TB-500
Thymosin Beta-4 fragment
Checked Oct 28, 2026
The short answer
No human evidence yet for tendon, muscle and injury repair and recovery in healthy or injured adults
Grade D for tissue repair: the repair results are in animals, and no human trial of the TB-500 fragment has been published, so there is nothing to say yet about whether it works in people.
- Approved?
- Not approved for any use.
- Safety: D, uncharacterized
- No human safety data exist for the TB-500 fragment; the parent protein was well tolerated in a 40-person IV Phase 1 in healthy volunteers, which does not transfer.
We tried it. This is what happened.
- BPC-157 and TB-500: why I stopped the two I trusted most PausedThey were my first two. They carried me through a hernia and a laser recovery. Then I stopped, because nothing I could measure said keep going.
The full answer: what it is for, the dose, the units
What people take it for: People inject it hoping to speed healing of tendons, muscle and joints, usually alongside BPC-157.
Does it work for tendon, muscle and injury repair and recovery in healthy or injured adults? D, no human evidence yet. Result: not tested in humans.
Grade D for tissue repair: the repair results are in animals, and no human trial of the TB-500 fragment has been published, so there is nothing to say yet about whether it works in people.
No approval for any use.
Safety: D, uncharacterized. No human safety data exist for the TB-500 fragment; the parent protein was well tolerated in a 40-person IV Phase 1 in healthy volunteers, which does not transfer.
Do not use if: Active or suspected malignancy (theoretical). Pregnancy untested.
Could it be placebo? No controlled trial of TB-500 exists for any use, so a placebo effect cannot be ruled out, and users almost always stack it with BPC-157 and rehab, which blurs attribution further.
The dose people use, and the units to draw
No verified dose statement found: no label, human trial, Huberman Lab or Dr. Abud Bakri episode, Examine or Attia page we could open gives a dose for the TB-500 fragment. The only human doses on record are for the full-length parent protein, thymosin beta-4, in other routes and conditions.
| Source | Dose | How often and how | Who it was for | Link |
|---|---|---|---|---|
| Ruff et al. 2010, Ann N Y Acad Sci (full-length thymosin beta-4, not TB-500) | 42, 140, 420 or 1260 mg per dose | Single intravenous dose, then the same dose daily for 14 days | 40 healthy volunteers (four cohorts of 10), randomized, placebo-controlled; safety study of the parent protein, not an efficacy trial | Abstract: dose levels and 14-day multiple-dose phase |
| Guarnera et al. 2010, Ann N Y Acad Sci (topical thymosin beta-4 gel, not TB-500) | Gel at 0.01%, 0.03% or 0.1% w/w; the abstract singles out 0.03% as the dose that may accelerate healing | Applied topically once daily for up to 84 days | 73 randomized patients with venous stasis ulcers (the registry record lists 72 enrolled), 8 European sites, double-blind, placebo-controlled Phase 2 | Abstract (0.03% dose, 73 patients); concentrations and once-daily schedule from the NCT00832091 arms table |
No source gives a dose for the TB-500 fragment itself: FDA's July 2026 briefing document reports no clinical studies or human exposure data for it, the Huberman Lab episode with Dr. Abud Bakri (June 2026) covers TB-500 only briefly (chapter near 1:38:13) and summaries of it and Huberman Lab's AI summary state no dose, though we could not open the transcript to confirm by ear, and we could not open a TB-500 page on Examine or find an Attia statement with a dose. The loading and maintenance ranges previously shown on this page traced to community guides and vendor-adjacent pages with no named eligible source, so they have been removed. The two rows above are for the parent protein in other routes and are not doses to copy.
Reported by the named source, never prescribed by us.
How many units do I draw?
The calculator turns vial mg, water mL and a dose in mg into insulin-syringe units; it does not suggest a TB-500 dose. Open the dose calculator
Why it might work
- TB-500Tβ4 fragment
- Binds actin
- Cell migrationrepair signals
- Healingassumed
Assumed pathway, not shown in people.
Assumed, not proven in humans: TB-500 is a fragment of thymosin β4 that binds actin and is thought to promote cell migration, blood-vessel growth, and tissue repair. Shown in animals; unproven in people, and the sold fragment differs from the studied molecule.
The trials, claim by claim
Every claim here is graded D for TB-500 itself. Two claims describe human trials of the full-length parent protein (thymosin beta-4), which is a different molecule, route and condition; they are shown for context and do not raise the TB-500 grade.
Promotes tissue repair and recovery.
Result: not tested in humans
Repair effects are documented in animal models (muscle, tendon, corneal, cardiac). There is no published human efficacy trial of TB-500.
Philp & Kleinman 2010, Tβ4 animal tissue-repair reviewAids cardiac repair after heart attack.
Result: not tested in humans
Animal post-MI data is the basis. A 2025 randomized trial of full-length recombinant thymosin beta-4 in 96 heart-attack patients found a smaller infarct only in those dosed within 8 hours; the overall difference was not significant. No heart-repair data exist for the TB-500 fragment itself.
