3 months for long-term protocols.

Research use only. All peptides supplied by REVIVE are labelled and sold strictly for in-vitro and research purposes — not for human consumption.

References

Howard AD, Feighner SD, Cully DF, et al. A receptor in pituitary and hypothalamus that functions in growth hormone release. Science. 1996;273(5277):974–977.
Raun K, Hansen BS, Johansen NL, et al. Ipamorelin, the first selective growth hormone secretagogue. Eur J Endocrinol. 1998;139(5):552–561.
Bowers CY. Unnatural growth hormone-releasing peptide begets natural ghrelin. J Clin Endocrinol Metab. 2001;86(4):1464–1469.
Sigalos JT, Pastuszak AW. The safety and efficacy of growth hormone secretagogues. Sex Med Rev. 2018;6(1):45–53.
Bowers CY, Granda R, Mohan S, et al. Sustained elevation of pulsatile growth hormone secretion and insulin-like growth factor I, insulin-like growth factor-binding protein-3, and markers of bone metabolism during 30-day treatment with a growth hormone-releasing hormone superagonist. J Clin Endocrinol Metab. 2004;89(11):5588–5594.