GHRP-2 GHRP-6 Hexarelin
What do these badges mean?
Evidence tier
- AHuman-validated — Human trials showing positive results and good safety.
- BAnimal-grade — No human trials yet, but solid animal/preclinical evidence of effect and safety.
- CAnecdotal — No human or animal trials — only anecdotal/observational reports.
- DInsufficient evidence — No or insufficient evidence (encyclopedia only — never recommended by the builder).
Safety light
- 🟢 Green — Only mild, manageable side effects; reasonable safety data.
- 🟡 Yellow — Needs active management, has a meaningful contraindication/interaction, or has thin long-term data.
- 🔴 Red — Risk of a hospital-level event — treat with serious caution.
Browse-only — not on the protocol builder's curated shortlist, so the builder won't recommend it.
How can it help me?
These three — GHRP-2, GHRP-6, and Hexarelin — are first-generation “growth hormone releasing peptides”: short injectable molecules that hit the ghrelin receptor and trigger a natural GH pulse from your pituitary. Same target, three different side-effect profiles — GHRP-6 famously spikes hunger, GHRP-2 less so, and Hexarelin is the strongest but fades fastest with continued use.
Honest read: they work, but most people today choose the cleaner newer peptides (like Ipamorelin) for fewer off-target effects — these are the classics worth understanding.
The full evidence — every human, animal, and lab study, graded — is one tap away: use the See the deeper science → toggle at the top.
Is it dangerous? What are the side effects?
The class profile is the GH-axis profile (mild flushing, water retention proportional to GH push, possible injection-site reactions, occasional headache) plus the off-target signature that distinguishes each compound:
| Compound | Class-shared | Distinguishing off-target |
|---|---|---|
| GHRP-2 | Mild water retention, flushing | Modest cortisol; mild appetite increase |
| GHRP-6 | Mild water retention, flushing | Intense hunger; stronger cortisol above saturation |
| Hexarelin | Mild water retention, flushing | Measurable cortisol + prolactin; 8-week desensitization ceiling |
Management defaults: start at the low end of the dose range, watch how your body responds for 1–2 weeks before escalating, cycle off as scheduled (don’t push past Hexarelin’s 8-week window), pull bloodwork if you’re running aggressive doses.
Hard contraindications: active malignancy or significant cancer-history concern (IGF-1 is a mitogen), active CHF or significant cardiac dysfunction (water-retention CV strain — the same physiology that ended MK-677 (Ibutamoren)'s elderly hip-fracture trial), uncontrolled diabetes (insulin-resistance signal compounds), pregnancy/breastfeeding, and any tested-athlete context (WADA-banned).
Regulatory status: None of the three are FDA-approved for any indication. All sit in the research-chemical / 503A gray zone. All three are WADA-prohibited and out-of-competition tested for in sport. The peptides themselves are sold internationally as “research compounds” — same regulatory tier as the other unapproved peptides in this wiki.
Part 1 — How to reconstitute it
What you'll need: bacteriostatic water (sterile, preserved water you mix the powder with) and a separate, larger reconstitution syringe just for mixing — not the small syringe you inject with.
Reconstitution math (universal across the three). A 5 mg vial reconstituted with 2 mL bacteriostatic water gives 2,500 mcg/mL. On a U-100 insulin syringe (100 units = 1 mL):
- 100 mcg dose = 0.04 mL = 4 units
- 150 mcg dose = 0.06 mL = 6 units
- 200 mcg dose = 0.08 mL = 8 units
How to mix it
- Tilt the vial and let the bacteriostatic water run slowly down the inside glass wall — never squirt it straight onto the powder.
- Swirl gently to dissolve. Never shake — shaking can damage the peptide.
- Store the reconstituted vial refrigerated and out of light.
- Use it within the beyond-use window your source specifies — reconstituted peptides are commonly used within a few weeks; confirm the window for your specific peptide.
Use the free reconstitution calculator to turn any vial size + water volume into exact units on an insulin syringe.
Part 2 — Typical dosing
The doses and schedules here are for educational and informational purposes only. These peptides are sold for research use only and are not FDA-approved drugs. This is not medical advice. Consult a qualified physician before beginning any protocol.
The syringe. Use a 0.3 mL U-100 insulin syringe — it's sized for these small subcutaneous doses. Inject subcutaneously (into the fat just under the skin) and rotate injection sites.
