Human trials of GHK-Cu for an actual medical condition are rare. One from 1994 stands out because it is randomized, placebo-controlled and run in people with diabetes who had open foot ulcers. It tested a topical gel of the glycyl-L-histidyl-L-lysine copper complex, called Iamin Gel[1].
The abstract is short, its numbers are large, and several things a careful reader would want to know are missing from it. This page goes through what it reports, what it leaves out, and why a result from a wound gel on a freshly debrided ulcer does not carry over to a face serum.
Key Takeaways
- The 1994 study is described as a multicenter, randomized, evaluator-blinded, placebo-controlled trial of Iamin Gel in diabetic neuropathic ulcers, with every patient on a standardized wound care protocol[1].
- In plantar ulcers the gel reached a median of 98.5% area closure against 60.8% for the vehicle gel (p < 0.05)[1].
- The authors report a larger effect in ulcers over 100 mm² at entry, and fewer infections (7% against 34%) in ulcers treated immediately after debridement[1].
- The abstract does not give how many patients were enrolled, how many dropped out, how long treatment lasted, the gel concentration or who paid for the work.
- Two 2026 reviews do not count this trial. One lists four human studies without it, and the other excludes anything published before 2005[2][3].
- We found no later trial of GHK-Cu in diabetic foot ulcers, so this result has not been confirmed by a second trial.
What the Trial Was
The study is described as multicenter, randomized, evaluator-blinded and placebo-controlled[1]. Evaluator-blinded means the people judging the wounds did not know which gel a patient was using. The patients had diabetic neuropathic ulcers, which are foot ulcers in people whose diabetes has damaged the nerves of the foot. The main results are given for plantar ulcers, the ones on the sole[1].
The product is named Iamin Gel. The published abstract prints the name as “lamin”, and a 2003 paper on the same brand prints it as Iamin, so this page treats them as one name. The abstract does not state the gel’s concentration. The 2003 paper describes its own product as Iamin 2% Gel, but nothing in the 1994 abstract confirms the two were the same strength[1][4].
The Standard Care Everyone Received
Every patient, whichever gel they got, was enrolled in what the authors call an aggressive standardized wound care protocol. It had four parts: sharp debridement at study entry, daily application of a metered dose of the drug, standardized pressure-relieving footwear, and education about diabetes control and activity[1]. That is a great deal of good care, and it shapes how the numbers should be read.
The comparison is gel against vehicle on top of that protocol. It is not gel against doing nothing. The vehicle group also had its ulcers cleaned out, offloaded with proper footwear and dressed daily, and the median vehicle ulcer still closed by 60.8%[1]. The abstract does not separate how much of the healing in each arm came from the protocol and how much from the gel.
What “Vehicle” Means, and Why It Matters
A vehicle is the base a drug is mixed into, supplied without the active ingredient. A vehicle control keeps the comparison fair because a moist gel sitting on a wound is not an inert thing. The 1994 trial was placebo-controlled, so it did use one[1].
The rat study from 2003 shows why this matters. Rats had 6 mm wounds cut into an ischemic skin flap and were treated daily for 13 days. By day 13 the wound area had shrunk by 64.5% with the copper complex gel, 45.6% with the vehicle gel alone and 28.2% with no treatment[4]. The vehicle covered about half the distance from no treatment to the active gel, and the active gel separated statistically from the vehicle on only days 3 and 9 of the comparisons reported[4].
That was a rat experiment on a different wound model. It does not say what happened in the human trial. It does show why a result that looks like gel against nothing can be mostly gel against a good dressing.
The Numbers the Abstract Gives
The headline result is area closure in plantar ulcers. The median closure was 98.5% with the gel and 60.8% with the vehicle, a difference reported as significant at p < 0.05. The abstract also says the proportion of patients healing 98% or better was higher with the gel, without giving that proportion[1].
The authors state that the rate of closure was three times faster with the gel than with standard care and vehicle[1]. That is their summary. The abstract gives no rates, units or time frame, so it cannot be checked from the record.
These are medians of percentage area closure, not counts of ulcers that fully healed. A median of 98.5% means that at least half the gel-treated ulcers were almost closed at the point of measurement. It does not tell a reader how many closed completely, or how long that took.
