Rusalatide
A piece of the clotting protein thrombin that speeds wound and bone healing in animals; in people it helped foot ulcers in one small trial
Rusalatide, known in research as TP508 and as the product Chrysalin, is a 23-amino-acid copy of a short stretch of human prothrombin. It keeps the part of thrombin that binds cells, including an RGD motif, and none of the enzyme activity that clots blood. In rats, rabbits and pigs it sped the closure of skin wounds, the repair of broken bones and the recovery of ischaemic heart muscle. In 60 people with diabetic foot ulcers, applying it twice a week healed more ulcers than placebo, but a large phase 3 trial in wrist fractures missed its main clinical goal and a later fracture study was stopped for lack of benefit. It has never been approved.
Used in human trials: 1 µg or 10 µg in saline, Twice weekly, Topical, applied to the ulcer (Study: diabetic foot ulcers, phase 1/2) Details ↓
Recommended Dosing
Used in human trials
No manufacturer dose exists for this use: these are amounts given in published trials, not recommendations.
What is it?
Thrombin is best known as the enzyme that turns fibrinogen into a clot, but at a wound it also signals to surrounding cells to start repair. Researchers looked for the part of thrombin responsible for those cell signals without the clotting. TP508 is the result: a synthetic peptide matching residues 508 to 530 of prothrombin, a stretch of the receptor-binding domain that includes the integrin-binding sequence arginine-glycine-aspartate (RGD). It lacks the catalytic site thrombin uses to clot blood.
The animal results were consistent. A single topical dose on full-thickness skin wounds in rats closed them faster, with more inflammatory cells early and bigger new blood vessels by day 7, and in surgically starved skin flaps it restored closure toward normal rates. Injected into rat femur fractures it made healing bone stronger, with more vessels in the callus and switched-on genes for growth factors and inflammation. In rabbit radius and ulna defects, released slowly from microspheres, it raised bone strength; in pigs with blocked or chronically narrowed coronary arteries it shrank infarcts and improved blood flow. Cell studies traced part of this to the αvβ3 integrin and to nitric oxide made by endothelial cells.
In people the record is thinner. A phase 1/2 trial in 60 patients with diabetic foot ulcers applied 1 or 10 µg in saline twice weekly with standard care: complete healing roughly doubled, closure ran about 80% faster and the median time to full closure fell by about 40%, with no more side effects than placebo. A phase 1/2 study in distal radius fractures was also reported positive. Then came one of the largest fracture trials of its time: rusalatide sped radiographic healing of wrist fractures but failed its primary clinical endpoint, time to removal of immobilisation, except in a subgroup of osteopenic women. A later phase 2 fracture study was terminated in 2007 because the drug showed no benefit over placebo.
Since then the peptide has been studied mainly as a possible treatment for radiation injury. In mice given lethal whole-body radiation, a single injection 24 hours later improved survival, protected the gut lining and stem cells, and restored endothelial function; PEGylated versions stayed in the blood longer. These are animal studies for an emergency use, not evidence for wound care in people.
Rusalatide was never approved and is not a medicine, and nothing on this page is a dose for anyone to use. The only published human dose below is the amount applied to foot ulcers in the phase 1/2 study, by trial staff and alongside standard wound care.
Mechanism of Action
Rusalatide carries thrombin's cell-signalling face without its clotting enzyme: it binds cell-surface receptors, including the αvβ3 integrin through its RGD motif, and switches on repair programmes in endothelial and other cells.
Nitric oxide and vessel function
It activates endothelial nitric oxide synthase and restores nitric oxide-dependent relaxation in ischaemic vessels (PMIDs 18757834, 19231390).
New blood vessels
Wounds and fracture calluses treated with it had more and larger functional vessels, and it enhanced sprouting driven by VEGF (PMIDs 10886811, 15885490, 23594718).
Repair genes and cell survival
In fractures it raised early growth factor and inflammatory genes and shifted proteins toward cell growth and survival (PMIDs 15885490, 17942078).
