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№ 032

GHRP-2 / GHRP-6

Older growth-hormone boosters and the predecessors to Ipamorelin. These GH secretagogues split two ways: GHRP-2 is the cleaner, GHRP-6 brings stronger appetite stimulation.

GH-axis
Evidence: Limited

GHRP-2 / GHRP-6: Older growth-hormone boosters and the predecessors to Ipamorelin. These GH secretagogues split two ways: GHRP-2 is the cleaner, GHRP-6 brings stronger appetite stimulation. GHRP-2 and GHRP-6 are older GH-axis peptides, the predecessors to Ipamorelin.

FDA ⓘ
Not approved
WADA
Banned
Typical dose
100-300 mcg sub-q
Half-life ⓘ
~15-30 minutes
Route ⓘ
Subcutaneous
Schedule
1-3x daily
In plain English

GHRP-2 and GHRP-6 are older GH-axis peptides, the predecessors to Ipamorelin. They tell your body to release more growth hormone, but with rougher side effects (cortisol bumps for GHRP-2, big appetite spikes for GHRP-6). Most people now run Ipamorelin instead, but these are cheap and well-studied.

Status & legalityWhat do these mean? →
Natty? ⓘ
Not natty
FDA ⓘ
Not approved

Not FDA approved.

Compounding ⓘ
Category 3

FDA has published safety concerns for both of these under its 503B policy, which the 503A category does not show. For GHRP-2 that listing is specific to injectable and nasal routes: risk of immunogenicity from aggregation and peptide impurities, an unnatural amino acid that complicates characterization, and reports of serious adverse events including increased insulin requirement, infection, pancreatitis and deaths among critically ill study subjects, with causality not established. GHRP-6 is listed without a route qualifier, for immunogenicity by certain routes plus effects on cortisol and raised blood glucose from reduced insulin sensitivity. Under 503A both sit in Category 3: nominated without enough supporting information for FDA to evaluate them, which leaves them outside FDA's Category 1 interim policy.

WADA ⓘ
Banned (S2)
Prescribed ⓘ

Not prescribed in conventional medicine.

Who it's for

  • →Users wanting older, well-characterized GH secretagogues
  • →GHRP-6 specifically: people in a bulk who want appetite stimulation
  • →GHRP-2: cleaner profile users who tolerate cortisol bumps

What to expect

  1. Week 1

    GH pulse and (with GHRP-6) appetite kick within hours of first dose.

  2. Week 4

    Cumulative recovery and sleep improvements. Bulkers see appetite-driven gains.

  3. Week 8

    IGF-1 measurably higher. Receptor desensitization starting, cycle off soon.

Looking at GHRP-2 / GHRP-6? Your next 3 steps

  1. 1Work out your syringe units

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How it works (mechanism)

Hexapeptide GH secretagogues that activate the ghrelin receptor (GHS-R1a). GHRP-2 has cleaner signaling than GHRP-6 but less appetite stimulation; GHRP-6 retains stronger ghrelin-mimetic effects on hunger.

Dosing protocol

Members only

Stacks well with

Members only

Side effects

01GHRP-6: aggressive hunger 30-60 min post-dose
02GHRP-2: cortisol and prolactin bumps
03Head-rush at injection
04Receptor desensitization with chronic use

When NOT to use

  • ⚠Active malignancy
  • ⚠Pregnancy / nursing

Bloodwork to monitor

  • • IGF-1 baseline + week 8
  • • Prolactin if running >8 weeks (GHRP-2)

Common mistakes

  • • Treating them as Ipamorelin equivalents, they have meaningful side effect differences
  • • Eating within 30 min of injection (kills the GH pulse)
  • • Skipping cycle breaks

What it actually is

GHRP-2 and GHRP-6 are the original growth hormone releasing peptides, developed in the 1980s and 1990s and the direct ancestors of ipamorelin. They are grouped here because people choose between them for one reason: GHRP-6 causes overwhelming hunger and GHRP-2 largely does not, while GHRP-2 raises cortisol and prolactin more. Neither is approved, and both are detectable in anti-doping testing.

