Why two dose charts disagree

The four mechanical reasons charts disagree

What a chart actually is: division done once, privately, then published as a grid. Change any one of the four inputs below and every number on the grid moves with it, while the division underneath never varies.

Reason one, the water: concentration is vial divided by water, so a chart that never prints its water volume has published half a division. An 8mg vial mixed at 2mL holds 4mg per mL, so a 2mg amount reads 50 units; the same vial mixed at 4mL holds 2mg per mL, and the same 2mg reads 100 units. Two charts, both correct, every row doubled.

Reason two, the vial: the total milligrams are assumed just as silently. One grid built on a 30mg vial at 2mL (15mg per mL) and another on a 60mg vial at the same water (30mg per mL) will put a stated 3mg amount at 20 units and 10 units respectively, with nothing on either page admitting a vial was ever chosen.

Reason three, flat dose versus per kilogram: some sources scale to body weight and some do not, and a chart converts whichever convention it happened to read. The BPC-157 review in our sources records rat work at 10 µg per kg; a chart converting that figure at an assumed 70kg prints 700mcg, while one assuming 100kg prints 1,000mcg, a gap of about 43% out of a single line of literature. The big obesity trials run the opposite convention: SURMOUNT-1 assigned participants to flat target doses of 5, 10, or 15mg of tirzepatide after a 20-week escalation, with a placebo arm alongside, flat numbers with no kilograms in them.

Reason four, the rounding rule: every chart rounds its exact figures to some printed precision, and a chart that never states which one has left a fourth input unstated. An exact draw of 0.087mL is 8.7 units, which a chart rounding to whole units publishes as 9 and one rounding to half units publishes as 8.5; the two grids now differ by about 6% on that row, from the rounding rule alone.

Check any chart yourself in three steps

The idea: every chart is a division with its inputs cropped off, so checking one means putting the inputs back. Three of them, in order.

Step one, the vial: find the total milligrams the grid was built on. Honest charts print it at the top; quiet ones can still be back-computed from any row, because the row's milligrams, its units, and the syringe scale together imply a narrow concentration range.

Step two, the water: find the milliliters added at mixing. Vial divided by water is the concentration the whole grid stands on, and if a chart prints neither, what remains is a list of numbers with no way in.

Step three, redo one row: milligrams divided by concentration gives milliliters, and milliliters times 100 gives U-100 units. A chart posting 2mg against 50 units implies 0.5mL behind that row, a 4mg per mL liquid, which could be an 8mg vial at 2mL, a 4mg vial at 1mL, or any pair that divides to 4. If the vial and water in front of you make that same 4mg per mL, the row transfers; if they make anything else, the grid belongs to a different mix.

Why we print the arithmetic instead of picking a winner

What picking would mean: choosing a vial and a water volume for a reader we have never met, then presenting that choice as the answer. Any chart that prints a grid has already made that choice for somebody; one more from us settles nothing.

What survives checking: an assumption in print. A figure that arrives with its vial and its water attached can be rebuilt from scratch by anyone; a figure that arrives bare can only be trusted or ignored, and trust is not a method.

Where the choice stays: with whoever owns the protocol and the clinician looking at the actual labs. Our compound guides print the inputs beside every figure and decline to crown a mix, and this page exists to explain why that is the honest format rather than indecision.

Why do peptide dosage charts say different things?

Because each chart is arithmetic built around assumptions chosen before the grid was drawn: a vial size, a water volume, a flat or per-kilogram dose convention, and a rounding rule at the syringe marks. Charts built on different inputs print different numbers for the same peptide while every grid stays internally correct, which is why arguments between two chart readers can have no liar in them. The fix is never a louder chart; it is recovering the four inputs and redoing the division.

Which dose chart is right?

Internally, both of them can be, when each chart's arithmetic is clean; for the vial in front of you, only the one whose assumptions match that vial. A grid is right when its vial, its water, its dose convention, and its rounding line up with what is actually being measured, and no chart can know the water that went into glass it never saw. That is why a disagreement between two charts of one vial cannot be settled from the outside: both can be working arithmetic, and neither one can see the mix in front of the reader.

How do I check a dose chart myself?

Find the vial size it assumes, find the water volume it assumes, then redo the division on any single row. Milligrams divided by concentration gives the milliliters, milliliters times 100 gives the U-100 units, and if your recomputed row matches the printed one and the concentration matches the mix in front of you, the chart transfers. A row that will not recompute, or a concentration the page never states, is where trust should stop.

What does a dose chart assume without saying?

Up to four things: the total milligrams in the vial, the water volume mixed into it, whether the dose is flat or scaled per kilogram of body weight, and how the final figure was rounded to a syringe mark. Any one of the four, changed quietly, reprints every number on the grid while the layout stays identical. That invisibility is the whole reason two charts can look alike, cite the same peptide, and disagree everywhere.

How this page is sourced

The two sources: one dosing convention each. The BPC-157 review documents per-kilogram dosing across the preclinical literature, including rat work at 10 µg per kg; SURMOUNT-1 documents the fixed flat-dose convention at phase 3 scale. Both papers were pulled from PubMed on 20 July 2026, the BPC-157 review read through to the full text for the per-kilogram figures.

What the worked example is: the 80mg vial run at three water volumes is not from a paper and does not need one. It is division on stated inputs, and every row of it reproduces on a calculator. An earlier version of that section rested instead on unnamed commercial dose charts we had read; it was removed on 29 July 2026, because a source that goes unnamed is a source a reader cannot check.

What this page does not claim: which graduations any particular syringe barrel carries. The rounding example above is about the precision a chart prints, not about the marks on anyone's plastic, and no source we could find specifies the second. The unit definition page states the same limit in full, and records the sentences it cut for it.

Everything else: the remaining numbers on this page are division and multiplication, re-derivable from the stated inputs.

The standard: the full sourcing and citation-verification standard for this site, including who checks a page before it ships, lives on the methodology page.

Last reviewed: 28 July 2026.

1. 1

   Józwiak M, Bauer M, Kamysz W, Kleczkowska P. Multifunctionality and Possible Medical Application of the BPC 157 Peptide: Literature and Patent Review. Pharmaceuticals (Basel). 2025;18(2):185. doi:10.3390/ph18020185. PMID 40005999.

2. 2

   Jastreboff AM, Aronne LJ, Ahmad NN, et al.; SURMOUNT-1 Investigators. Tirzepatide Once Weekly for the Treatment of Obesity. N Engl J Med. 2022;387(3):205-216. doi:10.1056/NEJMoa2206038. PMID 35658024.

More dose math

Four pages, each holding one of the assumptions above:

• The peptide dose math index: the whole cluster indexed in one place, tools and explainers together.
• Concentration vs dose: the property-versus-decision split every conversion chart is built on.
• How bac water volume changes your units: reason one stretched out in full, the same vial at five water amounts.
• KLOW dosage guide: the blend case of the example above: four peptides sharing one vial, and the units math run once per component.