PeptidePros

Compare · Head-to-head

GHRP-6 vs MK-677.

Evidence, risk, regulatory flags, cost, and vendor coverage compared side by side. We don’t sell peptides — we help you choose between them.

Which should you research first?

Start with GHRP-6, then use the table to confirm fit.

GHRP-6 is the cleaner first read based on the current evidence, risk, and regulatory data stored for this pair. The right answer can still change if your goal, sport testing status, vendor constraints, or monitoring tolerance makes the other option a better fit.

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01· Subject

GHRP-6

GH secretagogue with phase I PK data in humans. FDA has flagged compounding safety concerns.

Tier Bhigh risk

02· Subject

MK-677

Oral ghrelin-receptor agonist used as a GH secretagogue in research and bodybuilding markets.

Tier Cmed-high risk

01 · At a glance

Decision factorGHRP-6MK-677
Primary fitmuscle growth & strength and fat loss & metabolism comparisonsmuscle growth & strength and longevity & anti-aging comparisons
EvidenceTier BTier C
Riskhighmed-high
Experience levelintermediateadvanced
Budget tiermidmid
Administration routeintravenous, subcutaneousoral

02 · Use case & timing

Decision factorGHRP-6MK-677
Goal fitMuscle Growth & Strength, Fat Loss & Metabolism, GH Axis OptimizationMuscle Growth & Strength, Longevity & Anti-Aging, GH Axis Optimization
What users compare it forGH-axis stimulation; appetite stimulation commonly reported.Increased GH/IGF-1 signaling, appetite rise, and potential lean-mass increase in some human studies.
Onset timelineAcute GH response after IV dosing; PK shows hours-scale elimination.GH rises acutely; IGF-1 and body-composition effects are tracked over weeks to months.
Main tradeoffEvidence is stronger than most compounds in this category, but route, side effects, and vendor fit still matter.Evidence and product availability can still be uneven, so documentation matters more than hype.

03 · Safety & restrictions

Decision factorGHRP-6MK-677
Adverse effectsImmunogenicity/impurity concerns (FDA); cortisol effects; decreased insulin sensitivity; glucose metabolism risk.Edema, increased appetite, insulin resistance, elevated fasting glucose, joint discomfort, and possible cardiovascular safety concerns.
ContraindicationsNo formal label.Use caution in diabetes, insulin resistance, edema-prone states, heart failure risk, and active malignancy.
Interaction notesFlag glucose metabolism risk and endocrine-axis spillover as monitoring concerns.Combining with other GH-axis compounds increases endocrine complexity and may worsen glucose control.
Regulatory statusNot approvedNot approved
FDA flagFDA compounding cautionFDA compounding caution
WADA statusWADA S2WADA S2

04 · Age & monitoring

Decision factorGHRP-6MK-677
Supported age rangesNo age guidance yet25-34, 35-44, 45-54
Life-stage noteNot yet documentedMost often discussed for younger and midlife adults, but metabolic and fluid-retention risks narrow the fit quickly with age.
Monitoring burdenNot specifiedhigh
Follow-up cadenceNot yet documentedMore frequent early follow-up, then reassessment every few months if continued.

05 · Cost & sourcing

Decision factorGHRP-6MK-677
Typical cycle cost€35.76No reliable estimate yet
Estimated monthly cost€17.88No reliable estimate yet
Cost confidenceHigh confidenceNo estimate

06 · Before you buy

Decision factorGHRP-6MK-677
Tracked vendor listings1 listing0 listings
Sourcing noteTracked product pages are available, which makes it easier to review the listing before you click out.No tracked product page yet, so sourcing takes more manual review.
Stack-friendly?Usually stack-friendlyUsually stack-friendly

Sources and review notes

  1. Certain Bulk Drug Substances for Use in Compounding that May Present Significant Safety Risks - U.S. Food and Drug Administration - accessed 2026-05-15

    Used for FDA compounding-risk context and peptide safety flags.

  2. The Prohibited List - World Anti-Doping Agency - accessed 2026-05-15

    Used for athlete-facing WADA risk and peptide-class restrictions.

  3. Peptide therapeutics: current status and future directions - PubMed / Nature Reviews Drug Discovery - accessed 2026-05-15

    Used for broad peptide-therapeutics background and evidence framing.

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