BPC-157 and TB-500 are the two peptides people compare most often, and the comparison is usually about which one “works better” — a question this site does not answer. What it can answer is the maths, and the maths is where the two genuinely differ: same vial sizes, same formula, but the amounts people talk about sit on different scales, and that changes everything about the syringe reading. This page compares the two side by side, number for number, so you can see exactly where they behave the same and where they don’t.
What they are — briefly, and only what the maths needs
BPC-157 (Body Protection Compound-157) is a synthetic 15-amino-acid peptide modelled on a protective protein fragment found in human gastric juice. TB-500 is a synthetic 7-amino-acid fragment (Ac-LKKTETQ) taken from residues 17–23 of thymosin beta-4, a 43-amino-acid protein found in almost all human and animal cells. Neither is FDA-approved for any use; both are sold as research chemicals, and both are prohibited by WADA at all times (BPC-157 class S0, TB-500 class S2). The research behind both is overwhelmingly preclinical — mostly animal and cell studies, with very little human data. None of that changes the arithmetic, and this page does not go further into it.
One warning before the numbers: check what is actually in a “TB-500” vial
The name is used loosely in the market. The FDA and PubChem use “TB-500” for the 7-residue fragment (molecular weight around 889 g/mol), but many vendors’ certificates of analysis list the identity as full 43-residue thymosin beta-4 (around 4,963 Da). Those two molecules differ more than five-fold in mass. If the identity on your lot’s certificate does not match the fragment, the milligrams on the label do not mean what the calculator assumes. Check the identity line on your lot’s COA before trusting any calculation.
The vial sizes are the same
Both peptides are standardly sold as 5 mg and 10 mg vials (2, 15 and 20 mg appear on some vendor lists). So if you mix a 5 mg vial of either one with 2 mL of BAC water, you get the same concentration: 2,500 mcg/mL. The formula does not know or care which peptide it is — concentration is vial mg × 1,000 ÷ water mL, for both.
Where they differ: the amounts
BPC-157 amounts are discussed in hundreds of micrograms — an example amount of 250 mcg is the figure most guides use. TB-500 amounts are discussed in milligrams — an example amount of 2 mg is the figure most guides use. Same concentration, very different syringe readings:
Worked example — both peptides, 5 mg vial, 2 mL of BAC water:
- Concentration (both): (5 × 1,000) ÷ 2 = 2,500 mcg/mL
- Each unit holds 2,500 ÷ 100 = 25 mcg
- BPC-157, example amount 250 mcg: 250 ÷ 25 = 10 units (0.1 mL)
- TB-500, example amount 2 mg (2,000 mcg): 2,000 ÷ 25 = 80 units (0.8 mL)
Same vial, same water, same concentration — and one amount is 10 units while the other is 80. That is the whole comparison in one line: the difference is the amount entered, not the formula.
Worked example — 10 mg vials, 2 mL of BAC water:
- Concentration (both): (10 × 1,000) ÷ 2 = 5,000 mcg/mL
- Each unit holds 5,000 ÷ 100 = 50 mcg
- BPC-157, example amount 250 mcg: 250 ÷ 50 = 5 units (0.05 mL)
- TB-500, example amount 2 mg (2,000 mcg): 2,000 ÷ 50 = 40 units (0.4 mL)
How many amounts in the vial — and why TB-500 vials run out faster
Doses (or amounts) per vial = total mcg ÷ amount per injection. A 5 mg BPC-157 vial at an example amount of 250 mcg holds 5,000 ÷ 250 = 20 amounts. A 5 mg TB-500 vial at an example amount of 2 mg holds 5,000 ÷ 2,000 = 2.5 amounts — two full amounts and a partial one. Same vial size, same price range, very different counts, because the amounts are on different scales. A 10 mg TB-500 vial at 2 mg holds 10,000 ÷ 2,000 = 5 amounts.
Side by side
| BPC-157 | TB-500 | |
|---|---|---|
| What it is | 15-amino-acid peptide, gastric-juice fragment model | 7-amino-acid fragment of thymosin beta-4 (43 aa) |
| Standard vial sizes | 5 mg, 10 mg | 5 mg, 10 mg |
| Amounts discussed in | Micrograms (hundreds of mcg) | Milligrams (1–2 mg) |
| Example amount | 250 mcg | 2 mg (2,000 mcg) |
| Units at 2,500 mcg/mL | 10 units | 80 units |
| Amounts in a 5 mg vial | 20 (at 250 mcg) | 2.5 (at 2 mg) |
| FDA status | Not approved, research chemical | Not approved, research chemical |
| WADA | Class S0, prohibited at all times | Class S2, prohibited at all times |
The blend vial — two peptides, one calculation each
So-called “Wolverine” blend vials contain both peptides in one vial, usually 5 mg + 5 mg or 10 mg + 10 mg. Each peptide is calculated separately; the total is never one peptide’s amount. A 5 mg + 5 mg blend with 2 mL of water gives 2,500 mcg/mL of each component, so a draw of 10 units carries 250 mcg of BPC-157 and 250 mcg of TB-500. A 10 mg + 10 mg blend with 4 mL of water gives the same 2,500 mcg/mL of each — the same 10-unit draw. And a 5 mg + 10 mg blend with 2 mL gives 2,500 mcg/mL of BPC-157 and 5,000 mcg/mL of TB-500, so the same 10-unit draw carries 250 mcg of BPC-157 and 500 mcg of TB-500. The blend does not change the formula; it doubles the bookkeeping.
What the comparison cannot tell you
Which peptide is “better”, whether either works, whether they work together, and whether any amount is safe or appropriate — none of that is a maths question, and this site does not answer it. The published research is mostly animal and cell work, and the human evidence for both is thin (thinner for TB-500, where most cited evidence is about its parent protein, not the fragment itself). If you are choosing between them, that is a question for a licensed healthcare provider or pharmacist, not a calculator.
Frequently Asked Questions
Is the formula different for BPC-157 and TB-500?
No. Concentration = vial mg × 1,000 ÷ water mL, then units = dose mcg ÷ concentration × 100. Identical for both. Only the amount you enter differs.
Why is my TB-500 draw so much bigger than my BPC-157 draw?
Because TB-500 amounts are discussed in milligrams and BPC-157 amounts in hundreds of micrograms. At the same concentration, a 2 mg amount is eight times a 250 mcg amount, so it takes eight times the units.
Can I use the same water volume for both?
Yes — the water volume is your choice for each vial, and the same volumes are commonly discussed for both (1–3 mL per vial). What matters is writing down which volume you used for which vial, because the concentration follows from it.
What if my TB-500 vial is actually full thymosin beta-4?
Then the milligrams on the label describe a different molecule (around 4,963 Da instead of around 889 g/mol for the fragment), and any calculation based on the fragment’s identity is built on the wrong starting figure. Check the identity line on your lot’s certificate of analysis.
How do I calculate a blend vial?
Separately for each peptide. A 5 mg + 5 mg blend in 2 mL is 2,500 mcg/mL of each; a draw of 10 units carries 250 mcg of each. Never add the two milligram figures together and treat the total as one peptide.
Which one should I choose?
This site does not answer that. It is not a maths question. Ask a licensed healthcare provider or pharmacist.
Try the calculator: Peptide Calculator
Related guides
- BPC-157 Calculator
- TB-500 Calculator
- Reconstitution Guide
- How Many Doses Are in a Vial?
- mg to mcg Conversion Guide
Educational reference only — not medical advice. This guide describes maths and commonly reported handling steps only; it does not recommend any dose. Always confirm your dose and preparation with a licensed healthcare provider or pharmacist.