TB-500
Thymosin Beta-4 fragment
The Ground Truth Score
four plain questions, never one numberAnimal data, modest signal
Bottom line
Strong tissue-repair data in animals and essentially no human evidence, for efficacy or safety, on the synthetic fragment people actually inject.
Does the science back it?
Do real people feel it?
Is it safe?
Could it be placebo?
"Do real people feel it?" is anecdote, not proof, weighted up because the science is thin, never because it beats a trial. And "could it be placebo?" is not an insult: if you feel better, that's real to you. The point is only to know whether you're paying peptide prices for an expectation.
Why is the evidence this thin? It's mostly economics →
Dose at a glance
full dosing ↓Reported, not prescribed.
Reported, not prescribed. Verify your vial and your math.
First documented human use
No controlled human trial of TB-500 itself has ever been published. The parent molecule, Thymosin Beta-4, reached a Phase 2 trial for venous ulcers in 2009 (73 patients) whose results were never published.
The pitch
What people claim it does
Stated plainly and neutrally, exactly as you'll hear it. I grade each one below.
- Promotes tissue repair, flexibility and recovery after muscle and tendon injury.
- Reduces inflammation and may aid cardiac tissue repair after a heart attack.
- Frequently stacked with BPC-157 as a 'healing' combination.
The data behind each bullet
What actually backs it
Promotes tissue repair and recovery.
Repair effects are documented in animal models (muscle, tendon, corneal, cardiac). There is no published human efficacy trial of TB-500.
Animal repair models ↗Aids cardiac repair after heart attack.
Animal post-MI data is the basis. Preliminary human cardiac-recovery data emerging in early 2026 is sparse and not yet in major journals.
Cardiac animal data ↗Safe to use.
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.
Parent-compound Phase 1 ↗Mechanism
How it's assumed to work
Assumed · theoretical pathway
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.
Dosing & handling
What users and clinicians report
Reported, not prescribed. Loading: 750 mcg–2 mg subcutaneously, twice weekly for 4–6 weeks; maintenance ~750 mcg–1 mg twice monthly. Dr. Bakri describes a similar loading-then-maintenance pattern. Commonly co-administered with BPC-157.
There is no established clinical dose because there is no clinical trial. Every number here is community or authority report, not medicine.
Timing & food
A loading phase (~2×/week) then maintenance; timing relative to food isn't established. The infrequent schedule comes from the longer assumed duration of action.
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, which is why it's dosed less often, typically a ~2×/week loading phase.
Reconstitution sensitivity
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.
Real-world signal
What people actually report
Anecdote, not proof, weighted because the science is thin. Here's the record, graded on volume, consistency, and how credible the sources are.
Volume
Moderate, but it rarely travels alone; most reports live inside the BPC-157 'Wolverine' stack.
Consistency
Recovery reports are positive but almost totally confounded by the BPC-157 co-stack, with credible 'did nothing' reports recurring.
Source credibility
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.
Placebo risk, High
Reported benefits are almost entirely subjective recovery feel, and it's run inside stacks, so attribution to TB-500 specifically is weak and placebo is very plausible.
Risk panel
What could go wrong
Adverse events
None well-documented, because almost no one has been studied. Absence of reports is not evidence of safety here.
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.
Contraindications
Active or suspected malignancy (theoretical). Pregnancy untested.
Honest unknowns
Nearly everything in humans: efficacy, dose, long-term safety, and whether the injected fragment behaves like the parent protein at all.
Confound watch
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.'
History
Discovery → first use → status
Heads up: the legal status is moving (2026)
This one got put on the FDA's Category 2 'do not compound' list back in 2023. In April 2026 the FDA moved to pull it back off that list, and there's a July 2026 advisory meeting weighing whether it can be legally compounded again. None of that is final, and none of it makes anything proven or safe. It just means the legal picture is changing fast, so check the date on anything you read about whether this is allowed.
FDA peptide compounding update, 2026 ↗- 1960s–80sThymosin Beta-4, the parent protein, identified as an actin-regulating peptide.
- 2009Phase 2 trial of Tβ4 for venous stasis ulcers (73 patients), results never published.
- 2010sTB-500, a synthetic fragment, spreads through veterinary and gray-market athletic use.
- Sept 2023Placed in FDA Category 2.
- Apr 23 2026Removed from Category 2; PCAC review scheduled Jul 23 2026.
Verification
The COA standard, applied
Injected, so the BPC-157 standard applies in full: a batch COA with HPLC purity ≥98%, mass-spec identity, and LAL endotoxin, from Janoshik or Finnrick, never the vendor's own lab. Identity testing matters especially here: a peptide fragment is easy to mislabel or substitute.
The full verification standard →Sources
Where this comes from
The four lenses reflect the evidence and the real-world record as of the last review and will change as data arrives. Real-world signal and reported feedback are anecdote, not proof. Nothing here is medical advice or a prescription.