Young woman on laptop looking up when semaglutide starts working for weight loss

When Does Semaglutide Start Working For Weight Loss?

Written on August 21, 2023 by Sendra Yang, PharmD, MBA. To give you technically accurate, evidence-based information, content published on the Everlywell blog is reviewed by credentialed professionals with expertise in medical and bioscience fields.

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If someone asked you, “What is one way to lose weight?” You will probably say join a gym and exercise more, or eat a healthy diet and consume more fruits. The most common way people try to lose weight is to exercise more and eat less.[1] Over 60% of United States adults try these two methods — exercising and dieting — to drop the pounds, and around 50% try to lose weight by eating more fruits, vegetables, and salads.[1] With diet and exercise, semaglutide has been shown in clinical studies to reduce body weight by up to 15% in patients who are obese and overweight with a comorbid condition.[2-4]

If you are obese or overweight and have a weight-related condition, semaglutide may be an option. Your healthcare provider can help decide if semaglutide is right for you. This article shares information on semaglutide, the mechanism of action, and when it starts working for weight loss, along with some safety information and next steps.

Semaglutide For Weight Loss

Semaglutide was first approved in 2021 by the United States Food and Drug Administration (FDA) to treat obesity.[2,5] Prior to this, semaglutide had been FDA-approved for treatment in type 2 diabetic patients in 2017 as an injection and as an oral formulation in 2019.[7,8] The brand name of semaglutide for use in patients who are obese or overweight with a comorbid condition is Wegovy®.[2]

Dosing And Administration

Semaglutide is a subcutaneous injection that is given once weekly in the abdomen, thigh, or upper arm.[2] The starting dose is 0.25 mg once a week for 4 weeks. The dose is then increased every 4 weeks until the maintenance dose of 2.4 mg is reached. Dose escalation can be delayed by the healthcare provider for another four weeks if there is intolerance to the medication. If there is intolerance to the maintenance dose of 0.25 mg, then the drug should be discontinued in the patient.

The drug can be given any time of the day, regardless of meals.[2] If a dose of semaglutide is missed, and the next dose is more than two days out, administer the dose as soon as possible. If the dose is less than two days away from your next scheduled dose, then skip that dose and continue on your regularly scheduled day of the week.

Everlywell Weight Loss Support

Mechanism Of Action

Semaglutide belongs to the group of drugs called GLP1s.[2] GLP1 stands for glucagon-like peptide 1 receptor agonists.[5] GLP1 medications mimic the naturally produced GLP1 hormones in the body. GLP1 in the body is released in the gastrointestinal tract as a response to the foods you eat. GLP1 can stimulate insulin release from beta cells in the pancreas to maintain glucose levels in the blood. It can also delay gastric emptying, leading to a decrease in hunger. Though the mechanisms of how semaglutide works are not completely understood, it is thought to impact glucose control, metabolism, and is involved in appetite control. [2,5] Semaglutide may also be involved in several brain pathways that regulate appetite and food intake.[2]

When Does Semaglutide Start Working?

So, when does semaglutide start working for weight loss? The point at which semaglutide starts working for you, or when you can start seeing your weight drop, will vary from another person. Based on the STEP 1 clinical study, the semaglutide-treated group reported weight loss beginning with the first assessment after randomization at week 4, reaching its lowest reported weight loss at week 60.[2,4] STEP 1 included 1961 patients randomly assigned to treatment with semaglutide or placebo combined with diet and exercise.[4]

Dosage Forms And Strengths

Semaglutide is currently available as a clear and colorless injectable solution.[2] The injections come in five different pre-filled, disposable, and single-dose pens[2]:

  • 0.25 mg/0.5 mL
  • 0.5 mg/0.5 mL
  • 1 mg/0.5 mL
  • 1.7 mg/0.5 mL
  • 2.4 mg/0.5 mL


Common side effects of semaglutide are gastrointestinal-related.[2,5] These are nausea, vomiting, and diarrhea. Other frequently reported side effects associated with semaglutide may include headache, abdominal pain, nasopharyngitis, dizziness, gastroenteritis, constipation, and GERD.[2] Semaglutide has a boxed warning, or a serious safety warning by the FDA, for the risk of thyroid C-cell tumors.[2] Additional safety warnings and precautions are acute pancreatitis, gall bladder disease, kidney injury, increased heart rate, and hypersensitivity reactions. If you have a hypersensitivity reaction to semaglutide, you should avoid using the medication. You should also not use semaglutide with other products that contain the medication or with other GLP-1s.

Weight Management With Everlywell

Everlywell can help you with your weight loss journey with a comprehensive online weight loss program accessed via telehealth. This connects you with a certified clinician to discuss weight management. You may receive GLP-1 prescriptions if you qualify, regular one-on-one virtual visits with a healthcare provider, quarterly at-home lab tests or supplements, and lifestyle content and support for weight-related health conditions.

How Much Weight Can You Lose On Semaglutide?

How Fast Does Semaglutide Work for Weight Loss?

What Is Semaglutide?


  1. Data briefs - number 313 - July 2018. Attempts to lose weight among adults in the US, 2013-2016. Centers for Disease Control and Prevention. July 12, 2018. Accessed August 14, 2023.
  2. DailyMed - Wegovy®- semaglutide injection, solution. U.S. National Library of Medicine. Accessed August 14, 2023.
  3. Novo Nordisk A/S. Novo Nordisk files for US FDA regulatory approval of once-weekly semaglutide 2.4 mg for weight management. GlobeNewswire News Room. December 4, 2020. Accessed August 16, 2023.
  4. Wilding JPH, Batterham RL, Calanna S, Davies M, Van Gaal LF, Lingvay I, McGowan BM, Rosenstock J, Tran MTD, Wadden TA, Wharton S, Yokote K, Zeuthen N, Kushner RF; STEP 1 Study Group. Once-Weekly Semaglutide in Adults with Overweight or Obesity. N Engl J Med. 2021;384(11):989-1002. doi: 10.1056/NEJMoa2032183
  5. Alorfi NM, Algarni AS. Clinical Impact of Semaglutide, a Glucagon-Like Peptide-1 Receptor Agonist, on Obesity Management: A Review. Clin Pharmacol. 2022;14:61-67. doi: 10.2147/CPAA.S374741
  6. FDA approves first oral GLP-1 treatment for type 2 diabetes. U.S. Food and Drug Administration. Accessed August 17, 2023.
  7. FDA approves new drug treatment for Chronic Weight Management, first since 2014. U.S. Food and Drug Administration. Accessed August 17, 2023.
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