Semaglutide and appetite

The phrase “food noise”

People describing semaglutide often reach for ‘food noise’: the background preoccupation with eating that they say has become quieter. Some report feeling full sooner or losing interest in sweets and greasy food. Others describe aversion, queasiness or so little appetite that eating becomes difficult. These are anecdotal accounts, not clinical evidence, and they cannot establish how often an effect occurs.

I respect the wish for relief from that preoccupation, alongside the eventual weight change. I also hear a practical tension in the accounts: a welcome reduction in appetite and an unwelcome loss of interest in food can sound similar on paper. I would ask where the relief ends and the discomfort begins.

The vocabulary carries a useful request into the discussion. The trials provide a separate account of measured outcomes.

STEP 1 weight results

The STEP 1 randomised trial enrolled 1,961 adults with overweight or obesity and without diabetes. Mean body-weight change at 68 weeks was -14.9% with semaglutide and -2.4% with placebo. I trust that weight result within the group and period it describes.

They also answer the request more directly than an inventory of receptor names would. The outcome was weight. How much better someone felt, what their meals became like and whether they could tolerate treatment require their own answers.

In SURMOUNT-5, a direct comparison with tirzepatide, 751 adults with obesity were followed for 72 weeks. Mean weight change was -20.2% with tirzepatide and -13.7% with semaglutide (P<0.001). On that outcome, tirzepatide did better. I won't shield semaglutide from a comparison its trial record contains.

Disease outcomes

A weight-loss discussion can leave the most consequential outcomes off the table. SELECT enrolled 17,604 adults with established cardiovascular disease and overweight or obesity, without diabetes. For cardiovascular death, non-fatal myocardial infarction or non-fatal stroke, the hazard ratio was 0.80 (95% CI 0.72-0.90; P<0.001), a 20% relative risk reduction.

FLOW studied 3,533 people with type 2 diabetes and chronic kidney disease. For its composite of kidney failure, a decline in eGFR of 50% or more, or death from kidney or cardiovascular causes, the hazard ratio was 0.76 (95% CI 0.66-0.88), a 24% lower risk than placebo.

These trials put a further request on my agenda: reducing disease events. The cardiovascular and kidney findings have their own populations and endpoints; a change on the scale cannot stand in for either one.

How semaglutide works

Semaglutide mimics GLP-1, a hormone released after eating. It activates the GLP-1 receptor, supports insulin release when blood glucose is high, suppresses inappropriate glucagon release and slows stomach emptying. Appetite regulation in the brain also contributes to reduced food intake. The safety review describes this pharmacology alongside its clinical consequences.

The molecule has been modified to resist breakdown and bind albumin, a blood protein, giving it a long duration in the body. Approved formulations include an injection and an oral tablet. The existing US indications cover type 2 diabetes, chronic weight management, cardiovascular risk reduction in adults with established cardiovascular disease and overweight or obesity, and metabolic dysfunction-associated steatohepatitis, or MASH.

I prefer to discuss the named indication. Tesamorelin's pituitary action leads somewhere else entirely.

Semaglutide precautions

The semaglutide safety review describes predominantly mild-to-moderate, transient gastrointestinal adverse effects, with nausea in roughly one-third of patients, and increased biliary disease, including gallstones. Vomiting, diarrhoea and constipation also matter in the clinical and anecdotal accounts. ‘Transient’ can cover an unpleasant stretch of someone's life; I would never read it as a reason to dismiss the experience.

The boxed warning for thyroid C-cell tumours comes from rodent studies at supratherapeutic exposures. A personal or family history of medullary thyroid carcinoma or multiple endocrine neoplasia type 2 is a contraindication. Human thyroid- and pancreatic-cancer signals remain unresolved in the review because the events are rare. Acute pancreatitis is a class warning, and pre-existing diabetic retinopathy raises monitoring concerns when blood glucose improves rapidly. The approved labelling contraindicates use during pregnancy.

A compounded version of semaglutide has no FDA approval. The trials discussed here concern characterised pharmaceutical preparations; their results cannot verify the identity, purity or concentration of laboratory-use material.

There is also the question of stopping. Weight regain is a concern in the wider record, but the studies on this site's reference list do not quantify it after semaglutide withdrawal. I have no withdrawal figure to offer from those sources. It deserves an answer in a treatment conversation all the same.