Both activate the ghrelin receptor on the pituitary to trigger growth hormone release, the same mechanism as ipamorelin and hexarelin. Where they differ is selectivity. Ghrelin's receptor also drives appetite, and GHRP-6 hits that arm hard — the hunger is not a side effect so much as the mechanism showing through. GHRP-2 produces a comparable growth hormone pulse with much less appetite effect, at the cost of more cortisol and prolactin. Ipamorelin was the attempt to get the pulse without either problem.

Forms, and which is which

GHRP-6People who want the appetite

Strong hunger 30 to 60 minutes after dosing. Useful in a mass-gain phase, actively counterproductive in a cut.

Verdict: Choose it for the hunger or avoid it because of the hunger.

GHRP-2The pulse without the hunger

Much less appetite stimulation, more cortisol and prolactin rise than GHRP-6.

Verdict: A different trade, not a strictly better one.

IpamorelinAvoiding both problems

The selective successor: minimal cortisol, prolactin and appetite effect.

Verdict: The reason these two are largely historical.

Nasal preparationsAvoiding injection

Studied enough that metabolite detection after nasal administration has been published, but absorption is erratic and the delivered dose is not the labelled one.

Verdict: Documented to reach the body, and not in a predictable amount.

What it is claimed to do, graded

Trigger a growth hormone pulseModerate

Established for the class in human work going back to the 1990s, though only one randomised trial and two human trial records are indexed under these specific names.

GHRP-6 stimulates appetiteModerate

Reliable and mechanistically expected. Whether it is a benefit depends entirely on what you are trying to do.

Improve body compositionNone shown

No controlled human trial demonstrates fat loss or muscle gain from either.

Improve sleepNone shown

Commonly reported, untested in a controlled trial for these compounds.

Are cleaner than modern secretagoguesNone shown

The reverse is the documented position: ipamorelin exists because these two raise cortisol, prolactin or appetite in ways people did not want.

Grades describe how much human evidence exists for that specific claim, not whether it will work for you or whether it is safe.

Pros and cons

Pros
  • • Long history of human use, so the practical side-effect picture is well described
  • • GHRP-6's appetite effect is genuinely useful in a mass-gain phase
  • • Short half-lives mean mistakes clear fast
  • • Cheap and widely available
Cons
  • • Superseded by ipamorelin for good reasons — cortisol, prolactin or appetite depending on which you pick
  • • One randomised trial indexed under these names
  • • Never approved
  • • Detectable in anti-doping testing, with published urine assays
  • • Receptor desensitisation with continuous use

When to stop

  • • Prolactin symptoms: breast tenderness, low libido, mood change
  • • Fasting glucose drifting up across cycles
  • • The effect fading — that is desensitisation, and more dose will not fix it
  • • Any new cancer diagnosis

Interactions

Other ghrelin-receptor agonists (ipamorelin, hexarelin, MK-677)Avoid

Same receptor, redundant, and it accelerates desensitisation.

A GHRH analog (CJC-1295, sermorelin)Compatible

Different receptor, complementary mechanism. This is the intended pairing.

Food near the doseTiming

Elevated glucose and insulin blunt the pulse.

A calorie deficit, with GHRP-6Caution

The appetite stimulation makes maintaining a deficit substantially harder.

Dopamine agonistsMonitor

Sometimes added against GHRP-2's prolactin rise, which is managing a side effect rather than avoiding it.

Is this for you?

Probably worth reading further if
  • • People in a mass-gain phase who want GHRP-6's appetite effect deliberately
  • • Anyone pairing a GHRP with a GHRH analog and checking IGF-1 to see whether it did anything
Skip it if
  • • You are cutting and considering GHRP-6
  • • You have elevated prolactin or cortisol
  • • You have active cancer
  • • You are drug-tested in sport — these are specifically detectable

The one number

1 randomised trial indexed under these names, and published urine assays for anti-doping detection
Pepdex evidence index, PubMed; Drug Test Anal 2015 (PMID 25809000)

Sources for the claims above

Community patterns

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AI Coach, live sample
Member answer
is 250mcg of bpc enough for a knee injury?
For a knee, is the standard working dose and a solid place to start. The trick with BPC is consistency, give it weeks, not days. , run it , and don't drop below , results tend to fall off under that line. If nothing's moved by week 3, that's when earns its place.
how much bac water for a 10mg reta vial?
is the standard play for a 10 mg reta vial. That gives you , clean unit math across the whole titration: on a 100-unit insulin syringe. Run instead if you want fewer, more concentrated shots. Most people titrate up over , and that mix keeps the numbers cleanest.
what should i track on bloodwork for tirzepatide?
Lipid panel, ALT/AST (liver enzymes), and an A1C, baseline before you start then every 3 months. If you've got metabolic-syndrome history, add fasting glucose and insulin so you can actually watch insulin sensitivity improve. You don't need a big hormone panel for a GLP-1.

