Best TB-500 Vendors: COA-Verified Sources for 2026
Nearly every vendor selling “TB-500” is actually shipping the full 43-amino-acid Thymosin Beta-4 protein, not the 7-amino-acid fragment the name originally referred to. Of the eight vendors we graded for this guide, only Skye Peptides sells both as clearly labeled, separate SKUs. If you assumed you were buying the fragment, you probably weren't.
The bigger issue sits one layer deeper. A vendor can slap “TB-500” on any peptide in a vial, and only a mass spec COA proves what is actually in there. HPLC tells you how pure the target peak is. Only mass spectrometry confirms the peak is the molecule you think it is.
This guide grades eight vendors on COA depth (HPLC versus mass spec versus endotoxin), $/mg pricing across a $6.00 to $16.50 range, shipping practices, and specific batch data where vendors publish it. Every vendor gets a weakness called out. No free passes.
One note on regulation: TB-500 remained Category 2 after the March 2026 Peptide Sciences shutdown. That classification restricts compounding pharmacies, not research chemical vendors. Research-use-only sourcing is still open.
Here's who passes the COA test, who doesn't, and what you pay per mg for each. These are the best TB-500 vendors we could verify with published lab documentation.
1. Ascension Peptides: Triple-Tested COAs and Cold Chain for $9/mg
Ascension is the only vendor in this guide that routes every batch through SafeCert's triple-lab protocol. HPLC identity at one lab, mass spec confirmation at a second, endotoxin at a third. That is the COA chain most competitors claim and few actually document.
Pricing: $45 for 5mg works out to $9.00/mg. The Wolverine Stack (BPC-157 plus TB-500) runs $110. Solidly mid-tier in this field.
COA quality
SafeCert's triple-3P model means three independent labs sign off on every batch. One runs HPLC for purity, one runs LC-MS for molecular weight confirmation, one runs endotoxin via LAL assay. Most vendors skip at least one of those three. For TB-500 specifically, endotoxin matters more than buyers realize. LPS activates TLR4 and mimics the same cell migration and angiogenesis pathways TB-500 research targets, so a contaminated vial can confound any result you get. The COA verification methodology page walks through why the three-lab chain is the standard we grade against.
Shipping
Cold chain with ice pack is available on request. For lyophilized TB-500 this is belt-and-suspenders since the powder tolerates 1 to 3 days of ambient transit without meaningful degradation. If you reconstitute close to delivery or you're in a hot shipping corridor in July, it's the right default.
Weakness
Not the cheapest $/mg in the field. Polaris and Verified Peptides both beat Ascension on raw price by roughly 30%. If you run bulk in-vitro protocols where COA depth matters less than cost per mg, you can save real money elsewhere. Cold chain is also opt-in rather than default, which is a strike against vendors charging mid-tier prices. The Wolverine Stack is priced at parity with buying both peptides individually elsewhere, so the “bundle” is a convenience play, not a discount.
Best for / skip if
Best for researchers who want the most verifiable COA chain in a mid-tier budget. Skip if you need the absolute lowest $/mg for high-volume work and you're comfortable with HPLC-only documentation. For buyers running a single-variable protocol where batch identity confirmation is non-negotiable, Ascension's triple-3P paperwork is the cleanest way to defend a result.
2. Verified Peptides: 99.777% Purity with Full-Panel COA at $6.20/mg
Verified Peptides publishes a batch COA showing 99.777% purity from Janoshik Analytical and charges 31% less per mg than Ascension for the same documentation tier. The catch is knowing what a Janoshik full panel actually demonstrates.
Pricing: $62 for 10mg works out to $6.20/mg list. Bulk tiers drop it further: 10% off at 5–9 units, 15% off at 10–24, and 25% off at 25+ units, which lands you at $46.50 per vial. Polaris is a hair lower at $6.00/mg, but carries review-distribution problems we'll get to.