The Larger-Ulcer Subgroup
The authors report that the benefit was more pronounced in plantar ulcers larger than 100 mm² at study entry. In that group the median closure was 89.2% with the gel and -10.3% with the vehicle (p < 0.01)[1]. A negative median closure means the typical large ulcer in the vehicle group got bigger.
The authors attribute the gap to ulcers of this size failing to respond adequately to the standardized care without the gel[1]. That is a striking claim. It is also a subgroup, defined by ulcer size, and a subgroup is a smaller sample than the whole trial. The abstract does not say how many patients it contained or whether the split by size was planned before the trial began.
The Infection Result and the Timing Condition
The incidence of ulcer infections was 7% with the gel and 34% with the vehicle (p < 0.05)[1]. Read the wording closely, because it applies to the plantar ulcers treated immediately after debridement, not to every ulcer in the trial.
The abstract also states that treatment must begin immediately after the initial debridement to obtain the best closure[1]. That suggests some ulcers started treatment later, but the abstract does not describe them or say how they did. Infection is a clinically important outcome, and an effect on it would be notable. A percentage drawn from a timing-defined subset of unreported size is not strong enough to build on by itself.
What the Abstract Does Not Say
Several basic facts are absent from the record. It does not give the number of patients or ulcers, the number who dropped out, how many were in each arm, or how long treatment and follow-up lasted. It does not state the gel strength. It does not say whether the analysis counted every randomized patient. It does not disclose who funded the study or whether the authors had ties to the product’s maker.
The full paper may answer these questions. It is not openly available, so this page rests on the abstract alone. Nothing here should be read as a claim about funding or sponsorship. The 2003 rat paper names a manufacturer for its own gel, but that is a separate study[4].
Why the Two 2026 Reviews Left It Out
A 2026 review in Pharmaceutics describes a “complete human clinical record” that begins its human section with four studies: a 1998 comparative topical study with ultrastructural endpoints, a 2002 conference-level cosmetic report, a randomized post-laser study in which 13 participants completed follow-up and no objective advantage was shown, and a 2026 eyebrow study in 18 healthy participants[2]. The body text of that review does not name the 1994 trial and gives no reason for its absence.
A second 2026 review, in Archives of Internal Medicine Research, sets an inclusion window of 2005 to 2026. It names Mulder 1994 among foundational papers that fall outside that window and are referenced only through later reviews[3]. That is a stated design choice, not an error. The same review goes on to propose a future randomized trial in diabetic foot ulcers comparing standard care with standard care plus a GHK-Cu hydrogel dressing or microneedle patch[3].
Neither review claims the 1994 trial was wrong. The point is narrower. A reader relying on either summary would not learn that a diabetic ulcer trial of a GHK-Cu gel already exists. The site’s page on diabetic wound healing evidence covers the wider animal and materials literature, and this page is the closer look at the one human trial.
A Second Early Trial, in Venous Ulcers
A 1992 randomized, evaluator-blinded trial studied venous stasis ulcers. It compared silver sulfadiazine 1% cream, a “biologically active tripeptide copper complex” 0.4% cream, and an inert vehicle placebo, and 86 evaluable patients completed it[5].
Silver sulfadiazine statistically reduced ulcer size compared with the copper cream and with placebo. The abstract says there was no difference between the copper cream and the placebo[5]. The abstract never names the peptide, so it cannot confirm that the complex was GHK-Cu, and this site does not count it as GHK-Cu evidence. It is worth knowing about because, if it was GHK-Cu, the two early randomized trials ran in different ulcer types and pointed in opposite directions.
Has Anyone Repeated It?
We found no later randomized trial of GHK-Cu or a copper tripeptide in diabetic foot ulcers in the published literature.
Trial registries and unpublished work were not checked, and absence from the literature is not proof that nothing was done. The 2026 Pharmaceutics review does list a registered phase 2 trial of a GHK-Cu gel in standardized punch-biopsy wounds, which had posted no efficacy results as of August 2026[2]. Those are acute wounds, not diabetic ulcers.