Numbers redacted in this preview. Members get the full answer, on their own stack.

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Frequently asked

What is GHRP-2 / GHRP-6?+
GHRP-2 and GHRP-6 are older GH-axis peptides, the predecessors to Ipamorelin. They tell your body to release more growth hormone, but with rougher side effects (cortisol bumps for GHRP-2, big appetite spikes for GHRP-6). Most people now run Ipamorelin instead, but these are cheap and well-studied.
Is GHRP-2 / GHRP-6 FDA approved?+
Not FDA approved.
Is GHRP-2 / GHRP-6 legal?+
GHRP-2 / GHRP-6 is not FDA-approved, so there is no approved prescription version. Most supply is sold as "research only" by peptide vendors. A compounding pharmacy may only use substances the FDA permits for compounding, and many research peptides are not permitted — do not assume a compounded prescription is available. Possession is generally not criminalized but distribution without authorization may be. Verify local laws.
Is GHRP-2 / GHRP-6 banned by WADA?+
GHRP-2 / GHRP-6 is on the WADA prohibited list under Banned (S2).
Are you still natty after taking GHRP-2 / GHRP-6?+
No. GHRP-2 / GHRP-6 is a performance-enhancing peptide and would disqualify a strict natty claim.
Do doctors prescribe GHRP-2 / GHRP-6?+
Not prescribed in conventional medicine.
What's the typical dose of GHRP-2 / GHRP-6?+
Dosing depends on your goal, experience, and tolerance. The full GHRP-2 / GHRP-6 protocol (dose, frequency, and how to titrate) is in the members section on the entry page.
What are the side effects of GHRP-2 / GHRP-6?+
Common side effects include: GHRP-6: aggressive hunger 30-60 min post-dose; GHRP-2: cortisol and prolactin bumps; Head-rush at injection; Receptor desensitization with chronic use. Less common effects and full safety details are on the entry page.
How long until GHRP-2 / GHRP-6 starts working?+
GH pulse and (with GHRP-6) appetite kick within hours of first dose.
What can you stack with GHRP-2 / GHRP-6?+
GHRP-2 / GHRP-6 is commonly combined with complementary compounds. The full stacking protocol (what to pair, dosing, and timing) is in the members section on the entry page.
Where do people get GHRP-2 / GHRP-6?+
Pepdex does not sell, ship, or recommend suppliers. GHRP-2 / GHRP-6 is not FDA-approved; prescription versions require licensed clinical care, and "research only" markets carry real legal and quality risks. /coa explains how to verify a Certificate of Analysis and /guides/scam-vendor-spotting covers the red flags.

Common questions about GHRP-2 / GHRP-6

Tracked alongside GHRP-2 / GHRP-6

Same goal, different aisle — each graded on its own evidence in the Pepdex catalog.

MK-677 →
the oral secretagogue these peptides get compared to constantly
Creatine →
the strongest-evidence performance supplement in the catalog
Glycine →
sleep quality drives GH pulses; this is the benign first option
Melatonin →
same reason — the sleep window is the GH window

More in GH-axis

№ 022
HGH (Somatropin)

Recombinant human growth hormone, the protein itself, not a peptide that nudges your body to make more. Highest legal-risk compound in this catalog.

№ 012
MK-677 (Ibutamoren)

Oral ghrelin mimetic. Bumps GH and IGF-1 without injections. Strong appetite stimulation is the trade-off.

№ 007
Ipamorelin

Bumps your natural growth-hormone pulses without hitting cortisol or prolactin. A selective GH secretagogue.

№ 008
CJC-1295 (no DAC)

Pairs with Ipamorelin to amplify your natural growth-hormone pulses. A GHRH analog whose 'no-DAC' version stays short-acting on purpose.