COA quality
Janoshik Analytical is the reference lab serious vendors use. The specific batch we verified (TB02260810H, tested March 19, 2026) posted 99.777% HPLC purity, TFA not detected, endotoxin pass, and sterility pass on both bacteria and mold/yeast panels. Per-batch COAs ship with QR links, so a specific vial traces back to a specific lab report. Most HPLC-verified vendors land between 98% and 99.5%, so a documented 99.777% is a measurable step up, and the TFA-not-detected result is the kind of counter-ion data Janoshik publishes that most US labs omit. Our breakdown of what peptide purity numbers actually mean covers why the extra decimal places matter and when they don't.
Shipping and stacks
Same-day shipping on orders placed before 1:00 PM EST, with ice pack default rather than opt-in. A BPC-157/TB-500 blend (20mg total) is available if you want the stack in a single vial rather than two.
Weakness
No heavy metals panel surfaced in the documentation we reviewed, which is a visible gap against Skye's 20mg SKU that publishes those numbers explicitly. Catalog is also smaller than Ascension or Core Peptides, with less community history and fewer independent forum reviews to cross-check against the lab data.
The verdict
If your decision criterion is highest COA purity per dollar, Verified wins this guide outright. The price-to-documentation ratio is the strongest in the eight-vendor field and Janoshik is the lab you want to see named on the paperwork.
3. Skye Peptides: The Only Vendor Selling Both the Full Molecule and the Fragment
If you've been buying TB-500 anywhere else in this guide, you've been buying the 43-amino-acid full Thymosin Beta-4 protein. Not the 7-amino-acid fragment the name actually refers to. Skye is the only vendor we found selling both as clearly labeled separate SKUs.
The molecule distinction
TB-500 was coined in early research papers to describe the 17–23 active region of Thymosin Beta-4. Seven amino acids, Ac-LKKTETQ, believed to drive some of the actin-binding and cell migration effects of the parent molecule. The research peptide market then started applying the TB-500 label to the full 43-aa molecule for simplicity. For most buyer use cases this substitution doesn't materially change the experiment. For receptor-binding studies on the fragment specifically, it is the entire experiment. Our TB-500 molecule page goes deeper on the sequence and why vendors conflate the two.
COA quality
Janoshik full panel on every SKU, with batch numbers published. The 10mg TB-500 (batch TB25-10-004) posted 99.2% purity with endotoxin and sterility reports attached. The 20mg SKU (batch TB25-20-002) hit 99.6% and includes heavy metal panels, the only vendor in this guide publishing that data on TB-500. The 10mg Fragment 17–23 (batch TB4F25-10-001) posted 99.0% purity with endotoxin at 0.0075 EU/mg, well below the <5 EU/mg general limit and comfortably under the <0.01 EU/mg threshold NF-kB assays require.
Pricing and shipping
Login required to see real-time prices, which is a friction point we'd rather not see. Historical community reports put Skye in the mid-tier, similar to Verified or slightly above. First-time buyers get a 10% discount code. Same-day or next-day shipping is standard.
Weakness
The login wall makes catalog-level price comparison impossible, which is annoying when you're triaging vendors. The fragment SKU is a specialist product. Most buyers want the full TB-4 molecule and won't benefit from the option.
Direct recommendation
Skye is the right vendor for researchers who need the 17–23 fragment specifically, buyers who want heavy metals on the COA, and anyone running Janoshik-grade paperwork from a boutique operation. For everyone else, Verified or Ascension are cleaner choices.
4. Core Peptides: 4.8/5 Trustpilot Across 279 Reviews and GMP Documentation
You can't fake 279 verified Trustpilot reviews at 4.8 stars. Core Peptides has the most-reviewed and highest-rated community profile in this guide by a wide margin.
Pricing: $140 for 10mg works out to $14.00/mg. Premium tier. Roughly 2.25x the price of Verified Peptides for the same 10mg quantity.