(If you have a 10 mg vial + 2 mL water = 5,000 mcg/mL: halve the units for the same mcg dose.)
GHRP-2 dosing
| Tier | Dose | Frequency | Notes |
|---|---|---|---|
| Beginner | 100 mcg | Once daily before bed | Assess off-target tolerance |
| Intermediate | 150–200 mcg | 2× daily (fasted AM + bed) | Standard “more GH than Ipa” lane |
| Advanced | 200–300 mcg | 2–3× daily | Peak GH lever; cortisol/prolactin tracking advised |
Cycle: 8–12 weeks on / 4–8 weeks off. 5-on / 2-off micro-cycling within a block is the standard receptor-preservation move.
GHRP-6 dosing
| Tier | Dose | Frequency | Notes |
|---|---|---|---|
| Beginner | 100 mcg | 1–2× daily | Hunger arrives within 20 min — plan meals around it |
| Intermediate | 100 mcg | 2–3× daily | Mass-building / hard-gainer lane |
| Advanced | 100–150 mcg | 3× daily | Saturation ceiling ~1 µg/kg — going higher gives more side effects, not more GH |
Cycle: 8–16 weeks on / 4–8 weeks off. The appetite effect persists through the cycle (it doesn’t desensitize the way the GH response does).
Hexarelin dosing
| Tier | Dose | Frequency | Notes |
|---|---|---|---|
| Conservative | 50–100 mcg | 1–2× daily | Test desensitization tolerance |
| Standard | 100 mcg | 2–3× daily | Pre-workout / post-workout / pre-bed timing |
| Aggressive | 200 mcg | 2–3× daily | Bodybuilding lane; short cycles only |
Cycle: 4–8 weeks on / 4 weeks off — strict. The desensitization timeline doesn’t give you a choice. Baseline + mid-cycle bloodwork (prolactin, cortisol, IGF-1) is the standard for cycles longer than 6 weeks.
Timing (universal)
- Empty stomach — eating around the dose blunts the GH response.
- PM dosing rides the natural overnight GH pulse and is the default if dosing once daily.
- Pre-workout dosing is common for the workout-window GH-driven recovery effect.
What should I avoid combining — and what's synergistic?
Stacking — the GHRH side
All three pair with CJC-1295 for the dual-receptor synergy (same logic as CJC-1295 / Ipamorelin):
- CJC-1295 + GHRP-2 — the “max GH” stack for users for whom CJC + Ipa isn’t enough.
- CJC-1295 + Hexarelin — the “advanced potency + theoretical cardiac” stack; short cycles only.
- CJC-1295 + GHRP-6 — for hard-gainer / mass-building contexts where the appetite drive is the goal.
How can I buy this?
None of GHRP-2, GHRP-6, or Hexarelin are in Alyve’s current launch catalog — all three are flagged as roadmap candidates. Per the launch-15 framing, the cleaner GH-axis SKUs (Ipamorelin for the ghrelin lane, CJC-1295 / Sermorelin / Tesamorelin for the GHRH lane, and the CJC-1295 / Ipamorelin blend for the dual-receptor synergy) cover the daily-use mainstream cleanly. The three covered here serve specific advanced use cases — maximum potency (Hexarelin), maximum-GH-without-going-oral (GHRP-2), appetite-as-therapy (GHRP-6) — that map to a smaller, more sophisticated buyer.
If/when they land in the catalog, the natural stack-buy framing would be:
- CJC-1295 + GHRP-2 for the “max GH” stack.
- CJC-1295 + Hexarelin for the short-cycle advanced lane.
- GHRP-6 + protein + adequate lifting for the hard-gainer lane (with BPC-157 / TB-500 for recovery support).
In the meantime, the in-catalog answer at the same receptor — and the better daily-use default for nearly everyone — is Ipamorelin alone or in the CJC-1295 / Ipamorelin blend (in stock, 99.90% Freedom Diagnostics COA, lot CJI583). That’s the cleanest GHS-R1a agonist on the market: GH pulse without the hunger, cortisol, or prolactin baggage of the three peptides covered here.
Offer: Use coupon OHM-15 for 15% off — Alyve’s pricing is very competitive, and buying 3 vials of any given peptide in one purchase gets you over 30% off retail. (Full disclosure: OHM-15 attributes the sale to me — said plainly, as always.)
