DIY GHK-Cu serum at home: what the science actually supports

What did @melbournecitygirl actually say?

She dissolved a vial of GHK-Cu peptide in what she called "backwater" (likely bacteriostatic water), then mixed the solution with rose water or a leftover serum, poured it into a small glass jar, and applied it to her face and chest. She described the result as "liquid gold" and said she ditched her expensive skincare entirely in favor of this homemade mix. She's using GHK-Cu both topically and, as she mentions offhand, "internally" — which presumably means injection, though she doesn't detail her injection protocol here. She also made a version for her mother, who is "scared to inject," using rose water as the carrier instead of a commercial serum.

The video is essentially a formulation tutorial with zero measurements, no sterility discussion, and no acknowledgment that handling injectable-grade peptides outside a clinical or at least informed DIY framework carries real risks.

Does the science back this up?

GHK-Cu (copper tripeptide-1) does have a genuinely interesting research base for skin applications, so she's not making things up from scratch. But the home formulation method she describes has real scientific problems.

GHK-Cu has been studied for collagen synthesis stimulation, wound healing, and antioxidant activity. Pickart and Margolina (2018, Cosmetics) reviewed evidence that GHK-Cu upregulates collagen, elastin, and glycosaminoglycan synthesis in skin fibroblasts, and reduces oxidative damage. That's a real finding. Topical GHK-Cu is also an ingredient in commercially formulated products, so the concept of applying it to skin isn't fringe.

The problems start when you look at what she's actually doing. Peptide stability is highly pH- and temperature-sensitive. Mixing a reconstituted peptide with rose water, which has a pH around 5.5 and contains organic compounds that can introduce microbial contamination, is not a neutral act. Bacteriostatic water keeps a reconstituted peptide stable for a window of time under refrigeration. Diluting that into an unpreserved, unsterile carrier like rose water or a used serum dramatically accelerates degradation and increases contamination risk. There's no preservative system here, no measured concentration, and no evidence the mixture actually delivers meaningful peptide to viable skin layers.

What did they get wrong (or right)?

She gets partial credit for the underlying concept. GHK-Cu is one of the more evidence-backed cosmetic peptides. It's in commercial formulations for a reason, and the idea that topical application can support skin quality is not baseless. Pickart et al. have published repeatedly on its mechanism, and it's not a random TikTok invention.

What she gets wrong is almost everything about execution.

• "One meal of backwater" — she means bacteriostatic water, but the volume is unspecified, so there's no way to know the concentration she or her mother is applying.
• Mixing into rose water or a "leftover serum" introduces contamination risk and likely degrades the peptide faster than she realizes. Leftover serum, once opened, has a compromised preservative system.
• There's no mention of patch testing, no mention of skin barrier status, and copper peptides can cause irritation or paradoxical skin effects at high concentrations (Gorouhi and Maibach, 2009, International Journal of Cosmetic Science).
• The claim that she "ditched all expensive skincare" for this is the kind of sweeping statement that could lead followers to drop evidence-based routines like SPF — which would be a net negative regardless of what GHK-Cu does.

The offhand mention of using GHK-Cu "internally" in the same breath as a beauty tutorial normalizes injection of research peptides without any safety framing. That's a meaningful problem in a 92K-view video.

What should you actually know?

GHK-Cu is a legitimate area of cosmetic and wound-healing research, but legitimacy of an ingredient does not transfer automatically to legitimacy of a homemade formulation method. Commercial topical GHK-Cu products are formulated with specific pH ranges, penetration enhancers, and preservative systems that make the peptide stable and bioavailable. Dropping a reconstituted injectable peptide into rose water does none of that.

If you're interested in GHK-Cu for skin, the lower-risk path is a commercially formulated product where concentration and stability have been handled by an actual chemist. If you're using injectable GHK-Cu under guidance for other purposes, the leftover reconstituted solution is not a validated cosmetic ingredient — it's an unpreserved peptide in saline with a limited shelf life.

On the sterility point: bacteriostatic water contains benzyl alcohol as a preservative specifically to inhibit bacterial growth in a sealed vial. Once you open that vial, transfer the contents, and mix with a non-sterile carrier, that protection is largely gone. This matters more if you have any skin barrier compromise, active acne, or cuts.

The broader issue is that this video presents a zero-friction tutorial for something that requires more than a glass jar and good intentions.