Ask what the percentage measures

A front-label number is incomplete until you know its denominator and the material being counted. It might describe a named active, a supplier complex containing carriers or a combination of several technologies. The phrase 30% complex does not establish 30% pure peptide material. Neither does a larger number demonstrate a larger visible result.

Write the claim exactly before simplifying it. If a manufacturer says multi-peptide complex, keep that wording in your comparison. Replacing it with pure peptides changes the meaning and can create a false impression of concentration.

Compare like material with like material

The Ordinary’s Matrixyl 10% + HA, its copper serum and Medik8’s Advanced MP use different descriptions of their peptide systems. NIOD separately identifies 1% GHK-Cu and 1% GHK in CAIS3. Those figures should not be arranged on a single strength ladder or added together as if they all measured copper peptide.

Even two labels mentioning copper may concern different complexes or modified molecules. A meaningful concentration comparison needs the same identified substance and a clear basis of measurement. If that information is absent, the honest comparison is qualitative rather than numerical.

A hypothetical blend shows the arithmetic problem

Imagine a supplier solution that contains a small amount of peptide within a much larger carrier mixture. Adding 10% of that solution to a formula would not make the finished product 10% pure peptide. The amount of actual peptide would depend on its concentration in the supplied solution.

This example explains the ambiguity; it is not a claim about the undisclosed composition of any reviewed brand. Do not use it to invent a hidden concentration. If the manufacturer does not provide the needed information, leave the pure-peptide percentage unknown.

Concentration is not a complete performance score

A finished formula also involves the vehicle, stability, packaging, application and the outcome being evaluated. Increasing one component does not establish a proportional increase in benefit. A small concentration used in a well-defined trial can be more informative than a dramatic number without relevant testing.

A controlled study of a particular palmitoyl pentapeptide moisturizer illustrates why the exact preparation matters. Its result belongs to that intervention and comparison. It should not be used to infer that every formula with a larger percentage, or even a similarly named peptide, must work better.

Questions that protect a useful comparison

Ask whether the number refers to pure material or a supplied blend, whether it is by weight and which exact peptide is included. For a compounded product, request the supplied formulation details from the prescribing or dispensing team rather than relying entirely on a short marketing panel.

Then move back to the actual purchase: format, complete ingredients, evidence, instructions and cost. A percentage can add transparency when explained clearly. It should remain one piece of information, not a score that overrides everything else you know about the product or a promise of a particular level of skin improvement.

Sources & further reading

Official pages and evidence consulted for this article. Checked October 11, 2026. Provider pages establish advertised terms; they do not independently establish effectiveness.

  1. The Ordinary: Matrixyl 10% + HA, US Manufacturer
  2. The Ordinary: Multi-Peptide + Copper Peptides 1% Serum, US Manufacturer
  3. Medik8: Liquid Peptides Advanced MP, US Manufacturer
  4. NIOD: Copper Amino Isolate Serum 3 1:1, US Manufacturer
  5. Robinson et al.: 12-week randomized pal-KTTKS moisturizer study, 2005 Primary research
  6. CoreAge Rx: Bounce Back current product and plan Manufacturer