This page compares QSC and Core Peptides as research compound suppliers for MK-677 (Ibutamoren). Both suppliers offer MK-677 for research use. Key differentiators are purity verification methodology, batch documentation, shipping coverage, and catalog depth.
Side-by-Side Comparison
Factor
QSC
Core Peptides
Purity verification
QSC: Janoshik third-party independent COA — every batch
Core Peptides: typically in-house or unspecified third party
HPLC standard
QSC: ≥99% HPLC confirmed
Core Peptides: purity claim varies by batch
MS identity verification
QSC: Every batch — molecular identity confirmed by mass spectrometry
Core Peptides: not always documented per batch
Shipping regions
QSC: USA · EU · UK · Canada · Australia — domestic fulfilment in each
Core Peptides: narrower catalog in most categories
Compound availability
QSC: MK-677 available in multiple dose configurations
Core Peptides: availability and dosing may differ
Why Researchers Choose QSC for MK-677
The Janoshik COA is QSC’s primary differentiator. Janoshik Analytical is an independent Czech Republic testing laboratory that publishes results publicly. Every QSC batch is submitted externally — researchers can verify the COA is genuine and view results from the same independent lab. This is a higher standard than in-house QC.
QSC also stocks 99 compounds — the broadest research catalog available, covering peptides, SARMs, GLP-1 agonists, longevity compounds, oral steroids, and novel compounds like survodutide, mazdutide, and orforglipron that most competitors do not carry.
