Peptide product labels and laboratory calculations use several different kinds of information: a material name, an amount, a solution volume and sometimes a measured concentration. This glossary explains the terms without treating them as interchangeable.
Measurements and calculator terms
mg: milligram
A unit of mass. One milligram is one thousandth of a gram. A product labelled 5mg describes an amount of material; it does not state a liquid volume.
mcg or µg: microgram
A smaller unit of mass: 1mg equals 1,000mcg. The SI symbol is µg; mcg is the plain-text spelling used in our calculator.
mL: millilitre
A unit of volume equal to one thousandth of a litre. mL describes how much space a liquid occupies, rather than the mass of peptide it contains.
Concentration
The amount of a substance relative to a stated quantity of mixture. In our peptide concentration calculator, mass concentration is expressed as mg/mL or mcg/mL: entered peptide mass divided by final solution volume.
Final solution volume
The total volume of a solution after its components are combined. It is the denominator in a mass-per-volume calculation. Nominal container capacity is a separate measurement.
U-100 scale
A scale on a device designed for U-100 insulin, where 100 scale units correspond to 1mL. Its markings describe a volume relationship in our maths tool. They do not define a peptide amount, biological activity or recommended use.
Peptides and their physical form
Peptide
A compound made from amino-acid residues linked together. The precise residues, their order and any modifications help define the material; the word peptide alone is not a product specification.
Peptide bond
The amide linkage joining amino-acid residues in a peptide chain. Our peptide bond guide explains the connection between this linkage and a chain’s structure.
Lyophilisation
Freeze-drying: a process that removes water from a frozen material under reduced pressure. A lyophilised appearance alone does not establish purity, sterility or a storage period. See how lyophilisation is described for more context.
Sequence
The order of amino-acid residues in a chain. Sequence notation may also specify terminal groups, stereochemistry or other modifications; those details can distinguish different materials with similar names.
Material identity and testing
CAS Registry Number
An identifier assigned by CAS to a specific substance. A CAS number helps match names to chemical identity; it does not certify the contents or quality of an individual vial.
Batch testing
Analysis associated with a particular production batch. Interpreting a result requires the sample identity, batch reference, method, measured property and acceptance criteria. An identity result, a purity result and an amount measurement answer different questions.
Reference notes
Unit prefixes follow the NIST SI prefix table. The description of CAS identifiers follows CAS REGISTRY guidance. These references explain terminology; they do not endorse or test our products.