TB-500
Also sold as: TB500, Thymosin Beta-4 Fragment 17-23, Ac-LKKTETQ, N-acetylated heptapeptide LKKTETQ, TB-500 acetate, TB-500 (free base)
TB-500 is not on FDA's 503A bulks list, so it may not lawfully be used in pharmacy compounding, and FDA staff proposed not adding TB-500 (free base) or TB-500 acetate to that list ahead of the Pharmacy Compounding Advisory Committee meeting on 23-24 July 2026, stating that they identified no clinical studies or human exposure data using TB-500 by any route of administration. TB-500 is a synthetic seven-amino-acid fragment (Ac-LKKTETQ) of the 43-amino-acid protein thymosin β4 and is not thymosin β4 itself — FDA states the two are not the same substance, so evidence about full-length thymosin β4 is not evidence about TB-500.
Which molecule this is. TB-500 is NOT thymosin β4. TB-500 is a synthetic N-acetylated seven-amino-acid fragment (residues 17-23, LKKTETQ) of the full-length 43-amino-acid protein thymosin β4. FDA's 'no human exposure data' finding is scoped to the FRAGMENT — TB-500 (free base) and TB-500 acetate — and is accurate for that molecule. It is NOT a statement about full-length thymosin β4, which has a genuine multi-sponsor clinical programme in which the drug was administered to humans: RegeneRx/ReGenTree's RGN-259 ophthalmic solution (Tβ4 eye drops) reached Phase 3 for dry eye (NCT02974907, n=601, completed, results posted; NCT03937882 ARISE-3, n=700, completed), topical Tβ4 gel was tested in wound healing (NCT00832091, venous stasis ulcers, n=72, completed; NCT00311766, epidermolysis bullosa, n=30, TERMINATED for lack of patient availability and study-drug expiry), and Beijing Northland ran Phase 1a/1b of INTRAVENOUS recombinant human Tβ4 (NL005) in healthy volunteers (NCT04555824, n=54, completed; NCT04555850, n=30, completed). The caution the market elides: the full-length human programme is topical, ophthalmic and intravenous — none of it is IM/SC dosing of the acetylated fragment, which is what TB-500 was nominated and is sold for. A completed Phase 3 of Tβ4 eye drops, and a completed Phase 1 of IV recombinant Tβ4, are not human data for an injected seven-amino-acid fragment of a different molecule. Separately, on labelling: FDA documents that suppliers confuse the free base with the acetate — 'On several suppliers' websites, the CAS number for TB-500 (free base) (885340-08-9) is used for TB-500 Acetate.' That is a salt-form defect, and it is the one FDA actually found; we make no claim about what else is in the vial, because we have no analysis that would support one.
The FDA advisory committee vote, 23 July 2026
The Pharmacy Compounding Advisory Committee voted to recommend adding this substance to the 503A bulks list (8-6, one abstention), against FDA’s own staff, who had recommended not adding it.
It is still not on the list. An advisory committee makes recommendations; it does not change what is permitted. We checked the 503A bulks list on 29 July 2026 and it is still dated 14 May 2026, with this substance absent from it. Adding a substance requires separate FDA action, which has not happened.
Vote tally reported by ABC News and other outlets; FDA had not published minutes or a transcript as of 29 July 2026, so there is no primary document for the tally yet. We will replace it with FDA’s own record when it publishes. The bulks-list status is from the primary document.
FDA status
FDA has not approved this and it is not in active development toward approval. That says nothing about whether it is being sold — most substances in this category are.
Not an FDA-approved drug for any indication, and not in active development toward approval. That says nothing about whether it is sold — it is.
“The nomination was withdrawn and FDA is evaluating the substances at its discretion.”Checked against the source on .
503A compounding
The nominator withdrew the nomination. This is not a legalisation event — the substance is not on the 503A bulks list and remains non-compoundable.
