Where to Buy TB-500: Price & Vendor Guide

TB-500 is the active 17-23 amino acid fragment of thymosin beta-4 — the 889 Da synthetic heptapeptide (Ac-LKKTETQ) that captures the LKKTET actin-binding motif at a fraction of full TB-4's cost. Pricing on the research market ranges from $4/mg to $40/mg for essentially the same molecule, and vendor quality matters more than ever because a mislabeled full-TB-4 product can be 5× the cost per mg.

This guide covers what you should actually pay, which vial size fits the standard 500 mcg/day protocol, how to verify a COA for the heptapeptide specifically (not full TB-4), and vendor red flags. TB-500 is also the primary pair for BPC-157 in the wolverine stack, so factoring both into your purchase makes sense.

This is not a ranked vendor list — for that, see our Best TB-500 Vendors comparison. This guide teaches you how to evaluate any vendor yourself.

Understanding TB-500 Pricing

TB-500 is sold as a lyophilized powder in sealed glass vials. It's a short 7-amino-acid peptide and cheap to synthesize correctly — there's no excuse for a legitimate vendor to skip testing. The three factors that move price: vial size, manufacturer sourcing, and whether the vendor pays for third-party COAs.

Current Market Pricing (2026)

The pattern is clear: 10mg is the sweet spot for virtually every TB-500 protocol. The 5mg vial exists mainly as a low-commitment trial size — it costs 20-40% more per mg and doesn't align cleanly with the typical 20-28 day loading phases.

Cost Per Week at Common Doses

For current vendor-specific pricing with exact $/mg breakdowns, see our Best TB-500 Vendors comparison.

How to Verify TB-500 Quality

TB-500 is the synthetic heptapeptide Ac-LKKTETQ — the N-acetylated active fragment corresponding to residues 17-23 of endogenous thymosin beta-4. Its molecular weight is 889 Da. Full-length TB-4 is 43 amino acids at 4,921 Da. These are different molecules, and some vendors blur the line — either selling full TB-4 as "TB-500" (cheating you out of 5× the peptide mass) or claiming "TB-500" that's actually a non-acetylated fragment with reduced stability.

What a COA (Certificate of Analysis) Should Include

Identity Confirmation

• Mass spectrometry confirming the correct molecular weight (889 Da for TB-500)
• Amino acid sequence verification matching Ac-LKKTETQ
• Confirmation of N-terminal acetylation — critical for TB-500 stability

Purity Testing

• HPLC purity — look for 98%+ purity
• The chromatogram should show a single dominant peak with minimal non-acetylated or truncated impurities

Contamination Testing

• Endotoxin levels (bacterial contamination)
• Residual solvent analysis (acetonitrile, TFA)
• Heavy metals screening

How to Verify a COA Is Legitimate

1. Check the testing lab — Reputable labs include Janoshik Analytical, MZ Biolabs, and Colmaric Analyticals. Avoid vendors who only show "in-house" testing.

2. Verify on the lab's website — Janoshik COAs have a task number you can look up directly at janoshik.com. If the vendor won't provide a verifiable task number, that's a red flag.

3. Check the date — COAs should be recent (within 6 months).

4. Match the batch — The batch/lot number on the COA should match what's printed on your vial.

5. Look for the original PDF — Screenshots are easier to fake than full PDFs with lab letterhead and signatures.

Red Flags to Avoid

• No COA available — any vendor unwilling to provide testing results is not worth the risk
• Only in-house testing — self-reported purity numbers are meaningless
• MW shown as ~4,921 Da — that's full TB-4, not TB-500. Real TB-500 is 889 Da
• Missing acetylation confirmation — non-acetylated fragments degrade faster and have reduced bioactivity
• Prices well below $4/mg — implausible for correctly-synthesized, N-acetylated TB-500
• No return or reship policy — reputable vendors stand behind their products

Choosing the Right Vial Size

Vial size selection is straightforward for TB-500 — only two common sizes exist (5mg and 10mg), and the 28-day reconstitution window caps how far you can stretch a single vial.

The 28-Day Rule

Once reconstituted with bacteriostatic water, TB-500 is stable for up to 28 days refrigerated. Sterile water (no preservative) drops this to 24 hours. See our TB-500 reconstitution guide for step-by-step mixing.

⚠️ = exceeds 28-day window per reconstitution

Solution at 2mg/week loading on a 10mg vial: you can slightly exceed 28 days (at 35 days you're only 7 days over), but most community protocols transition to maintenance dosing within 4 weeks, making the overage moot. If running strictly by the book, reconstitute ~6mg at a time and leave the rest as powder.

