Semaglutide and the cardiovascular result
SELECT earns most of my enthusiasm here. STEP 1 and FLOW add different benefits, in different people, with different questions attached.
Cardiovascular disease without diabetes
In SELECT, 17,604 adults had established cardiovascular disease and a body-mass index of at least 27. None had diabetes. Semaglutide reduced the risk of the combined outcome of cardiovascular death, nonfatal heart attack or nonfatal stroke by 20% relative to placebo. Each word in that outcome matters: the trial supports the combined result, rather than a separate verdict on every component.
I’m bullish on SELECT’s clinical endpoint. A body-weight change can be important in its own right, but SELECT asked whether serious events happened. The participants’ existing disease is also essential. This trial gives no general licence to predict cardiovascular protection in healthy adults.
Appetite in STEP 1
Semaglutide mimics GLP-1, a gut hormone involved in hunger and glucose control. It increases insulin release when glucose is high, suppresses inappropriate glucagon release, slows stomach emptying and acts on appetite circuits in the brain. Changes to its structure slow its breakdown and help it bind to a blood protein, prolonging its action.
STEP 1 enrolled 1,961 adults with overweight or obesity, without diabetes. At 68 weeks, mean body-weight change was -14.9% with semaglutide and -2.4% with placebo. Those are group averages. My optimism about weight treatment has a concrete basis in STEP 1, even with individual responses unresolved.
The appetite story also has a less comfortable side: nausea and other gastrointestinal symptoms can accompany treatment. Fullness and discomfort can coexist.
Kidney outcomes in FLOW
FLOW studied 3,533 adults with type 2 diabetes and chronic kidney disease. Its main outcome combined kidney failure, a large sustained fall in kidney filtering, or death from kidney or cardiovascular causes. Semaglutide reduced the risk of this combined outcome by 24% relative to placebo.
That is another reason for optimism, rooted in another population. Counting deaths inside a combined outcome does not establish fewer deaths on their own. Nor does a trial in chronic kidney disease answer a prevention question about healthy kidneys. The distance between those claims is clinically consequential.
Tolerability and rarer risks
The semaglutide safety review describes predominantly transient, mild-to-moderate gastrointestinal effects and increased biliary disease, including gallstones. Some people discontinue because the digestive effects are hard to tolerate. Pancreatitis remains a class warning; uncertainty about an increased risk deserves to stay visible.
The thyroid tumour warning began with rodent findings. Human thyroid and pancreatic cancer signals remained unconfirmed in the review, with too few cases for firm conclusions. The label contraindicates treatment with a personal or family history of medullary thyroid carcinoma or MEN 2. Rapid glucose improvement can also worsen existing diabetic retinopathy. Substantial weight loss can include lean tissue, which raises a separate question about strength.
Semaglutide has approved prescription uses. The trials concern the medicines actually tested; a research label supplies no matching assurance of identity, strength or sterility.
Experiences people describe
People describe less hunger and fewer intrusive thoughts about food, along with nausea, constipation, diarrhea, sulfur-smelling burps, heartburn and early fatigue. Taste changes, hair shedding and injection-site soreness also appear in accounts. These are anecdotal reports, not clinical evidence; they cannot establish cause or side-effect rates.
To me, quieter food thoughts describe a meaningful change in daily life. A scale cannot capture that experience. They also leave unanswered who reported nothing, who stopped, and what else changed. For a direct weight comparison with tirzepatide, SURMOUNT-5 is the relevant next stop.