The single nomination — Wells Pharmacy Network, Document ID FDA-2015-N-3534-0304 — was withdrawn (withdrawal Document ID FDA-2015-N-3534-0484). Withdrawal did NOT stop the evaluation, and this is the fact that reconciles a 'withdrawn' status with an active staff proposal before the advisory committee on 23-24 July 2026: FDA writes that it 'has decided to evaluate both TB-500 (free base) and TB-500 acetate on its own initiative because it is unclear which substance the nominator intended to nominate.' So the substance is still being adjudicated despite the nominator walking away. Withdrawal is a nominator's act, not a legalisation event: TB-500 did not enter Category 1, it is not on the 503A bulks list, and it remains non-compoundable. Reporting that leaving Category 2 means access is coming has the direction backwards.
“The nomination was withdrawn and FDA is evaluating the substances at its discretion.”Checked against the source on .
Evidence
We found no credible evidence of efficacy at any level of quality.
Zero human administration of the fragment, and no positive nonclinical evidence for it either. FDA also writes: 'The nomination did not include, and FDA has not identified, any clinical studies or human exposure data using TB-500 via any ROA.' Two precisions matter more than the tier. (1) The animal wound-healing data is on a DIFFERENT PEPTIDE. In a 2003 study in aged mice, researchers reported that topical application of the NON-acetylated heptapeptide LKKTETQ increased epidermal closure and collagen content at the wound site (Philp et al. 2003). FDA's own caution: because acetylation irreversibly alters charge, hydrophobicity and size, 'the pharmacological profile of the non-acetylated heptapeptide LKKTETQ cannot be directly extrapolated to the N-acetylated heptapeptide TB-500.' TB-500 is the acetylated one. Limitations FDA notes: no dose-response assessment, and it is unknown whether the effect generalises to other wound types. (2) The only in-vitro study of TB-500 (free base) ITSELF was NEGATIVE — in a 2024 scratch assay in cultured fibroblasts, researchers reported wound closure was not significantly different between TB-500 (50 μg/mL) and vehicle; FDA writes that TB-500 'appeared to be devoid of wound-healing properties' (Rahaman et al. 2024), a study which itself lacks a concentration-response analysis. Reported in full, because it cuts against the marketing rather than for it: under the same conditions in that same study, a TB-500 METABOLITE, N-acetylated LKKTE, 'caused a small, but significant wound closure' — which is why FDA says it 'remains unknown whether TB-500 (free base) and TB-500 acetate could have wound-healing properties in vivo and, if so, whether their pharmacological activity depends on the conversion of the TB-500 moiety to a pharmacologically active metabolite.' A metabolite signal is a hypothesis about a mechanism, not evidence for the sold product. The evidence base for the substance sold under this name is borrowed from a molecule it is not.
“In conclusion, nonclinical pharmacological evidence is currently lacking to support the potential for TB-500 to promote wound healing, and nonclinical toxicological studies are not available to inform safety considerations for potential clinical uses of TB-500 (free base) or TB-500 acetate.”Checked against the source on .
What FDA found
FDA’s own words. These are the most citable thing on this site, and the least likely to appear anywhere funded by someone selling the compound.
FDA staff propose not adding TB-500 (free base) or TB-500 acetate to the 503A Bulks List, ahead of the Pharmacy Compounding Advisory Committee meeting on 23-24 July 2026.
A staff proposal is not a final determination. The briefing document states: 'The FDA will not issue a final determination on the issues at hand until input from the advisory committee process has been considered and all reviews have been finalized.'
TB-500-Related Bulk Drug Substances — FDA Briefing Document, Pharmacy Compounding Advisory Committee Meeting, July 23-24, 2026 — FDA, 23 July 2026“Accordingly, we propose not adding TB-500 (free base) or TB-500 acetate to the 503A Bulks List.”
Checked against the source on .FDA identified no human exposure data of any kind on TB-500 by any route of administration — no clinical studies, no pharmacokinetic or pharmacodynamic data, and no published case reports.
Read with the moleculeNote or this finding will be misquoted in both directions. It is TRUE and scoped to the 17-23 fragment. It is NOT a finding that thymosin β4 lacks human data — full-length Tβ4 has completed Phase 3 ophthalmic trials and completed Phase 1 intravenous trials. Anyone citing this line against Tβ4, or citing Tβ4's trials to rebut this line, has swapped the molecules.
