Where to buy TB-500.

You can buy TB-500 from research-chemical suppliers online, and that's the only route there is: no pharmacy stocks it and no prescription exists to write. No compounding pharmacy may make it either, so the real question behind where to buy TB-500 is which molecule the vendor puts in the vial.

TB-500

Referenced in this guide

Batch-matched COAHPLC + mass specResearch use only

The TB-500 referenced throughout this article, supplied as a research compound with a certificate of analysis matched to the lot you receive — the check this site argues you should hold any supplier to.

Shop TB-500

Where can you buy TB-500?

You can buy TB-500 from research-chemical suppliers online. That's the only route, and we want to say it plainly rather than pad the list. Here's why the other doors are shut.

• Research-chemical suppliers. Lyophilized powder under Research Use Only labeling, $50–$120 per 5 mg vial, no prescription. The only place to buy it.
• A retail pharmacy. Closed. No Thymosin β4 or TB-500 product is FDA-approved for anything, so there's nothing to dispense.
• A compounding pharmacy. Closed. 503A compounding needs an approved active ingredient or a shortage listing, and TB-500 has neither.
• A clinical trial. Trials are running on full-length Tβ4 for eye conditions, not on TB-500 as sold. That isn't a route to this product.

Since the seller is your only quality control, the rest of our guide is about checking the seller.

Six vendors, all checked on 13 August 2026, with the TB-500 price each was charging that day. Read the vial size before the number, and the certificate columns before either — on this compound the certificate is the only thing that tells you which molecule you bought. The full ten-vendor version is our vendor comparison.

† 10 mg vial; neither Peptriva nor Red Rock sells a 5 mg size, so those prices cover twice the material of the 5 mg rows and the per-milligram figures are not comparable. Red Rock publishes no certificate of analysis at all, despite advertising verified COAs. Swiss Chems sells its BPC-157 as the arginine salt rather than the plain peptide, which is worth carrying if you price-check that vendor across compounds. Where To Buy Peptides earns a commission on purchases made through its links, Peptriva included — see our disclosure.

The identity check specific to TB-500: CAS 885340-08-9 on the identity line — and because the name covers two different molecules, ask in writing which one is in the vial, full-length Tβ4 at 43 amino acids or the Ac-LKKTETQ heptapeptide at 7.

What is TB-500, and how does it differ from Thymosin β4?

TB-500 is a marketing name, not a defined molecule. That's the central identity problem, and it's why the mass line on the CoA matters more here than anywhere else in this library.

Thymosin β4, written Tβ4, is a 43-amino-acid peptide your body already makes. It accounts for 70–80% of all β-thymosins in the human body, as Ying and colleagues describe, and it circulates in plasma. That already sets it apart from purely synthetic research peptides.

TB-500 refers either to that full-length molecule or to a synthetic fragment carrying the active LKKTETQ sequence. LKKTETQ is the part that binds actin, the protein that builds cell scaffolding.

The 2026 Sports Medicine review by Mendias and Awan explicitly distinguishes the two. Full-length Tβ4 at 43 residues is one thing. TB-500 as a fragment is another.

The form most commonly sold is the acetylated heptapeptide Ac-Leu-Lys-Lys-Thr-Glu-Thr-Gln. That's the LKKTETQ core, formula C₃₈H₆₈N₁₀O₁₄, MW 889.0 g/mol, CAS 885340-08-9.

Here's the part that should change what you buy. The biology vendors quote is mostly the biology of the full-length molecule: G-actin binding, angiogenesis, cell migration, Ac-SDKP cleavage, endothelial repair.

The fragment keeps the actin-binding motif. It doesn't necessarily reproduce everything downstream. So check which form is in your vial before you carry any claim over from the full-length literature.

How do you verify TB-500 before you buy?

Four checks decide whether a TB-500 vial is worth buying. Which form it is. The WADA status. The storage. And the price. The standard eight vendor criteria apply on top, but the first of these four does most of the work.