Bock-Marquette et al., Nature 2004, post-MI cardiac repair (mouse)Full-length thymosin beta-4 reduced infarct size after a heart attack only in early-treated patients.
Result: not tested in humans
96-patient randomized, placebo-controlled, double-blind trial of recombinant full-length human thymosin beta-4 (not TB-500). Infarct was smaller only in the subgroup dosed within 8 hours of PCI; the overall difference was not significant. Grade D for TB-500 because the fragment was not tested.
Zhang et al. 2025, Cardiovasc ResTopical thymosin beta-4 gel was safe in a Phase 2 venous-ulcer trial.
Result: not tested in humans
73 randomized patients, dose-escalation, parent protein, topical route. The authors said the 0.03% dose may have the potential to accelerate healing, and about a quarter of patients healed within 3 months. Does not transfer to injected TB-500.
Guarnera et al. 2010, Ann N Y Acad SciSafe to use.
Result: not tested in humans
Phase 1 of the PARENT compound (Tβ4) showed no serious adverse events at 42-1260 mg over 14 days. No safety data exists for the synthetic fragment TB-500 in humans, and long-term effects are unknown.
Ruff et al. 2010, Tβ4 Phase 1 (IV, 42-1260 mg, no SAE)Risks and the label warnings
Adverse events
No reports tied to TB-500 alone: FDA's July 2026 review found no human exposure data for the fragment and no adverse-event reports (one report involved a BPC-157 plus TB-500 product). Absence of reports is not evidence of safety here.
Contraindications
Active or suspected malignancy (theoretical). Pregnancy untested.
Theoretical concerns
As a pro-angiogenic, pro-migratory peptide, the same theoretical tumor-growth concern that applies to BPC-157 applies here, and is even less studied.
What nobody knows yet
Nearly everything in humans: efficacy, dose, long-term safety, and whether the injected fragment behaves like the parent protein at all.
What else could explain the result
TB-500 is almost always run alongside BPC-157 and a rehab block. When the combo 'works,' there is no way to credit TB-500 specifically, the cleanest attribution any honest user can make is 'something in the stack, or time.'
Is the vial what it says?
Injected, so the BPC-157 standard applies in full: a batch COA with HPLC purity ≥98%, mass-spec identity, and LAL endotoxin, from an independent lab, never the vendor's own lab. Identity testing matters especially here: a peptide fragment is easy to mislabel or substitute.
Half-life and storage
Half-life: Longer than BPC-157. The parent molecule (thymosin β4) shows a human half-life around 1-2 hours, plus an assumed tissue-residence effect.
Once mixed: Standard peptide fragility, refrigerate the reconstituted vial, don't shake, replace BAC water ~28 days. Worth knowing: the marketed 'TB-500' fragment is not the full molecule most human safety data refers to.
What I noticed, and what people report
Case study
- BPC-157 and TB-500: why I stopped the two I trusted most PausedThey were my first two. They carried me through a hernia and a laser recovery. Then I stopped, because nothing I could measure said keep going.
What people report
Volume of reports: mixed. Reports exist but contradict each other.
Moderate, but it rarely travels alone; most reports live inside the BPC-157 'Wolverine' stack.
Recovery reports are positive but almost totally confounded by the BPC-157 co-stack, with credible 'did nothing' reports recurring.
Trust the mixed-outcome forums (MESO-Rx, equine boards); discount the guide sites that supply the suspiciously precise stats.
- Usually reported as half of a 'healing stack' with BPC-157, so isolated TB-500 reports are scarce.
- Users describe better flexibility and recovery, but in vague terms.
- Few specific side-effect reports, which reflects how little it's been used carefully, not proven safety.
Reports are anecdote, not proof.
Can you tell if it is working?
No objective way to prove TB-500 works, track the specific injury (pain, range of motion, strength, return to activity, or targeted ultrasound/MRI of that exact lesion), not any lab, blood, or wearable.
Bloodwork
Nothing on a routine panel confirms this one. Anyone who says otherwise is guessing.
TB-500 is a synthetic fragment of thymosin beta-4, an actin-sequestering peptide that acts locally at injury sites to promote cell migration, angiogenesis, and tissue repair. It produces no systemic hormone, enzyme, or metabolite that a routine panel measures, so a working dose does not register in standard bloodwork.
Read this before you spend on labs
Routine bloodwork cannot confirm TB-500 is working. Its action is local tissue repair (tendon/ligament/muscle/soft tissue), and there is no published human efficacy trial and no LabCorp/Quest analyte that tracks its biological effect. Reported benefits are largely subjective recovery feel, which makes placebo very plausible. Judge progress by functional endpoints (pain, range of motion, return to activity) or targeted imaging of the specific injury, not blood. Inflammatory markers like CRP/ESR are far too nonspecific and confounded to attribute any change to this peptide, so do not use them as a proxy.
