TB-500
Research Reliability -
A synthetic fragment of Thymosin Beta-4 studied for tissue repair and flexibility — a regulated peptide, not an OTC supplement.
Appetite
Mood
Sleep
TB-500
Description
TB-500 is a synthetic version of a peptide fragment derived from Thymosin Beta-4, a protein involved in actin regulation and cell migration during wound healing. It is frequently discussed alongside BPC-157 in injury-recovery stacks, with proposed (largely preclinical) mechanisms around reduced inflammation and improved flexibility in healing connective tissue. Like BPC-157, it was placed on the FDA's restricted compounding Category 2 list in 2023, removed in April 2026, and remains under active 503A compounding review — it is not FDA-approved and not legally marketable as a dietary supplement; legitimate access runs through a physician and compounding pharmacy, not direct-to-consumer vendors.
Effects
First days–weeks
studied for tissue repair and recovery
Weeks
reported benefits are gradual
Note
research/clinical use only, under supervision
How it Feels
Another repair-oriented peptide belonging in a clinical or research setting rather than a self-directed stack. Any reported recovery benefit builds over weeks and is not a felt, day-to-day effect. It requires proper oversight and carries real sourcing and regulatory caveats.
Usage
Entry Dose
Research/clinical use only — not a self-administered OTC supplement
Standard Dose
Research protocols use 2–5mg/week, by prescription/compounding only
Max Dose
Set by prescribing physician
Onset
Days–weeks
Combinations
Pairs well with
Synergistic
BPC-157 — commonly co-administered in physician-guided recovery protocols targeting different aspects of tissue repair
Adequate protein intake — supplies the amino acid building blocks for the tissue remodeling these peptides are studied to support
Avoid combining
Contraindicated
Self-sourcing or self-administering outside a physician/compounding-pharmacy relationship — legal and quality-control risk
Active or history of cancer — cell-migration and proliferative mechanisms are a theoretical concern
Competitive athletics — check current anti-doping status
Pregnancy — contraindicated
Biomarkers to Track
Subjective
(Daily)
Pain and stiffness at injury site (1–10)
Range of motion
Functional recovery milestones
Objective
(Quarterly)
Physician-ordered imaging at injury site
Inflammatory markers (hs-CRP)
Functional strength testing
A research peptide belonging in a clinical setting. Limited human data and regulatory and sourcing caveats apply.
Anyone without medical supervision, and pregnant women.
Sourcing it casually, and assuming recovery claims are established.
Animal / preclinical only
The only human RCT evidence for thymosin beta-4-related compounds is a small trial of topical, full-length Tb4 eye drops for dry eye, not the injectable TB-500 fragment used by biohackers for systemic tissue repair. Injectable TB-500 has no human efficacy trials; it is used entirely off-label.
Sosne G et al. (2015). Cornea, 34(4), 491-496. Phase 2 RCT (topical full-length thymosin beta-4 eye drops for severe dry eye, n=9). PMID: 25826322.