There are no proven peptides for scars or fibrosis. The two most discussed, GHK-Cu and thymosin beta-4 (sold in fragment form as TB-500), look interesting in cell and animal studies, but the one small human scar-related trial of GHK-Cu found no benefit.[6] For raised scars and keloids, the treatments with trial support are silicone gel sheeting and steroid injections, often combined with other therapies.[1][2][3]
This guide sorts the options by evidence, from standard care to lab-only peptides. It is part of our healing peptides hub.
Evidence-graded table
| Peptide or treatment | Evidence level | What was shown | FDA status | Our profile |
|---|---|---|---|---|
| Silicone gel sheeting (not a peptide) | Human RCTs (weak) | Thinner, less red scars; trials at high risk of bias[1] | Standard care | Not applicable |
| Steroid injections, with or without 5-FU (not peptides) | Human RCTs | Combination therapy beat steroid alone for keloids and raised scars[3] | Standard care | Not applicable |
| GHK-Cu (topical) | Small human studies | No difference after CO2 laser resurfacing in 13 patients[6] | Cosmetic ingredient; not approved as a drug | GHK-Cu |
| Thymosin beta-4 (full protein) | Animal or lab only (for fibrosis) | Less lung scarring in mice; smaller heart damage in one trial[8][9] | Not approved | TB-500 |
| Ac-SDKP | Animal or lab only | Less lung fibrosis in rodents[10] | Not approved | Not applicable |
| BPC-157 | No evidence for scars | Not tested for scarring in people | Not approved | BPC-157 |
Scars vs fibrosis: what’s the difference?
Both are the body laying down too much collagen. A scar forms in skin after an injury or incision. Hypertrophic scars stay within the wound edges, while keloids grow beyond them. Fibrosis is the same process inside organs, such as the lungs, liver, kidneys or heart, where stiff scar tissue can impair function.
That matters for peptides. Many “healing” peptides are marketed because they increase collagen production, which is the opposite of what an overgrown scar needs.
Start with what works for skin scars
Silicone gel sheeting. A Cochrane review of 20 trials in 873 people found silicone sheeting reduced scar thickness and improved color, and lowered the rate of raised scars in people prone to them. The authors judged the evidence weak because most trials were at high risk of bias, but silicone remains a standard, low-risk first step.[1]
Steroid injections and combinations. An international expert panel reported growing support for laser therapy and for 5-fluorouracil, particularly combined with injected corticosteroids, for raised scars and keloids.[2] A 2020 meta-analysis found combination therapies outperformed triamcinolone (a steroid) alone.[3]
Other tools include pressure garments for burns, cryotherapy, surgery with follow-up treatment and radiation for some keloids. A dermatologist or plastic surgeon chooses based on the scar’s type, age and location.
GHK-Cu: a collagen booster, not a scar eraser
GHK-Cu is a copper-binding tripeptide found in human blood. In a 1988 lab study, it stimulated collagen production by fibroblasts (the cells that build connective tissue) at extremely low concentrations.[4] Later gene-expression work suggests it influences many repair pathways.[5]
The human scar data are thin. In a randomized trial after CO2 laser resurfacing of the skin around the mouth, 13 patients completed treatment with or without GHK-Cu products. Blinded evaluators and computer analysis found no difference in how quickly redness faded, and both groups improved equally.[6]
FDA moved injectable GHK-Cu off its list of compounding substances with significant safety risks after its nomination was withdrawn, but its entry still describes possible immune reactions and limited safety data.[14] Our GHK-Cu research guide covers the wound and skin studies, and BPC-157 vs GHK-Cu compares the two.
Microneedling and peptide serums
Clinics often pair microneedling, which makes tiny channels in the skin, with peptide serums such as GHK-Cu for acne or surgical scars. The idea is that the channels help the peptide get past the outer skin barrier. A 2026 systematic review of 64 GHK-Cu records found that the human literature is thin and mostly small cosmetic cream trials, and that microneedle delivery of GHK-Cu had not yet been tested in a single adequately powered human randomized trial.[13] Any benefit from such treatments may come from the microneedling itself rather than the peptide. Ask what is being applied, and make sure it is sterile and intended for use on broken skin.
Thymosin beta-4 and fibrosis research
Thymosin beta-4 is a natural 43-amino-acid protein that helps cells move during repair. In animal wound models it sped up skin healing, and two phase 2 ulcer trials suggested faster closure in patients who healed.[7]
For fibrosis specifically:
- Lung: inhaled recombinant thymosin beta-4 reduced bleomycin-induced lung fibrosis in mice.[8]
- Heart: a recombinant version reduced heart scarring in mice and, in a randomized, placebo-controlled trial of 96 heart attack patients treated after stenting, was linked to smaller damaged areas. The authors called for larger trials.[9]
None of this applies directly to TB-500, which is a short synthetic fragment that has not been tested in people. Because beta-thymosins also help cells migrate, researchers have studied their role in cancer spread, which is one reason for caution with unregulated use.[11] See TB-500 dosage for why no human dose exists.
Preclinical antifibrotic peptides
Ac-SDKP, a four-amino-acid peptide cut from thymosin beta-4, reduces fibrosis in animal models of lung and kidney disease, including silica-induced lung scarring in rodents.[10] It has not reached approved human treatment.
Practical cautions for scar care
- Apply nothing to an open or freshly stitched wound unless your surgeon approves it.
- Cosmetic copper peptide creams are different from injectable peptides; see our copper peptides for hair guide for how topical products are studied.
- A scar that grows quickly, bleeds, itches intensely or changes color should be examined, because a few skin cancers can mimic scars.
- Research-grade injectable peptides are not made to drug standards and may be contaminated or mislabeled.
Questions for your dermatologist or surgeon
- Is my scar hypertrophic or a keloid, and what is the first-line treatment?
- When should I start silicone, and for how long?
- Would steroid injections, laser or a combination suit me?
- Is any topical product I use safe on this scar?
For wound healing more broadly, see our guide to the best peptides for wound healing.
