Peptides and skin healing after laser, microneedling and surgery

Key points

• In rats, full-length thymosin beta-4 was associated with 61% more re-epithelialization at day 7, and in incisions with narrower scars and no loss of strength [1][3].
• In aged mice, the heptapeptide LKKTETQ, the sequence of short-chain TB-500 without acetylation, promoted repair comparable to that of the full protein [2].
• The three phase 2 trials of thymosin beta-4 gel (venous ulcers, pressure ulcers and epidermolysis bullosa) showed no clear difference from placebo in the number of closed wounds. In venous ulcers, safety was comparable to placebo [5][6][7][8].
• BPC-157 cream improved healing after CO2 laser injuries and deep burns in mice, and an independent group replicated it in alkali burns in rats [10][11][14].
• GHK-Cu increased collagen in rat wounds and reduced ischemic wound area by 64.5%, but after CO2 laser in humans it showed no objective benefit [15][16][18].

US status (October 2026): TB-500 and BPC-157 are not FDA-approved and have no lawful compounding pathway. Topical GHK-Cu is returning to FDA’s 503A Category 1, while injectable GHK-Cu has no pathway. See TB-500, BPC-157 and GHK-Cu.

A controlled wound is a healing model

Ablative laser resurfacing, microneedling and any surgical incision are planned wounds. What you want from them is exactly what repair biology studies: fast re-epithelialization, good perfusion, orderly collagen and a scar that does not show. Three peptides account for most of that literature: thymosin beta-4 and its fragment TB-500, BPC-157 and GHK-Cu. They are often sold together in blends marketed as “GLOW.”

One rule runs through this article: every finding is attributed to the molecule its study used. Two molecules are sold under the name TB-500, the Ac-LKKTETQ fragment (short chain) and full-length 43-amino-acid thymosin beta-4 (long chain). Almost all of the literature, including every human trial, concerns the full protein. The difference is explained in TB-500 is not thymosin beta-4. The logic of combining the three peptides is in GLOW, KLOW and Wolverine.

Thymosin beta-4 gives more epithelium and a finer scar in animals

Full-length thymosin beta-4. In a rat full-thickness wound model, the protein given topically or intraperitoneally increased re-epithelialization by 42% over saline at day 4 and by as much as 61% at day 7. Wounds contracted at least 11% more and showed more collagen and more vessels [1]. In vitro, as little as 10 pg increased keratinocyte migration 2- to 3-fold [1]. In db/db diabetic mice it increased contraction and collagen deposition, and in 26-month-old mice, whose healing was significantly delayed, it accelerated repair [2].

LKKTETQ fragment. In the same study, the synthetic heptapeptide LKKTETQ, which reproduces the actin-binding domain, promoted repair in the aged mice comparable to that of the full protein [2]. It is the sequence of short-chain TB-500, without the N-terminal acetylation, and it is the main published in-vivo skin finding for the fragment.

The finding closest to aesthetic concerns is the incision work. In rats, incisional wounds treated locally with full-length thymosin beta-4 healed with minimal scarring, were narrower and lost no breaking strength. They had more organized, mature collagen and few myofibroblasts [3]. For fat grafting there is an in-vitro finding: in adipose-derived stem cells from liposuction patients, thymosin beta-4 at 100 and 1000 ng/mL increased proliferation and resistance to apoptosis [4].

The thymosin beta-4 gel trials did not clearly separate from placebo

Full-length thymosin beta-4 has the broadest clinical program in skin wounds of any molecule here: three phase 2 trials of a RegeneRx topical gel (RGN-137 in the venous trial record). In venous ulcers, a phase 2 trial at eight European sites randomized 73 patients. Safety was comparable to placebo, the 0.03% concentration suggested possible acceleration, and about 25% of patients achieved complete closure within 3 months [5]. The registry results show wounds closed at day 84 in 12 of 55 patients on thymosin beta-4 vs 4 of 17 on placebo [6]. In pressure ulcers (72 patients), the figures were 8 of 54 vs 3 of 18 [7].

In epidermolysis bullosa, the trial was stopped early for “Lack of patient availability and expiration of study drug”: 30 of the 36 planned participants were randomized [8]. Wounds closed in 8 of 22 patients on thymosin beta-4 and 5 of 8 on placebo, with no significant difference. There was one adverse event in the active group and no serious ones [8]. The program’s authors highlight another angle: among patients who did heal, thymosin beta-4 accelerated closure by almost a month in the venous and pressure ulcer trials [9].

