Glepaglutide

Thymosin beta-4 (Tbeta4) is a small 43 amino acid peptide found in nearly every cell in the body, originally isolated from the thymus. Its main job is binding and sequestering G-actin, the building block of the cell's internal scaffolding, which lets it influence cell movement, wound repair, and tissue regeneration. It is researched heavily for healing of skin, cornea, and heart tissue, but it is not an FDA-approved drug. (The injectable sold as TB-500 is a synthetic fragment marketed as related to Tbeta4, not the full natural peptide.)

B7-33 is a 27-amino-acid, single-chain peptide cut down from the B-chain of human relaxin-2, the hormone that loosens tissue during pregnancy. Relaxin itself has strong anti-scarring effects but is a complex two-chain molecule that is hard and expensive to make, so an Australian group (Hossain and colleagues, 2016) designed B7-33 as a simpler version. In rodent models it reduced heart and lung fibrosis about as well as full relaxin. It has never been tested in humans.

Apraglutide is a once-weekly GLP-2 analog for short bowel syndrome, originally from VectivBio and now owned by Ironwood Pharmaceuticals. Its phase 3 STARS trial hit its main goal in 2024, but in April 2025 Ironwood said the FDA wanted a confirmatory trial, partly because patients in STARS got less drug exposure than planned due to how doses were prepared and given. That new trial, STARS-2, started in June 2026, so approval is years away (a submission before end of 2029 has been mentioned).

BPC-157 is a synthetic 15-amino-acid peptide (sequence Gly-Glu-Pro-Pro-Pro-Gly-Lys-Pro-Ala-Asp-Asp-Ala-Gly-Leu-Val) based on a fragment of a protective protein found in human gastric juice. It is studied almost entirely in animals for tendon, ligament, gut, and tissue healing, and it has racked up hundreds of preclinical papers. The catch: it is not approved by any regulator for any use, and the human evidence is a handful of small pilot studies, not real clinical proof.

TB-500 is a synthetic peptide that copies the active region of thymosin beta-4, a natural protein that controls how cells build and move their internal skeleton. Most TB-500 products reproduce the short LKKTETQ sequence (residues 17 to 23) responsible for binding actin and driving cell migration, which is why it gets marketed for tendon, muscle, and wound repair. Here is the honest part: there are essentially no completed human trials of the TB-500 fragment itself, and almost all the human clinical data is for the full-length thymosin beta-4 molecule, which is related but not the same thing.

Pentadecapeptide almost always means BPC-157, a synthetic 15-amino-acid chain (Gly-Glu-Pro-Pro-Pro-Gly-Lys-Pro-Ala-Asp-Asp-Ala-Gly-Leu-Val) derived from a protein found in human gastric juice. It is one of the most hyped 'healing' peptides online, marketed for tendon, gut, and muscle repair, but here is the catch: essentially all of the supporting evidence is from rats and mice. There is no FDA approval and no completed human clinical trial proving it does any of this.