NOTES FROM VIV’S WORLD

Peptide calculator: mg, mcg, mL and U-100 units

The hardest part of a peptide calculation is often keeping the units straight. Milligrams and micrograms measure mass. Milliliters measure volume. A syringe’s markings measure volume according to its calibration. These quantities are related, but they are not interchangeable.

Start with concentration

Concentration is the amount of substance divided by the final solution volume: mg ÷ mL = mg/mL. The calculator assumes the labeled amount is accurate and the substance is evenly distributed in the stated final volume. It cannot verify either assumption. The final solution volume is the total volume, which is not always identical to the amount of liquid added.

Convert mg and mcg first

One milligram equals 1,000 micrograms. To convert mcg to mg, divide by 1,000. Confusing these units creates a thousand-fold error. Always check the unit on your prescription and label, and ask a pharmacist to resolve any uncertainty.

Convert an already specified amount to volume

The formula is specified amount in mg ÷ concentration in mg/mL = volume in mL. For a purely mathematical example, 10 mg in a final volume of 2 mL gives 5 mg/mL. An arbitrary 0.25 mg amount would correspond to 0.05 mL. These sample numbers do not describe a recommended dose, product, or preparation.

What U-100 markings mean

On a U-100 syringe, 100 marked units correspond to 1 mL. Multiply a volume in mL by 100 to express it in those markings. In the arithmetic example above, 0.05 mL corresponds to 5 U-100 markings. This conversion applies only to U-100 calibration. It does not apply to U-40 or other syringes, and it does not convert biological potency units such as IU into mg.

Know what the result leaves out

The peptide calculator shows concentration, volume, and U-100 markings based solely on your entries. It does not validate product identity, sterility, stability, syringe capacity, measurement precision, or whether the entered amount is medically appropriate. Displayed results are rounded; a small calculated volume may not be measurable on your syringe. Do not round a result into an injection instruction. Have your pharmacist verify the concentration and equipment.