TB-500 Dosing Guide: Protocol, Reconstitution & Evidence
TB-500 is a synthetic fragment of Thymosin Beta-4 and one half of the most-run peptide pairing there is. This guide covers the loading structure people actually use, the syringe-volume problem nobody warns you about, and why TB-500 and Tβ4 are not interchangeable.
Also known as Thymosin Beta-4 fragment, TB4-Frag
TB-500 quick start
- Route
- Subcutaneous injection is the most common research-context format. Intramuscular is also described.
- Dose context
- 2–5 mg twice weekly through a loading phase, dropping to around 2 mg weekly for maintenance. This structure has been stable in the community for years. It is convention rather than a trial finding, but people who deviate from it tend to come back to it.
- Measure
- At 3.0 mL reconstitution of a 10 mg vial, 1 unit on a U-100 syringe is about 33 mcg. A 2 mg dose is 60 units.
- Cycle context
- A 4–6 week loading phase followed by reduced-frequency maintenance is the common structure.
- Status
- Not FDA-approved. On the WADA Prohibited List. Not the same molecule as full-length Thymosin Beta-4.
Dosing context and schedule
What follows is drawn from the published record and from what the community has settled on. Reference points, not prescriptions — your situation is yours.
| Phase | Dose | Volume | Units (U-100) | Note |
|---|---|---|---|---|
| Loading (weeks 1–4) | 2–5 mg | 0.60–1.50 mL | 60–150 units | Twice weekly. 10 mg vial in 3.0 mL. Doses above 100 units require splitting across two syringes. |
| Maintenance | 2 mg | 0.60 mL | 60 units | Once weekly or every other week. |
Cycle structures
| Approach | Duration | Review point | Note |
|---|---|---|---|
| Loading then maintenance | 4–6 weeks loading | Week 4 | The most commonly described structure. |
| Short structure | 4 weeks | Week 4 | Loading only. |
| Continuous use | Not characterised | — | No human study addresses long-term administration. |
What people actually run
The converged protocol
2–5 mg twice weekly for a 4–6 week loading phase, then 2 mg weekly or every other week as maintenance. SubQ, site does not appear to matter much given the systemic mechanism.
The loading-then-maintenance structure is a community convention rather than a trial finding, but it has been stable for years and most people who deviate come back to it.
Because doses are in milligrams rather than micrograms, draw volumes get large. A 2 mg dose from a 10 mg vial in 3 mL is 60 units — most of a 1 mL syringe. At the top of the loading range you will exceed 100 units and need to split. Reconstitute with less water if that becomes annoying.
This is one of the more frequently counterfeited peptides, and it is expensive enough that people notice. Third-party testing is worth more here than almost anywhere else in the library.
Half-life figures of "2–3 days" circulate widely and are not from a human PK study. Treat the twice-weekly loading schedule as what works in practice rather than as pharmacokinetically derived.
What the evidence actually says
The honest picture
Two things get conflated constantly, and separating them makes everything else clearer. Thymosin Beta-4 is a naturally occurring 43-amino-acid protein with real human trial data behind it, including ophthalmology and cardiac work. TB-500 is a shorter synthetic fragment covering the actin-binding region. Evidence for one is not automatically evidence for the other, and some vendors blur that on purpose — knowing the difference is what stops you overpaying for the wrong thing.
TB-500 itself has no published human efficacy trial, for the same structural reason as BPC-157: no patent, no sponsor, no nine-figure trial. What it has instead is a long and consistent track record in the recovery community, and protocols that have stayed stable for years.
One practical note worth carrying: the widely quoted "2–3 day half-life" does not come from any human PK study. The twice-weekly loading schedule does work in practice — just hold it as accumulated experience rather than something derived from measurement, and adjust off how you actually respond.
How it is proposed to work
Thymosin Beta-4 is an actin-sequestering protein present in most cell types and involved in cell migration, wound repair and angiogenesis. TB-500 reproduces the portion of the sequence responsible for actin binding.