Published Research
The studies behind rusalatide (TP508), read from their PubMed abstracts: one human trial, four reviews including the account of its phase 3 fracture result, and the animal and cell work in wounds, bone, heart and radiation injury. One systematic review is carded because its abstract names rusalatide although its title does not.
Diabetic foot ulcers: phase 1/2
In 60 patients, 1 or 10 µg in saline applied to the ulcer twice weekly with standard care and offloading gave 45% and 72% more complete healing than placebo (per protocol), about 80% faster closure and 40% shorter time to closure; heel ulcers healed in 6 of 7 against 0 of 5. Adverse events were equal between groups.
Phase 3 in wrist fractures
After positive phase 1/2 trials in foot ulcers and distal radius fractures, a large phase 3 fracture trial showed faster healing on X-ray but missed its primary endpoint, time to removal of immobilisation, in the whole population; a subgroup of osteopenic women met it.
How it accelerates repair
A review of preclinical work: the 23-residue peptide from thrombin's receptor-binding domain recruits inflammatory cells, stimulates migration, proliferation and matrix production and speeds revascularisation in skin and bone; early human studies in ulcers and radius fractures were positive.
Technology evaluation of Chrysalin
A 2005 evaluation describes Chrysalin as a synthetic 23-amino-acid peptide mimicking part of human thrombin, then in phase 2 for diabetic foot ulcers and phase 3 for fractures and cartilage repair.
Growth factors for diabetic foot ulcers
A systematic review of 26 randomised trials of growth factors and recombinant proteins, rusalatide acetate among them, found the strongest agreement for EGF and too few, heterogeneous trials to judge most other agents.
Skin wounds in rats
One topical application of 0.1 µg closed full-thickness wounds 39% more than controls by day 7; 1.0 µg wounds were 35-43% smaller on days 7 and 10, with earlier inflammatory cell recruitment and larger new vessels.
Wounds in ischaemic skin
In surgically created ischaemic flaps and grafts in rats, a single 0.1 µg application raised early closure rates by 30% to 225% and restored closure in flaps to near the rate of normal skin.
Rat femur fractures
A single injection made fractures stronger on torsion testing, increased blood vessels in the callus and switched on early growth factor, inflammatory and angiogenesis genes.
Fracture healing at the protein level
Antibody arrays of rat fracture tissue after one injection showed shifts in proteins for cell cycle, growth and survival over death, across pathways including PI3K/AKT, NF-κB and ERK/MAPK.
High-energy fractures in mice
In 80 mice with crushed thigh muscle and open femur fractures, 100 µg into the fracture gap gave the stiffest bone at five weeks, with less scar tissue and more vessels in muscle and gap.
Bone defects in rabbits
Released from biodegradable polymer microspheres into radius and critical-size ulna defects, 10-200 µg increased torque and energy to failure and radiographic healing scores against control microspheres.
Radiation injury to the gut (mice)
One injection 24 hours after lethal whole-body radiation increased survival and delayed death, preserved intestinal crypts, raised E-cadherin and crypt stem cell markers and reduced apoptosis.
Radiation and blood vessels
It reversed radiation's effects on nitric oxide signalling and tube formation in human endothelial cells, sped DNA break repair, restored aortic sprouting in irradiated mice and improved survival when given 24 hours after exposure.
Short half-life, PEG derivatives
Because TP508 has a short plasma half-life, PEG chains were attached; in mice a 30 kDa PEG derivative lasted about 19 times longer and a 5 kDa one was more active, while intermediate sizes lasted longer but did not work.
Vessel growth under low oxygen
An injection in mice increased endothelial sprouting from aortas taken 24 hours later, boosted the response to VEGF and largely prevented the blunting of sprouting by hypoxia.
Heart attack model in pigs
In 14 pigs with an hour of coronary occlusion, a 0.5 mg/kg bolus and infusion reduced infarct size and cell death and improved endothelium-dependent relaxation of small coronary vessels; pumping function did not differ.
Chronic ischaemia in pig hearts
In pigs with chronically narrowed coronary arteries, it raised perfusion of ischaemic regions up to 16-fold, doubled wall thickening and restored nitric oxide-dependent vessel relaxation; in human endothelial cells it activated eNOS.
