What is TB-500?
TB-500 is a synthetic research peptide built around the active region of Thymosin Beta-4 (often written Tβ4), a small protein of 43 amino acids that occurs in nearly every cell of the human body. Tβ4 is the most abundant member of the beta-thymosin family and one of the principal regulators of actin, the structural protein that lets cells change shape and move. TB-500 reproduces the part of that protein responsible for binding actin, which is why researchers treat it as a focused tool rather than the whole, harder-to-handle protein.
Chemically, TB-500 has a molecular mass of about 4,963 Da. That figure is useful when you source material: a mass-spectrometry result on a Certificate of Analysis should match it closely, which is the simplest way to confirm you have the real peptide and not a truncated by-product.
How TB-500 works: actin, migration and repair
The defining activity of TB-500 is actin sequestration. By binding monomeric (G-)actin, it influences how quickly the cytoskeleton assembles and disassembles — and that, in turn, governs how readily cells migrate toward an injury. The literature describes four interlocking roles, all reported in animal and cell-culture models rather than humans.
| Function | Mechanism | Reported relevance |
|---|---|---|
| Actin regulation | Sequesters G-actin, the most abundant cytoskeletal protein | Foundational to cell shape and movement |
| Cell migration | Modulates actin polymerisation so cells move to damaged zones | Faster repopulation of an injury site |
| Angiogenesis | Supports formation of new blood vessels | Improved perfusion of healing tissue |
| Inflammation control | Documented anti-inflammatory and immunomodulatory effects | A calmer local repair environment |
What the TB-500 research evidence shows
Unlike many research peptides, Thymosin Beta-4 has reached human clinical trials in specific formulations, which gives the underlying biology more weight than animal data alone.
- Cardiac repair. Bock-Marquette et al. (2004, Nature) reported that Tβ4 improved cardiomyocyte survival and promoted new vessel growth in injured heart tissue — a landmark paper that drew attention to the molecule.
- Skin and wound healing. Malinda et al. (1999, Journal of Investigative Dermatology) reported accelerated wound closure with increased keratinocyte and endothelial-cell migration.
- Corneal repair. RGN-259, a Tβ4 eye-drop developed by RegeneRx Biopharmaceuticals, advanced into phase 2/3 clinical trials for dry-eye and corneal wound healing — a rare example of a beta-thymosin reaching late-stage human study.
TB-500 reconstitution and dosing in research
TB-500 is shipped as a lyophilized (freeze-dried) powder and reconstituted with bacteriostatic water before use in a model. The concentration is simply mass divided by volume.
- Bring the TB-500 vial and bacteriostatic water to room temperature (about 15 minutes).
- Swab the rubber stopper of both the peptide vial and the water vial with alcohol.
- Draw the chosen volume of bacteriostatic water with a sterile insulin syringe — 2 mL is a common choice.
- Angle the needle against the inner glass wall and let the water trickle down; do not spray it onto the lyophilized powder.
- Roll the vial gently between your palms until the solution is clear. Never shake.
- A 5 mg vial in 2 mL gives 2.5 mg/mL (2,500 µg/mL); the same vial in 1 mL gives 5 mg/mL.
- Store the reconstituted solution at 2–8 °C, protected from light, and use within 3–4 weeks.
For dosing, preclinical protocols cluster around 2–10 µg per kg of bodyweight per dose, applied a few times per week — figures drawn from animal models, not human guidance. The full concentration-math walkthrough (how to convert a µg target into a volume to withdraw) is shared with the BPC-157 dosage guide, which uses the same method.
Sourcing TB-500: what to check
Because TB-500 is widely sold, the burden is on the researcher to verify quality. A very low price is usually a signal of poor purity or careless storage rather than a bargain.
- Purity ≥ 99% by HPLC, with a recent batch COA from a named laboratory such as Janoshik.
- Mass near 4,963 Da confirmed by mass spectrometry on that COA.
- White, intact lyophilizate — any yellow or brown tint suggests degradation.
- Vial sealed under vacuum or inert gas to prevent oxidation, and shipped light-protected.
For the cross-compound view of purity, storage and red flags, see the complete research peptides guide.
TB-500 and BPC-157 in regeneration research
The most studied pairing in this space combines TB-500 with BPC-157. The logic is complementary mechanisms: TB-500 works systemically via actin and cell migration, while BPC-157 acts locally and drives angiogenesis. Our BPC-157 research guide breaks down that compound in full.