Disclaimer: None of the information in this article constitutes medical advice, and is just the opinion of the writer(s) and published for informational purposes only. We recommend that patients follow their doctor’s guidance in regard to prescription medication.
Semaglutide is a drug that’s used to treat both type 2 diabetes and obesity. The drug is sold under the brand names Rybelsus and Ozempic for treating diabetes, and under the brand name Wegovy when used for weight loss.
Even though the same active drug ingredient (semaglutide) is used in all three medications, the dosages differ as we'll explain later.
In this article we’ll review medical studies on semaglutide to determine if it’s safe and effective for treating type 2 diabetes and for promoting weight loss. We’ll highlight side effects of the medication and explain how it works.
Does Semaglutide Work for Diabetes?
As we referenced in the intro section, semaglutide is primarily a diabetes drug, and is approved by the Food and Drug Administration (FDA) for this purpose. The drug has been studied for its efficacy at lowering blood sugar in hundreds of medical trials as we highlighted in our recent Ozempic review article.
A meta-review published in the Diabetes, Obesity and Metabolism journal analyzed data from 7 clinical trials on semaglutide and type 2 diabetes. The researchers found that the drug reduced HbA1c levels (a marker of blood sugar) by 1.01% and 1.38% at relatively low doses.
A separate clinical trial published in 2018 found that semaglutide reduced the blood sugar spike after a meal high in dietary fats consumed by obese patients.
An extremely thorough medical review published in the well-respected Drugs journal cited 96 individual medical studies and found that the average range of treatment effect for semaglutide compared to placebo for blood sugar reduction was -0.4% to -1.6%.
We can conclude from the available medical research that semaglutide is effective for treating type 2 diabetes, although its effect on blood sugar appears to be relatively modest.
Does Semaglutide Work for Weight Loss?
Semaglutide appears to be effective for weight loss in overweight and obese patients. It’s only FDA-approved for weight loss in an injectable and branded form, which we reviewed thoroughly in our Wegovy weight loss reviews article.
This drug is approved for weight loss in both diabetic and non-diabetic patients.
Semaglutide is typically prescribed at a higher dose for weight loss than for type 2 diabetes. The injectable weekly dose used for weight loss is 2.4 milligrams (mg) while the injectable weekly dose used for diabetes ranges between 0.5 and 2 mg.
A clinical trial on injectable semaglutide’s weight loss effect was published in the New England Journal of Medicine in 2021. The aim of the trial was to assess whether the injections could help overweight and obese patients lose weight.
Half of the trial participants received semaglutide injections and the other half received a placebo injection. Both groups also made healthy lifestyle changes like reducing their overall calories consumed.
The semaglutide group lost significantly more weight than the group receiving placebo injections. The average body weight loss in semaglutide patients was 14.9%, while the average body weight loss in placebo patients was only 2.4%. This equates to a weight loss of 37.25 pounds for a patient with a baseline weight of 250 pounds. The trial lasted slightly longer than one year.
Oral semaglutide may also be effective for weight loss in overweight patients, though less so than the injections. The drug is only FDA-approved for weight loss in injectable form, so we would consider the potential weight loss from oral semaglutide to be a secondary benefit for overweight diabetics prescribed the drug, but we would not recommend using oral semaglutide for weight loss alone.
A medical study on the weight loss effects of semaglutide was recently published in the Diabetes, Obesity & Metabolism journal. All of the trial participants had type 2 diabetes. Over the 12 weeks of the trial, the patients on semaglutide lost 5.95 pounds on average.
We will conclude that semaglutide is effective for weight loss in both injectable and oral form, but would only recommend it in injectable form since that’s the form approved by the FDA to treat weight loss.
Semaglutide Side Effects
The side effects of semaglutide and their severity will likely depend on whether a patient uses an oral or injectable form of the drug.
The FDA label for both forms of semaglutide contains a “black box” warning indicating increased risk of thyroid tumors in some patients. This is the most severe type of warning issued by the FDA, and is used to reference side effects which may be severe or life-threatening.
The studies suggesting potentially increased tumor risk were animal studies, not human studies, but we would still strongly recommend that patients speak with their doctor about this side effect before using the drug. It may be advisable for patients with a personal or family history of thyroid disorders to choose a different medication, but only a doctor can advise such.
Thyroid tumors are a rare potential side effect of semaglutide. The more common side effects are milder.
A medical review on the safety of semaglutide documented the following side effect rates: nausea occurred in upwards of 20% of patients, vomiting occurred in a range of 4% to 11.5% of patients, and diarrhea occurred in 4.5% to 11.3% of patients. Older patients experienced more side effects.
How Does Semaglutide Work?
Semaglutide is in a class of drugs called glucagon-like peptide-1 receptor agonists (GLP-1RA). These compounds help normalize glucose levels by activating GLP-1 receptors in the pancreas which causes insulin release.
According to a medical review, GLP-1RA medications may also block the release of a hormone called glucagon which is commonly elevated in type 2 diabetics. Glucagon causes the body to increase blood sugar levels, so the combination of limiting this hormone and increasing insulin combine to be effective for blood sugar reduction.