When you use my coupon code to buy peptides with these sellers, you enjoy a discount off retail price, and I make a small commission which helps me to continue to offer this peptide educational site to you for free. I only have affiliate relationships with peptide manufacturers that show evidence that their peptides are 100% manufactured in the US, 3rd party lab tested for purity, transparent COAs posted on their websites, and that have good customer service.
The first-generation injectable GH secretagogues that hit the same ghrelin receptor as Ipamorelin and MK-677 (Ibutamoren) — but each carries its own off-target signature. The trade-off is potency vs cleanliness. Hexarelin is the strongest GH pulse in the class (and uniquely engages a cardiac receptor); GHRP-2 is the workhorse “more GH than Ipamorelin can give you” lever; GHRP-6 is the one whose ghrelin-driven hunger is so dominant it became the therapeutic mechanism for hard gainers. Ipamorelin won the daily-use war specifically by not doing what these three do at off-target sites — which is the cleanest cross-sell story in the GH-axis catalog.
| Field | GHRP-2 | GHRP-6 | Hexarelin |
|---|---|---|---|
| Class | Synthetic hexapeptide, GHS-R1a agonist | Synthetic hexapeptide, GHS-R1a agonist | Synthetic hexapeptide, GHS-R1a + CD36 agonist (dual receptor) |
| GH release magnitude | Strong — peak plasma GH 30–100 ng/mL (8–20× baseline) | Strong (similar to GHRP-2 at low doses; saturates ~1 µg/kg) | Strongest in class — 2–3× GH release of GHRP-2 / GHRP-6 / Ipamorelin at equivalent doses |
| Cortisol | Moderate (comparable to CRH at standard doses) | Stronger above the ~1 µg/kg saturation threshold | Measurable |
| Prolactin | Mild — lower than TRH-induced | Moderate at higher doses | Measurable |
| Appetite (hunger) | Increased but manageable | Dominant clinical effect — intense hunger 15–60 min post-dose | Moderate — overshadowed by potency and desensitization |
| Desensitization timeline | Slower — 8–12 week cycles common | Persists through cycle; 8–16 wk on / 4–8 wk off | Fastest in class — GH response drops ~week 8 |
| Best-fit use case | Maximum GH lever when Ipamorelin isn’t enough | Hard gainers, post-surgical, mass-building (hunger = therapeutic) | Maximum GH pulse + theoretical cardioprotection (short cycles only) |
| Regulatory | Research chemical; WADA-banned | Research chemical; WADA-banned | Research chemical; WADA-banned |
| Alyve product | Not in current launch catalog — flagged as roadmap candidate. Ipamorelin is the selective in-catalog option at the same receptor. | Same | Same |
What they are
GHRP-2, GHRP-6, and Hexarelin are three synthetic hexapeptides (six amino acids each) developed across the 1980s–90s as the first generation of growth hormone releasing peptides — short, injectable molecules that hit the ghrelin receptor (GHS-R1a) on pituitary somatotrophs and trigger a GH pulse. Same target, three different chemical scaffolds, three different off-target profiles.
This is the same receptor Ipamorelin hits (Ipamorelin is technically the fourth GHRP), and the same target MK-677 (Ibutamoren) hits orally. The receptor map is worth holding:
| Lane | Receptor | Members |
|---|---|---|
| GHRH side | GHRH-R | Sermorelin, CJC-1295, Tesamorelin |
| Ghrelin side, injectable | GHS-R1a | Ipamorelin, GHRP-2, GHRP-6, Hexarelin |
| Ghrelin side, oral | GHS-R1a | MK-677 (Ibutamoren) |
The reason CJC-1295 gets stacked with Ipamorelin (the CJC-1295 / Ipamorelin blend) is that the GHRH and ghrelin pathways trigger GH release through separate intracellular cascades in the same pituitary cells — hitting both simultaneously produces more GH than either alone, by roughly the synergy you’d predict. The same logic applies to stacking CJC-1295 with any of the three covered here: GHRP-2 + CJC, GHRP-6 + CJC, Hexarelin + CJC are all real protocols people run. They just bring the off-target effects along with the extra GH.
