Reconstituting a TB-500 vial comes down to one number: how many units do you draw on the syringe? This calculator gives you that in one step. Enter how many milligrams are in your vial, how much bacteriostatic water you're adding, and your target dose, and it returns the exact insulin-syringe mark, the concentration you've made, and how many doses the vial holds.
If you want the full background on the compound first, our TB-500 complete guide covers the science and the best peptides for recovery hub puts it in context; for other compounds, the general peptide dosage calculator handles the same math. TB-500 has a feature that catches people out: it's dosed in whole milligrams (commonly 2-5 mg), which is a lot of peptide compared to the microgram doses of most research peptides. That means TB-500 draws ride right up near the top of the syringe — a typical dose can fill the entire barrel, and the wrong water choice can push it past what one syringe holds. The calculator flags that before you find out at the vial. Below the tool we walk through the math, the syringe-ceiling problem, and what real TB-500 users actually mix.
Key Takeaways
- Two-step math: concentration = vial mg ÷ bac water mL, then units = (dose mg ÷ concentration) × 100 on a U-100 syringe.
- Anchor example: a 5 mg vial + 2 mL of bacteriostatic water = 2.5 mg/mL; a 2.5 mg dose = 1.0 mL = a full 100-unit syringe, and the vial gives 2 doses.
- TB-500 draws are large. Our usage data shows a median draw of about 60 units, with the upper quarter at the 100-unit ceiling. Too much water can push a dose over one syringe.
- More water = a more diluted vial = a larger number of units for the same milligram dose. The amount of TB-500 never changes with the water.
- The mg-vs-mcg slip is the dangerous one. TB-500 is milligrams; confusing it with micrograms is a 1,000× error.
- Research compound. Not FDA-approved, WADA-prohibited, limited human data — treat every figure as calculation context, not advice.
| You enter | Value | The calculator returns | Value |
|---|---|---|---|
| TB-500 in vial | 5 mg | Concentration | 2.5 mg/mL |
| Bacteriostatic water | 2 mL | Volume to draw | 1.0 mL |
| Target dose | 2.5 mg | Draw to this mark | 100 units (U-100) |
| Syringe type | U-100 | Doses per vial | 2 |
How do you calculate a TB-500 dose?
TB-500 reconstitution is two steps: work out the vial's concentration, then convert your milligram dose into a volume you can read on the syringe. The units you draw are just that volume on the insulin scale.
In plain arithmetic:
- Concentration (mg/mL) = vial mg ÷ bac water mL. A 5 mg vial in 2 mL is 5 ÷ 2 = 2.5 mg/mL.
- Volume (mL) = dose mg ÷ concentration. A 2.5 mg dose at 2.5 mg/mL is 2.5 ÷ 2.5 = 1.0 mL.
- Units = volume × 100 on a U-100 syringe (100 units = 1 mL). So 1.0 mL = 100 units — the whole barrel.
Collapsed into the single formula the calculator runs:
units = (dose mg ÷ (vial mg ÷ bac water mL)) × 100 = dose mg × bac water mL ÷ vial mg × 100
Sanity-check our example: 2.5 × 2 ÷ 5 × 100 = 100 units. For doses per vial, divide the vial's milligrams by your dose: 5 mg ÷ 2.5 mg = 2 doses.
Our take: Most peptide calculators assume small draws. TB-500 breaks that assumption: a standard 2.5 mg dose on the most common mix is the entire syringe. That's not an error — it's just how a milligram-dosed peptide behaves at a modest concentration. But it means you have almost no headroom, so the water you choose decides whether your dose fits at all. The next sections are about staying under that ceiling.
How much bacteriostatic water should you add to TB-500?
With TB-500, pick the water volume that keeps your dose at or under one syringe while still reading on clear marks — because more water, not less, is what pushes a TB-500 dose past the 100-unit ceiling. This is the reverse of the small-dose peptides.
The trade-off runs the opposite way from a microgram-dosed peptide. There, more water helps by enlarging a tiny draw. With TB-500's large milligram doses, more water enlarges an already-large draw until it overflows: a 2.5 mg dose is 100 units at 2.5 mg/mL (5 mg in 2 mL) but 200 units — two full syringes — at 1.25 mg/mL (5 mg in 4 mL). So for TB-500 the instinct to "add more water for an easier read" backfires; you often want less water to keep the dose inside one barrel.
