LL-37 vs MK-677
Well Studied vs Well Studied
synergistic Mechanism-based · 47% LL-37 and MK-677 work through complementary pathways. Growth hormone signaling supports tissue repair processes. A well-established combination in recovery protocols.
Molecular Data
LL-37 MK-677
Weight — 624.77 Da
Half-life Short (rapid proteolytic degradation) ~24 hours
Chain 37 amino acids —
Type Cationic antimicrobial peptide Non-peptide ghrelin receptor agonist
Key Benefits
LL-37
01 Direct wound healing acceleration
02 Broad-spectrum antimicrobial activity
03 Activity against resistant bacteria (MRSA, MDRPA)
04 Enhanced tissue regeneration
05 Immune modulation
06 Local antimicrobial protection
MK-677
01 97% increase in 24-hour growth hormone secretion
02 40-72% elevation in IGF-1 levels
03 Enhanced sleep quality with improved REM patterns
04 Preferential lean tissue gains of 1.1-2.7kg over 8-12 months
05 15% basal metabolic rate increase within 2 weeks
06 Oral administration (no injections required)
Dosing Protocols
LL-37
0.5-1.6 mg/mL topical gel or 100-150 mcg injectable / Topical: Daily to twice weekly on wounds. Injectable: Once daily subcutaneous
Systemic immune support 100-150mcg Once daily
MK-677
Start 12.5mg daily, increase to 25mg based on tolerance / Once daily, preferably at bedtime on empty stomach
Side Effects
LL-37
Generally well-tolerated
Mild injection site reactions (injectable)
Local irritation at application site (topical)
MK-677
Appetite stimulation (>50% of users)
Water retention (30-40%)
Lethargy (20-30%)
Fasting glucose elevation (5-15mg/dL)
Note on testosterone suppression: at doses up to 20 mg daily, MK-677 is unlikely to cause significant testosterone suppression on its own. Above 20 mg daily, the likelihood of suppression and other side effects (insulin resistance, water retention, lethargy) increases. The case report documenting 85.7% testosterone suppression involved co-administration with LGD-4033, a SARM known to be profoundly suppressive, making the SARM the likely primary driver of that suppression.
Contraindications
Pre-existing hypersensitivity to peptides
Compromised immune status (relative contraindication)
Non-sterile wound environments
Heart disease or congestive heart failure
Diabetes or pre-diabetes
Active cancer
Severe cardiovascular disease
Pregnancy or breastfeeding
Research Evidence
LL-37 MK-677
Status Well Studied Well Studied
References 4 studies 7 studies
Latest 2025 July 2024
FDA Approved No No
This comparison is for educational and research purposes only. Consult a healthcare professional before use.