The best-known GHK-Cu wound healing study reported greater wound shrinkage when a copper-peptide gel was started right after diabetic foot ulcers were cleaned, but not when it was started four weeks later. Another wound trial was negative, and a larger development program later missed its main goals. These findings don't establish benefits from GHK-Cu injections.
GHK-Cu is a peptide, a short chain of protein building blocks, bound to copper. The useful question is what a particular preparation did for a particular wound.
What the GHK-Cu wound healing study asked
Could a wound gel called Iamin Gel add something to organized wound care? Mulder and colleagues' 1994 trial in Wound Repair and Regeneration enrolled 181 people with diabetes and leg or foot ulcers. Eligible ages were 21–90. People with bone infection or gangrene (dead tissue) in the affected limb were excluded.
Treatment groups were assigned by chance. Evaluators didn't know which treatment patients received. The headline comparison involved plantar ulcers, wounds on the sole: 28 people received immediate gel treatment and 32 received vehicle, the same base without the active ingredient.
Treatment lasted up to eight weeks, followed by six weeks of observation. Everyone received debridement, removal of dead tissue, plus pressure-relieving footwear and diabetes education.
That comparison matters. Wound care was part of both treatments. The study asked whether the gel added a benefit within that care, rather than whether it could replace it.
What 98.5% closure actually meant
The median wound-area reduction was 98.5% with Iamin Gel versus 60.8% with vehicle. Median means the middle result. This wasn't the percentage of people whose wounds completely healed. Larger ulcers showed a bigger difference. The same trial had a second part: 99 people used the plain base for four weeks before switching to a 2% or 4% gel. Those delayed groups did no better than the plain base on wound shrinkage or on how fast the wound edge moved in. The authors concluded that the gel needed to start right after the wound was cleaned.
The paper's “three times faster” described calculated inward movement of the wound edge, in millimeters per day. It didn't establish that everyone healed in one-third the time. Area reduction, edge movement and complete healing answer different questions.
What the safety report leaves open
The full paper reports these findings:
| Finding | What was reported |
|---|---|
| Ulcer infections in the immediate plantar-ulcer comparison | 7% with gel versus 34% with vehicle |
| Overall unwanted events | No clear overall difference between groups; individual side-effect rates weren't listed |
Four participants left after the initial assessment only. The researchers kept their data and used people's last measurements when follow-up ended early. The paper doesn't list how many people left each group overall. It also says that patients whose ulcer infection did not respond after a week of antibiotics were taken off the study. A scientist from ProCyte, the gel's maker, was a co-author.
A short wound study also cannot establish long-term safety from repeated injections. Fewer wound infections in one comparison don't answer that separate question.
The other wound trials change the picture
The earlier counterweight is Bishop and colleagues' 1992 Journal of Vascular Surgery trial. It concerned venous ulcers, wounds associated with poor return of blood through leg veins. Eighty-six patients with usable data completed the study.
Its 0.4% copper-peptide cream did no better than placebo, the comparison cream without active treatment. Silver sulfadiazine cream reduced ulcer size more than either. Different wounds and preparations limit direct comparison, but the result rules out a simple claim that copper peptides consistently improve wound closure.
There was also a larger diabetic-ulcer program. In an October 18, 1994 BioWorld report, ProCyte's Karen Hedine described preliminary findings from its phase III trial in 511 diabetic patients at 30 medical centers: the gel missed both primary endpoints, with no statistically significant advantage over placebo for wound-size reduction or the number of patients achieving closure.
That is a company account in contemporaneous reporting, rather than a published trial paper. It still matters when judging whether the earlier positive result was confirmed.
The product took a device route to market. FDA records show ProCyte's Iamin Gel Wound Dressing received clearance on February 5, 1996. The 510(k) process compares a device with an existing device; that clearance wasn't approval of GHK-Cu as a drug. The GHK-Cu discovery history follows that transition.
What newer studies can add
As of October 29, 2026, the day this article was written, an August 20 review in Aesthetic Surgery Journal provides useful context. It counted 20 eligible aesthetic studies: 18 preclinical laboratory or animal studies and two human trials with treatment assigned by chance. Its search ended in March 2026. This is an aesthetic evidence count, not a count of every medical wound trial. The clinical evidence guide covers that wider review.
The CuHeal registry record, last updated February 27, 2026, lists recruiting status, 60 planned adults and no posted results. It compares gel with vehicle on paired small arm wounds. Its main measure is time until new skin completely covers the wound. Diabetes is excluded, so it won't directly confirm a benefit for diabetic foot ulcers. The October GHK-Cu update tracks the broader research.
Why a wound gel doesn't establish injection or blend benefits
The common online leap is from a topical gel, meaning applied to the wound surface, to injections or cosmetic rejuvenation. Neither follows from this trial. Changing the route, preparation or goal creates a new question. A shared ingredient name also doesn't establish that a compounded preparation matches the tested product. The injection-versus-topical comparison examines those differences.
Gene-expression findings, measurements of how actively cells read their instructions, don't close that gap. Pickart and Margolina's 2018 review describes laboratory gene data. Those measurements aren't clinical healing or evidence that a person becomes younger.
KLOW combines GHK-Cu with BPC-157, TB-500 and KPV, other peptides. A result from one wound gel cannot establish what that complete blend adds. The provider has to consider the actual preparation and the evidence for its intended use.
What belongs in a wound-care visit
Diabetic foot ulcers need specialist wound care. The International Working Group on the Diabetic Foot's 2023 guideline places additional treatments within established care from a team of professionals. A peptide discussion cannot replace assessment of the wound and its underlying causes.
GHK-Cu through Promise is a compounded medication, meaning a pharmacy prepares it for a prescription. This is different from an FDA-approved product: the formulation offered here is not FDA-approved. FDA explains that it doesn't verify compounded medicines' safety, effectiveness or quality before marketing.
As of October 29, 2026, the day this article was written, the HHS notice filed October 28 announces a draft peptide-compounding policy. GHK-Cu isn't among the six substances in Appendix A; the HHS policy explainer covers its conditions.
A licensed provider may still prescribe — that decision is between you and your doctor.
At Promise, a licensed provider reviews every request, and not everyone qualifies. If prescribed, a licensed U.S. compounding pharmacy prepares and dispenses the medication. The visit needs a clear goal, an explanation of which evidence applies and a plan for follow-up.