TB-500-Related Bulk Drug Substances — FDA Briefing Document, Pharmacy Compounding Advisory Committee Meeting, July 23-24, 2026 — FDA, 23 July 2026“FDA is particularly concerned about the absence of human data on drug products containing these substances administered via any route of administration.”
Checked against the source on .TB-500 appears in no category of the 503A bulks list — not Category 1, 2 or 3 — and is not on the list of substances permitted for use in 503A compounding.
Verified by grepping the text-extracted document (updated 2026-05-14) directly for 'TB-500', 'TB500', 'thymosin' and 'beta-4': zero hits anywhere. Category 2 contains exactly six substances (Cesium Chloride, Domperidone, Germanium Sesquioxide, Ibutamoren Mesylate, Kisspeptin-10, Quinacrine HCl for intrauterine administration) and TB-500 is not among them. Note what this establishes and what it does not. It establishes the operative legal fact: TB-500 is not on the 503A bulks list, so it may not lawfully be used in 503A compounding for ANY use — that follows from absence from the list itself, not from the scope of FDA's evaluation. It does NOT establish WHY it is absent; this document cannot distinguish withdrawn from never-nominated. For the withdrawal, see legalStatus, which is sourced to the briefing document that states it.
Bulk Drug Substances Nominated for Use in Compounding Under Section 503A of the Federal Food, Drug, and Cosmetic Act — FDA, 14 May 2026Checked against the source on .FDA found a lack of evidence to evaluate the effectiveness of TB-500 for its nominated use of wound healing, and identified no information anywhere in the medical literature in which TB-500 was administered to patients for any disease or condition. The nominator also never specified which wound type TB-500 is intended to treat.
This is an EVIDENTIARY VACUUM, NOT A REGULATORY LOOPHOLE. FDA never assessed whether TB-500 works for tendon, muscle or joint recovery — the uses it is actually marketed for — because the nomination was for wound healing and submitted no human data even for that. FDA states plainly: 'We note that the nominator has not provided information about what specific type of wound that TB-500 is intended to be used for.' 'FDA did not evaluate it for recovery' means nobody submitted evidence, not that the recovery claims survived scrutiny. On the nominator's own citations, note a tension inside the document rather than resolving it: footnote 43 states only 'The nominator cited three references in their nomination; three references are studies on Thymosin β4', while the body of the safety section describes two of the submitted articles (Philp et al. 2003; Shah et al. 2018) as 'nonclinical pharmacological studies of the non-acetylated heptapeptide LKKTETQ'. Either way the point stands and needs no inference: none of them is a study of TB-500 administered to humans.
TB-500-Related Bulk Drug Substances — FDA Briefing Document, Pharmacy Compounding Advisory Committee Meeting, July 23-24, 2026 — FDA, 23 July 2026“There is a lack of evidence to evaluate the effectiveness of TB-500 (free base) and TB-500 acetate products for the nominated use of wound healing. The nomination did not include, and FDA did not find any information in the medical literature where, TB-500 was administered to patients to treat any disease or condition including its use in wound healing.”
Checked against the source on .FDA defines TB-500 as a synthetic N-acetylated heptapeptide containing residues 17 through 23 (LKKTETQ) of the full-length 43-amino-acid peptide thymosin β4, and states directly that thymosin beta-4 and TB-500 are not the same substance, noting that seller websites use the two names interchangeably.
The two quoted sentences are from different sections, joined with an ellipsis: the definition opens section II.D.1.a (General Pharmacology of the Drug Substance) and the identity statement is footnote 35. Both are quoted verbatim, and the definition is here rather than only in the moleculeNote docblock because the quickAnswer asserts it — a docblock is a comment, not a Source, and cannot carry a claim. FDA files the second sentence as footnote 35, attached to the list of conditions TB-500 is marketed online for. The footnote is the whole argument of this record in FDA's own voice: the clinical programme buyers are implicitly relying on belongs to a 43-amino-acid protein, and the product is a seven-amino-acid acetylated fragment of it. FDA's evaluation is of the fragment and the conclusions are about the fragment.
