Comparing GLP-1 Agonists for Weight Loss

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There’s a special class of diabetes medications known as the GLP-1 agonists. These medications are well known in the medical community to cause weight loss.

Although this group of drugs is technically used to treat type 2 diabetes, some of those drugs have gone on to become weight loss drugs in their own right.

But how do they work? And how do they all compare to each other?

Let’s compare six different GLP-1 agonist drugs: semaglutide, liraglutide, dulaglutide, exenatide, lixisenatide, and albiglutide for their effects on weight loss.

What are GLP-1 agonists?

This class of diabetic medication is known as the GLP-1 agonists. They all work in similar ways, by stimulating the effects of a hormone called Glucagon-like peptide-1 or GLP-1.

This hormone stimulates the release of insulin, and therefore helps diabetics with poor insulin control.

Even though they can be quite effective at treating diabetes, they’re not commonly used first-line for diabetes. There are a few reasons for this.

1. most GLP-1 agonists need to be injected, making it somewhat inconvenient to take. Some people are deathly afraid of needles, and having to potentially deal with one every day is not a pleasant prospect.
2. we already have more effective drugs for diabetes, like metformin. Some of these drugs are really old, and have decades of research backing their safe and effective use. So newer diabetes drugs will always find it difficult to compete with such well established medications already in use.
3. probably the biggest reason of all, is the cost. GLP-1 agonists are typically many times more expensive than other diabetic drugs. In fact, they tend to be the most expensive diabetic drugs on the market. So insurance companies hate paying for them if other cheaper alternatives are available.

They do have some benefits over other diabetes drugs, like having a low risk of hypoglycemia, but the real hidden gem of these GLP-1 agonist medications, is the ability to cause significant weight loss.

You see, stimulating GLP-1 also makes us feel full, so all these drugs help people lose weight primarily by suppressing their appetite, and making them eat less.

Semaglutide and liraglutide are probably some of the better known medications in this class, at least in Canada it seems, and also the drugs I have the most experience with.

I’ll be stepping back to broaden the scope to include other GLP-1 agonists, and focus on the differences between all six drugs under 10 different brand names.

Comparing all GLP-1 agonists

Comparing names, uses, and dosing

The GLP-1 agonists are a large group of drugs owned by many different companies and marketed under many more different brand names.

Semaglutide is sold under the trade names Wegovy, Ozempic, and Rybelsus.

They’re all the same drug, just that Wegovy is approved for weight loss, and Ozempic and Rybelsus are approved for diabetes.

Wegovy and Ozempic are given by injection, with Wegovy being dosed twice as much as Ozempic, which more strongly suppresses appetite and helps with weight loss better, but is expected to cause more side effects than Ozempic.

Wegovy and Ozempic are injected once per week.

Rybelsus is unique in that it’s the only GLP-1 agonist taken as a pill, rather than injected. Rybelsus is taken once per day.

Liraglutide is sold under the trade names Saxenda and Victoza. Saxenda is approved for weight loss, and Victoza is approved for diabetes.

Again, Saxenda is typically given at a higher dose than Victoza, which gives it a stronger appetite suppression, usually at the expense of having stronger side effects. Saxenda and Victoza are injected daily.

Dulaglutide is sold under the trade name Trulicity. It’s only approved for diabetes and is injected once per week.

However, it’s commonly used off-label for weight loss around the world.

Exenatide is sold under the trade names Byetta and Bydureon. Both are approved only for diabetes.

Byetta is a smaller dose injected twice per day, while Bydureon is a larger dose injected once a week.

Lixisenatide is sold under the trade name Adlyxin. It’s only approved for diabetes and is injected daily.

Albiglutide is sold under the trade name Tanzeum and was only approved for diabetes. It was injected once per week.

So there are a lot of drugs here, and I’m going to try to break it down as succinctly as I can for you without putting you to sleep.

This means I’ll be potentially omitting information I believe to be unimportant, simplifying a lot of information from studies, and making a number of assumptions that will help me to draw more definitive conclusions.

So if you’re a researcher and prefer to dig into the research studies yourself, I’ve left all the references I used down below in the description for you to peruse at your convenience.

All that aside, let’s compare these drugs.

Comparing side effects

GLP-1 agonists carry similar side effects, with the most common being nausea, vomiting, and diarrhea. Let’s compare the frequency of these more common side effects.

They also carry the same potential risks of rarer side effects like damage to the liver or pancreas, gallstones, kidney failure, an increase in thyroid cancers, and so on.

However, it’s somewhat more difficult to compare the frequency of these more serious risks between the drugs since they happen so rarely.

A comparison of research studies suggest that Wegovy and Ozempic are likely to cause the most side effects, with Wegovy likely to cause more due to its higher dose than Ozempic.

Saxenda and Victoza also have a higher frequency of side effects, however the lower dose in Victoza likely makes it more tolerable than Saxenda.

Rybelsus and Trulicity are often associated with a moderate amount of side effects.