Recommended Vial Size by Protocol

Short trial or tolerance test:

• 5mg vial — lowest upfront cost, 10 days at 500 mcg/day
• Not cost-effective beyond first trial

Standard 500 mcg/day healing protocol:

• 10mg vial — lasts exactly 20 days, inside the 28-day window
• The most popular and cost-effective size

Wolverine stack (with BPC-157):

• 10mg TB-500 + 10mg BPC-157 — run both at 500 mcg/day for a 20-day cycle
• See our wolverine stack guide for dosing protocol

Buying Multiple Smaller vs One Large Vial

Our recommendation: The 10mg vial is the right choice for almost every user. At 500 mcg/day you use the full vial in 20 days, inside the stability window, at the best per-mg price.

Vendor Evaluation Methodology

When comparing TB-500 vendors, we evaluate three weighted factors:

Price Competitiveness (40%)

We normalize to cost per milligram for fair comparison. A vendor selling 10mg at $50 ($5/mg) scores higher than one selling 5mg at $40 ($8/mg), all else being equal.

COA & Testing (30%)

We verify that COAs are:

• From recognized third-party labs
• Recent (within the last 6 months)
• Verifiable on the lab's website
• Confirming the 889 Da molecular weight and N-acetylation — critical distinctions

Reputation (30%)

Community feedback from peptide forums, shipping reliability, customer service responsiveness, and business track record. We give extra weight to vendors with consistent multi-year operations and clear labeling that distinguishes TB-500 from full TB-4.

Shipping and Storage

What to Expect When Your Order Arrives

Lyophilized TB-500 should arrive as a white or off-white powder cake in a sealed glass vial. Check:

• Vial integrity — no cracks, proper rubber seal, aluminum cap intact
• Powder appearance — solid cake or loose powder, NOT liquid or discolored
• Labeling — batch/lot number, milligram content, "for research use only", preferably with "Ac-LKKTETQ" or "fragment 17-23" notation
• Cold pack — reputable vendors ship with cold packs in summer months

Storage Guidelines

Key point: Keep unreconstituted vials refrigerated. TB-500 is sensitive to pre-filled syringes — draw each dose fresh from the vial rather than pre-loading multiple syringes.

Frequently Asked Questions

Is TB-500 legal to buy?

TB-500 is sold as a research chemical and is legal to purchase in most jurisdictions for research purposes. It is not FDA-approved, and it is banned by WADA for use in competitive human sports. Research vendors label product "not for human consumption."

How much does TB-500 cost per month?

At the community-standard 500 mcg/day protocol, TB-500 runs $31-77/month from a reputable vendor using a 10mg vial. Paired with BPC-157 in the wolverine stack, budget an additional $25-50/month for combined therapy.

What vial size should I buy?

For 500 mcg/day, a 10mg vial lasts exactly 20 days — inside the 28-day window and the best per-mg value for most users. Choose 5mg only for short trials or tolerance testing. Both sizes can be split across reconstitution batches if using lower doses.

What purity should I look for?

Look for vendors providing third-party COA testing showing 98%+ purity via HPLC, plus mass spec confirming the 889 Da molecular weight and N-terminal acetylation of the Ac-LKKTETQ sequence. A 4,921 Da result means you're looking at full TB-4, not TB-500.

Can I buy TB-500 from a pharmacy?

No. TB-500 is not FDA-approved and is only available through research peptide vendors. Some compounding pharmacies offer full-length thymosin beta-4 via prescription for specific conditions, but this is a different compound with different pricing.

How do I know if a vendor is trustworthy?

Check for: third-party COA testing confirming the 889 Da MW and acetylation, verifiable lab results, responsive customer service, community reputation on peptide forums, consistent pricing, and a clear return/reship policy. See our Best TB-500 Vendors for pre-vetted options.

Related Guides

• Best TB-500 Vendors — ranked vendor comparison with live pricing
• TB-500 Dosing Guide — 500 mcg/day protocol, cycling, and safety
• TB-500 Reconstitution Guide — step-by-step mixing and dilution charts
• TB-500 Benefits — healing, tendons, recovery effects
• TB-500 Results Timeline — what to expect week by week
• TB-500 Bloodwork Guide — what to track on a healing protocol
• Compare TB-500 Prices by $/mg — every vendor ranked side by side
• Calculate Your TB-500 Cycle Cost — estimate vials needed and total cost
• Current Peptide Deals & Coupons — active vendor discount codes

Related Reading

• BPC-157 vs TB-500 — which healing peptide fits your goal
• TB-4 vs TB-500 — full thymosin beta-4 vs the 7-amino-acid fragment
• Wolverine Stack: BPC-157 + TB-500 — the classic recovery pairing
• Thymosin Beta-4 + BPC-157 Stack — full TB-4 alternative

References

This article is for educational and informational purposes only. It is not medical advice and should not be used to diagnose, treat, or prevent any condition. Consult a licensed healthcare provider before using any peptide.