Peptide reconstitution: what mg, mL and units mean
Peptide reconstitution changes the concentration used in the math. It does not change the peptide amount written on the vial.
A volume needs the labelled peptide amount, total liquid volume, and syringe scale. DailyMed set 81199e55-ade9-46de-a5a3-c0415acee403 defines U-100 as 100 insulin units/mL (verified 21 August 2026). One U-100 scale unit therefore equals 0.01 mL. BD document BD-2189 identifies its device as a 1 mL U-100 insulin syringe (verified 21 August 2026). The full 1 mL span therefore equals 100 scale units. A physical graduation can span more than one scale unit. BD-2189 lists 2-unit minor graduations for that device (verified 21 August 2026).
What changes when a peptide vial is reconstituted?
The labelled peptide amount stays the same in the math. The concentration changes when the total liquid volume changes.
A 5 mg label amount in a total volume of 2 mL gives 2.5 mg/mL. The same 5 mg label amount in a total volume of 4 mL gives 1.25 mg/mL. These are derived math results rather than tests of the vial.
For evidence about identity and content, read what is actually in the vial.
What does a U-100 scale unit measure?
The current HUMULIN R label defines U-100 as 100 insulin units/mL. BD-2189 identifies a 1 mL U-100 insulin syringe. The same BD row lists 2-unit minor graduations.
Sources, verified 21 August 2026: DailyMed set 81199e55-ade9-46de-a5a3-c0415acee403 and BD document BD-2189. DailyMed is an agency record. BD-2189 is a manufacturer technical sheet.
| Term on this page | Meaning in the math |
|---|---|
| 1 mL | The complete volume spanned by 100 U-100 scale units. |
| 1 U-100 scale unit | 0.01 mL on that scale. |
| Physical graduation | A product-specific interval that may span more than one scale unit. |
| mcg per scale unit | The peptide amount given by the formula for 0.01 mL. |
A scale unit is an arithmetic increment. It is not a claim about the smallest physical graduation on every syringe.
BD-2189 lists 2-unit minor graduations for its 1 mL U-100 syringe (verified 21 August 2026). Each minor interval on that model spans 0.02 mL by arithmetic.
The scale unit is a volume position in this page's peptide math. It does not measure peptide activity.
How does the reconstitution math work?
The math starts with values from the label and the entered total liquid volume. It uses three steps:
concentration (mcg/mL) = labelled vial amount (mg) x 1,000 / total liquid (mL)
volume (mL) = stated peptide amount (mcg) / concentration (mcg/mL)
U-100 scale units = volume (mL) x 100The first line changes milligrams to micrograms before it divides by volume. The second line turns a stated peptide amount into volume. The third line shows that volume as a number on the U-100 scale.
A worked example
Assume a label says 5 mg and the entered total liquid volume is 2 mL. The formula gives 2,500 mcg/mL. One U-100 scale unit then means 25 mcg.
A stated amount of 250 mcg gives a volume of 0.1 mL in the math. That volume equals 10 U-100 scale units. On the 1 mL syringe described by BD-2189, 10 scale units cover five 2-unit minor intervals (verified 21 August 2026).
The example checks the formula. It does not select an amount or a schedule.
What does the peptide reconstitution chart show?
Each cell shows micrograms per U-100 scale unit from the formula. Every value assumes the labelled vial amount and entered total liquid volume are right.
| Labelled vial amount | 1 mL total | 2 mL total | 3 mL total | 5 mL total |
|---|---|---|---|---|
| 2 mg | 20 mcg | 10 mcg | 6.67 mcg | 4 mcg |
| 5 mg | 50 mcg | 25 mcg | 16.67 mcg | 10 mcg |
| 10 mg | 100 mcg | 50 mcg | 33.33 mcg | 20 mcg |
| 15 mg | 150 mcg | 75 mcg | 50 mcg | 30 mcg |
The chart compares math results. It is not a list of recommended peptide amounts.
Can the math confirm what is in the vial?
The math can test whether entered values agree with each other. It cannot name a substance or measure its purity.
Janvier et al. show why that limit matters. Their paper tested a targeted set of falsified polypeptide products on the Belgian market. The set does not show rates across the wider market.
| What the paper measured | Result | Source and funding | Verified |
|---|---|---|---|
| Purity in the GHRP and melanotan II preparations | 97.0% to 99.9% | PMID 30029448; the paper discloses no funder | 2026-08-21 |
| Purity in the cysteine-containing peptides | 5% to 75% | PMID 30029448; the paper discloses no funder | 2026-08-21 |
| Lead contamination | One sample | PMID 30029448; the paper discloses no funder | 2026-08-21 |
| Elemental-impurity concentration | Up to ten times the ICH limit for parenteral drugs in multiple samples | PMID 30029448; the paper discloses no funder | 2026-08-21 |
| Arsenic form | All detected arsenic was inorganic | PMID 30029448; the paper discloses no funder | 2026-08-21 |
The sample set contained 27 preparations (PMID 30029448, section 2.2; no funder disclosed; checked 21 August 2026). It encompassed the ten most frequently encountered peptide drugs on the Belgian market (PMID 30029448, section 2.2; no funder disclosed; checked 21 August 2026). The products came from three suspected illegal internet pharmacies (PMID 30029448, section 2.2; no funder disclosed; checked 21 August 2026).
The paper does not establish what is inside an untested vial.
For what a test document can establish, read what a certificate of analysis proves. For the separate germ and diluent question, read sterility and infection.
Does this page decide a peptide dose?
This page does not select a peptide amount. It reports links among entered amounts, concentration, volume, U-100 scale units, and product-specific physical graduations.
An amount used in a study belongs on the relevant compound page with that study's identifier and funder.
The shared vial and evidence guide links this calculation question to related test and symptom pages.