The daily injected Byetta may also cause a very high frequency of side effects, however the weekly injected Bydureon significantly reduces the side effect frequency.

Adlyxin has a moderate frequency of side effects compared to the rest, and Tanzeum appears to have the lowest of the bunch.

It’s interesting to note that having to give yourself injections more often does not necessarily mean more side effects.

The frequency of side effects and frequency of dosing do not seem to be correlated.

Also the only drug not injected on this list, Rybelsus, also does not necessarily have less side effects than the injected drugs.

Comparing availability and cost

In general, the GLP-1 agonists are some of the more expensive drugs on the market.

Wegovy and Saxenda are the most expensive, costing around $1000 to $2000 per month depending on your dose.

The other drugs are also quite expensive out of pocket, although insurance can reduce the cost to a few thousand dollars a year.

All the drugs are available only by prescription, so you’ll need to see your doctor to get it prescribed to you.

At the moment, Wegovy is not yet available in Canada, having only recently been given FDA approval, but will likely be available very soon.

Bydureon has recently been discontinued, apparently because it wasn’t selling too well. Albiglutide was discontinued back in 2018, also due to poor sales.

Comparing weight loss effects

These head to head comparisons help to give us an idea of how effective each might be against each other. But keep in mind that studies do not always translate perfectly to real life.

The research seems to suggest that the semaglutide drugs cause the most weight loss, with Wegovy likely to be the strongest.

The liraglutide drugs follow closely, with Saxenda likely to be one of the strongest.

Next is Trulicity, showing some moderate effects on weight, while the remaining drugs show moderate to mild effects on weight in comparison.

Tanzeum appears to have the least effect on weight.

It’s interesting to note that generally speaking, the stronger the drug affects weight loss, the stronger its negative side effects, and less tolerable it might be to take.

Perhaps this is one of the downsides of taking more effective weight loss medications.

Another interesting correlation is that the more effect the drugs have on weight loss, the higher the cost of the drug is priced.

It’s important to remember that these weight loss effects are just initial results, and all the drugs have shown rebound effects over time that cancel out any initial weight loss if a proper weight loss diet was not followed.

So it’s not going to matter how strong or expensive your GLP-1 agonist is in the long run if you aren’t going to follow good weight loss habits.

Summary

All the GLP-1 agonists have at least some effect on weight. Although most of them are approved only for diabetes, a few of them have been adapted for the sole purpose of losing weight.

Their weight loss counterparts tend to be dosed higher, and cost much more.

Rybelsus, which is oral semaglutide, is currently available only for type 2 diabetes, but Novo Nordisk is likely trying to get it approved as a weight loss drug as well. They’ll probably jack up the dose, and the price, give it a spiffy name, and boom, you’ve got a brand new weight loss pill.

Based on their similar mechanism of action, if one of these drugs didn’t work for you at all in the first place, it’s likely that switching to another is not going to significantly help.

Also, if you couldn’t tolerate using one of these drugs and had to discontinue them for medical or safety issues, you might not be able to use one of the other ones.

But if one of them has worked really well for you, and has stopped helping you lose weight, you could consider switching to one of the more effective ones to help further support your weight loss.

Unfortunately switching to a more “effective” GLP-1 agonist is also no guarantee that you’ll lose much more weight either.

For example, if you’ve already tried, say Saxenda for weight loss, I wouldn’t expect there to be too big a difference if you switch to Wegovy, based on my experiences with patients switching to and from semaglutide and liraglutide.

I’m not saying there definitely won’t be any difference, just that you’ll need to decide for yourself whether, paying for Wegovy out of pocket is worth trying, especially if your insurance is already covering your Saxenda.

Anyways in the long run, the amount of weight loss will depend more on your adherence to a good weight loss diet, and the building of good dietary habits, rather than what drug you took, especially since these drugs are not going to work forever, and your body will get used to them.

Learn more about

• What to Expect With Saxenda
• What Forms of Semaglutide are Available?
• Ozempic vs Rybelsus vs Saxenda vs Victoza for Weight Loss
• What to Expect With Wegovy
• 5 Things To Know Before Starting Weight Loss Medication
• Other weight loss medications

See also

• 
  Comparing Weight Loss Drugs in 2024
  Ozempic and Mounjaro are highly effective at treating obesity, however there are many other approved and off-label options that also work.
• 
  Bupropion vs Contrave vs Naltrexone
  Contrave is a synergistic combination of buproprion and naltrexone, which can be replicated to some degree using the generics individually.
• 
  New Obesity Drugs in 2024
  New obesity drugs target more than just GLP-1 and do much more than suppress appetite for a more nuanced approach to weight loss.
• 
  Mounjaro: Who Loses the Most Weight?
  White or Asian younger women who use metformin and have lower sugar and lipid levels tend to experience more weight loss with Mounjaro.
• 
  How does Oforglipron compare?
  Orforglipron, Semaglutide, and Danuglipron are oral GLP-1 agonists that are all similar enough that cost may end up being the winning factor.