COA quality
Core publishes COAs showing >99% HPLC purity with GMP-synthesized documentation. What Core doesn't do consistently is publish the lab name on every COA. HPLC purity reports are there, but mass spec identity confirmation is less visible than at Verified or Ascension. You're trusting the documentation chain rather than being shown every link. For context on how to weight Trustpilot and review-volume signals against COA depth, see our vendor evaluation framework.
Shipping
Standard US shipping, no cold chain default. TB-500 is lyophilized, so ambient transit is acceptable, but vendors charging premium prices increasingly ship with ice packs as the baseline.
Weakness
Price. At $14/mg you pay 2.25x what Verified charges for what is, on paper, a shallower COA. HPLC purity is there, but visible mass spec confirmation and a named lab are not. You are buying review volume and GMP paperwork, not deeper lab verification. For a first-time TB-500 buyer who wants a “probably won't have a bad experience” vendor, that trade can be worth it. For a returning buyer comparing paperwork, it's harder to defend.
What the reviews actually say
Community reports on Core cluster around two themes: consistent shipping speed and predictable reconstitution behavior (no cloudy vials, no precipitate). That's the signal you pay for when you choose Core. It's not a COA signal, it's a QC signal derived from years of repeat customers, and it's a legitimate data point even if it doesn't show up on a lab report.
Best for / skip if
Best for buyers who weight community verification heavily and prefer vendors with explicit GMP synthesis documentation. Skip if you want the most COA depth per dollar or if you're ordering at a scale where a 2.25x price premium materially changes your protocol budget.
5. BioLongevity Labs: Premium-Tier Triple-3P Testing with US GMP Synthesis
BioLongevity Labs is the most expensive TB-500 in this guide at $16.50/mg. That's 2.75x the price of Polaris Peptides. The question isn't whether it's expensive. The question is whether US GMP synthesis plus SafeCert triple-3P testing is worth 2.75x to your specific protocol.
Pricing: $164.97 for 10mg works out to $16.50/mg. Premium tier, no discounting. For small-n experiments where total peptide cost is a line item rather than a budget constraint, affordable. For bulk users, prohibitive.
COA quality
SafeCert triple-3P. Same three-lab protocol Ascension runs. HPLC purity, LC-MS identity, endotoxin via LAL assay. Synthesis is documented as US-based GMP, which is the primary differentiator over Ascension's offering. Our full BioLongevity Labs review walks through the US synthesis chain and why it matters for regulated lab environments.
Weakness
Price. At a 100%+ premium over Ascension for the same SafeCert protocol, US synthesis is the only objective upgrade you're paying for. For most buyer use cases, synthesis origin doesn't change the molecule in the vial. The mass spec COA still confirms the same molecular weight whether the peptide was synthesized in San Diego or Shanghai. One disclosure: BioLongevity Labs is a peptidegrades.com affiliate partner. This review was conducted under the same methodology we apply to every vendor, and the weakness call-out is the same one we'd make without the relationship. We don't soften pricing analysis for affiliate partners.
When the premium is worth it
If an IRB or institutional purchasing policy specifies US-synthesized material, BioLongevity clears that requirement cleanly. If a downstream regulatory submission will ask for synthesis provenance, the documentation is there. For those narrow use cases, the premium isn't a markup, it's a compliance cost.
The verdict
BioLongevity is the right vendor when documentation provenance is genuinely mission-critical. Regulated lab environments, institutional purchasing with audit requirements, buyers who specifically want US synthesis on the paperwork. For individual researchers running the same protocol Ascension and Verified serve, the price premium is hard to justify.
6. Polaris Peptides: Cheapest $/mg, but 21% 1-Star Reviews Demand Caution
Polaris is the cheapest TB-500 in this guide with actual HPLC plus mass spec documentation. $6.00/mg, 99.687% average purity on published COAs. The catch is that 21% of their reviews are 1-star and the complaints cluster around cloudy vials and inconsistent reconstitution.
