Status

Pending FDA review. TB-500 is part of the broader compounded peptide PCAC re-evaluation; status parallels BPC-157. Join the waitlist to be notified the moment your provider can prescribe it.

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Recovery · Tissue repair Rx · Prescription required

TB-500.

Thymosin β-4 Fragment

A synthetic fragment of Thymosin β-4. Promotes cell migration, vascularization, and tissue remodeling — the systemic complement to BPC-157's local repair.

From $250 / month
MW 889.0 Molecular weightThe mass of the active fragment in g/mol. Small enough to compound cleanly; large enough to retain biological activity.
Sequence 17 aa Peptide chain length17 amino acids — the active region of full-length Thymosin β-4 (Tβ4), a 43-aa protein discovered in 1981.
Route Sub-Q How you take itSubcutaneous: under the skin. Same technique as a GLP-1 or insulin pen.
Cycle 4–6 wk Cycle lengthTypical loading is 4–6 weeks at 2× weekly, then maintenance. The systemic effect builds gradually.
Discovered 1981 First isolatedThymosin β-4 was first characterized in 1981 (Low & Goldstein). The TB-500 fragment was developed for therapeutic use in the 1990s–2000s.
Begin your protocol Free assessment · No card · Rx required
TB-500 Recovery
MW 889.0 Length 17 aa Route Sub-Q Cycle 6 wk
Begin →
01 The case

Systemic repair, where it's needed.

TB-500 is a synthetic fragment of Thymosin β-4 — a protein your cells already make. Tβ4 is the most abundant actin-sequestering protein in mammalian tissue. Its job is to manage the cytoskeleton during cell migration, the moment that distinguishes 'stuck' tissue from healing tissue.

Where BPC-157 acts locally on the injury site, TB-500 travels systemically. It promotes endothelial migration, angiogenesis, and the recruitment of stem cells to damaged tissue. Cardiac and muscle preclinical models show repair effects that go beyond what local-only peptides can produce.

The two are commonly stacked. BPC handles the local lesion, TB-500 supports the systemic vascularization that makes deep repair possible.

02 Mechanism

What it does.

Six effects flow from one mechanism — actin sequestration in migrating cells.

TB-500 C₃₇H₅₈N₉O₁₂
⌬ Actin sequestration Manages cytoskeleton in migrating cells
∿ Endothelial migration Vascular cells move to repair sites
↗ Angiogenesis New capillary formation
⊖ Anti-inflammatory Modulates inflammation downward without blocking healing
⌒ Wound contraction Promotes coordinated tissue closure
◐ Stem cell mobilization Recruits progenitor cells to repair sites
03 Evidence

Forty years of Tβ4 research.

Thymosin β-4 has been studied since 1981. The TB-500 fragment is younger, but built on a long mechanism literature.

G-actin

sequestration is the established upstream mechanism

Low & Goldstein · 1981
17 aa

active fragment of full-length Tβ4 (43 aa)

Peptide chemistry
30+

years of Tβ4 mechanism research in the literature

PubMed indexed
Cardiac

preclinical repair models — myocardial regeneration

Tβ4 review
04 Who it's for

Built for systemic repair.

TB-500 is most often prescribed where the repair burden is widespread or systemic, or as the partner to BPC-157 in heavy recovery stacks.

⚛

Soft-tissue injury

Tendon, ligament, muscle — especially when widespread.

◐

Cardiac / muscle

Preclinical evidence in myocardial and skeletal muscle repair.

⌒

Skin / wound healing

Wound contraction and dermal remodeling.

∿

Hair growth

Stem cell mobilization to follicular niches.

↗

Tendon repair

Systemic vascularization complements local repair.

⊖

Vascular support

Angiogenesis where perfusion is the bottleneck.

05 Protocol

A sample protocol.

TB-500 is dosed less frequently than BPC-157 — its systemic half-life is longer. Your physician sets the cadence.

Sample parameters

Illustrative
Route
Subcutaneous injection
Dose
2–2.5 mg
Frequency
2–3× per week
Cycle
4–6 weeks
Storage
Refrigerated, light-protected

Twice weekly is enough. TB-500's systemic distribution means daily dosing is unnecessary. Compounded fresh by a 503A pharmacy to USP 797 sterile standards.