1. Confirm the form: fragment or full-length

This is the check that matters most, and the one most vendors skip. The 2026 Sports Medicine review notes that TB-500 in the research-chemical market can be full-length Tβ4, the LKKTETQ heptapeptide, or something unrelated.

The molecular weights are miles apart. Tβ4 sits near 4963 Da. The fragment sits at 889.0 g/mol. Mass-spec on the CoA settles it in one number. In our reading, a CoA listing TB-500 with no molecular weight has failed the most basic identity check there is.

2. WADA Section S2, banned year-round

TB-500 sits on the WADA Prohibited List under Section S2, which covers peptide hormones, growth factors and mimetics. Section S2 substances are banned in competition and out of it. There's no permitted window for an athlete.

The 2026 AJSM review notes that Tβ4 and TB-500 promoted angiogenesis and tissue repair in preclinical models and remain banned in sport. Validated LC-MS detection methods already sit in standard anti-doping panels. Buying it for research is legal. Competing on it is not.

3. Storage, because the actin-binding motif oxidizes

The LKKTETQ sequence and the methionine residues in full-length Tβ4 all oxidize. Oxygen, light and moisture each degrade activity. Lyophilized powder at −20°C lasts years. Pre-reconstituted liquid loses activity over weeks, even in a fridge.

A vendor shipping pre-reconstituted TB-500 at room temperature is shipping you a degraded product. Lyophilized is the only form we'd accept from a serious supplier.

4. Pricing, at $50–$120 per 5 mg vial

Synthesis cost diverges sharply between the two forms. The LKKTETQ heptapeptide, 7 residues plus one acetylation, is among the cheapest peptides to make. Full-length Tβ4 at 43 residues costs meaningfully more.

A vendor selling both at one price is charging the same markup regardless of cost. Below $40 per 5 mg, ask about purification. Above $150 per 5 mg, you're paying retail markup, unless they're genuinely shipping authenticated full-length Tβ4.

What does TB-500 cost in 2026?

TB-500 costs $50–$120 per 5 mg vial in 2026. That range is wider than most peptides we cover, for one simple reason: the name covers two molecules with very different synthesis costs.

• 5 mg vial (LKKTETQ fragment): $50–$100 ($10–$20/mg). The most common retail size.
• 5 mg vial (full-length Tβ4): $80–$120 ($16–$24/mg). A premium for the longer peptide — if the vendor actually ships it.
• 10 mg vial: $90–$180 ($9–$18/mg). Better per-mg value than the 5 mg.
• Multi-vial discounts: 10–25% off for 3- or 6-packs at most vendors.

Below $40 per 5 mg, ask about purification standards. The HPLC step is what separates crude TB-500, impurities included, from ≥98% material. Above $25 per mg, you're paying retail markup rather than chemistry. Our one exception is authentic full-length Tβ4, which sits at the higher end for legitimate reasons.

Is TB-500 legal to buy?

TB-500 is legal to buy in the US as a research reference compound, and it isn't a controlled substance. No Tβ4 or TB-500 product is FDA-approved for anything, which is exactly why the research route is the only one.

Tβ4 is in clinical trials for dry eye disease and neurotrophic keratopathy, plus cardiovascular work. Nothing has been approved as of 2026.

The closest approved thymosin is thymalfasin, sold as Zadaxin. That's thymosin α1, a different molecule entirely. Four things follow for you.

• Research-compound sale is legal. TB-500 ships lawfully in the U.S. under Research Use Only labeling (21 CFR § 809.10(b)(9)). It isn't a controlled substance.
• Selling for human use isn't. A vendor marketing TB-500 as a treatment for tendon injuries, joint pain, or recovery has crossed into FDA jurisdiction.
• WADA prohibition is year-round. Section S2 bans both in-competition and out-of-competition. There's no permitted window.
• Major sports leagues prohibit it. TB-500 is in standard anti-doping panels across professional sports.

The 2026 Sports Medicine review calls TB-500 an unapproved peptide with scarce human safety data, where unregulated supply creates real potential for harm. US law lets you buy it as a research reference compound. Putting it into a person sits outside that permission entirely.

