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TB-500 in California: Legal Status & Provider Guide (2026)
Quick Answer
TB-500 is a prescription substance in the United States. TB-500 / Thymosin Beta-4 is explicitly identified in FDA guidance as not suitable for 503A/503B compounding. Federal compliance risk for providers offering it is high. Patients should understand the legal status before use. In California, compounding is governed by the California State Board of Pharmacy (CSBP). California allows nurse practitioners and physician assistants with standardized procedures or physician collaboration to prescribe compounded peptides. California's telehealth laws (AB 2019 and subsequent legislation) require an established patient-provider relationship before prescribing. Out-of-state prescribers cannot prescribe to California patients without a California license.
Federal Legal Status
FDA Approval Status
TB-500 is a synthetic peptide derived from thymosin beta-4. It is not FDA-approved and not on the FDA bulk substances lists for compounding. FDA has explicitly listed thymosin beta-4 in guidance indicating it cannot be compounded by 503A/503B facilities.
Compounding Pharmacy Rules (Federal)
TB-500 (thymosin beta-4) is specifically mentioned in FDA guidance as a substance that does not meet the criteria for 503A bulk compounding. It cannot be lawfully compounded by facilities subject to FDA oversight. Some providers offer it under research or investigational frameworks, but this carries significant federal compliance risk.
Also Known As
Thymosin Beta-4 · Tβ4
Primary Research Areas
- Tissue repair
- Wound healing
- Inflammation reduction
- Angiogenesis
California Pharmacy Board & Compounding Rules
Compounding Overview
The California State Board of Pharmacy enforces strict compounding standards, often exceeding federal minimums. California has its own sterile compounding licensure category and requires all sterile compounding pharmacies to hold a specialty license. California pharmacies must comply with USP 797 (sterile) and USP 795 (non-sterile) standards. The California Medical Board also imposes strict telemedicine prescribing standards that affect peptide clinics operating as telehealth platforms serving California residents.
Notable Rules
- California requires a specialty sterile compounding license in addition to a standard pharmacy license.
- USP 797 and 795 compliance is mandatory for all California-licensed compounding pharmacies.
- The California Medical Board has specific guidance on prescribing practices for "off-label" and compounded medications.
- Out-of-state pharmacies must be licensed by CSBP to ship prescription compounds into California.
- California prohibits prescription dispensing without an established patient-provider relationship in most telehealth contexts.
Prescribing Requirements in California
California allows nurse practitioners and physician assistants with standardized procedures or physician collaboration to prescribe compounded peptides. California's telehealth laws (AB 2019 and subsequent legislation) require an established patient-provider relationship before prescribing. Out-of-state prescribers cannot prescribe to California patients without a California license.
About TB-500
TB-500 is the synthetic version of the naturally occurring thymosin beta-4, a protein ubiquitous in human and animal cells. Research has focused on its role in wound healing, angiogenesis, and tissue repair. Human clinical trial data is limited.
For more research information, mechanism of action, and provider availability, see the TB-500 research profile on PeptideBase.
Frequently Asked Questions
- Is TB-500 the same as thymosin beta-4?
- TB-500 is a synthetic peptide fragment derived from thymosin beta-4, specifically the actin-binding domain. The two are often used interchangeably in informal contexts, though they are not identical. FDA guidance on thymosin beta-4 applies to TB-500 in practice.
TB-500 Providers in California
No providers currently listed in California for TB-500. Browse the full directory to find providers offering TB-500.
Browse all TB-500 providers →TB-500 Legal Status in Other States
Pharmacy board rules and compounding regulations vary by state. Compare TB-500 legal status across other major markets:
Content review: This educational overview is prepared by the PeptideBase editorial team and reviewed for factual accuracy. Reviewer byline coming soon (gated on 4.4). Last updated: .