Peptide serums are difficult to compare because the marketing is dense and the disclosure is thin. This is a short list of what is worth your attention.
Worth comparing
Disclosed concentration
If two products both publish a percentage for the same peptide, that is a genuinely comparable number. It is also the rarest disclosure in the category — most peptide products publish none.
Within the Amplified Glow range, the two copper peptide serums publish 0.15% and 0.1% GHK-Cu respectively, which makes them directly comparable on that attribute. See the side-by-side comparison.
Net contents and price per millilitre
Straightforward and objective, provided you compare same-format products. How to interpret price per ounce covers the traps.
Fragrance status
A binary, checkable attribute that matters to a lot of people. Remember that no statement is not the same as a fragrance-free statement.
Whether a full ingredient list is published
A yes/no attribute, and a good proxy for how much a brand expects you to take on trust.
Not worth comparing
The number of named peptides
A serum naming five peptides is not better than one naming two. Without concentrations, a longer list may mean a more complete formula or may mean five ingredients present at trace levels so they can appear in marketing. The count alone cannot distinguish those.
Marketing descriptors
"Advanced", "clinical-inspired", "science-backed", "multi-peptide complex" — none of these has a definition, so none can be compared. Skip them entirely.
Ingredient research
Two products containing the same peptide are not equivalent, and research about that peptide does not distinguish between them. It is background about the ingredient, not evidence about either product. Every ingredient page on this site says so in its own words — see GHK-Cu for the fullest version.
A worked example
The two Amplified Glow copper peptide serums, on the attributes that are actually comparable:
| Attribute | GHK-Cu + SNAP-8 Renewal Serum | Copper Peptide Renewal Serum |
|---|---|---|
| Disclosed GHK-Cu | 0.15% | 0.1% |
| Net contents | 30 mL | 60 mL |
| Price | $21.00 | $30.00 |
| Price per 100 mL | $70.00 | $50.00 |
| Fragrance status | Fragrance free | Fragrance free |
| Full INCI published | No | No |
Six rows, all checkable, and the comparison does not resolve to a winner — one is better on concentration and total price, the other on cost per millilitre. That is an honest outcome, and it is more useful than a ranking that hides the trade-off.