Glossary

The site's texts link to these terms. The glossary has 34 terms so far and is being extended.

Agonist: A substance that binds to a receptor and activates it in the same way as the body's own signalling molecule. A GLP-1 receptor agonist, for example, mimics the GLP-1 hormone. The opposite is an antagonist, which blocks the receptor.
Amino acid: The building block of proteins and peptides. Human proteins use 20 common amino acids.
Animal study: A study in, for example, rats or mice. The result does not automatically apply to humans.
Bacteriostatic water: Sterile water with a small amount of benzyl alcohol to slow bacterial growth.
Case series: A description of a group of patients who received the same treatment, with no comparison group. It cannot show whether a change was caused by the treatment.
Clinical trial phases 1-3: Steps of human research: phase 1 safety in a small group, phase 2 effect and dose, phase 3 a large comparison.
COA (certificate of analysis): A lab report stating what a sample contains and how pure it is.
Conference abstract: A short summary of a study presented at a scientific meeting. It is usually not peer-reviewed like a published article, and it gives few details of the methods.
Endotoxin: A contaminant derived from bacterial cell walls. Fimea says endotoxins in injectable products can cause serious harm. A product can be free of live microbes and still contain endotoxin.
Evidence level (A-E): The site's mark after a source reference: A = randomised human trial or meta-analysis, B = observational human study or case series, C = animal study, D = cell or laboratory study, E = not peer-reviewed. In addition, "official" = official product information and "regulator" = a regulator's assessment or decision, not research evidence.
Fimea: The Finnish Medicines Agency, Finland's medicines regulator. It supervises medicines and grants national marketing authorisations.
GLP-1: A gut hormone (glucagon-like peptide 1) that raises insulin release and reduces appetite. Semaglutide and tirzepatide mimic its action.
Half-life: The time it takes for the level of a substance in the blood to fall by half.
Hila: The Pharmaceuticals Pricing Board. It decides whether a medicine is reimbursable and confirms its reasonable wholesale price.
HPLC: High-performance liquid chromatography. Measures purity: how much of a sample is one substance.
In vitro: An experiment in cells or tissue in a lab, not in a living organism.
IU (international unit): A unit that describes a substance's biological effect rather than its weight. Oxytocin doses, for example, are given in units.
Kanta: Kanta services: Finland's national digital health services, which store e-prescriptions and patient records, for example.
Kela: The Social Insurance Institution of Finland. It runs Finnish social security, including the health insurance reimbursement of medicines.
Lyophilisation (freeze-drying): A drying method in which a solution is frozen and the water is removed under low pressure. Peptides are often sold as a freeze-dried powder because they keep better dry than in solution.
Marketing authorisation: A regulator's permission to sell a product as a medicine. Research peptides usually do not have one.
Medicines list (Fimea): Fimea's decision "List of substances used as medicines and substances regarded as medicines" (the latest in the Finnish Statute Book is 230/2025). Substances in annex 1 of the list are regulated as medicines in Finland, so they cannot be sold as food supplements.
Microgram (µg, mcg): One thousandth of a milligram: 1 mg = 1000 µg. The abbreviations µg and mcg mean the same; the dose pages use µg and the calculator mcg. A milligram (mg) is a thousand times larger, so mixing up the units is a dangerous mistake.
MS (mass spectrometry): Measures molecular mass. Tells whether the substance is the right substance.
Novel food: A food or ingredient that was not used for human consumption to a significant degree in the EU before 15 May 1997. Selling it requires an EU authorisation.
Orphan medicine: The EU's orphan designation is given to a medicine meant for a life-threatening or chronically debilitating condition that affects no more than 5 in 10,000 people in the EU. The designation is not a marketing authorisation: it only says the medicine is being developed for a rare disease.
Peptide: A short chain of amino acids. Where a peptide ends and a protein begins is a convention, often around 50 amino acids.
Pharmacokinetics: How the body absorbs a substance, distributes it to tissues, changes it and removes it.
Placebo and placebo response: A placebo looks like a treatment but contains no active substance. The placebo response is symptom relief that comes from expectations, the natural ups and downs of symptoms or something other than the substance itself.
Preclinical study: Cell and animal studies done before any human studies.
Randomised controlled trial: Participants are allocated by chance to the treatment being studied or to a comparison, such as placebo. The strongest way to separate the effect of a treatment from chance and expectations.
Reconstitution: Dissolving a dry powder in a liquid before use, for example a peptide powder in bacteriostatic water.
U-100 syringe: An insulin syringe whose scale shows 100 units per ml. The units measure volume, not the amount of substance.
WADA and the Prohibited List: The World Anti-Doping Agency. Its Prohibited List names the substances and methods banned in sport. The list is updated at least once a year: the new version is published in October and comes into force on 1 January. Some substances are banned at all times, others only in competition.