Because ProtocolPlus tracks reconstitutions, we can show the vial-strength × water-volume combinations real TB-500 users log.
The pattern: 2 mL is the dominant water choice, and the 5 mg vial leads — giving 2.5 mg/mL where a 2.5 mg dose is exactly one syringe. The 10 mg vial at 2 mL (5 mg/mL) is the other common pick, which keeps a 2.5 mg dose at a comfortable 50 units. Notice the crowd avoids high water volumes here — for TB-500, that's how they keep doses inside the barrel.
A worked walkthrough: choosing water to stay under the ceiling
Say you have a 5 mg vial and your dose is 2.5 mg. Run the candidate water volumes and watch whether the dose fits one syringe:
- 1 mL → 5 mg/mL. 2.5 mg = 50 units. Comfortable, with headroom to spare.
- 2 mL → 2.5 mg/mL. 2.5 mg = 100 units. Fits exactly — the entire barrel, no headroom.
- 3 mL → 1.67 mg/mL. 2.5 mg = 150 units. Overflow — needs two draws.
For TB-500 the winner is often the lower water volume, the reverse of a microgram-dosed peptide: 1 mL keeps the dose at a manageable 50 units. If you prefer the popular 2 mL mix, just know your 2.5 mg dose is the full syringe and there's no room to go higher without splitting. The calculator's overflow flag is built around exactly this decision.
Switching vials: always recalculate
Moving to a different vial strength changes the concentration, so the same dose draws to a different mark. Go from a 5 mg vial to a 10 mg vial and even at the same 2 mL the concentration doubles (2.5 → 5 mg/mL), so a 2.5 mg dose that was a full 100 units becomes a comfortable 50. Never carry a unit number across vials — re-run the calculator every time the vial strength or water volume changes.
How do you read TB-500 units on an insulin syringe?
On a U-100 insulin syringe, 100 units = 1 mL, so a unit is a hundredth of a millilitre — the calculator converts your milligram dose into that unit mark. The "units" you read are a measure of volume, not of how much TB-500 you're taking.
Three calibrations exist, and the calculator supports all three:
| Syringe | Full barrel | A 2.5 mg dose at 2.5 mg/mL reads as | Best for |
|---|---|---|---|
| U-100 (standard) | 100 units = 1.0 mL | 100 units (full barrel) | Most TB-500 use |
| U-50 | 50 units = 0.5 mL | over the barrel | Smaller TB-500 draws only |
| U-40 (older/vet) | 40 units = 1.0 mL | 100 units | Rare — double-check your barrel |
The lesson for TB-500: because draws are large, a U-100 1 mL barrel is usually the right choice — a smaller U-50 (0.5 mL) barrel simply can't hold a typical full dose. Always confirm which syringe you're holding, and keep that 100-unit ceiling in mind.
The syringe-ceiling problem: TB-500's signature pitfall
Because TB-500 is dosed in whole milligrams, a standard dose can fill the entire U-100 syringe — and adding water to "make it easier to read" can push it past 100 units, where it no longer fits in one barrel. This is the most important practical point for TB-500.
A draw over 100 units doesn't fit one U-100 syringe (100 units = 1 mL). With TB-500 it happens easily: a 2.5 mg dose is already 100 units at 2.5 mg/mL, so any more dilution overflows. Across our tracked TB-500 reconstitutions the median draw is about 60 units, but the upper quarter sits right at the 100-unit ceiling — far higher than any microgram-dosed peptide.
The fix is counterintuitive if you're used to small peptides: use less water (a stronger vial) so the same dose occupies less volume. A 2.5 mg dose is 100 units at 2.5 mg/mL but only 50 units at 5 mg/mL (5 mg in 1 mL, or 10 mg in 2 mL). If a single draw still exceeds the barrel, split the dose across two draws.
TB-500 is also worth flagging on the legal side: it is prohibited in sport at all times under the World Anti-Doping Agency's growth-factor category (World Anti-Doping Agency, 2026, "The Prohibited List", retrieved 2026-06-16), and it is not an FDA-approved drug — context that belongs alongside any dosing math.
The distribution leans high and bumps against the 100-unit wall — the opposite shape of a microgram-dosed peptide. That wall is exactly why a TB-500 calculator needs to flag overflow, and why your water choice should aim to keep the dose comfortably under it.
