Glossary

Starting on GLP-1 medication means learning a new vocabulary fast. This glossary collects the terms I kept running into while researching and documenting my own Mounjaro journey. For a broader walkthrough, see the Mounjaro 101 post.

B

BMI

Body Mass Index — weight in kilograms divided by height in metres squared. Many insurers and prescribers use BMI thresholds (often alongside other health conditions) when deciding whether to cover or approve GLP-1 treatment.

C

Constipation

One of the most commonly reported side effects on GLP-1 drugs. Slower digestion plus low fiber or hydration can make it worse. See the constipation post for practical tips.

F

Food noise

The constant mental chatter about eating — cravings, planning the next snack, feeling preoccupied with food. Many people on GLP-1 medication report this quieting significantly, which is one of the most noticeable day-to-day changes.

G

Gastric emptying

How quickly food leaves your stomach and moves into the small intestine. GLP-1 drugs deliberately slow this process, which helps you feel full longer — but slowing it too much can contribute to side effects.

Gastroparesis

Sometimes called "stomach paralysis" — when stomach muscles do not contract normally and food sits too long. Rare but serious; reported more often with semaglutide than tirzepatide in public discussions. Seek medical help if you have persistent severe nausea, vomiting, or inability to keep food down.

GLP-1

Short for glucagon-like peptide-1, a hormone your gut releases after eating. It signals fullness, slows digestion, and helps regulate blood sugar. Drugs like Mounjaro mimic or amplify this effect.

GLP-1 receptor agonist

A medication that activates GLP-1 receptors in the body, reducing appetite and slowing gastric emptying. Tirzepatide and semaglutide both work through this pathway, though they are not identical molecules.

J

Jab day

The fixed day each week you take your injection — same day, roughly the same time. Many people pick a day near the weekend so mild side effects are easier to manage away from work.

K

KwikPen

A pre-filled multi-dose pen device used to inject Mounjaro. One pen typically holds four weekly doses for a given strength (e.g. 2.5 mg). Some pharmacies supply four separate single-dose syringes instead.

M

Mounjaro

Brand name for tirzepatide, made by Eli Lilly. In many countries it is prescribed for weight management and/or type 2 diabetes depending on local approvals. Weekly subcutaneous injection.

O

Ozempic

Brand name for semaglutide approved for type 2 diabetes. Because it shares the same molecule as Wegovy, it is frequently mentioned in weight-loss conversations even when the prescription indication is diabetes.

P

Plateau

A stretch where weight loss stalls despite staying on medication and keeping habits in check. Common on any long weight-loss journey; not necessarily a sign the drug has stopped working.

R

Rebound weight gain

Weight regained after stopping GLP-1 medication, especially if eating habits have not changed. A common reason people plan for long-term use or a careful tapering strategy with their doctor.

S

Semaglutide

The active ingredient in Wegovy (weight loss) and Ozempic (type 2 diabetes). Like tirzepatide, it is a GLP-1-based medication, but the molecule, dosing, and approved indications differ by brand and country.

Starter dose

The lowest strength you begin on — for Mounjaro this is typically 2.5 mg per week for the first four weeks. The goal is to let your body adjust before moving to higher doses.

Subcutaneous injection

An injection into the fatty tissue just under the skin, usually in the abdomen, thigh, or upper arm. Mounjaro and similar GLP-1 drugs are self-administered this way once per week.

T

Telehealth / online clinic

A remote medical service where you consult a licensed prescriber online and receive a prescription if appropriate. In countries without public coverage, this is often how people access Mounjaro — but costs for the medication itself are usually still out of pocket.

Tirzepatide

The active ingredient in Mounjaro (and Zepbound in some markets). It is a dual GIP/GLP-1 receptor agonist — it targets two hormone pathways rather than GLP-1 alone, which is why it is often grouped separately from semaglutide-based drugs.

Titration

The step-by-step increase in medication strength over time (e.g. from 2.5 mg to 5 mg, then 7.5 mg, and higher if needed). Your prescriber sets the schedule based on tolerance, side effects, and treatment goals.

W

Wegovy

Brand name for semaglutide at a dose approved specifically for chronic weight management. Often discussed alongside Mounjaro when people compare GLP-1 options.

Have a term you think belongs here? Send it over — or check the FAQ page for answers to the questions that come up most often.