What can the studies actually tell us?

Was it tested in people?
Cells in a dish and animals can raise research questions. Ask whether the claim being made rests on a study in people.
Was the product used the same way?
A cream, a gel and an injection need their own evidence. Ask exactly what the study tested.
Was the result the same as the claim?
Ask whether the researchers measured a visible change, a lab finding or how participants felt about the product.
Was there a comparison?
Ask what the result was compared with. Keep the study’s limits beside the result, rather than reading the result alone.

Studies in people give limited answers about skin

A 2025 review found unexpectedly little research in people on GHK-Cu wrinkle products.

A 2026 review found that research in people remains limited, with most studies testing face creams in small groups.

Ask for the study in people that supports the exact item being offered.

As of September 2026, a ClinicalTrials.gov search found no listed study testing GHK-Cu injections in people.

ClinicalTrials.gov is the US public list of studies. That dated search does not cover every study that may exist elsewhere.

Read the discussion of studies in people.

Look for the limits described in the opening summary.

The skin measurements and the participants’ satisfaction answered different questions. Read both results before judging a claim.

The search found no listed injection study at that time. Ask whether a newer study in people supports the injection being offered.

Ask what evidence supports each item being offered, along with what it costs.