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Read the result with its limits

What the
evidence says.

A group result needs context.

Use the research to shape your questions. Bring your own history into the care conversation.

Weight change in a study

What happened in the weight-loss trial?

STEP 1 studied adults with obesity, or excess weight plus a related health problem, who did not have diabetes.

At 68 weeks, average weight loss was 14.9% with semaglutide injections and 2.4% with a dummy injection.

Semaglutide:14.9%average weight loss.
Dummy injection:2.4%average weight loss.
Trace the study result
  • Both groups had lifestyle support, with regular visits and counselling; the study was funded by the medicine’s maker.
  • The average for this group does not predict any person’s own result.
  • Participants who stopped semaglutide in the STEP 1 follow-up regained about two-thirds of their lost weight over the next year.
  • Ask what the plan involves over time, including if treatment stops.

Alongside the hoped-for benefit

What problems come up in the label?

The Food and Drug Administration (FDA) handles medicine reviews; the September 2026 product label lists cautions to talk through during care.

Stomach trouble

In adult Wegovy (semaglutide) injection trials, nausea—feeling sick to the stomach—was reported by 44% on medicine and 16% on a dummy injection.

  • Vomiting, loose stools, and trouble passing stools also appear among the common side effects in the label.
  • Ask who to contact if symptoms make daily life hard.

The tumour caution

Semaglutide labels carry a boxed warning, the strongest kind, about thyroid tumours: growths linked in the label to neck symptoms such as a lump.

The tumours were found in rats and mice.

  • It remains unknown whether semaglutide causes these tumours in people.
  • The label rules out use if you or a relative had medullary thyroid cancer (MTC), the specific rare cancer type named in this warning.
  • It also rules out use for MEN 2, a rare illness passed down in families, or a past serious allergy to semaglutide or its ingredients.

If a relative had thyroid cancer, ask the doctor to check which kind.

Bring any family records of inherited illness, so the doctor can check for MEN 2 before deciding about this medicine.

Symptoms to take seriously

The label warns that severe belly pain that does not go away, sometimes reaching the back, can signal serious swelling inside the body.

Contact the doctor promptly about pain like this. Ask how to get help if the doctor cannot be reached.

  • Severe breathing trouble, or swelling in your face or tongue, may signal a life-threatening allergic reaction.
  • MedlinePlus advises calling 911 or going to the closest emergency room for severe symptoms like these.

Checking a care page

Which claims deserve a pause?

Keep the product name and how you will get care in view. Ask for an explanation that can be checked.

  • As of September 2026, no FDA-approved generic semaglutide can be sold in the U.S. A generic is an approved copy of a medicine sold under a brand name.
  • As of September 2026, giving out prescription medicine without a prescription breaks U.S. law.
  • As of September 2026, the FDA warns against research-labelled semaglutide for personal use: its quality is unknown and it may cause harm.
  • Ask which product is proposed and who will answer questions about it.

Words that come up in care

What do these terms mean?

Ask for a plain explanation whenever a term gets in the way.

Compounded medicine
A preparation made by a pharmacy or doctor rather than a finished drug-company product.
Prior authorization
The insurer’s approval before it will cover a medicine.
Formulary
The medicine list an insurance plan uses to decide what it will cover.
Follow the evidence

Sources for this page

The published weight-change study

The report describes the people enrolled, the comparison group, and the average changes. Read it alongside the limits above.

Read the study report
The follow-up after treatment ended

This report follows a smaller group after they stopped treatment. Read what happened to their weight over the next year.

Read the follow-up report
The medicine’s label

The government-hosted label gives the study comparisons, listed effects, and reasons a product may not fit someone’s history.

Read the Wegovy (semaglutide) product information
Recognising a severe allergic reaction

MedlinePlus, from the U.S. National Library of Medicine, explains symptoms and emergency care.

Read the MedlinePlus explanation
Checking the product claims

The FDA discusses research-labelled products and the difference between approved medicines and compounded preparations.

Read the FDA product concerns
Checking a claimed generic’s approval

Read the FDA’s list of drug approvals to check the record behind a claim that a medicine is an approved copy.

Open the FDA drug-approval records
The prescription requirement

The U.S. Code is the federal law behind the prescription requirement described here.

Read the federal law on prescriptions
Insurance terms and coverage

The agency that runs Medicare explains the drug plan and the separate temporary program. Use these details when asking what you would pay.

Read Medicare’s coverage explanation