Bottom line
TB-500 (a synthetic thymosin beta-4 fragment) is marketed for localized tissue repair, has no published human efficacy trial, and produces no systemic hormone or metabolite that any orderable lab or consumer device measures. Its claimed effects are local healing and recovery, which have no validated objective proxy on a wearable, DEXA, CGM, VO2max, urine, or stool test, nothing on those modalities changes as a signature of this peptide working, and any trend there is confounded by training, sleep, or illness, not confirmation. The only honest way to gauge whether it is helping is injury-specific: functional endpoints (pain scores, range of motion, strength, return to activity) or targeted imaging (ultrasound/MRI) of the exact tendon, muscle, or ligament being treated, compared before and after. Those are localized clinical assessments, not standing quantified-self trackers. Blood adds nothing here either (tier=none). Bottom line: there is no accessible objective tracker for TB-500 across any modality, anyone selling a biomarker for it is guessing.
Logging baseline vs retest is the whole game. The Truth Tracker is our free log for bloodwork, DEXA, genetics, and wearable data, bring your own numbers.
How to track itHistory
First documented human use: No controlled human trial of TB-500 itself has ever been published. The parent molecule, Thymosin Beta-4, was tested as a topical gel in a Phase 2 venous-ulcer trial (73 patients, published 2010) and as an IV infusion in a placebo-controlled Phase 1 in healthy volunteers.
Update: an FDA advisory panel voted in favor of this one on July 23-24, 2026
The FDA's Pharmacy Compounding Advisory Committee voted to recommend adding this to the 503A Bulks List, meaning compounding pharmacies could legally prepare it. The vote: 8-6, with one abstention. Now read the fine print, because it matters more than the headline. The vote is advisory and changes nothing today: FDA still has to go through formal rulemaking, which can take a year, and it has overruled its own panels before. As of November 2, 2026, FDA has not published a proposed rule and this is not on the 503A Bulks List. Separately, HHS published a draft enforcement-discretion policy in the Federal Register on October 30 (docket HHS-OASH-2026-0496) that says HHS does not intend to act against pharmacies that compound certain single-ingredient peptides under conditions. The notice itself says compounded drugs are not FDA-approved. That is enforcement discretion: a draft, not a rule, not approval, and not a ruling that the compound works, and HHS can revise it. The list of named peptides and routes sits in an appendix we could not open, so which peptides it names is as press and law firms report it, not as we read it. FDA's own scientists recommended AGAINST adding it, citing thin human evidence and unassessed immunogenicity risk, and the committee voted the other way. That committee is also not neutral: it was reconstituted with recent appointees, and several work at or run clinics that sell peptide treatments. And none of this is a finding that the compound works. A compounding-eligibility vote is not drug approval, and it is not evidence. Our grade here is unchanged, because the evidence did not change.
Vote tallies as reported by the press (STAT, McDermott Will and Schulte); FDA has not posted tallies, minutes or a transcript, and its meeting materials are on its meeting page. Rechecked November 2, 2026 against FDA and Federal Register primary pages: FDA has published no proposed rule, docket FDA-2025-N-6895 closed July 22, 2026, and HHS published a draft enforcement-discretion policy in the Federal Register on October 30, 2026 (docket HHS-OASH-2026-0496). Nothing here is final, so check the current policy and rule before acting.. FDA, PCAC meeting, July 23-24 2026
- 1960s-80sThymosin Beta-4, the parent protein, identified as an actin-regulating peptide.
- 2009Phase 2 trial of topical Tβ4 gel for venous stasis ulcers (73 patients) finished; results published in 2010.
- 2010sTB-500, a synthetic fragment, spreads through veterinary and gray-market athletic use.
- Sept 2023Placed in FDA Category 2.
- Apr 2026Dropped from Category 2 after its nominators withdrew their nominations; not placed in any other category.
- Jul 23 2026PCAC voted 8-6 (1 abstention) to recommend TB-500 for addition to the 503A Bulks List. Evaluated for wound healing; FDA staff recommended against. Advisory only: no FDA proposed rule as of Oct 12 2026, and no evidence grade moves on a compounding vote.
All sources
- Guarnera et al. 2010, topical thymosin beta-4 in venous ulcers (Phase 2)
- Zhang et al. 2025, recombinant thymosin beta-4 in 96 STEMI patients (Cardiovasc Res)
- FDA briefing document for TB-500, July 2026 advisory committee
- Dr. Abud Bakri, clinical authority
- Ruff D, et al. A randomized, placebo-controlled, single and multiple dose study of intravenous thymosin beta4 in healthy volunteers. Ann N Y Acad Sci. 2010. PMID 20536472(dose table)
- Guarnera G, et al. Thymosin beta-4 and venous stasis ulcers: a phase 2 dose-escalation trial. Ann N Y Acad Sci. 2010. PMID 20536470; ClinicalTrials.gov NCT00832091(dose table)
Not medical advice. Grades reflect the evidence as of the date above and will change as data arrives. Reports from users are anecdote, not proof. Talk to a licensed clinician before you act on anything here.