Peptide serums are often sold with a line about “repair”, and searchers ask the obvious next question: do they help scars? This page answers it from the trial record as it stood on 22 October 2026. It covers what a scar is in this research, the single peptide trial that tested scars in people, and where the copper-peptide and acne-scar claims come from. It recommends no product and no treatment; scar care is a conversation for a dermatologist or surgeon.
How large the scar literature is
Scars are a well-studied problem. PubMed held 2,045 randomized controlled trials mentioning a scar on 22 October 2026. Silicone gel or topical silicone alone appears in 74 of them. Those trials cover surgical scars, burns, keloids and acne scars, and test silicone, pressure garments, steroid injections, lasers, botulinum toxin and many other approaches.
Searching for peptides inside that record is where it becomes thin. Joining peptide* to scar or keloid terms, among randomized or clinical trials, returned 16 records. Read one by one, they sort like this:
- The heart — 11 of the 16 concern scarring of heart muscle after a heart attack, in trials of stem cells, drugs or pacing, where a peptide appears only as a blood marker (natriuretic peptides, procollagen fragments).
- Other uses of the words — a peptic-ulcer trial, a keloid trial of vitamin D and platelet-rich plasma injections, and a collagen-enriched drink for burn patients.
- A peptide put on a human skin scar — one trial, and a later laboratory paper using biopsies from the same programme.
The one trial: aCT1
The trial was published in 2017 in the Journal of Investigative Dermatology (Grek et al., PMID 27856288). Its peptide, aCT1 (alpha connexin carboxyl-terminus 1), mimics the tail of connexin 43, a protein that forms channels between neighbouring cells and takes part in inflammation and repair. In animals it had sped wound closure and reduced scar tissue.
The design was within-patient: people with two laparoscopic incisions of at least 10 mm had one treated with an aCT1 gel plus standard occlusive dressings and the other with standard care alone, chosen at random. The gel went on immediately after the incision was made and again 24 hours later — two applications to a fresh wound, not months of use on an old scar. The results, as the abstract states them:
- At 1 month, no significant difference in scar appearance between the two incisions.
- At 9 months, a 47% better score on the Vancouver Scar Scale for the aCT1 side (p = 0.0045), a better global assessment (p = 0.0009), and improvements in pigmentation, thickness, surface roughness and suppleness.
- Adverse events were similar on both sides.
A 2021 follow-up used biopsies from an earlier phase 1 study and found one structural difference at 29 days: collagen fibres in aCT1-treated scars were less aligned, closer to the basket-weave of unwounded skin than the parallel bundles typical of scars (Montgomery et al., PMID 34246197).
Who ran it, and where it went. The corresponding author of the 2017 trial worked for FirstString Research, the company developing aCT1, and company scientists are co-authors of both papers. The gel was later called Granexin. On 22 October 2026, FDA's Drugs@FDA database returned no approval record for it, and its phase 3 trial in diabetic foot ulcers (NCT02667327, 124 participants, sponsor Xequel Bio) is listed as terminated, reason “Sponsor Decision (No safety or efficacy concerns)”. It is a drug candidate, used on fresh surgical wounds, and it is not an ingredient in any cosmetic.
The copper peptide claim
Copper peptides (GHK-Cu) are the cosmetic peptide most often linked to scars, usually through the phrase “tissue remodelling”. PubMed held 4 records joining scars with GHK or copper peptides on 22 October 2026: a laboratory study of how GHK and its copper complex affect TGF-β, a scarring-related signal, in cultured skin fibroblasts; a 2008 review of GHK and tissue remodelling; an older overview of wound treatment; and a nanocarrier study about the central nervous system. None is a human scar trial. What the copper-peptide human evidence does contain — a handful of small facial studies, the most quoted of them available only as a conference abstract — is set out on our copper peptides page, and none of it measured scars.
Acne scars
Acne scars are the scar question most readers of a beauty site have. A PubMed search joining acne scars with peptides returned 3 records on 22 October 2026: a 2022 review of new acne treatments, a 2026 review of light therapy for skin regeneration, and a 2026 laboratory and animal study of anti-inflammatory microneedle patches. No clinical trial of a peptide product on acne scars appeared. Our peptides and acne page found the same absence for acne itself: one peptide-containing product among 1,411 randomized acne trials. The acne-scar treatments with trial records are mostly procedures — resurfacing lasers, microneedling, subcision, fillers — which a dermatologist selects by scar type. Microneedling paired with copper peptides has its own page, microneedling and copper peptides, with the same caution about what was measured.
Related questions this page does not cover
- PDRN, often marketed beside peptides, is fish DNA rather than a peptide; its small scar record is mostly injections and sits on our PDRN page.
- Stretch marks are dermal scars too, and their trial census — 76 randomized trials, none of a peptide — is on our peptides for stretch marks page.
- The search's retraction filter returned one record, a rat study of vitamin D and ginger in diabetic wounds, unrelated to topical peptides.
What the record supports
A peptide has improved surgical scars in one company-run randomized trial — but that peptide is an unapproved wound drug applied twice to fresh incisions, and its later development stopped. The peptides in serums and creams have no controlled human scar trial at all in PubMed, copper peptides included. Silicone, with 74 randomized trials, sits at the other end of the evidence. A product that promises scar “repair” through peptides is making a claim the published literature does not yet test.
Sources
PubMed searches run 22 October 2026: (scar[tiab] OR scars[tiab]) AND randomized controlled trial[pt] (2,045); the same with topical silicone or silicone gel (74); peptides with scar or keloid terms among randomized or clinical trials (16, each title read); (scar[tiab] OR scars[tiab]) AND (copper peptide* OR GHK) (4); acne scar*[tiab] AND peptide*[tiab] (3); granexin OR "aCT1 peptide" (10); scar and peptide terms with Retracted Publication[pt] (1). Abstracts opened: PMIDs 27856288 and 34246197. ClinicalTrials.gov API: NCT02667327 (status, reason stopped, sponsor). openFDA Drugs@FDA: search for Granexin (no match). Corrections go to the contact page.