The cadence

Your week 7 days · 2× weekly
MAM
T
W
TAM
F
S
S
Your cycle 10 wk · 6 on, 4 off (illustrative)
1on
2on
3on
4on
5on
6on
7off
8off
~3 min per dose Site rotates: abdomen · thigh
06 What arrives

In the box.

Compounded fresh, cold-chain shipped overnight from a U.S.-based 503A pharmacy. Everything you need to start the same week.

⚲
Compounded vials

Multi-dose vial · USP 797 sterile · beyond-use date printed.

⊕
Injection supplies

Insulin syringes, alcohol pads, bacteriostatic water for reconstitution.

❄
Cold-pack shipping

Insulated overnight delivery with ice pack. Tracked door to door.

📖
Step-by-step guide

Reconstitution, dosing math, injection technique, sharps disposal.

07 Often paired with

Stacks that work.

TB-500 is rarely used alone — its systemic action complements local repair and the GH axis.

BPC-157

The classic pairing. BPC handles the local lesion, TB-500 the systemic vascularization.

Recovery stackFrom $225/mo →
Sermorelin

Anabolic environment amplifies repair across both peptides' active windows.

GH axisFrom $195/mo →
08 Safety

Side effects, fine print, responsibility.

TB-500 is generally well tolerated. Most reports are mild and dose-dependent.

✓

What to expect

  • 01Mild injection-site reactions — redness, light bruising. The most common report.
  • 02Occasional fatigue early on — transient, often within the first week.
  • 03No serious drug interactions — established in the published literature to date.
  • 04Effects build over weeks — the systemic action accumulates — not a same-week effect.
!

Not for

  • 01Pregnancy or breastfeeding. Insufficient safety data.
  • 02Active malignancy. TB-500 promotes angiogenesis; not appropriate during cancer treatment.
  • 03Use without oversight. Always under a licensed physician's supervision.
  • 04Known peptide allergy. Disclose any prior peptide-class reactions during intake.

Compounded TB-500 is not an FDA-approved drug product. It is dispensed by a licensed 503A compounding pharmacy under a prescription written by a U.S.-licensed physician for individual investigational and off-label use under provider supervision. Statements on this page have not been evaluated by the FDA. Individual results vary.

09 Questions

Frequently asked.

What is TB-500?+

TB-500 is a synthetic 17-amino-acid fragment of Thymosin β-4, an actin-sequestering protein your cells already produce. It promotes cell migration, angiogenesis, and tissue remodeling — the systemic complement to local repair peptides like BPC-157.

How is it different from BPC-157?+

BPC-157 acts locally and is dosed daily. TB-500 acts systemically and is dosed twice weekly. They target different aspects of repair — and are commonly stacked.

How long until I see effects?+

Most members notice change at 2–4 weeks; full effect at 6–10 weeks. The systemic action accumulates rather than producing a same-week response.

Is it FDA-approved?+

No. TB-500 is dispensed by 503A compounding pharmacies under a U.S.-licensed physician's prescription for individual investigational use. Status parallels BPC-157 in the ongoing PCAC review.

Can I stack it?+

Yes — TB-500 is most commonly stacked with BPC-157 (the classic recovery pairing), Sermorelin (GH axis), or Glutathione (redox foundation). Your physician designs the stack.

Side effects?+

Mild injection-site reactions are the most common report. Occasional transient fatigue in the first week. No serious adverse effects established in the published literature.

Begin Ten minutes of intake

Begin your TB-500 protocol.

Free assessment. A board-certified U.S. physician on the prescription. Bloodwork only if your protocol calls for it. Compounded fresh and cold-chain shipped overnight.

Start your intake Free · No card required · Rx required to ship

Other compounds in the roster.

All 8 therapies →
BPC-157

15-aa fragment from gastric juice. Tendon, ligament, gut. The repair signal stack-mate.

From $225/mo Sermorelin

GHRH analog. Sleep depth, lean mass, recovery — pulses your own GH at night.

From $195/mo

Deeper guides on TB-500.

All guides →