Pricing: $60 for 10mg works out to $6.00/mg list, with bulk tiers dropping to $45.00 per vial at 100+ units. Cheapest $/mg in the guide among vendors publishing mass spec documentation. A BPC-157/TB-500 blend (10mg/10mg) is also available for buyers who want the stack in a single vial.
COA quality
HPLC plus MS published per batch. Average purity across batches we checked: 99.687%, with molecular weight confirmed by mass spec. Testing depth on paper is real. However, Polaris does not publish endotoxin results on every batch. For TB-500 specifically, that's a meaningful gap. LPS contamination activates the exact TLR4-mediated pathways TB-500 research targets, and peptide purity averages can mask batch-to-batch variance that endotoxin testing would catch.
The problem
Review distribution. 21% 1-star is well above the industry norm (Core Peptides sits near 5% 1-star for comparison). Polaris also carries a 4.2/5 Trustpilot across only 33 reviews, a sample size too thin to smooth out bad batches the way Core's 279-review profile does. Community reports cite cloudy post-reconstitution vials, which can indicate precipitate, incomplete dissolution, or bacterial contamination. Any of those outcomes ruins a protocol.
Weakness
Batch inconsistency at the reported rate, plus the missing endotoxin data on every batch. Also worth flagging: two separate Polaris Peptides domains exist (polarispeptides.com and polarispeptidesusa.com). Confirm the official one with the vendor before ordering. Domain collisions in this category are a common source of mis-ordering and occasionally outright counterfeit listings.
Direct recommendation
Polaris is for the buyer who understands the QC risk, orders 5mg first to test the batch, and specifically needs the lowest $/mg with mass spec documentation. If you cannot afford a bad batch derailing your protocol timeline, pay 3% more and use Verified Peptides. The $0.20/mg premium is cheap insurance.
7. Limitless Life: 24-Month Shelf Life with Published HPLC 3P COAs at $10.99/mg
If you buy TB-500 in bulk and hold it in a –20°C freezer for months before using it, Limitless Life is the only vendor in this guide publishing a specific 24-month stability claim backed by three separate COA types per batch.
Pricing: $54.99 for 5mg works out to $10.99/mg. Mid-premium. More expensive than Ascension ($9.00/mg), cheaper than Core or BioLongevity.
COA quality
Three COA types published per batch. HPLC purity, mass spec identity, endotoxin via LAL. Third-party HPLC verification documented. Structural depth is comparable to Ascension's SafeCert protocol.
What's unique
The 24-month shelf life claim is the real differentiator. TB-500 contains methionine (unlike BPC-157), which is oxidation-sensitive. Most vendors won't publish shelf-life numbers because it's protocol-dependent and risky to commit to on paper. Limitless committing to 24 months at –20°C for lyophilized product is the most specific stability documentation we found across the eight-vendor field. See our TB-500 peptide page for more on why methionine oxidation makes shelf-life claims rare in this category.
Weakness
5mg-only SKU caps bulk purchasing. If your protocol needs 20 to 50mg on hand, you're placing multiple orders and paying the small-quantity premium each time. The 24-month claim is also vendor-published rather than independently validated by a named third party, which is a softer evidence tier than batch purity.
Best for / skip if
Best for researchers who buy once and hold inventory for extended protocols where stability documentation is load-bearing. Skip if you turn peptide over in 90 days anyway, because you're paying for a durability promise you won't use.
8. EZ Peptides: Newest Entrant with QR-Linked COAs and International Shipping
EZ Peptides is the newest vendor in this guide, launched in early 2025, and they did one thing better than every incumbent. Per-vial QR codes that link directly to the specific batch COA. No login walls, no PDF hunts.
Pricing: $35 for 5mg works out to $7.00/mg. Mid-pack.