The proposed mechanism is that actin regulation supports cell migration to injured tissue, alongside angiogenic effects. Animal work has reported effects on wound healing, cardiac tissue after ischaemia, and corneal repair.
Whether a fragment reproduces the behaviour of the full protein is a real open question, not a technicality. Fragments frequently behave differently from their parent molecules.
When to talk to a doctor first
Most people run TB-500 without incident. These are the specific situations where it is worth a conversation with a clinician before you start — not reasons to rule it out, but reasons to go in with your eyes open.
- If you have an active or suspected malignancy — same reasoning as BPC-157. TB-500 promotes vessel formation, which is how it helps tissue repair and, in principle, how a tumour would grow. Not excluded either way in humans, so worth clearing with your doctor first.
- If you are pregnant or breastfeeding — no reproductive data exists, so this is one to postpone.
- If you compete in a tested sport — TB-500 is prohibited, and some programmes screen for it specifically.
- If the injury is not improving — get it looked at properly. TB-500 works alongside a diagnosis, not in place of one.
What to expect
Most of what people notice is mild and settles within the first week or two. The list below is ordered by how often it actually comes up, so you know what is routine and what is worth paying attention to.
Common, and usually settles
- Injection site reactions.
- Transient fatigue or head-rush shortly after administration, reported anecdotally.
Less common
- Headache.
- Temporary lethargy in the first days of a loading phase.
Rare — stop and get advice
- No serious adverse events have been characterised in controlled human trials of TB-500, because such trials have not been conducted.
- The angiogenic mechanism and its theoretical relationship to tumour growth remains the principal unresolved concern.
Reconstitution guide
TB-500 ships as a lyophilised powder and gets mixed with bacteriostatic water before use. How much water you add sets the concentration, which sets how many syringe units make up each dose. One unit on a U-100 syringe is 0.01 mL — the tables below do the arithmetic for the vial sizes you are most likely to be holding.
10mg vial most common
| Water added | Concentration | 2mg | 5mg |
|---|---|---|---|
| 2mL (common) | 5 mg/mL | 0.40 mL 40 units | 1.00 mL 100 units |
| 3mL | 3.33 mg/mL | 0.60 mL 60 units | 1.50 mL 150 units * |
5mg vial
| Water added | Concentration | 2mg | 5mg |
|---|---|---|---|
| 2mL (common) | 2.5 mg/mL | 0.80 mL 80 units | 2.00 mL 200 units * |
| 3mL | 1.67 mg/mL | 1.20 mL 120 units * | 3.00 mL 300 units * |
* More than 100 units — that is more than a single U-100 insulin syringe holds. Either use a larger syringe, split it across two draws, or mix with less water to concentrate it. Adding less water is usually the easier fix.
Standard steps
- Inspect the vialConfirm the label and that the powder cake is intact. Do not use a cracked or compromised vial.
- Let it reach room temperatureSitting out for a few minutes reduces condensation inside the vial when the seal is broken.
- Disinfect both stoppersWipe the compound vial and the bacteriostatic water vial with a fresh alcohol swab and let them air-dry.
- Draw the bacteriostatic waterUse a sterile syringe to draw the volume you have chosen from the reconstitution table.
- Add the water down the vial wallInject slowly so it runs down the inside wall rather than spraying directly onto the powder. This limits foaming.
- Dissolve gentlySwirl or roll the vial between your hands until the cake dissolves. Never shake — agitation damages peptide bonds. The solution should end up clear.
- Label and refrigerateWrite the reconstitution date and concentration on the vial. Store at 2–8°C. Do not freeze.
Timeline and monitoring
- Weeks 1–2Early loading phase. No published human timeline exists.
- Weeks 4–6End of the typical loading structure and the usual review point.
- Beyond 6 weeksMaintenance dosing at reduced frequency, where a longer structure is used.
- After useNo withdrawal effect described in the literature.