Binding the αvβ3 integrin
Immobilised TP508, residues 508-530 of prothrombin, supported endothelial cell adhesion through its RGD motif and the αvβ3 integrin, activated FAK and ERK1/2, and induced nitric oxide in endothelial cells.
Agonist when fixed, antagonist in solution
Fixed to a surface it promoted αvβ3-dependent endothelial attachment and migration like thrombin, while in solution it blocked several angiogenic effects of thrombin; a version with RAD instead of RGD was inactive.
Dosing Data
Rusalatide's only published human dose is the amount applied to diabetic foot ulcers in its phase 1/2 trial. The abstracts of its fracture trials give no dose. It was never approved, so there is no labelled dose.
Educational information, not medical advice. Each dose above is tagged with its source: an approved label, a published human study, animal data, or amounts reported by users. None is a recommendation for you. An unapproved compound has no established safe or effective human dose, and products sold for “research use only” are not made or tested for people. Talk to a doctor before acting on anything on this site, including before you start, stop or change any medicine or dose. Full medical disclaimer.
What a Buyer Needs to Know
What is sold, how it is mixed, stored and taken, and what is known about its safety, quality and legal status. Each part names its source. Where we have none, it says unknown.
What is sold
Unknown: we hold no label and no published test that says what forms or vial sizes Rusalatide is sold in. A vial's own label is a seller's claim, not a source.
Mixing a vial: a worked example
No worked example: none of the doses on this page is a fixed amount in mg or mcg injected under the skin or into a muscle (the routes given are: topical). There is no home-mixing step to show. The reconstitution calculator does the arithmetic for any vial.
Source: the route and amount of each dose row in Dosing Data below.
Storage before and after mixing
Unknown: no label or published stability study on file says how to store Rusalatide, before or after mixing. The mixing guide sets out the general rules, with their sources: keep a mixed vial in the fridge, and use it promptly, as the bacteriostatic water label says of any drug dissolved in it. The 28 days often quoted is the limit for an opened multiple-dose vial from a manufacturer, an outer limit set for sterility, not a time a mixed solution has been shown to keep. Nobody has published how long Rusalatide stays intact once mixed.
How it is taken
As it was given in human studies: Topical, applied to the ulcer (Twice weekly; Study: diabetic foot ulcers, phase 1/2).
For injection technique, sites and needle disposal, see the mixing guide.
Source: Used in human trials: the route and frequency of each row in Dosing Data below.
What to expect, and when
How long it stays in the body: a half-life of Short; no figure in the abstracts read (a 30 kDa PEG derivative lasted about 19 times longer in mice). After about five half-lives almost none is left.
When effects appear: unknown; no source on this page gives a time to effect for Rusalatide. Results reported in the studies are under Published Research.
Source: half-life: PMID 28097629.
Side effects, and when to stop or get help
From the Side Effects section: Local wound reactions and adverse events occurred equally with rusalatide and placebo in the foot ulcer trial (PMID 17244316); No drug-related changes in laboratory tests and no serious adverse events reported in that trial (PMID 17244316); The phase 3 fracture trial's abstracted report gives efficacy, not safety, results (PMID 18803458). Full list and cautions ↓
When to stop or get help: unknown; no label or trial on file sets rules for stopping Rusalatide. Treat a severe or unexpected reaction as a reason to stop and see a doctor.
Source: the Side Effects section below (“From the human trial and the review of its fracture trials”).
Interactions
Unknown: a PubMed search for human interaction studies of Rusalatide (reviewed 2026-10-30) found none. Unknown is not the same as safe to combine.
Every peptide's record, with its source: the interaction matrix.
Checking what you bought
Unknown: no published independent test of Rusalatide products is in our lab-results database yet, so how products sold under this name measure up is not known.
To read a certificate of analysis, paste it into the COA decoder; it checks the measured mass against Rusalatide's expected mass, 2,311.5 Da, from this entry's molecular data. Trust & Verification explains what independent testing can and cannot show.
