Scoring a vendor instead of trusting a vibe
There are dozens of peptide vendors online. Most of them look identical: clean site, confident copy, a testimonial section, a discount code.
The scorecard separates them. Rate each vendor on eight criteria. Score 6 or higher out of 8 to proceed. Below 6, find another source.
The eight criteria
1. Third-party COA for every batch: not in-house testing, and not a COA for one representative batch. Every batch.
2. HPLC purity ≥98% consistently across batches: one good result is a data point. Consistency across batches is a manufacturing process.
3. Endotoxin testing included in the COA: the most commonly omitted test, and the one that matters most for anything injectable.
4. Real company information: a physical address, a working support contact, a return policy. A company that cannot be reached cannot be held to anything.
5. Consistent stock availability: not random in-and-out. Erratic stock suggests a reseller buying whatever is available rather than a supplier with a stable manufacturing relationship.
6. Community reputation over months, not days: verified reviews and forum discussion with a history. A wave of positive reviews inside two weeks is a marketing campaign, not a track record.
7. Transparent about regulatory status: does not claim FDA approval for compounds that do not have it. A vendor willing to lie about regulatory status will lie about other things.
8. Batch-to-batch consistency: COA results stable over time. Purity that swings between 91% and 99% across lots indicates a process that is not under control.
Why the threshold is 6 and not 8
Because a perfect score is rare and waiting for it means never buying anything. Six out of eight means the fundamentals of testing, identity and contamination are covered even if the softer criteria are not.
But note which criteria are load-bearing. A vendor scoring 6 by failing on stock availability and community reputation is different from a vendor scoring 6 by failing on endotoxin testing and batch consistency. Use judgement about which two you are willing to lose.
The quality markers that map onto this
Our beginner's guide states the same standard from the buyer's side:
- Third-party COAs on every batch showing HPLC purity ≥98% and MS identity confirmation
- US-based GMP manufacturing: Good Manufacturing Practice standards ensure consistency
- Endotoxin testing confirming absence of bacterial contamination
- Cold-chain shipping, because peptides degrade without refrigeration in transit
- Published COAs: vendors who hide their testing results are a red flag
The economics
A contaminated or underdosed peptide is not a partial result. It is a wasted cycle, a wasted month, and no way to interpret what happened.
If a compound does not work, you need to know whether that is because the compound does not work for you or because the vial contained 60% of what the label claimed. Sourcing rigour is what makes your own results interpretable.