TB-500-Related Bulk Drug Substances — FDA Briefing Document, Pharmacy Compounding Advisory Committee Meeting, July 23-24, 2026 — FDA, 23 July 2026“TB-500 is a synthetic N-acetylated heptapeptide containing the amino acid sequence 17 through 23 (LKKTETQ) of the full-length (43-amino acid) peptide thymosin β4. … Several websites state that TB-500 is a synthetic version of thymosin beta-4 and often use the terms interchangeably. However, as noted previously, thymosin beta-4 and TB-500 are not the same substance.”
Checked against the source on .TB-500 is not a United States Adopted Name, and FDA reports having encountered multiple salts and derivatives — including different active moieties — sold commercially under the TB-500 name. FDA treats that naming inconsistency as a safety risk in itself.
Read precisely, and note the restraint this record imposes on itself. FDA says it has encountered different active moieties sold under the TB-500 name; it does NOT say what those moieties are, how often, or that any of them is full-length thymosin β4, and we make no such claim — see the retraction note at the head of this file. What FDA does document concretely is the free base/acetate confusion: 'On several suppliers' websites, the CAS number for TB-500 (free base) (885340-08-9) is used for TB-500 Acetate.' The nomination package itself carried four separate identity inconsistencies — the CoA was for the acetate while the nominated substance was the free base, and the molecular formula given matched neither. FDA's conclusion is that both TB-500 (free base) and TB-500 acetate are 'not physically and chemically well characterized'.
TB-500-Related Bulk Drug Substances — FDA Briefing Document, Pharmacy Compounding Advisory Committee Meeting, July 23-24, 2026 — FDA, 23 July 2026“FDA has encountered multiple salts, and derivatives, including different active moieties, sold commercially under the same common name. Inconsistent naming conventions that do not follow established chemical nomenclature standards (e.g., INN, IUPAC, USAN) represent a safety risk for patients as they may be dosed with a different BDS than the physician ordered.”
Checked against the source on .No outsourcing facility has ever reported compounding a TB-500 drug product to FDA, and FDA found no pharmacy marketing one. FDA concluded the available data are too limited to understand TB-500's historical use in compounding at all.
The historical-use criterion is one of the four FDA balances, and TB-500 fails it for want of a record rather than on the merits: 'currently available data and published literature are too limited for FDA to understand the historical use of TB-500-related BDSs in compounded drug products.' Two facts sit underneath. TB-500 appears to have first been synthesised in 2003, and its first documented preparation was VETERINARY — FDA writes that 'a veterinary preparation of TB-500 appeared in 2011 and was marketed to boost performance in equine and greyhound sports (Ho et al. 2012).' The human market came after the animal-performance market, not after a clinical programme.
TB-500-Related Bulk Drug Substances — FDA Briefing Document, Pharmacy Compounding Advisory Committee Meeting, July 23-24, 2026 — FDA, 23 July 2026“No outsourcing facilities have reported compounding drug products containing TB-500 to FDA. Two websites were found that state that they obtain TB-500 from a compounding pharmacy, but no details were provided about the pharmacy from which the product is obtained; additionally, no pharmacies were found that market compounded drug products containing TB-500.”
Checked against the source on .TB-500 is not an approved drug anywhere FDA checked. There is no USP or NF monograph for TB-500 (free base) or TB-500 acetate, neither is a component of any FDA-approved drug, and there are no approved TB-500 products in ten other named countries or in the EU.
FDA states separately: 'There is no applicable United States Pharmacopeia (USP) or National Formulary (NF) drug substance monograph for TB-500 (free base) or its acetate form, and neither is a component of an FDA-approved drug.' This forecloses the common deflection that TB-500 is 'approved elsewhere' or 'pharmacopeial somewhere'. It is neither. Note the scope: FDA is speaking about TB-500, the fragment. Full-length thymosin β4 is likewise not an approved drug in the US, but that is a different substance with a different and genuinely clinical record — see moleculeNote.