• 61%: more re-epithelialization at day 7 with full-length thymosin beta-4 in rats [1]
• 64.5%: reduction in ischemic wound area with topical GHK-Cu at day 13, vs 28.2% untreated [16]
• 30 of 36: patients randomized in the epidermolysis bullosa trial, stopped early [8]

BPC-157 skin data come mostly from one group

The finding most directly relevant to aesthetic practice is a Zagreb group study with CO2 laser. In mice with dorsal laser injuries, a neutral cream with BPC-157 applied once daily consistently improved healing, macroscopically and microscopically, at days 1, 7 and 21 [10]. In deep partial-thickness burns covering 20% of body surface, the cream reduced edema, inflammatory cells and necrosis, increased capillaries and collagen, preserved more follicles, reversed the poor re-epithelialization of controls at two weeks and increased the breaking strength of burned skin. Silver sulfadiazine only increased collagen and reduced inflammatory cells [11]. The peptide also counteracted the healing delay induced by methylprednisolone [12].

Two papers from other laboratories point the same way. In hyperglycemic rats, BPC-157 gel (as PL 14736) produced a dose-dependent acceleration of excisional wound healing, equivalent at the highest doses to becaplermin (PDGF-BB), with a trend toward more granulation tissue containing mature collagen [13]. A group in Xi’an, China, observed faster closure and more collagen at day 18 in alkali burns in rats, with increased VEGF in the wound and regulation of the ERK1/2 pathway [14]. Tendon and gut studies are in BPC-157 in the laboratory.

GHK-Cu works in some models and not in others

In wound chambers implanted in rats, GHK-Cu injections produced a concentration-dependent increase in collagen, glycosaminoglycans, DNA and protein. Type I and III collagen mRNAs rose, and a control tripeptide had no effect [15]. In open wounds within an ischemic flap, the topical gel reduced initial area by 64.5% at day 13, vs 45.6% with vehicle and 28.2% untreated, with less TNF-alpha, MMP-2 and MMP-9 [16]. In previously irradiated skin flaps there were no differences in ischemia, vessel number or VEGF [17].

For microneedling, the available data concern penetration, not efficacy. In human skin in vitro, 134 ± 12 nanomoles of peptide and 705 ± 84 nanomoles of copper crossed microneedle-pretreated skin in 9 hours, vs almost none through intact skin, with no obvious signs of irritation in the safety models [19]. The only human trial after CO2 laser (13 patients) found no objective differences in erythema or wrinkles, although satisfaction was higher with GHK-Cu (P = 0.04) [18]. The other topical trials are in GHK-Cu: four decades of papers, few trials.

Scars and keloids have laboratory signals only

We found no peptide trials in keloids or hypertrophic scars. In keloid tissue, thymosin beta-4 mRNA was 66.98% lower than in hypertrophic scar and 62.48% lower than in normal skin, and the authors propose that its insufficient expression may contribute to keloid formation [21]. In human dermal fibroblasts, GHK and GHK-Cu at 1 nM reduced IGF-2-induced TGF-β1 secretion, although free copper did the same [20]. Together with the fewer myofibroblasts in thymosin beta-4-treated incisions [3], these are coherent hypotheses that no one has tested in patients.

Where the evidence ends

• Almost everything is animal or in vitro. The full-length thymosin beta-4 gel trials did not clearly separate from placebo in the number of closed wounds [6][7][8], and the GHK-Cu trial after CO2 laser showed no objective benefit [18].
• For the LKKTETQ fragment there is a single in-vivo skin finding, in mice, and without the acetylation of commercial TB-500 [2].
• The BPC-157 skin literature comes mainly from the Zagreb group [10][11][12]. Outside replication exists and is scarce [13][14].
• GHK-Cu results depend on the model: positive in rat ischemic wounds and null in irradiated skin [16][17].
• We found no published studies of the GLOW blend and no human trials of these peptides injected in aesthetic procedures.

What this means for you. The open questions are concrete: whether the fewer myofibroblasts seen with thymosin beta-4 translate into finer scars in humans [3], whether the BPC-157 effects after CO2 laser in mice reproduce outside Zagreb [10], and whether microneedle-enhanced GHK-Cu penetration improves any clinical outcome [19]. Until they are answered, topical GHK-Cu is the only one of the three with a compounding pathway, and only for non-injectable use. If a vendor offers you TB-500 or a “GLOW” blend for post-procedure care, read peptide supplier diligence and research-use-only peptides first.