What are the red flags when buying TB-500?

Seven things would stop us buying a TB-500 vial. The first one is close to disqualifying on its own, because without it you don't know what you bought.

• CoA that just says "TB-500" with no MW. A third-party tested CoA must distinguish full-length Tβ4 (~4963 Da) from the LKKTETQ fragment (889.0 g/mol). Vendors who can't answer shouldn't be selling.
• Mass-spec that doesn't match the declared form. CoA claims full-length Tβ4 but mass reads near 889 Da? You got the fragment. CoA claims the fragment but mass reads near 4963 Da? Something else is in the vial.
• Pre-reconstituted liquid without cold chain. The actin-binding motif oxidizes. Lyophilized powder stored cold retains activity. Pre-reconstituted shipped at room temp is degraded before you open it.
• "TB-500 Stable," "TB-500 Plus," or branded variants. If the structure isn't published, the product isn't third-party tested for literature-matching purposes.
• Clinical or athletic claims on the product page. "TB-500 heals tendons." "TB-500 for recovery." That's FDA enforcement territory and WADA radar.
• Missing CAS number. The LKKTETQ fragment is CAS 885340-08-9. Absence on the CoA is a red flag.
• Capsules, sprays, or transdermal patches. No published research validates these for either form. The injectable lyophilized peptide is what the literature uses.

TB-500

5 mg ≥99% pure Lyophilized

Ac-LKKTETQ heptapeptide, CAS 885340-08-9, MW 889.0 g/mol. The same reference compound used across the cited preclinical studies. COA with HPLC trace and mass-spec identity confirmation ships with every order.

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Frequently asked questions

Is TB-500 legal to buy?

TB-500 is legal to buy in the US as a research reference compound labeled for laboratory use. No Thymosin β4 product is FDA-approved, and TB-500 isn't a controlled substance. Selling it for human consumption is illegal. Buying it as research material is not. It also appears on the WADA Prohibited List under Section S2, banned in and out of competition.

How much does TB-500 cost?

You'll pay roughly $50–$120 per 5 mg vial in 2026, and $90–$180 for 10 mg. That range reflects whether the vendor shipped the cheap 7-residue Ac-LKKTETQ heptapeptide or the 43-residue full-length Tβ4. Most vendors won't tell you. Mass-spec on the CoA will. The price tag rarely does.

Is TB-500 the same as Thymosin β4?

No. Tβ4 is the full-length 43-amino-acid peptide, MW near 4963 Da. TB-500 is a marketing name for either that molecule or a synthetic 7-residue fragment carrying the LKKTETQ sequence at 889 g/mol. The 2026 Sports Medicine review distinguishes the two explicitly. Mass-spec on the CoA is your only reliable check.

What should a TB-500 CoA show?

The CoA should name the form: either the Ac-LKKTETQ heptapeptide, CAS 885340-08-9, MW 889.0 g/mol, or full-length Tβ4 near 4963 Da. Then HPLC purity ≥98% with the chromatogram, mass-spec matching the declared MW within half a dalton, and Karl Fischer water content of 2–8%. The lab should be ISO/IEC 17025 accredited.

Why is TB-500 WADA-banned?

TB-500 falls under WADA Section S2, covering peptide hormones, growth factors and mimetics. The basis is Tβ4's documented angiogenic and tissue-repair activity, and WADA lists substances that push tissue regeneration past physiological norms. Validated LC-MS methods are already in standard panels. A positive test carries sanctions under your federation's rules.

TB-500 vs BPC-157 — which one for research?

Different mechanisms, different evidence bases. BPC-157 has the larger preclinical literature in tissue-repair models, mostly from the Sikiric group in Zagreb.

Tβ4, the molecule behind TB-500, has more diverse mechanistic biology: G-actin sequestration, CCN5 signaling, Ac-SDKP endothelial repair, and mitochondrial transfer through tunneling nanotubes. It also has ongoing clinical research in ophthalmology.

The two get co-investigated because the pathways complement rather than overlap. Our BPC-157 vs TB-500 comparison goes through it.