Glossary: peptides, studies and rules

The substances and the body

Amino acid: the building block of peptides and proteins.
Peptide: a short chain of amino acids.
Protein: a long chain of amino acids.
Hormone: a signal the body releases that acts elsewhere in the body.
Receptor: a docking point on cells that a hormone or medicine binds to.
Agonist: a substance that activates a receptor. Semaglutide is a GLP-1 agonist.
GLP-1 and GIP: hormones from the gut that raise insulin after meals. Read more in GLP-1, GIP and glucagon explained.
Glucagon: a hormone from the pancreas that among other things raises blood sugar and energy use.
HbA1c: long-term blood sugar. Shows average blood sugar over the last two to three months.
Growth hormone: a hormone from the pituitary gland that controls growth and metabolism.
IGF-1: a substance the liver makes when growth hormone rises, and that carries much of its effect.

Cell study (in vitro): experiments on cells in the laboratory.
Animal study: experiments on animals, usually mice or rats.
Case report: a description of one patient. Often the first clue that sparks larger studies.
Pilot study: a small, often short study that tests whether a larger study is possible.
Observational study: researchers follow people without deciding who gets what.
Registry study: an observational study using data from health registries, often with very many people.
Randomised controlled trial (RCT): chance decides who gets the substance and who gets placebo or another treatment.
Placebo: a dummy treatment, for example salt water, that looks like the real substance.
Double-blind: neither the participants nor the researchers know who gets what.
Phase 1, 2 and 3: the stages of testing a new medicine. Phase 1 tests safety in a few people, phase 3 tests effect and safety in many.
Systematic review: a review of all studies on a question, using a fixed method.
Meta-analysis: a systematic review where the results of several studies are combined statistically.
n: the number of participants in a study.
Research stage: how far the research has come. We use four stages. Read more in How to read a study.

Prescription only: the medicine is only available with a prescription from a doctor.
EMA: the European Medicines Agency, which assesses medicines for the EU.
DMP: the Norwegian Medical Products Agency, responsible for medicines in Norway.
WADA: the World Anti-Doping Agency, which publishes the list sport follows each year.
Sports list: WADA's yearly overview of substances in sport. See how the peptides fit with sport in Anti-doping.
Clinical trials: studies in humans in several phases, from small safety studies to large studies that form the basis for approval.
Research compound: a promising substance studied in the laboratory and in trials, on its way to possibly becoming a medicine.