How they work (the shared mechanism)
All three bind GHS-R1a on pituitary somatotrophs → phospholipid-dependent signaling cascade → pulsatile GH release. Peak GH typically lands 30–45 minutes after a SubQ injection. Downstream: liver IGF-1 production → systemic IGF-1 elevation → the muscle/bone/recovery/sleep benefits the GH-axis catalog as a whole delivers.
Where they diverge is what else the GHS-R1a hit does, and (for Hexarelin) a second receptor in the picture.
The “potency vs cleanliness” trade-off is the central decision framework for this whole class. Ranking from cleanest profile to dirtiest:
Ipamorelin > GHRP-2 > GHRP-6 ≈ Hexarelin
Ipamorelin was specifically engineered for selective GHS-R1a binding — it triggers the GH-release branch of ghrelin signaling without meaningfully activating the cortisol, prolactin, or hunger branches that the other three do. That selectivity is the reason it became the daily-use default in the GH-axis world. The other three are stronger or have a specific use case, but they bring more off-target signaling along.
The foundational primary literature under this whole class:
- Arvat E et al. 1997: established that GHRP-2 and Hexarelin produced GH responses exceeding the maximal effective dose of GHRH in healthy adults. That’s the canonical study showing the ghrelin-side lever is at least as strong as the GHRH-side lever.
- Laferrere B et al. 2005: established GHRP-2’s appetite-increasing effect cleanly in humans.
GHRP-2 — the strong, workhorse GH lever
Mechanism: Synthetic hexapeptide; binds GHS-R1a in pituitary + hypothalamus.
GH release: Strong — peak plasma GH 30–100 ng/mL within 15–30 minutes (8–20× baseline, depending on dose and individual response). Exceeds the maximum effective dose of GHRH alone on its own.
Off-target profile:
- Cortisol: Moderate — comparable to CRH at standard doses.
- Prolactin: Mild — lower than TRH-induced elevation.
- Appetite: Increased but manageable — not the dominant clinical effect, unlike GHRP-6.
Best use case: GH-axis users who need more potency than Ipamorelin can deliver and are willing to accept mild off-target signaling to get it. Common in advanced GH-stack protocols.
GHRP-6 — the ghrelin-driven hunger peptide
Mechanism: Synthetic hexapeptide; binds GHS-R1a. Carries the full behavioral and hormonal baggage of ghrelin-receptor agonism — including the appetite signal at its strongest.
GH release: Strong at low doses (similar to GHRP-2), but saturates above roughly 1 µg/kg — pushing the dose past saturation gives you more side effects, not more GH.
Off-target profile:
- Hunger: The strongest of any GHRP. Users report intense hunger within 15–20 minutes of injection, lasting 30–60 minutes. This is the dominant clinical effect — most people stop on dose-discovery noticing the hunger before anything else.
- Cortisol: Stronger than GHRP-2, especially above the ~1 µg/kg saturation threshold.
- Prolactin: Moderate at higher doses.
The therapeutic reframe (important). GHRP-6’s hunger effect is usually described as a side effect — but for a specific clinical context, it is the therapeutic mechanism:
- Hard gainers who can’t eat enough to support muscle growth on training.
- Post-surgical recovery patients with nutritional intake problems.
- Mass-building phases where appetite is the rate-limiting factor.
In those contexts, the intense hunger is exactly what you’re paying for. For literally any other use case, GHRP-2 or Ipamorelin is the better-engineered answer.
Hexarelin — the strongest GH pulse + the cardiac wildcard
Mechanism: Synthetic hexapeptide; dual-receptor activity — uniquely:
- GHS-R1a in pituitary + hypothalamus — like all GHRPs, drives the GH pulse.
- CD36 receptor on cardiac tissue — absent in Ipamorelin and GHRP-2. This is Hexarelin’s most distinctive pharmacological feature.
GH release: The strongest in the class — 2–3× the GH release of Ipamorelin / GHRP-2 / GHRP-6 at equivalent doses. Peak GH release at 30–45 minutes post-injection.
Off-target profile:
- Cortisol: Measurable.
- Prolactin: Measurable.
- Desensitization: Fastest of any GHRP. GH response drops noticeably around week 8 of daily administration as the GHS-R1a downregulates. This is the operational ceiling on Hexarelin — you literally can’t run it long enough to get continuous effect; the molecule forces cycling on you.