TB-500-Related Bulk Drug Substances — FDA Briefing Document, Pharmacy Compounding Advisory Committee Meeting, July 23-24, 2026 — FDA, 23 July 2026“TB-500 is not recognized in either the European or Japanese Pharmacopeias. There are no approved products containing TB-500 in Canada, Australia, the United Kingdom, Belgium, Ireland, France, Norway, Germany, Spain, and Italy. Additionally, there are no products containing TB-500 that have been authorized for use in the European Union by the European Medicines Agency.”
Checked against the source on .TB-500 is on the World Anti-Doping Agency prohibited list under section S2.3, and was identified in a 2016 study of doping forums as one of the two most frequently discussed peptides and growth factors.
Prohibited-list status is an anti-doping fact, not an FDA safety or efficacy finding, and it should not be recruited as either — WADA prohibits substances for performance reasons regardless of whether they work as marketed. It is recorded because it is the operative fact for any tested athlete and it is checkable. FDA also notes WADA approved a project in 2013 to determine detection limits for TB-500's metabolites and implement them into peptide-screening methods. On the demand side, in a 2016 analysis of thirteen online doping forums, researchers reported that TB-500 was one of the two most frequently mentioned peptides and growth factors, emerging as a topic after 2010 with discussion trending upward since (Pineau et al. 2016). FDA's own framing of that study is a caution, not a corroboration: 'It is unclear whether the products discussed are compounded products or how the products are obtained.'
TB-500-Related Bulk Drug Substances — FDA Briefing Document, Pharmacy Compounding Advisory Committee Meeting, July 23-24, 2026 — FDA, 23 July 2026“TB-500 is on the list of prohibited substances under section S2.3 of the WADA.”
Checked against the source on .
Documented safety signals
No FAERS reports and no published adverse-event cases were retrieved. Two reports in the Human Foods Complaint System concern 'blended TB-500 and BPC-157', but include no safety assessments.
An empty adverse-event database is NOT a safety finding, and reading it as one inverts the document. FDA's position is that risks are UNKNOWN, not absent: 'potential safety risks associated with the use of TB-500 in humans are unknown.' Absence of reports on a substance with zero human exposure data and voluntary reporting is uninformative — FDA attaches its standard FAERS limitations footnote for exactly this reason. The FAERS search ran through 26 March 2025; the HFCS search covered 1/1/2004 to 3/10/2025.
TB-500-Related Bulk Drug Substances — FDA Briefing Document, Pharmacy Compounding Advisory Committee Meeting, July 23-24, 2026 — FDA, 23 July 2026Checked against the source on .FDA flags a significant immunogenicity risk for TB-500 by the proposed intramuscular and subcutaneous routes, potentially amplified by aggregation and peptide-related impurities. No immunogenicity or aggregation studies were submitted or identified.
Note the burden as FDA frames it: 'The nomination did not include, and FDA has not identified, information about TB-500-related substances to suggest that these substances do not present such risks.' The route matters — this concern attaches to the injectable use TB-500 is sold for, and is not answered by full-length Tβ4's topical, ophthalmic and intravenous safety record, which is a different molecule.
TB-500-Related Bulk Drug Substances — FDA Briefing Document, Pharmacy Compounding Advisory Committee Meeting, July 23-24, 2026 — FDA, 23 July 2026“Peptides administered via injectable ROAs, such as the proposed IM and SC routes, may pose a significant risk for immunogenicity, potentially amplified by aggregation as well as potential peptide-related impurities.”
Checked against the source on .No nonclinical toxicity data: FDA identified no acute or repeat-dose toxicity studies, no nonclinical pharmacokinetic studies via the nominated intramuscular route, and no genotoxicity assessment for TB-500.
The gap runs deeper than the missing human data. FDA's conclusion is that 'nonclinical toxicological studies are not available to inform safety considerations for potential clinical uses of TB-500 (free base) or TB-500 acetate' — so the animal record cannot backstop the empty human record either. FDA did identify nonclinical PK studies showing TB-500 (free base) reaches the systemic circulation via the SC and IP routes and is hydrolysed into smaller peptides, but writes that it 'did not identify nonclinical PK studies in which animals received TB-500 (free base) or TB-500 acetate via the nominated IM ROA.'