References

1. Malinda KM, et al. Thymosin beta4 accelerates wound healing. J Invest Dermatol. 1999;113(3):364-8. PMID 10469335. Link
2. Philp D, et al. Thymosin beta 4 and a synthetic peptide containing its actin-binding domain promote dermal wound repair in db/db diabetic mice and in aged mice. Wound Repair Regen. 2003;11(1):19-24. PMID 12581423. Link
3. Ehrlich HP, Hazard SW 3rd. Thymosin beta4 enhances repair by organizing connective tissue and preventing the appearance of myofibroblasts. Ann N Y Acad Sci. 2010;1194:118-24. PMID 20536458. Link
4. Li W, et al. In Vitro Study of Thymosin Beta 4 Promoting Transplanted Fat Survival by Regulating Adipose-Derived Stem Cells. Aesthetic Plast Surg. 2024;48(11):2179-2189. PMID 38409346. Link
5. Guarnera G, DeRosa A, Camerini R. The effect of thymosin treatment of venous ulcers. Ann N Y Acad Sci. 2010;1194:207-12. PMID 20536470. Link
6. ClinicalTrials.gov. NCT00832091: A Randomized, Double-Blind, Placebo-Controlled, Dose-Response Study of the Safety and Efficacy of Thymosin Beta 4 in the Treatment of Patients With Venous Stasis Ulcers (RegeneRx). Results posted. Link
7. ClinicalTrials.gov. NCT00382174: A Randomized, Double-Blind, Placebo-Controlled, Dose Response Study of the Safety and Efficacy of Thymosin Beta 4 in the Treatment of Patients With Pressure Ulcers (RegeneRx). Results posted. Link
8. ClinicalTrials.gov. NCT00311766: A Randomized, Double-Blind, Placebo-Controlled, Dose-Response Study of the Safety and Efficacy of Thymosin Beta 4 in the Treatment of Patients With Epidermolysis Bullosa (RegeneRx). Results posted. Link
9. Treadwell T, et al. The regenerative peptide thymosin β4 accelerates the rate of dermal healing in preclinical animal models and in patients. Ann N Y Acad Sci. 2012;1270:37-44. PMID 23050815. Link
10. Bilic M, et al. The stable gastric pentadecapeptide BPC 157, given locally, improves CO2 laser healing in mice. Burns. 2005;31(3):310-5. PMID 15774286. Link
11. Mikus D, et al. Pentadecapeptide BPC 157 cream improves burn-wound healing and attenuates burn-gastric lesions in mice. Burns. 2001;27(8):817-27. PMID 11718984. Link
12. Sikiric P, et al. Corticosteroid-impairment of healing and gastric pentadecapeptide BPC-157 creams in burned mice. Burns. 2003;29(4):323-34. PMID 12781609. Link
13. Seveljević-Jaran D, et al. Accelerated healing of excisional skin wounds by PL 14736 in alloxan-hyperglycemic rats. Skin Pharmacol Physiol. 2006;19(5):266-74. PMID 16785777. Link
14. Huang T, et al. Body protective compound-157 enhances alkali-burn wound healing in vivo and promotes proliferation, migration, and angiogenesis in vitro. Drug Des Devel Ther. 2015;9:2485-99. PMID 25995620. Link
15. Maquart FX, et al. In vivo stimulation of connective tissue accumulation by the tripeptide-copper complex glycyl-L-histidyl-L-lysine-Cu2+ in rat experimental wounds. J Clin Invest. 1993;92(5):2368-76. PMID 8227353. Link
16. Canapp SO Jr, et al. The effect of topical tripeptide-copper complex on healing of ischemic open wounds. Vet Surg. 2003;32(6):515-23. PMID 14648529. Link
17. Parker NP, et al. Effects of topical copper tripeptide complex on wound healing in an irradiated rat model. Otolaryngol Head Neck Surg. 2013;149(3):384-9. PMID 23744835. Link
18. Miller TR, et al. Effects of topical copper tripeptide complex on CO2 laser-resurfaced skin. Arch Facial Plast Surg. 2006;8(4):252-9. PMID 16847171. Link
19. Li H, et al. Microneedle-Mediated Delivery of Copper Peptide Through Skin. Pharm Res. 2015;32(8):2678-89. PMID 25690343. Link
20. Gruchlik A, Chodurek E, Dzierzewicz Z. Effect of GLY-HIS-LYS and its copper complex on TGF-β secretion in normal human dermal fibroblasts. Acta Pol Pharm. 2014;71(6):954-8. PMID 25745767. Link
21. Nie FF, Wu JQ, Qin ZL. [Expression of thymosin beta 4 mRNA expression in keloid tissues and fibroblasts cultured from keloid and its significance]. Zhongguo Wei Zhong Bing Ji Jiu Yi Xue. 2005;17(2):80-3. PMID 15698487. Link

This is general information, not medical or legal advice. Rules vary by state and change. Confirm your own facts with counsel.