Why a Wound Gel Is Not a Skincare Serum
In the 1994 trial the gel was applied daily from the day of sharp debridement, onto an ulcer from which dead tissue had just been cut away[1]. That is an open wound with its surface barrier removed. A serum goes onto intact skin, where the outer layer limits how much of a peptide gets through. The site’s page on GHK-Cu skin permeation research covers what is known about that barrier.
The test conditions also differ in dose, vehicle, supervision and outcome. A metered clinical dose, applied under a protocol with offloading footwear, measured the healing of an ulcer. A serum is used for appearance. Evidence for the first does not transfer to the second, and a controlled human test of GHK-Cu after a skin procedure, covered in the CO2 laser trial write-up, found no objective advantage[2]. The broader wound healing summary places both in context.
What It Does and Does Not Mean
The 1994 abstract reports a randomized, evaluator-blinded, placebo-controlled trial in which a GHK-Cu gel was associated with greater closure of diabetic plantar ulcers and fewer infections in a timing-defined subset[1]. It is a meaningful signal from a design that deserves respect.
It is also an abstract with no sample size, no dropout figures, no funding statement, no confirmation by a second trial that we could find, and a control arm that did well on its own. It is not a reason for anyone with a diabetic foot ulcer to treat it with a cosmetic product. Foot ulcers in diabetes need care from a clinician, and the debridement, offloading and infection control in that trial were doing real work.
Frequently Asked Questions
Was there a randomized trial of GHK-Cu in diabetic foot ulcers?
Yes, one. A 1994 multicenter, randomized, evaluator-blinded, placebo-controlled study of Iamin Gel in diabetic neuropathic ulcers. We found no later trial of GHK-Cu in diabetic foot ulcers.
What did the 1994 trial find?
In plantar ulcers the gel reached a median area closure of 98.5% against 60.8% for the vehicle gel. The effect was larger in ulcers over 100 mm2 at entry, and infections were 7% against 34% in ulcers treated immediately after debridement.
Does the abstract say how many patients took part?
No. The abstract does not give the number of patients, the dropouts, the treatment duration, the gel concentration or the funding source. The full paper may contain these details but is not openly available.
What does the vehicle control mean?
A vehicle is the gel base without the active ingredient. In a 2003 rat study of the same brand, the vehicle alone shrank wounds by 45.6% against 28.2% with no treatment, so a vehicle is not a do-nothing comparison.
Does this mean GHK-Cu serums help diabetic ulcers?
No. The trial used a clinical gel on freshly debrided ulcers inside a standardized wound care protocol. A cosmetic serum on intact skin is a different product, dose and setting, and diabetic foot ulcers need clinician care.
Is there a second early trial of a copper tripeptide cream?
A 1992 randomized trial in venous stasis ulcers compared silver sulfadiazine, a 0.4% tripeptide copper complex cream and placebo in 86 evaluable patients. The copper cream did not differ from placebo. The abstract does not name the peptide, so it may not be GHK-Cu.
References
- Mulder GD, et al. Enhanced healing of ulcers in patients with diabetes by topical treatment with glycyl-l-histidyl-l-lysine copper. Wound Repair and Regeneration (1994). PMID 17147644
- Mateescu DM, et al. GHK-Cu as a Bioactive Metallopeptide and Drug-Delivery Cargo: Coordination Chemistry, Formulation Science, Therapeutic Evidence, and a Translational Roadmap. Pharmaceutics (2026). PMID 42797253
- Najafi N, et al. A Systematic Review of the Mechanisms and Therapeutic Applications of GHK-Cu (Glycyl-L-Histidyl-L-Lysine-Copper Complex) in Topical Microneedle Delivery: A Case for Expanded Clinical Trials. Archives of Internal Medicine Research (2026). PMID 42787770
- Canapp SO, et al. The effect of topical tripeptide-copper complex on healing of ischemic open wounds. Veterinary Surgery (2003). PMID 14648529
- Bishop JB, et al. A prospective randomized evaluator-blinded trial of two potential wound healing agents for the treatment of venous stasis ulcers. Journal of Vascular Surgery (1992). PMID 1495150
These statements have not been evaluated by the Food and Drug Administration. This information is not intended to diagnose, treat, cure, or prevent any disease. Content is for informational purposes only and is not medical advice; consult a qualified healthcare provider before starting any supplement. As an Amazon Associate we earn from qualifying purchases.