Where each TB-500 dose lands on the syringe
TB-500's common doses — roughly 2 to 5 mg — map to very different unit marks depending on your concentration, and the larger ones overflow a single syringe on a dilute vial. The table shows where each lands at the usual concentrations.
| Dose | At 2.5 mg/mL (5 mg + 2 mL) | At 5 mg/mL (10 mg + 2 mL) | At 1.25 mg/mL (5 mg + 4 mL) |
|---|---|---|---|
| 2 mg | 80 units | 40 units | 160 units — over 1 syringe |
| 2.5 mg | 100 units | 50 units | 200 units — over 1 syringe |
| 5 mg | 200 units — over 1 syringe | 100 units | over 1 syringe |
Our take: Read across the 5 mg row: a 5 mg dose only fits one syringe at 5 mg/mL (10 mg vial in 2 mL), and overflows everywhere more dilute. For TB-500, the concentration you choose is the decision about whether your dose fits at all — which is why our calculator leads with the overflow flag rather than burying it. For weekly loading protocols that use larger totals, see the linked dosing guide; split each injection so no single draw exceeds the barrel.
How many TB-500 doses are in a vial, and what does each cost?
Doses per vial is vial milligrams ÷ your dose — and because TB-500 doses are large, a vial holds only a handful. Dividing the vial price by that number gives a true cost per dose.
A 5 mg vial at a 2.5 mg dose yields just 2 doses; a 10 mg vial at 2.5 mg gives 4. That's far fewer than a microgram-dosed peptide, so TB-500 runs through vials quickly during a loading phase. Across our tracked TB-500 vials the median works out to roughly 2 doses per completed vial at about $35 per dose. Cost per dose is the figure to compare across products.
| Economics output | How it's computed | Example (10 mg vial, 2.5 mg dose, $80 vial) |
|---|---|---|
| Doses per vial | vial mg ÷ dose mg | 4 doses |
| Cost per dose | vial price ÷ doses per vial | $20.00 |
| Weekly cost | cost per dose × doses per week | $40.00 (2×/week) |
| Approx. monthly cost | weekly × 4.3 | ~$172 |
For a full loading-and-maintenance plan rather than a single calculation, see our TB-500 dosing and protocol guide.
TB-500 reconstitution chart: units by vial and dose
This chart shows the concentration each vial makes at the common water volumes and the U-100 units to draw, so you can see at a glance which combinations keep your dose under the syringe ceiling. For any other setup, use the calculator.
| Setup | Concentration | 2 mg | 2.5 mg | 5 mg |
|---|---|---|---|---|
| 5 mg + 1 mL | 5 mg/mL | 40 u | 50 u | 100 u |
| 5 mg + 2 mL | 2.5 mg/mL | 80 u | 100 u | over 1 syringe |
| 10 mg + 2 mL | 5 mg/mL | 40 u | 50 u | 100 u |
| 10 mg + 3 mL | 3.33 mg/mL | 60 u | 75 u | over 1 syringe |
The cleanest setups for a 2.5 mg dose are 5 mg + 1 mL or 10 mg + 2 mL (both 5 mg/mL → 50 units), which leave headroom. The popular 5 mg + 2 mL mix puts a 2.5 mg dose at exactly the 100-unit ceiling — fine, but with nowhere to go. The most-searched single conversions, for a quick sanity check:
- 2 mg TB-500 on a 5 mg/mL vial = 0.4 mL = 40 units.
- 2.5 mg TB-500 on a 5 mg/mL vial = 0.5 mL = 50 units; on a 2.5 mg/mL vial = 100 units.
- 5 mg TB-500 on a 5 mg/mL vial = 1.0 mL = 100 units (a full syringe).
mg, mcg, units, and mL: keeping the four numbers straight
Milligrams measure the TB-500; millilitres and units measure the liquid you draw. The dangerous slip with TB-500 is reading its milligram dose as if it were micrograms, or vice versa — a 1,000× error. Keep the families separate and the math is easy.