The cardiac angle — worth knowing, worth verifying carefully. The CD36 receptor on cardiac tissue is the proposed mechanism for Hexarelin’s preclinical cardioprotective effects — improvements in ischemia/reperfusion models, post-MI cardiac function. This is theoretically interesting and could position Hexarelin as a member of a cardiac-protection stack alongside MOTS-c and TB-500 (both with their own cardiac data). The human translation of the CD36 work is not yet established and the safety profile of Hexarelin for chronic cardiac use is unstudied — so this stays in the “interesting class-distinguishing pharmacology” file, not the “established cardioprotective therapy” file.
Best use case: Maximum GH pulse for short, high-intensity cycles. Bodybuilding-style use where the 4–8 week ceiling fits the periodization. Worst case: any attempt at long-term continuous use — the molecule defeats itself.
Real-world protocol
The doses and schedules here are for educational and informational purposes only. These peptides are sold for research use only and are not FDA-approved drugs. This is not medical advice. Consult a qualified physician before beginning any protocol.
Reconstitution math (universal across the three). A 5 mg vial reconstituted with 2 mL bacteriostatic water gives 2,500 mcg/mL. On a U-100 insulin syringe (100 units = 1 mL):
- 100 mcg dose = 0.04 mL = 4 units
- 150 mcg dose = 0.06 mL = 6 units
- 200 mcg dose = 0.08 mL = 8 units
(If you have a 10 mg vial + 2 mL water = 5,000 mcg/mL: halve the units for the same mcg dose.)
GHRP-2 dosing
| Tier | Dose | Frequency | Notes |
|---|---|---|---|
| Beginner | 100 mcg | Once daily before bed | Assess off-target tolerance |
| Intermediate | 150–200 mcg | 2× daily (fasted AM + bed) | Standard “more GH than Ipa” lane |
| Advanced | 200–300 mcg | 2–3× daily | Peak GH lever; cortisol/prolactin tracking advised |
Cycle: 8–12 weeks on / 4–8 weeks off. 5-on / 2-off micro-cycling within a block is the standard receptor-preservation move.
GHRP-6 dosing
| Tier | Dose | Frequency | Notes |
|---|---|---|---|
| Beginner | 100 mcg | 1–2× daily | Hunger arrives within 20 min — plan meals around it |
| Intermediate | 100 mcg | 2–3× daily | Mass-building / hard-gainer lane |
| Advanced | 100–150 mcg | 3× daily | Saturation ceiling ~1 µg/kg — going higher gives more side effects, not more GH |
Cycle: 8–16 weeks on / 4–8 weeks off. The appetite effect persists through the cycle (it doesn’t desensitize the way the GH response does).
Hexarelin dosing
| Tier | Dose | Frequency | Notes |
|---|---|---|---|
| Conservative | 50–100 mcg | 1–2× daily | Test desensitization tolerance |
| Standard | 100 mcg | 2–3× daily | Pre-workout / post-workout / pre-bed timing |
| Aggressive | 200 mcg | 2–3× daily | Bodybuilding lane; short cycles only |
Cycle: 4–8 weeks on / 4 weeks off — strict. The desensitization timeline doesn’t give you a choice. Baseline + mid-cycle bloodwork (prolactin, cortisol, IGF-1) is the standard for cycles longer than 6 weeks.
Timing (universal)
- Empty stomach — eating around the dose blunts the GH response.
- PM dosing rides the natural overnight GH pulse and is the default if dosing once daily.
- Pre-workout dosing is common for the workout-window GH-driven recovery effect.
Stacking — the GHRH side
All three pair with CJC-1295 for the dual-receptor synergy (same logic as CJC-1295 / Ipamorelin):
- CJC-1295 + GHRP-2 — the “max GH” stack for users for whom CJC + Ipa isn’t enough.
- CJC-1295 + Hexarelin — the “advanced potency + theoretical cardiac” stack; short cycles only.
- CJC-1295 + GHRP-6 — for hard-gainer / mass-building contexts where the appetite drive is the goal.