Legal status
US: Not FDA Approved (Not approved: Drugs@FDA (openFDA) holds no record and the EMA medicines list no entry (searched October 30, 2026)). Sport: Prohibited (S0 catch-all).
Country by country ↓ · Regulatory tracker
Source: this entry's approval status and the WADA Prohibited List, as in Legal Status below.
Side Effects & Contraindications
Reported Side Effects
From the human trial and the review of its fracture trials.
Contraindications & Cautions
No label exists. These cautions follow from its record.
Legal Status
Rusalatide is an investigational drug that was never approved. Its development for wounds and fractures has stopped.
Frequently Asked Questions
?What is TP508?
TP508, named rusalatide, is a 23-amino-acid synthetic peptide copied from human prothrombin. It keeps the cell-binding part of thrombin and none of its clotting activity.
?Does it heal wounds in people?
In one 60-patient trial, applying it to diabetic foot ulcers twice a week healed more ulcers than placebo. No larger wound trial has been published.
?What happened with fractures?
A large phase 3 trial in wrist fractures showed faster healing on X-ray but missed its main clinical endpoint, and a later fracture study was stopped because the drug did no better than placebo.
?Is it related to BPC-157 or TB-500?
No. All three are discussed as healing peptides, but rusalatide comes from thrombin and acts partly through the αvβ3 integrin; it shares no sequence with the others.
?Why is it studied for radiation injury?
In mice, one injection a day after lethal radiation improved survival and protected the gut and blood vessels. That work is aimed at nuclear emergencies and has not been tested in people.
?Is it approved anywhere?
No. It was never approved, and the version tested in trials is not available.
References
- [clinical-trial] Fife C, et al. "Thrombin peptide Chrysalin stimulates healing of diabetic foot ulcers in a placebo-controlled phase I/II study." Wound Repair Regen, 2007;15(1):23-34. PMID: 17244316.
- [review] Carney DH, et al. "Could rusalatide acetate be the future drug of choice for diabetic foot ulcers and fracture repair?." Expert Opin Pharmacother, 2008;9(15):2717-26. PMID: 18803458.
- [review] Ryaby JT, et al. "Thrombin peptide TP508 stimulates cellular events leading to angiogenesis, revascularization, and repair of dermal and musculoskeletal tissues." J Bone Joint Surg Am, 2006;88 Suppl 3:132-9. PMID: 17079379.
- [review] Rodgers KE. "Technology evaluation: Chrysalin (Orthologic)." Curr Opin Mol Ther, 2005;7(3):264-72. PMID: 15977425.
- [review] Mahdipour E, et al. "The Role of Recombinant Proteins and Growth Factors in the Management of Diabetic Foot Ulcers: A Systematic Review of Randomized Controlled Trials." J Diabetes Res, 2020;2020:6320514. PMID: 32733969.
- [pubmed] Stiernberg J, et al. "Acceleration of full-thickness wound healing in normal rats by the synthetic thrombin peptide, TP508." Wound Repair Regen, 2000;8(3):204-15. PMID: 10886811.
- [pubmed] Norfleet AM, et al. "Thrombin peptide TP508 accelerates closure of dermal excisions in animal tissue with surgically induced ischemia." Wound Repair Regen, 2000;8(6):517-29. PMID: 11208179.
- [pubmed] Wang H, et al. "Thrombin peptide (TP508) promotes fracture repair by up-regulating inflammatory mediators, early growth factors, and increasing angiogenesis." J Orthop Res, 2005;23(3):671-9. PMID: 15885490.
- [pubmed] Li X, et al. "TP508 accelerates fracture repair by promoting cell growth over cell death." Biochem Biophys Res Commun, 2007;364(1):187-93. PMID: 17942078.
- [pubmed] Hanratty BM, et al. "Thrombin related peptide TP508 promoted fracture repair in a mouse high energy fracture model." J Orthop Surg Res, 2009;4:1. PMID: 19175943.
