THE RECOVERY PEPTIDES
TB-500 Explained — Thymosin Beta-4, Cell Migration, and Recovery Dosing
By G1 Peptides · Medically reviewed by the G1 Peptides clinical team · Updated September 24, 2026 · 2 min read
THE SHORT ANSWER
TB-500 is a synthetic fragment of thymosin beta-4, a protein present in almost every cell that regulates actin — the scaffolding cells use to move. Thymosin beta-4 promotes cell migration into wounds, new blood-vessel formation, and reduced inflammation in animal and early human studies. TB-500 is dosed in milligrams, typically a twice-weekly loading phase followed by less frequent maintenance, and is usually paired with BPC-157.
What it is
Thymosin beta-4 (Tβ4) is a small protein found in nearly all cells and at high concentration in platelets and wound fluid. Its core function is binding actin, the protein that forms the internal scaffolding cells use to change shape and move. By managing actin, Tβ4 lets cells migrate into a wound — the first step of repair. It also promotes new blood-vessel growth, reduces inflammation, and has been studied for heart, eye, skin, and nerve repair (Goldstein 2012).
TB-500 is a synthetic peptide built around Tβ4's actin-binding region — the fragment thought responsible for most of the migration effect. It is what pharmacies compound; the research literature is mostly on full-length Tβ4, so the extrapolation should be stated plainly.
The evidence
- Wound healing: accelerated closure of skin wounds in animal models, including in diabetic and aged animals; early human trials of topical Tβ4 in chronic wounds showed faster healing.
- Cardiac: Tβ4 promoted cardiac cell survival and repair after heart attack in mice — the finding that drove much of the interest.
- Eye: Tβ4 eye drops advanced through clinical trials for dry eye and corneal wounds.
- Muscle and tendon: improved repair in animal injury models, with reduced scarring and inflammation.
- Safety: well tolerated in animal studies and in human topical and injectable trials of Tβ4.
For injected TB-500 in musculoskeletal injury specifically, there is no controlled human trial. As with BPC-157, use rests on the preclinical record, the safety profile, and clinical experience.
How it is used
- Loading: 2–2.5 mg by subcutaneous injection twice weekly for four to six weeks.
- Maintenance: 2–2.5 mg every one to two weeks, or a lower dose weekly.
- Pairing: with BPC-157 in most recovery protocols — they are studied for complementary mechanisms (blood-vessel signalling versus cell migration) and are combined in G1's Wolverine pen and blend vials.
Because doses are milligram-scale, vial size matters: 2.5 mg from a 10 mg vial in 2 mL is 50 units — half a syringe; the same dose from a 5 mg vial in 2 mL is a full 100 units. The TB-500 calculator shows the draw for any combination and flags anything over one syringe.
Safety
Injection-site reactions and occasional transient fatigue or headache after the larger loading doses are the reported effects. The same precautions as BPC-157 apply: avoided in active cancer because of its pro-angiogenic activity, not used in pregnancy, and prohibited by WADA.
Next: GHK-Cu explained.
FREQUENTLY ASKED
Is TB-500 the same as thymosin beta-4?
Not quite. Thymosin beta-4 is the full 43-amino-acid protein; TB-500 is a synthetic peptide based on its active region (the actin-binding segment). TB-500 is what compounding pharmacies supply; most of the published research is on full-length thymosin beta-4.
Why is the dose so much higher than BPC-157?
Different molecule, different potency. TB-500 is used in milligram doses because that is the range that showed effects in animal models, whereas BPC-157 is active at micrograms. It is why TB-500 usually comes in 5 or 10 mg vials.
How long does a course run?
A common structure is four to six weeks of loading at 2–2.5 mg twice weekly, then a maintenance dose every one to two weeks for as long as the provider recommends. Your provider sets the actual schedule.
This article is educational and is not medical advice. Peptides are prescription medications; whether any of them is appropriate for you is a decision for a licensed provider who knows your history.