TB-500 is dosed in milligrams (2-5 mg), unlike microgram-dosed peptides such as BPC-157, so if you switch between them, watch the unit. 1 mg = 1,000 mcg. Here is a 2.5 mg dose expressed four ways on a 2.5 mg/mL vial, one quantity wearing four labels:
| Label | Value | What it describes |
|---|---|---|
| Dose in milligrams | 2.5 mg | mass of TB-500 |
| Dose in micrograms | 2,500 mcg | mass of TB-500 |
| Volume to draw | 1.0 mL | liquid volume |
| Units to draw (U-100) | 100 units | liquid volume on the syringe |
Why concentration is the number that actually matters
Concentration (mg/mL) is the hinge of every TB-500 calculation — and for TB-500 it's what decides whether your large dose fits in one syringe. It connects the milligrams in the vial to the units on the syringe.
Concentration is an exchange rate between milligrams of TB-500 and millilitres of liquid. A 2.5 mg/mL vial trades every 1 mL for 2.5 mg; your dose occupies a volume set by that rate, and the syringe scale turns it into a unit mark. Make the vial stronger (less water) and the same dose occupies less volume — fewer units, and crucially, more room under the 100-unit ceiling. That's why, for high-dose TB-500, concentration choice is mostly an overflow-avoidance choice.
It's also why you can never compare unit numbers across reconstitutions. "Draw 50 units" means 1.25 mg on a 2.5 mg/mL vial but 2.5 mg on a 5 mg/mL vial — double. Every unit instruction online is valid only for that exact vial and water volume.
Splitting TB-500 doses and weekly loading
Many TB-500 routines use a weekly total that's split across two or more injections — and each individual injection is what you run through the calculator, not the weekly sum. Splitting also keeps any single draw under the syringe ceiling.
If a routine calls for, say, 5 mg in a week split into two 2.5 mg injections, you calculate 2.5 mg per draw — on a 5 mg/mL vial that's 50 units twice, rather than one impossible 100-unit-plus draw. Splitting is the natural answer to TB-500's large draws: it keeps each injection measurable and inside one barrel. Whether and how to load or split is a protocol decision outside the calculator's scope; the tool simply converts each per-injection dose into an accurate unit mark.
How to reconstitute TB-500, step by step
Add the bacteriostatic water slowly down the vial wall, swirl gently until clear, and never shake. The peptide is delicate, and rough mixing degrades it before your first dose.
- Calculate first. Use the tool above to set your water volume and target unit mark, and check the overflow flag.
- Room temperature, then swab both stoppers with a fresh alcohol swab.
- Draw your measured water into a reconstitution syringe.
- Add slowly down the wall of the TB-500 vial, onto the glass rather than the powder.
- Swirl, don't shake until the solution is completely clear.
- Inspect. Clear and particle-free, or don't use it.
- Label and refrigerate at 2-8 °C, then dose at the unit mark the calculator gave you.
Reconstitution troubleshooting
- The powder won't fully dissolve. Give it a few minutes and keep swirling gently; warmth helps. A vial that stays cloudy or shows particles shouldn't be used.
- Foam or a hard vacuum pull. Some vials are under vacuum; vent briefly with an empty needle or add the water slowly down the wall.
- A draw over 100 units. Not a mixing error — your concentration is too low for the dose. Re-mix a fresh vial with less water, or split the draw.
Common TB-500 reconstitution mistakes
- Adding water to "make it easier to read." With TB-500's large doses, more water pushes you over the ceiling — usually you want less.
- Confusing mg with mcg. A 1,000× error; TB-500 is milligrams.
- Reading "units" as milligrams. Units are a volume; always convert through the calculator.
- Copying someone else's unit count. Valid only for that person's exact concentration.
- Wrong syringe (a U-50 0.5 mL barrel can't hold a full dose; U-40 vs U-100 mismatch), and not labeling the date.
TB-500 vial sizes, supplies, and water
TB-500 vials almost always come in 5 mg or 10 mg (2 mg is less common), and the 10 mg vial gives you more concentration headroom for staying under the syringe ceiling. Pick the size that keeps your dose on a readable, non-overflowing mark.
- 5 mg — common; in 2 mL it's 2.5 mg/mL, where a 2.5 mg dose is a full syringe (no headroom).
- 10 mg — in 2 mL it's 5 mg/mL, keeping a 2.5 mg dose at a comfortable 50 units with room to spare.