Side effects & management
The class profile is the GH-axis profile (mild flushing, water retention proportional to GH push, possible injection-site reactions, occasional headache) plus the off-target signature that distinguishes each compound:
| Compound | Class-shared | Distinguishing off-target |
|---|---|---|
| GHRP-2 | Mild water retention, flushing | Modest cortisol; mild appetite increase |
| GHRP-6 | Mild water retention, flushing | Intense hunger; stronger cortisol above saturation |
| Hexarelin | Mild water retention, flushing | Measurable cortisol + prolactin; 8-week desensitization ceiling |
Management defaults: start at the low end of the dose range, watch how your body responds for 1–2 weeks before escalating, cycle off as scheduled (don’t push past Hexarelin’s 8-week window), pull bloodwork if you’re running aggressive doses.
Hard contraindications: active malignancy or significant cancer-history concern (IGF-1 is a mitogen), active CHF or significant cardiac dysfunction (water-retention CV strain — the same physiology that ended MK-677 (Ibutamoren)'s elderly hip-fracture trial), uncontrolled diabetes (insulin-resistance signal compounds), pregnancy/breastfeeding, and any tested-athlete context (WADA-banned).
Regulatory status
None of the three are FDA-approved for any indication. All sit in the research-chemical / 503A gray zone. All three are WADA-prohibited and out-of-competition tested for in sport. The peptides themselves are sold internationally as “research compounds” — same regulatory tier as the other unapproved peptides in this wiki.
The Alyve product
None of GHRP-2, GHRP-6, or Hexarelin are in Alyve’s current launch catalog — all three are flagged as roadmap candidates. Per the launch-15 framing, the cleaner GH-axis SKUs (Ipamorelin for the ghrelin lane, CJC-1295 / Sermorelin / Tesamorelin for the GHRH lane, and the CJC-1295 / Ipamorelin blend for the dual-receptor synergy) cover the daily-use mainstream cleanly. The three covered here serve specific advanced use cases — maximum potency (Hexarelin), maximum-GH-without-going-oral (GHRP-2), appetite-as-therapy (GHRP-6) — that map to a smaller, more sophisticated buyer.
If/when they land in the catalog, the natural stack-buy framing would be:
- CJC-1295 + GHRP-2 for the “max GH” stack.
- CJC-1295 + Hexarelin for the short-cycle advanced lane.
- GHRP-6 + protein + adequate lifting for the hard-gainer lane (with BPC-157 / TB-500 for recovery support).
In the meantime, the in-catalog answer at the same receptor — and the better daily-use default for nearly everyone — is Ipamorelin alone or in the CJC-1295 / Ipamorelin blend (in stock, 99.90% Freedom Diagnostics COA, lot CJI583). That’s the cleanest GHS-R1a agonist on the market: GH pulse without the hunger, cortisol, or prolactin baggage of the three peptides covered here.
Offer: Use coupon OHM-15 for 15% off — Alyve’s pricing is very competitive, and buying 3 vials of any given peptide in one purchase gets you over 30% off retail. (Full disclosure: OHM-15 attributes the sale to me — said plainly, as always.)
Sources
- Arvat E, et al. GHRP-2 and Hexarelin exceed max GHRH-induced GH release in humans. J Clin Endocrinol Metab 1997.
- Laferrere B, et al. Growth-hormone-releasing peptide-2 increases food intake in humans.
- Hexarelin CD36 cardiac receptor mechanism and preclinical cardioprotective data.
- Research note — GHRP-2 vs GHRP-6 vs Hexarelin (text aggregation: mechanism, off-target profiles, dose protocols, cycle structures, desensitization timelines).
- One practitioner T. CJC-1295 / Ipamorelin Masterclass — Ipamorelin selectivity vs GHRP-2/6 framing.
- Holyfield. CJC-1295 / Ipamorelin mechanism + timeline — Ipa “no cortisol/prolactin/hunger” framing.
- peptidedeck.com — Hexarelin peptide reference. https://www.peptidedeck.com/peptides/hexarelin-peptide
- peptidepedia.org — GHRP-2 vs GHRP-6 guide. https://peptidepedia.org/guides/ghrp-2-vs-ghrp-6
- Alyve COA summary (no GHRP-2 / GHRP-6 / Hexarelin SKUs — not in launch catalog).
See also: Ipamorelin, CJC-1295, CJC-1295 / Ipamorelin, Sermorelin, Tesamorelin, MK-677 (Ibutamoren), MOTS-c, TB-500.