Bloodwork worth discussing
Markers a clinician may consider relevant before or during a protocol. This is context for a conversation, not a self-ordering list.
| Marker | Why it is relevant |
|---|---|
| Complete blood count | General baseline before an extended protocol. |
| Comprehensive metabolic panel | Baseline organ function. |
| Age-appropriate cancer screening | Reasonable given the angiogenic mechanism. Worth discussing with a clinician. |
Supplies by cycle length
A 10 mg vial provides 5 doses at 2 mg, or 2 doses at 5 mg.
| Cycle length | Vials | Syringes | BAC water | Planning note |
|---|---|---|---|---|
| 4 weeks loading | 2 vials | 8 syringes | 1 × 10 mL bottle | 2 mg twice weekly. |
| 6 weeks loading | 3 vials | 12 syringes | 1 × 10 mL bottle | 2 mg twice weekly. |
| 12 weeks total | 4 vials | 18 syringes | 2 × 10 mL bottles | 6 weeks loading, then weekly maintenance. |
What the research record contains
Full-length Thymosin Beta-4 has been studied in humans, including trials in ophthalmology and cardiac repair. Those studies do not establish anything about TB-500.
TB-500 itself has no published human efficacy trials. The animal literature covers wound models, cardiac ischaemia and corneal injury.
Half-life claims for TB-500 that circulate widely are not traceable to a published human pharmacokinetic study. Treat specific numbers with suspicion.
TB-500 is among the more frequently counterfeited peptides sold online. Third-party analytical testing is worth more here than in most categories.
Storage and handling
- Lyophilised powder: refrigerate at 2–8°C.
- Reconstituted: refrigerate only, never freeze.
- Typically used within 30 days of reconstitution.
- Because loading doses draw large volumes, plan reconstitution volume around the syringe size you actually own.
Troubleshooting
My dose exceeds 100 units.
A 1 mL U-100 syringe holds 100 units. Either split the dose across two injections, or reconstitute with less water to concentrate the solution.
Is TB-500 the same as Thymosin Beta-4?
No. TB-500 is a synthetic fragment of the actin-binding region. Human research on full-length Tβ4 does not transfer to the fragment.
How do I know it is real?
You do not, without third-party testing. This compound is expensive and frequently counterfeited, which makes a certificate of analysis from an independent lab worth asking for.
Loading versus maintenance — is that structure evidence-based?
No. It is a community convention. No trial has compared loading structures in humans.
Regulatory status
Not approved by the FDA for any use.
On the WADA Prohibited List. TB-500 has been specifically named in anti-doping cases, particularly in equine sport.
Sold as "research use only" material. That labelling reflects the seller's legal position, not product quality.
How it compares
| Compared with | Difference that matters |
|---|---|
| BPC-157 | Commonly paired, on the theory that BPC-157 acts locally and TB-500 systemically. The pairing rationale is theoretical — no human study has tested the combination. |
| Thymosin Beta-4 | The parent protein, not the same molecule. Tβ4 has human trial data; TB-500 does not. |
Frequently asked questions
How long until it works?
No published human timeline exists. Reports describing specific windows are anecdotal.
Can it be combined with BPC-157?
Constantly — it is probably the most-run peptide pairing there is. No trial has tested the combination, but the accumulated experience behind it is substantial.
Why are the doses in milligrams when other peptides are in micrograms?
TB-500 is used at roughly ten times the mass of compounds like BPC-157, which is why draw volumes are much larger and syringe capacity becomes a practical constraint.
Is the half-life really several days?
That figure is widely repeated and not traceable to a human pharmacokinetic study. It should be treated as unverified.
References
- WADA Prohibited List — S0 Non-Approved SubstancesWorld Anti-Doping Agency
This page is an educational research reference and is not medical advice. TB-500 is not approved for human use in any jurisdiction. Dose figures reflect the published record and what the community has converged on — starting points to weigh, not instructions. Consult a qualified healthcare provider before starting any protocol.