A quick supplies checklist: the lyophilized TB-500 vial, bacteriostatic water (sterile water with 0.9% benzyl alcohol) as the diluent, a reconstitution syringe (1-3 mL), a U-100 1 mL insulin syringe (you need the full barrel), alcohol swabs, and a marker for the date. Use bacteriostatic — not preservative-free or non-injectable — water for a multi-dose vial.
How long does reconstituted TB-500 last?
Once mixed, TB-500 is far less stable than the dry powder, and there's no validated shelf life — the common ~28-day refrigerated convention is a usage habit, not data. Judge by appearance, not just the calendar.
Peptides in solution degrade through hydrolysis, deamidation, oxidation, and aggregation, sped up by heat, light, and agitation, so a mixed vial belongs in the refrigerator at 2-8 °C, kept dark, and never frozen. Discard any vial that turns cloudy, changes color, or shows particles. For the deeper science, see our peptide storage and stability guide.
TB-500 and BPC-157: a quick note
TB-500 is often stacked with BPC-157 for recovery, but they reconstitute and dose differently — TB-500 in whole milligrams, BPC-157 in micrograms — so never reuse one's unit count for the other. A 2.5 mg TB-500 dose is around 100 units; a 250 mcg BPC-157 dose on the same concentration is just 10 units. If you run both, calculate each separately and label your syringes, or use a dedicated BPC-157 and TB-500 blend calculator for a combined vial. For the comparison, see TB-500 vs BPC-157.
What the evidence says about TB-500 dosing
TB-500's dosing figures come from community practice rather than human dose-finding trials — most of the science is on its parent molecule, thymosin beta-4, and is preclinical — so the milligram amounts people use are conventions, not validated human doses. We give them only so you know what to enter into the calculator.
TB-500 is a synthetic fragment of thymosin beta-4 (Tβ4), a naturally occurring regenerative peptide. The wound-healing and tissue-repair evidence largely comes from animal and laboratory studies of Tβ4 (PubMed, 2017, "Thymosin beta-4 promotes dermal healing", retrieved 2026-06-16), with early human work limited to a small number of registered trials of the parent peptide (ClinicalTrials.gov, "Thymosin Beta-4 in Patients With Venous Stasis Ulcers," NCT00832091, retrieved 2026-06-16). There is no approved label, no standard human dose, and no validated shelf life for reconstituted TB-500. Treat the common 2-5 mg figures as a community convention to calculate from if you choose to, not as evidence-based guidance.
How precise does your TB-500 draw need to be?
Because TB-500 draws are large (often 50-100 units), they're among the easier peptides to measure accurately — one unit of error is a small fraction of a 100-unit draw. On a 2.5 mg/mL vial, one U-100 unit is 0.025 mg, so rounding a 100-unit draw by a unit shifts the dose by 0.025 mg, negligible against 2.5 mg. The precision concern for TB-500 isn't reading small marks; it's staying under the 100-unit ceiling in the first place, which the concentration choice handles.
Frequently asked questions
Sources
Factual claims (status, evidence, anti-doping) are sourced below. Dose values in examples are illustrative, not recommendations; human TB-500-specific efficacy data is limited (most evidence is on parent thymosin beta-4, preclinical). ProtocolPlus usage figures are first-party app data.
- ClinicalTrials.gov — Study of Thymosin Beta-4 in Patients With Venous Stasis Ulcers (NCT00832091). https://clinicaltrials.gov/study/NCT00832091 — retrieved 2026-06-16.
- PubMed (2017) — Kim & Kwon, Thymosin beta-4 promotes dermal healing (preclinical mechanism). https://pubmed.ncbi.nlm.nih.gov/27450738/ — retrieved 2026-06-16.
- NCBI / PMC8228050 — Thymosin beta-4 in tissue repair and regeneration (review). https://pmc.ncbi.nlm.nih.gov/articles/PMC8228050/ — retrieved 2026-06-16.
- WADA — The Prohibited List (S2.3 Growth Factors: thymosin-β4 and its derivatives, e.g. TB-500, prohibited at all times). https://www.wada-ama.org/en/prohibited-list — retrieved 2026-06-16.
About this guide. Written by Jordan Vance, peptide and biohacking researcher (placeholder, replace before publish), and medically reviewed by Dr. Maya Ellison, MD, biochemistry (placeholder, replace before publish), for the ProtocolPlus Research Team. This calculator and article are educational and not medical advice.