GHRP-6 vs MK-677: side-by-side comparison
Growth Hormone Releasing Peptide 6 · Growth Hormone Releasing Hexapeptide · SK&F 110679
A synthetic hexapeptide ghrelin mimetic that was one of the first GH secretagogues developed. Stimulates growth hormone release through the GHS-R1a receptor. Known for causing intense appetite stimulation (the "hunger peptide"), which can be beneficial for bulking but problematic for cutting. Less selective than GHRP-2 with higher cortisol and prolactin elevation.
Ibutamoren · MK677 · Nutrobal
An oral ghrelin mimetic that stimulates GH pulses. Technically not a peptide but a non-peptide agonist of the ghrelin receptor that increases growth hormone and IGF-1 levels.
4 / 10 natty scale / 4
Same lane
Both sit in the same class and are run for bulking, recovery. This is a like-for-like comparison: read the gaps as real trade-offs.
The tape
Core ratings
The same three rulers every entry on the site is scored with, read head to head.
Natty scale
1 natural · 10 heavy
Effectiveness
Documented effect · of 5Δ0.5
Side-effect severity
Documented burden · of 5Δ0.5
Cost side
Body-load fingerprint
Where each one actually lands its strain, on the calculator's thirteen channels. Tap a row for what it means and which labs track it.
Cardiometabolic
Organ strain
Hormonal
Systemic
Injection & site care
Bars show strain at each one's typical protocol, not your dose. ≈ marks values inferred from side-effect data or category rather than hand-graded. For your numbers, run the calculator.
Logistics
The vitals
Benefit side
What each is for
Shared goals carry both dots; a goal with one dot belongs to that side alone.
Run for
Documented upside
- Slightly higher peak GH levels than GHRP-2
- Powerful appetite stimulation for bulking/hard gainers
- Lower receptor affinity than hexarelin means slower/milder desensitization at standard saturation doses
- Synergistic when combined with GHRH peptides
- Well-studied with extensive research data
Run for
Documented upside
- Oral administration (no injections)
- Improved sleep quality
- Increased appetite
- Elevated IGF-1 levels
- Enhanced recovery
The downsides
Side effects, aligned
Each entry's documented side effects, sorted onto the same body systems so the gaps and the overlaps are visible. Tap any effect for the detail.
None documented
None documented
None documented
None documented
The exit
Hormonal fallout & recovery
What each does to your own hormone axis while on, and what leaving it costs.
GHRP-6
Does not affect HPT axis. No PCT required.
MK-677
Does not suppress testosterone. No PCT required.
Read-out
How they separate
- 01
Enhancement
They land at almost the same point on the natty scale (4/10 vs 4/10): a similar distance beyond natural.
- 02
Side-effect bill
MK-677's documented side-effect severity is heavier (3/5 vs 2.5/5). The body-load fingerprint above shows where that weight actually lands.
- 03
Body load
The widest gap at typical protocols is prolactin (GHRP-6 4/10 vs 0/10), then kidney load (MK-677 2.8/10 vs 0/10).
- 04
Coming off
Neither requires PCT: both leave the natural testosterone axis running.
- 05
Logistics
GHRP-6 runs as subcutaneous, MK-677 as oral; typical runs are 4-12 weeks vs 8-12 weeks.
- 06
Tested athletes
Both are WADA-prohibited: neither belongs anywhere near tested competition.
Generated from each entry's data file. Descriptive, not a recommendation; nothing here is medical advice.