TB-500 · pharmacokinetics · research use only
TB-500 half-life: the gap between plasma and tissue.
The most-asked question about TB-500's kinetics is also the most misunderstood: the circulating peptide clears in hours, yet research schedules dose it only twice a week. That is not a contradiction — it reflects two different clocks. TB-500, the synthetic active fragment of Thymosin Beta-4, has a short measured plasma half-life but a much longer functional persistence in tissue. This page explains that gap as a research reference, frames it against BPC-157's very different kinetics, and is not a human protocol or medical advice.
Short plasma half-life
Measured in circulation, TB-500 clears quickly — its plasma half-life is reported on the order of a few hours, comparable to many small synthetic peptides. If plasma concentration were the only thing that mattered, the compound would need near-daily administration. It does not, and that is the whole point of the next card.
How that shapes dosing →Long tissue persistence
TB-500's actin-binding fragment is studied for a biological effect that outlasts the circulating peptide. The functional persistence reported in tissue-repair models is considerably longer than plasma clearance would suggest — which is why a twice-weekly cadence is the norm in the literature even though blood levels fall away within a day.
TB-500 research overview →Why twice-weekly, not daily
Research protocols model TB-500 around the tissue clock, not the plasma clock: a loading window of roughly 5–10 mg per week split across two administrations, then a lower maintenance total. The dosing-frequency choice follows directly from the half-life mismatch — fewer, larger administrations rather than small daily ones.
Loading vs maintenance →Contrast with BPC-157
BPC-157 is the peptide TB-500 is most often paired with, and its kinetics run the opposite way: BPC-157 also shows a short systemic half-life but is typically modelled on a daily microgram schedule, while TB-500 runs twice-weekly in milligrams. The two compounds sit on parallel research schedules precisely because their clocks differ.
BPC-157 half-life →Lot purity changes the curve
Half-life figures from the literature assume the material is what the label says. Titan's TB-500 is a 5mg lyophilized powder with an HPLC main-peak result against a ≥99% internal purity target and mass-spec identity confirmation on a lot-matched release sheet. A degraded or mislabelled lot shifts the effective amount and any kinetic modelling built on it.
See the testing workflow →Research-use framing
TB-500 has no regulatory approval for human use. The half-life and persistence figures here are reproduced as a laboratory reference for in-vitro and modelling work — not instructions for human use. Titan supplies TB-500 strictly as a research reagent, and nothing on this page is medical or dosing advice.
Research-use policy →The detail, in plain terms
The two clocks, side by side.
TB-500's kinetics only make sense when plasma clearance and tissue persistence are read as separate variables. These are the figures a research protocol weighs — reproduced as a reference, not a human protocol.
- Compound
- TB-500 — synthetic active fragment of Thymosin Beta-4.
- Plasma half-life
- Short — reported on the order of a few hours.
- Tissue persistence
- Considerably longer than plasma clearance (functional effect outlasts blood levels).
- Resulting cadence
- Twice-weekly in research protocols, not daily.
- Loading reference
- ≈5–10 mg/week split twice weekly for ~4–6 weeks (see dosage page).
- Format
- 5mg lyophilized vial, $89.99 — reconstitute before in-vitro use.
Questions researchers ask
Before you order.
- What is the half-life of TB-500?
- TB-500's plasma half-life is short — reported on the order of a few hours. However, its biological persistence in tissue is considerably longer, which is the more relevant figure for how the compound is studied. The two numbers describe different things: how fast the peptide leaves circulation versus how long its functional effect is modelled to last in tissue.
- Why is TB-500 dosed only twice a week if it clears in hours?
- Because research protocols follow the tissue clock, not the plasma clock. The actin-binding fragment is studied for an effect that outlasts the circulating peptide, so schedules use a twice-weekly cadence — fewer, larger administrations — rather than near-daily dosing. The short plasma half-life does not require daily administration in the models reported in the literature.
- How does TB-500's half-life compare to BPC-157?
- Both show short systemic half-lives, but they are modelled differently: BPC-157 is typically run on a daily microgram schedule while TB-500 runs twice-weekly in milligrams. The two are frequently paired in tissue research precisely because their kinetics and cadences differ — see the BPC-157 half-life and stack pages for the comparison.
- Does lot purity affect TB-500 kinetics?
- Half-life figures assume the material matches its label. A degraded or mislabelled lot changes the effective amount and undermines any kinetic modelling. Titan's TB-500 ships with an HPLC main-peak result against a ≥99% internal purity target and mass-spec identity confirmation on a lot-matched release sheet, so the starting material is characterised before any modelling.
- Is TB-500 approved for human use?
- No. TB-500 has no regulatory approval for human use. Titan Peptide Lab supplies it strictly as a research-use-only reagent for in-vitro laboratory work — not for human or animal consumption, and not for diagnostic, therapeutic, or preventative use.