TB-500-Related Bulk Drug Substances — FDA Briefing Document, Pharmacy Compounding Advisory Committee Meeting, July 23-24, 2026 — FDA, 23 July 2026Checked against the source on .
Questions people actually ask
Every answer cites the document behind it. Where the honest answer is “nobody knows”, that is the answer you will get.
- Is TB-500 legal in 2026?
TB-500 is not an FDA-approved drug, is not a component of any FDA-approved drug, and has no United States Pharmacopeia or National Formulary drug substance monograph — and it is not on FDA's 503A bulks list of substances that may be used in pharmacy compounding, which is why a 503A pharmacy may not lawfully compound it for any use. FDA staff proposed not adding TB-500 (free base) or TB-500 acetate to that list ahead of the Pharmacy Compounding Advisory Committee meeting on 23-24 July 2026. Separately from US drug law, TB-500 is on the World Anti-Doping Agency prohibited list under section S2.3, so it is banned for tested athletes.
TB-500-Related Bulk Drug Substances — FDA Briefing Document, Pharmacy Compounding Advisory Committee Meeting, July 23-24, 2026 — FDA, 23 July 2026“There is no applicable United States Pharmacopeia (USP) or National Formulary (NF) drug substance monograph for TB-500 (free base) or its acetate form, and neither is a component of an FDA-approved drug. … Accordingly, we propose not adding TB-500 (free base) or TB-500 acetate to the 503A Bulks List.”
Checked against the source on .- Did TB-500 become legal again when the FDA nomination was withdrawn?
No. The single nomination for TB-500 — submitted by Wells Pharmacy Network — was withdrawn by the nominator, and a nominator withdrawing is not an FDA decision, an approval, or a legalisation event. TB-500 did not move onto the 503A bulks list; it is absent from that list entirely, which is what makes it non-compoundable. The withdrawal did not even stop the review: FDA states it decided to evaluate both TB-500 (free base) and TB-500 acetate on its own initiative, and its staff proposed not adding either to the list ahead of the Pharmacy Compounding Advisory Committee meeting on 23-24 July 2026.
TB-500-Related Bulk Drug Substances — FDA Briefing Document, Pharmacy Compounding Advisory Committee Meeting, July 23-24, 2026 — FDA, 23 July 2026“The nomination was withdrawn and FDA is evaluating the substances at its discretion.”
Checked against the source on .- Is TB-500 the same thing as thymosin beta-4?
No. FDA states that thymosin beta-4 and TB-500 are not the same substance, and notes that seller websites use the two names interchangeably. TB-500 is a synthetic N-acetylated seven-amino-acid fragment — residues 17 through 23, LKKTETQ — of the full-length 43-amino-acid protein thymosin β4. The distinction decides what the evidence means: FDA identified no clinical studies and no human exposure data for TB-500 itself by any route of administration, and because thymosin β4 is a different substance, evidence about thymosin β4 is not evidence about TB-500. FDA also cautions that because acetylation irreversibly alters a peptide's charge, hydrophobicity and size, the profile of the non-acetylated heptapeptide LKKTETQ cannot be directly extrapolated to the N-acetylated heptapeptide TB-500.
TB-500-Related Bulk Drug Substances — FDA Briefing Document, Pharmacy Compounding Advisory Committee Meeting, July 23-24, 2026 — FDA, 23 July 2026“Several websites state that TB-500 is a synthetic version of thymosin beta-4 and often use the terms interchangeably. However, as noted previously, thymosin beta-4 and TB-500 are not the same substance.”
Checked against the source on .- Is there any human evidence that TB-500 works?
