Tissue repair

BPC-157 is a synthetic 15-amino-acid peptide, a fragment of a protein found in human gastric juice. Clinicians and athletes increasingly use it for musculoskeletal injuries. In rats it consistently speeds healing of many tissues. Human data amount to three small, uncontrolled pilot reports, all by the same first author. It is not approved by the FDA and is banned in professional sport.

Cartalax is the tripeptide Ala-Glu-Asp (AED), one of the short "peptide bioregulators" developed by Vladimir Khavinson's group in St Petersburg and promoted for cartilage. In cell cultures it switched on cartilage-forming genes in ageing human stem cells and lowered markers of ageing in chondrocytes. There are no published human trials, and almost every study comes from the developers' own group.

GHK-Cu is the copper complex of GHK (glycyl-histidyl-lysine), a tripeptide found in human plasma, saliva and urine whose levels fall with age. In lab studies it raises collagen and elastin production and supports skin cells, and it is a common ingredient in anti-wrinkle products. The best human evidence is one 1994 trial in which a GHK-Cu gel sped the healing of diabetic foot ulcers. The cosmetic studies are described mainly in reviews by the peptide's discoverer, and an independent review found few published clinical studies.

TB-500 is a product built on Ac-LKKTETQ, a synthetic, acetylated copy of the seven-amino-acid actin-binding region of thymosin beta-4. It began as a veterinary preparation and is marketed for wound healing and tissue repair. It has never been tested for efficacy in humans. In a lab study, the intact peptide did not speed wound closure; one of its breakdown products did.

Thymosin beta-4 (Tβ4) is a 43-amino-acid protein found in almost every cell, where it is the main store of unused actin, the building block of the cell skeleton. After injury it promotes cell migration, new blood vessels and repair in animal models. In people it has been tested as eye drops for dry eye, in small phase 2 trials with mixed results, and as an intravenous drug in safety studies. It is not approved as a medicine.