Every roundup on SerumScience follows the same method so that our ratings mean something and can be compared across articles. Here is exactly how we evaluate a peptide serum.
Our four criteria
- Formula transparency. Is the peptide named specifically (e.g. copper tripeptide-1, palmitoyl pentapeptide-4)? Is a concentration disclosed? A clear label scores higher than a vague “peptide complex.”
- Peptide alignment. Does the supporting formula make cosmetic sense — helpful humectants, sensible pH, minimal needless fragrance?
- Texture & layering. We use each product for several weeks and assess how it feels, how fast it absorbs, and whether it plays well under moisturiser and sunscreen.
- Value. Price measured against what is actually in the bottle — not just the sticker.
What our ratings mean
Scores are out of 5 and are SerumScience editorial ratings assigned by our reviewer, Mara Ellison. They are not aggregated customer star counts and they are not supplied by brands. A 4.5 means we would happily recommend and re-buy it; anything we would not use ourselves does not make the list.
How we source products
We buy products ourselves or use editorial samples, and we disclose affiliate links on every roundup (see our disclosure). Sampling a product does not earn it a higher score — the criteria above are applied identically to everything.
What we will not do
We do not fabricate before/after results, quote live prices that go stale, or make medical claims. Any imagery is representative. SerumScience covers cosmetic skincare only and never advises on injectables or dosing.