Sated · GLP-1 Guides

GLP-1 Glossary: the words, in plain English

Last reviewed August 2026 · by the Sated team · not medical advice

• GLP-1

  Glucagon-like peptide-1, a hormone your gut releases after eating that signals fullness and slows digestion. "A GLP-1" is also shorthand for the medications that mimic it.

  Ozempic, Wegovy, Mounjaro and Zepbound all work on this pathway, which is why they share so many effects and side effects.

• GIP

  Glucose-dependent insulinotropic polypeptide, a second gut hormone. Tirzepatide acts on both GIP and GLP-1 receptors, where semaglutide acts on GLP-1 alone.

  This dual action is the main pharmacological difference between Mounjaro and Ozempic or Wegovy.

• Semaglutide

  The active ingredient in Ozempic, Wegovy and Rybelsus. A GLP-1 receptor agonist with a half-life of about a week, which is why the injections are weekly.

  Ozempic and Rybelsus are licensed for type 2 diabetes; Wegovy is the weight-management brand of the same molecule.

• Tirzepatide

  The active ingredient in Mounjaro and Zepbound. It acts on both GIP and GLP-1 receptors, and has a half-life of around five days.

  Mounjaro and Zepbound are the same molecule under different brand names and licences.

• Titration

  The process of stepping a dose up gradually rather than starting at the full amount, to let the body adjust and reduce side effects.

  Standard steps are usually a minimum of four weeks apart. Staying longer at a dose is common and is not falling behind. See the dose schedule calculator.

• Run-in dose

  The first, lowest dose of a GLP-1, which exists to build tolerance rather than to treat anything.

  2.5 mg of Mounjaro and 0.25 mg of Wegovy are run-in doses, which is why nobody stays on them long term without a specific reason.

• Maintenance dose

  The dose you settle on once titration finishes and stay on ongoing.

  It does not have to be the highest available dose. The best maintenance dose is the lowest one that does the job with side effects you can live with.

• Food noise

  The constant intrusive mental chatter about food: planning it, craving it, negotiating with yourself about it. Distinct from physical hunger.

  Its sudden absence is one of the most commonly described effects of these medications, and many people find the quiet stranger than expected. Full guide.

• Dose day

  The day of your weekly injection. Many people notice a repeating pattern of appetite and side effects across the days that follow.

  Spotting your own pattern usually takes two or three cycles of noting how you feel, and makes it much easier to plan meals around.

• Gastric emptying

  How quickly food leaves your stomach. GLP-1 medications slow it deliberately, which is why you feel full for longer.

  This same mechanism is behind much of the nausea, reflux, constipation and sulphur burps people report.

• Sulphur burps

  Burps that taste or smell of rotten eggs, caused by hydrogen sulphide produced as sulphur-rich food ferments in a slow-emptying stomach.

  Reported more often with tirzepatide. What triggers them and what helps.

• Lean mass

  Everything in your body that is not fat, including muscle. Some lean mass is lost in any weight loss; the aim is to lose as little as possible.

  Protein intake and resistance training are the two levers that protect it. Full guide.

• Protein target

  A daily protein goal, commonly 1.2 to 1.5 g per kg of body weight while losing weight on a GLP-1.

  The target falls as you lose weight because it is calculated per kilogram, so it is worth recalculating. Calculator.

• NSV (non-scale victory)

  A sign of progress that has nothing to do with weight: rings fitting, stairs feeling easier, better bloods, better sleep.

  Worth recording deliberately, because they keep arriving during the weeks when the scale does not move.

• Stall or plateau

  A period where weight stops falling despite nothing obviously changing. Extremely common and usually temporary.

  Often a good moment to check protein intake and whether the scale is hiding a body-composition change rather than a genuine halt.

• Injection site rotation

  Deliberately varying where you inject, between abdomen, thigh and upper arm and within each area, so the same spot is not used repeatedly.

  Reduces the risk of lumpy fatty tissue building up at one site. Rotation map.

• Lipohypertrophy

  Lumps of thickened fatty tissue that build up where injections are repeatedly given in the same spot.

  Long known from insulin use. It can affect how the medication is absorbed, which is the practical reason rotation matters.

• Half-life

  How long it takes for half a dose to clear your system. Semaglutide is about a week; tirzepatide about five days.

  Long half-lives are why these are weekly injections, and why levels build over the first weeks rather than peaking immediately.

• Ozempic face

  A media term for facial volume loss during rapid weight loss. It is caused by losing fat quickly, not by the medication specifically.

  The same thing happens with fast weight loss by any method. Slower loss and adequate protein both help.

• Compounded semaglutide

  Semaglutide mixed by a compounding pharmacy rather than manufactured by the licence holder.

  Regulators including the MHRA and FDA have warned about unlicensed and counterfeit supply. If you are considering it, discuss it with a prescriber and be careful about the source.

• Pen

  The prefilled injector device the medication comes in. Depending on the brand it may be single-dose or multi-dose with a dial.

  Needles are single-use, and pens have specific storage rules; the patient information leaflet in your box is the authority.

Sources

• NHS: Tirzepatide (Mounjaro)
• NHS: Semaglutide (Wegovy, Ozempic)
• Mounjaro patient information leaflet (emc)

Related guides

• Food noise, and why it goes quiet
• Dose schedule calculator
• Protein calculator

Sated is a wellness companion, not a medical device, and this glossary is general information, not medical advice, diagnosis or treatment. Definitions are written for everyday understanding rather than clinical precision. Your medication's patient information leaflet and your prescriber's guidance always take precedence. Mounjaro, Zepbound, Ozempic, Wegovy and Rybelsus are trademarks of their respective owners; Sated is not affiliated with any pharmaceutical company.