- [pubmed] Sheller MR, et al. "Repair of rabbit segmental defects with the thrombin peptide, TP508." J Orthop Res, 2004;22(5):1094-9. PMID: 15304284.
- [pubmed] Kantara C, et al. "Novel regenerative peptide TP508 mitigates radiation-induced gastrointestinal damage by activating stem cells and preserving crypt integrity." Lab Invest, 2015;95(11):1222-33. PMID: 26280221.
- [pubmed] Olszewska-Pazdrak B, et al. "Nuclear Countermeasure Activity of TP508 Linked to Restoration of Endothelial Function and Acceleration of DNA Repair." Radiat Res, 2016;186(2):162-74. PMID: 27388041.
- [pubmed] McVicar SD, et al. "Radiomitigation and Tissue Repair Activity of Systemically Administered Therapeutic Peptide TP508 Is Enhanced by PEGylation." AAPS J, 2017;19(3):743-753. PMID: 28097629.
- [pubmed] Olszewska-Pazdrak B, et al. "Systemic administration of thrombin peptide TP508 enhances VEGF-stimulated angiogenesis and attenuates effects of chronic hypoxia." J Vasc Res, 2013;50(3):186-96. PMID: 23594718.
- [pubmed] Osipov RM, et al. "Thrombin fragment (TP508) decreases myocardial infarction and apoptosis after ischemia reperfusion injury." Ann Thorac Surg, 2009;87(3):786-93. PMID: 19231390.
- [pubmed] Fossum TW, et al. "TP508 (Chrysalin) reverses endothelial dysfunction and increases perfusion and myocardial function in hearts with chronic ischemia." J Cardiovasc Pharmacol Ther, 2008;13(3):214-25. PMID: 18757834.
- [pubmed] Derkach DN, et al. "RGD-dependent binding of TP508 to integrin alphavbeta3 mediates cell adhesion and induction of nitric oxide." Thromb Haemost, 2010;104(1):172-82. PMID: 20508901.
- [pubmed] Tsopanoglou NE, et al. "On the mode of action of thrombin-induced angiogenesis: thrombin peptide, TP508, mediates effects in endothelial cells via alphavbeta3 integrin." Thromb Haemost, 2004;92(4):846-57. PMID: 15467917.
- [registry] ClinicalTrials.gov API v2, read October 30, 2026: NCT00131482 (phase 2, 'A Study to Evaluate the Safety and Effectiveness of Different Doses of Chrysalin', Capstone Therapeutics, 274 enrolled, terminated March 2007; reason: 'Treatment with Chrysalin did not demonstrate benefit compared to placebo.'). https://clinicaltrials.gov/study/NCT00131482
- [other] ChEMBL CHEMBL2111105 (rusalatide; synonyms TP508, Chrysalin, rusalatide acetate): HELM PEPTIDE1{A.G.Y.K.P.D.E.G.K.R.G.D.A.C.E.G.D.S.G.G.P.F.V.[am]}, full molecular formula C97H147N29O35S, molecular weight 2311.48. Read October 30, 2026. https://www.ebi.ac.uk/chembl/compound_report_card/CHEMBL2111105/
- [other] UniProt P00734 (THRB_HUMAN, prothrombin): the TP508 sequence AGYKPDEGKRGDACEGDSGGPFV occupies positions 551-573 of the precursor, which includes the 43-residue signal and propeptide. Read October 30, 2026. https://www.uniprot.org/uniprotkb/P00734/entry
- [other] US FDA, Drugs@FDA (openFDA drugsfda endpoint), searched October 30, 2026: no application for rusalatide, TP508 or Chrysalin.
Sources & Citations
Every study on this page was read from its PubMed record on October 30, 2026. Trial registration comes from ClinicalTrials.gov, the sequence from ChEMBL and UniProt, and regulatory status from Drugs@FDA and the EMA medicines list, all read the same day. Grey Peptides sells nothing and links to no vendor.
Medical Disclaimer: This content is for educational and informational purposes only. It is not medical advice, and nothing here is an instruction to obtain or use any compound. Talk to a licensed clinician about your own situation.