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Disclosure: We earn a commission from vendors on this page. Rankings are based on objective criteria including price, COA availability, and reputation.

Best NSI-189 Vendors of 2026

Ranked by Price, Purity, and Reputation

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Quick Comparison

1Swiss ChemsShips WorldwideCOA
10/10
20mg$2.00/mg

Bulk Pricing

Per-vendor quantity breaks — pick a vial size to see the bulk price. Must purchase the full pack.

Swiss ChemsCOA
as low as $0.033/mg
$39.9920mg × 60$0.033/mg
View at Swiss Chems

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How We Score Vendors

Our scoring is based on three weighted factors:

Price Competitiveness (40%)

Normalized to cost per milligram for fair comparisons across vial sizes.

COA Availability (30%)

Third-party lab testing confirming purity, identity, and absence of contaminants.

Vendor Reputation (30%)

Community feedback, shipping reliability, customer service, and business track record.

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