What are the potential benefits of Thymosin Beta-4 Fragment (Ac-SDKP)?

Bone marrow stem cell protection during chemotherapy. Cardiac and renal antifibrotic activity. Anti-inflammatory via macrophage and cytokine modulation. Elevates naturally with ACE inhibitor use. Potential in heart failure, kidney disease, and lung fibrosis

What compounds work synergistically with Thymosin Beta-4 Fragment (Ac-SDKP)?

Thymosin Beta-4 Fragment (Ac-SDKP) has been studied alongside ACE inhibitors, TB-500 (Thymosin Beta-4), G-CSF for potential synergistic effects.

Thymosin Beta-4 Fragment (Ac-SDKP) — Mechanism, Benefits, Research & Synergies

Overview

Ac-SDKP (N-acetyl-seryl-aspartyl-lysyl-proline) is a naturally occurring tetrapeptide released from thymosin beta-4 by prolyl oligopeptidase and ACE2 cleavage. It is a powerful regulator of hematopoietic stem cell proliferation, inhibiting entry of pluripotent hematopoietic stem cells into the S-phase of the cell cycle—protecting them from cycle-dependent cytotoxic damage during chemotherapy. Ac-SDKP also exerts significant antifibrotic effects in the heart, kidneys, and lungs, and is hydrolyzed by ACE (angiotensin-converting enzyme), explaining why ACE inhibitors elevate plasma Ac-SDKP levels.

Mechanism of Action

Ac-SDKP acts through multiple mechanisms: (1) Hematopoietic stem cell cycle arrest—inhibits G0-S transition via BMP4/SMAD pathway suppression, protecting stem cells from S-phase cytotoxic chemotherapy; (2) Antifibrotic—suppresses TGF-β1-induced myofibroblast differentiation and collagen synthesis in cardiac and renal fibroblasts; (3) Anti-inflammatory—reduces macrophage activation and TNF-α/IL-6 production; (4) Angiogenic—promotes endothelial cell migration and tube formation. Its ACE-mediated hydrolysis links it to the renin-angiotensin system.

Potential Benefits

Bone marrow stem cell protection during chemotherapy
Cardiac and renal antifibrotic activity
Anti-inflammatory via macrophage and cytokine modulation
Elevates naturally with ACE inhibitor use
Potential in heart failure, kidney disease, and lung fibrosis

Research Dosage Notes

The following reflects doses used in published research studies. This is not medical advice.

Clinical myeloprotection: 1–5 mg/kg IV prior to chemotherapy cycles in trials. No established standard dosing.

Amino Acid Sequence

Ac-Ser-Asp-Lys-Pro

Side Effects & Safety

Well-tolerated in clinical studies
Potential excess stem cell cycle suppression at very high doses

Synergistic Compounds

The following compounds have been studied alongside Thymosin Beta-4 Fragment (Ac-SDKP) for potential complementary or synergistic effects:

ACE inhibitorsTB-500 (Thymosin Beta-4)G-CSF

Learn More

Beginner's GuideNew to peptides? Start here Stacking GuideSynergistic combinations Administration RoutesSubQ, IM, oral, nasal & more Reconstitution CalculatorCalculate exact dosing Peptides vs SARMsFull comparison How Peptides Are MadeSPPS, purification & QC

References & Further Reading

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Quick Facts

Molecular Weight	488.5 g/mol
Research Status	Preclinical and Phase I/II clinical data for myeloprotection. Antifibrotic effects well-established in animal models. Clinical development ongoing.

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Thymosin Beta-4 Fragment (Ac-SDKP)