MK-677 vs NA Semax Amidate
Well Studied vs Well Studied
monitor Mechanism-based · 51% Both MK-677 and NA Semax Amidate can raise blood pressure. Monitor BP regularly and consider adding cardiovascular support (cardarine, telmisartan, or similar).
Molecular Data
MK-677 NA Semax Amidate
Weight 624.77 Da 1,007.16 Da
Half-life ~24 hours 2-10 hours
Chain — 7 amino acids
Type Non-peptide ghrelin receptor agonist Modified ACTH analog
Key Benefits
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)
NA Semax Amidate
01 Direct brain access via olfactory nerves
02 Rapid onset (15-30 minutes)
03 Proven cognitive efficacy
04 Extended half-life vs standard Semax
05 Enhanced BDNF upregulation
Dosing Protocols
MK-677
Start 12.5mg daily, increase to 25mg based on tolerance / Once daily, preferably at bedtime on empty stomach
NA Semax Amidate
600-1200mcg per administration / 1-2x daily for 10-30 days
Research protocol 200mcg 1x daily
Neuroprotection study 400mcg 1x daily
Side Effects
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.
NA Semax Amidate
Mild nasal irritation (intranasal)
Slight headache initially
Contraindications
Heart disease or congestive heart failure
Diabetes or pre-diabetes
Active cancer
Severe cardiovascular disease
Pregnancy or breastfeeding
Not recommended during pregnancy
Active nasal congestion or sinus infection
Individuals on neurotransmitter-affecting medications without consultation
Research Evidence
MK-677 NA Semax Amidate
Status Well Studied Well Studied
References 7 studies 5 studies
Latest July 2024 2025
FDA Approved No No
This comparison is for educational and research purposes only. Consult a healthcare professional before use.