TB-500 and Cannabis Interaction Profile: What the Evidence Actually Shows

Is there a known interaction between TB-500 and cannabis?

No. FDA's July 2026 evaluation found no published article in which TB-500 was given to a person, and none of the three papers the nominator cited involved TB-500 in humans [1]. With no human data on TB-500 alone, there is nothing from which to describe how cannabis would change its effects or risks.

What TB-500 is and what is known about it

TB-500 is a synthetic 7-amino-acid, N-acetylated fragment (residues 17 to 23) of the 43-amino-acid protein thymosin beta-4; it is not full-length thymosin beta-4 and not thymosin alpha-1 [1]. Animal studies indicate it reaches the bloodstream after subcutaneous or intraperitoneal injection and is broken down into smaller peptides; FDA found no human pharmacokinetic or pharmacodynamic data [1]. There is no approved dose [1].

What safety information exists

An FDA adverse-event database search through March 26, 2025 retrieved no TB-500 reports, and its food and supplement complaint system returned two cases about a blended TB-500 and BPC-157 product with no safety assessment [1]. FDA found no nonclinical toxicity studies and no immunogenicity studies of TB-500 [1].

FDA's BPC-157 review describes a 40-year-old woman who used a research-purpose BPC-157 plus TB-500 (5 mg/5 mg) product subcutaneously twice daily and developed widespread skin hyperpigmentation and gum darkening within a week, recurring when she tried it again two weeks later; because the product held two peptides, FDA said it could not tell whether either caused it [2].

Regulatory status

FDA found no USP or National Formulary monograph for TB-500, no FDA-approved drug containing it, and no approved product in Canada, Australia, the UK, Belgium, Ireland, France, Norway, Germany, Spain or Italy, or authorized by the European Medicines Agency [1]. It sits in the 'nominated but withdrawn' table of FDA's page on bulk substances that may present significant safety risks; removal from the older category 2 was not a finding that it is safe [4].

FDA's advisory committee voted on July 23, 2026 in favor of adding it to the bulks list, against FDA staff's recommendation; that advice is non-binding and TB-500 is not on the list [5][6]. A separate HHS draft policy, filed October 28, 2026, says HHS does not intend to take enforcement action against certain state-licensed pharmacies and physicians compounding TB-500 acetate for injection if its conditions are met; it is a non-binding draft, not an approval [6].

WADA names 'Thymosin-beta4 and its derivatives e.g. TB-500' in S2.3, prohibited at all times, in 2026 and on the 2027 List [3][7].

For someone using cannabis

Whether cannabis changes TB-500's effects, or the reverse, has not been measured in any study found. The one safety concern FDA states for injectable TB-500 is immunogenicity, potentially amplified by peptide aggregation and impurities [1]; no source links that concern to cannabis.