Best Peptide Vendors 2026: Who's Still Shipping After the Shutdowns

After the shutdown of Peptide Sciences (March 2026), Science.bio (January 2026), and Amino Asylum (June 2025), the pool of reputable research peptide vendors has narrowed considerably. This guide ranks what to look for in the vendors that remain.

What Changed in 2024–2026

The research peptide landscape consolidated rapidly. FDA warning letters hit Prime Peptides, SwissChems, and Xcel Peptides in December 2024. The ITC issued exclusion orders against tirzepatide importers. Amino Asylum was raided. Then the two largest vendors — Peptide Sciences and Science.bio — both went offline within three months of each other. See our full shutdown timeline.

How to Evaluate the Remaining Vendors

The vendors that survived the 2024–2026 enforcement wave share common traits. Every criterion below should be verified before placing an order:

1. Third-party COAs on every product page. The COA must be available upon request, without creating an account. It must include HPLC chromatogram (visual trace, not just a purity percentage), mass spectrometry identity confirmation, batch-specific lot number, and the name of the independent testing laboratory.

2. Zero therapeutic claims. Any vendor that uses words like "treats," "heals," "cures," or "for weight loss" is positioning products as drugs. This is the pattern that triggered every FDA warning letter and shutdown in 2024–2026.

3. ≥98% HPLC purity, ideally ≥99%. Lower purity often indicates incomplete synthesis or degradation. Premium vendors consistently deliver ≥99% across their catalog.

4. US-based operations with real contact information. A physical address, responsive support, and a documented compliance policy. Anonymous vendors operating through a web form are higher risk.

5. Payment flexibility. The best vendors in 2026 accept credit and debit cards — not just cryptocurrency. Card acceptance requires passing payment processor compliance reviews, which is itself a signal of legitimacy.

For the complete evaluation framework, see our vendor checklist guide.

Common Red Flags

Prices 40–50% below market. Peptide synthesis has a real cost floor. Deep discounts usually mean underdosed product, impure synthesis batches, or relabeled raw material without proper QC.

"Former [Vendor] inventory." After Science.bio closed, several resellers claimed to be selling their remaining stock. There is no way to verify chain of custody, storage conditions, or purity of transferred inventory. Buy from vendors who synthesize and test their own batches.

No reviews or all reviews are identical. Fabricated review sections are common. Look for specific, varied reviews that mention actual products and experiences.

Pepta Labs — How We Compare

Pepta Labs was built for the post-2024 regulatory environment. Every compound meets a ≥99% HPLC purity standard verified by an independent third-party lab. Full COAs are available upon request from every product page before purchase. We now accept credit and debit cards at checkout alongside Cash App, Venmo, Zelle, Bitcoin, and Ethereum. All products carry RUO labeling with zero therapeutic claims. See our Compliance Policy.