No. FDA conducted a literature search and reported that no articles were found in which TB-500 was administered to humans — no clinical studies, no pharmacokinetic or pharmacodynamic data by any route, and no case reports. The nonclinical record does not fill the gap either: FDA concluded that nonclinical pharmacological evidence is currently lacking to support the potential for TB-500 to promote wound healing, and the only in-vitro study of TB-500 itself was negative — in a 2024 scratch assay in cultured fibroblasts, researchers reported wound closure was not significantly different between TB-500 and vehicle (Rahaman et al. 2024). The animal wound-healing data cited for TB-500 is on a different peptide, the non-acetylated heptapeptide LKKTETQ, which FDA says cannot be directly extrapolated to TB-500.
TB-500-Related Bulk Drug Substances — FDA Briefing Document, Pharmacy Compounding Advisory Committee Meeting, July 23-24, 2026 — FDA, 23 July 2026“After conducting a literature search, no articles were found in which TB-500 was administered to humans.”
Checked against the source on .- Can I get TB-500 from a compounding pharmacy?
Not lawfully. TB-500 is not on FDA's 503A bulks list, so a 503A compounding pharmacy may not use it to compound a drug product for any use, and FDA reported that no outsourcing facility has ever told FDA it compounds a TB-500 product and that it found no pharmacy marketing one. FDA did find two websites claiming to obtain TB-500 from a compounding pharmacy, but they named no pharmacy. FDA also found several websites selling TB-500 powder for reconstitution which state that the products are intended for research use only.
TB-500-Related Bulk Drug Substances — FDA Briefing Document, Pharmacy Compounding Advisory Committee Meeting, July 23-24, 2026 — FDA, 23 July 2026“No outsourcing facilities have reported compounding drug products containing TB-500 to FDA. Two websites were found that state that they obtain TB-500 from a compounding pharmacy, but no details were provided about the pharmacy from which the product is obtained; additionally, no pharmacies were found that market compounded drug products containing TB-500.”
Checked against the source on .- What did FDA propose at the July 2026 PCAC meeting about TB-500?
FDA staff proposed not adding TB-500 (free base) or TB-500 acetate to the 503A bulks list, in a briefing document dated 15 May 2026 prepared for the Pharmacy Compounding Advisory Committee meeting on 23-24 July 2026. FDA's stated basis was the lack of data on physicochemical characterisation, the lack of historical use in compounding, the non-existent information on these substances administered in humans, and the risk that peptides given by the proposed intramuscular and subcutaneous routes may pose for immunogenicity, together with the existence of FDA-approved therapies for wounds. A staff proposal is not a final determination: the document states FDA will not issue one until the advisory committee input has been considered and all reviews finalised.
TB-500-Related Bulk Drug Substances — FDA Briefing Document, Pharmacy Compounding Advisory Committee Meeting, July 23-24, 2026 — FDA, 23 July 2026“On balance, the physiochemical characterization, information on historical use, lack of any evidence of effectiveness, and safety information for both TB-500 (free base) and TB-500 acetate weigh against their being added to the 503A Bulks List.”
Checked against the source on .- Is TB-500 safe?
Unknown, and FDA says so explicitly rather than reassuringly: its position is that potential safety risks associated with the use of TB-500 in humans are unknown, because there is no human data on it by any route. That is not a clean safety record. FDA identified no acute toxicity, repeat-dose toxicity, genotoxicity, carcinogenicity, or developmental and reproductive toxicity studies of TB-500 (free base) or TB-500 acetate, so the animal record cannot backstop the empty human record. FDA flags that peptides given by the proposed intramuscular and subcutaneous routes may pose a significant risk for immunogenicity, potentially amplified by aggregation and peptide-related impurities, and notes that the nomination included no information suggesting these substances do not present such risks. A search of FAERS through 26 March 2025 retrieved no reports, which is uninformative for a substance with no documented human exposure and voluntary reporting.
TB-500-Related Bulk Drug Substances — FDA Briefing Document, Pharmacy Compounding Advisory Committee Meeting, July 23-24, 2026 — FDA, 23 July 2026“The nomination did not include, and FDA has not identified, any clinical studies or human exposure data using TB-500 via any ROA. Therefore, potential safety risks associated with the use of TB-500 in humans are unknown.”
Checked against the source on .