In regard to weight loss, semaglutide may be effective because it reduces hunger and increases the sense of fullness. The medication delays gastric emptying which causes patients to feel full longer.
The weekly dosage of injectable semaglutide ranges from 0.25 mg to 2.4 mg, according to the FDA label linked earlier in this article.
According to the Rybelsus FDA label, oral semaglutide is available at doses of 3 mg, 7 mg and 14 mg.
Doctors will typically prescribe a medication like semaglutide on the lower range of the dosage scale to see how a patient reacts. If the medication is effective, they can remain at a lower dosage which may confer a lower risk of side effects. If the patient is unresponsive, dosage will typically have to be titrated up over time.
Semaglutide User Reviews
Drugs.com is an online resource where prescription medication users can publish personal reviews of the drugs they take. Semaglutide has a higher rating for obesity (6.7) than for type 2 diabetes (5.7) on their site.
The top positive review of semaglutide for type 2 diabetes is written by a user named “Zell” who claims the medication improved their blood sugar levels and weight:
“What a miracle! 9 months later and I’m down 40 lbs, my a1c dropped from 8.1 to 5.6, and I have virtually no symptoms from the drug other than fullness. The symptoms in the beginning did not last long either.”
The top negative review of semaglutide for type 2 diabetes is published by a user named “Stingie” who claims that one single dose of the medication caused them to experience significant side effects:
“I did one injection and have been ill since. Have had acid reflux, burping, vomiting, constipation, headache and dizziness. I tried to eat small meals and drink plenty of water as directed by my physician, but I have been unable to hold anything down.”
The top positive review of semaglutide for weight loss comes from a user named “Philly” who claims to have lost a significant amount of weight while taking the drug:
“6 months. -65 pounds. Hypertension gone. Pre Diabetes gone. Sleep apnea gone. Lower leg skin breakdown gone.”
The top negative review of semaglutide for weight loss is written by a user named “Kmac” who claims the drug caused them to experience severe side effects:
“I spent 6 weeks of my life with an upset stomach, the absolute worst reflux and heartburn I have ever had, and constant nausea. I had to literally force myself to eat. Would not recommend. The side effects and the price is not worth it.”
The cost of semaglutide will vary based on what branded version a patient is prescribed.
According to GoodRx, at the time of writing this article the retail cost of Wegovy is around $1,400 for a 30-day supply.
The cost of Ozempic is reported as around $900, and the cost of Rybelsus is currently around $900 as well.
Most patients don't pay retail prices but instead pay a price that's subsidized by health insurance, so we strongly recommend that patients speak with their doctor and insurer about the cost of semaglutide.
All three semaglutide drug manufacturers also have price savings pages on their websites which we’ve linked below. These resource pages contain offers for additional discounts like savings cards:
Doctor Discusses Whether Semaglutide Causes Weight Loss
One of the most popular YouTube videos on semaglutide and weight loss is published by a channel called "Medscape" and has achieved over 80,000 views at the time of updating this article. The video appears unsponsored:
Our Weight Loss Supplement Recommendations
There exist several over-the-counter (OTC) weight loss supplements that don't require a prescription, and which have medical research backing.
We are not suggesting that these products are as effective as semaglutide; just that it may be worthwhile for an overweight patient to discuss these options with their doctor given their documented efficacy and lack of significant side effects. They may also be used in addition to prescription weight loss medication.
We recommend dietary fiber as a safe and effective weight loss supplement, especially when combined with caloric restriction.
A landmark medical study found that moderate caloric restriction (750 calories per day below baseline) combined with dietary fiber intake (a minimum of 20 grams per day) caused an average weight loss of 16.03 pounds over 6 months. That’s a pace of 32 pounds per year of weight loss in overweight individuals simply by adding fiber to a moderately-restricted-calorie diet.
The fiber supplement we recommend is SuperGut Fiber Mix. It contains a clean and effective formulation: a blend of three different types of unflavored dietary fiber and zero additive ingredients. It can be mixed into liquids or foods. Interested consumers can buy SuperGut fiber at this link.
We recommend using two fiber mixes per day, which provides 16 g of total fiber. Diet should provide the remaining fiber necessary to meet the 20 g minimum threshold.
Medium-chain triglyceride (MCT) oil is another dietary supplement which has been shown in clinical trials to cause weight loss.
MCT oil is quickly absorbed by the body and increases metabolic rate, which causes fat loss. A meta-study on MCT oil documented weight loss of 1.12 pounds over 10 weeks. This equates to a potential annualized weight loss of 5.84 pounds with MCT oil supplementation.
We recommend Bulletproof MCT Oil as our top MCT oil product, because it has a clean and effective formulation. The only ingredient is MCT oil derived from coconuts, and the product has no questionable additives. Interested consumers can buy Bulletproof MCT Oil at this link.
The effective dose range of MCT oil for weight loss (based on the medical review) is 1.7 g to 10 g per day. Bulletproof's MCT oil provides 14 g in one tablespoon, so around two-thirds of one tablespoon should be a maximally-effective dosage.