COA quality
QR-linked per-batch COAs with HPLC purity and identity confirmation. The published lab is not consistently named on every batch, which is a gap against Verified Peptides (explicitly Janoshik) and the SafeCert vendors. EZ is early in its COA maturity curve. The documentation infrastructure is modern, the content inside the documentation is still catching up.
Shipping
International shipping is the rare feature here. Nearly every US-based research peptide vendor ships US-only. For researchers in Canada, the EU, or Australia, EZ is often the only viable option in this guide, because the alternative is not shipping at all. That alone earns them a spot.
Weakness
Newest vendor in the guide with under 18 months of operating history. Community review volume is low, which means fewer independent data points to sanity-check against. Lab naming on COAs is inconsistent. Our full vendor grading list re-runs when new data surfaces.
The verdict
EZ is the right pick for international buyers where the competition basically doesn't exist, and for US buyers who value modern COA UX and are comfortable with a vendor still building its reputation. If track record is load-bearing in your decision, wait six months or go with Ascension or Verified.
FAQ
Is TB-500 the same as Thymosin Beta-4?
No. TB-500 originally referred to the 17–23 amino-acid fragment of Thymosin Beta-4, a 7-residue peptide (Ac-LKKTETQ). Nearly every vendor on the market now sells the full 43-amino-acid molecule under the TB-500 label. Skye Peptides is the only vendor we found selling both as clearly labeled separate SKUs, which is the only way to know which molecule you're actually buying.
Is TB-500 legal to buy after the March 2026 FDA enforcement action?
Yes, for research use. The March 2026 Peptide Sciences shutdown targeted compounding pharmacies, not research chemical vendors. TB-500 remains Category 2, and Category 2 restricts pharmacy compounding, not research supply. TB-500 is expected to remain Category 2 after the 2026 review because of ongoing cancer proliferation concerns in the underlying literature.
What does a good TB-500 COA include?
Three tests. HPLC for purity, mass spec or LC-MS for identity confirmation, and endotoxin via LAL assay. HPLC-only COAs are insufficient because HPLC tells you how pure the target peak is but cannot confirm what molecule that peak is. Endotoxin matters specifically for TB-500 because LPS activates TLR4 at 1 to 10 pg/mL, mimicking the cell migration pathways TB-500 research targets. A contaminated vial confounds the result.
What's the Wolverine Stack, and which vendor has the best one?
A BPC-157 plus TB-500 bundle. The mechanisms complement: TB-500 drives systemic cell migration via the bloodstream, BPC-157 activates local tissue repair via VEGFR2. Ascension Peptides sells the stack at $110 with triple-3P COA coverage on both peptides. Several vendors carry variants in the $52 to $110 range with varying documentation depth. Our best BPC-157 vendors guide covers sourcing the BPC-157 half in detail.
Why isn't Penguin Peptides ranked in the main list?
Penguin offers a 2mg vial (the only vendor in this category to do so) at $30 to $70 across sizes, which is genuinely useful for small-protocol buyers. But they publish no verifiable COA with a named lab. We don't rank vendors we can't verify. If you specifically need the 2mg trial size, Penguin is the only option, and our Penguin Peptides review covers the transparency gap in more detail.
Why isn't Ion Peptide ranked?
Ion has strong community signals (4.7/5 Trustpilot, 189 reviews, 91% 5-star) and publishes HPLC plus MS COAs from a named US lab. Their TB-500 product page returned a 403 error during our research window, so we couldn't verify live pricing or current stock. Our Ion Peptides review has the earlier data, and we'll re-grade when the product page is accessible.
How should I store TB-500?
Lyophilized: –20°C freezer, protected from light. The powder tolerates 1 to 3 days of ambient transit without meaningful degradation, which is why most vendors don't default to cold chain shipping. Reconstituted: 2 to 8°C refrigerator, use within 2 to 4 weeks. TB-500 contains methionine, which is more oxidation-sensitive than BPC-157, so minimize freeze-thaw cycles on the reconstituted solution.