Talking about drugs of any kind is usually not something I focus on. I’m an advocate of natural bodybuilding and fitness. It’s also out of my scope of practice to advise anyone whether to take weight loss drugs or not. I can only share the facts I’ve come across for informational purposes only. Consult a good doctor for medical advice. But this new class of weight loss drugs such as Ozempic is ALL over the mainstream news and social media. You can’t escape hearing about it. I can’t escape being asked about it either. So I decided I had to address this topic head on…
What you’re about to read are my personal thoughts from a fitness professional’s perspective that I’m offering because readers keep asking me. These are my opinions, but they are based on taking a close look at the scientific literature.
Also please note, this is not a criticism of anyone using the drugs under medical advice. Anyone who has worked with their doctor to use medication and has achieved healthy weight loss, especially maintained it, and especially done it in conjunction with fitness-oriented lifestyle changes has nothing but my congratulations.
So let’s jump in…
What Is Ozempic? What Are GLP-1 drugs?
Ozempic is one of the brand names for semaglutide. Another one is Wegovy. A similar drug is tirzepatide (trade names Mounjaro and Zepbound), and there are others in this category as well.
These drugs are known as a GLP-1 agonists. GLP-1 is glucagon like peptide, a hormone secreted in your gastrointestinal tract that makes you feel fuller. (Remember, there are hormones that make you feel hungrier, but there also hormones that make you feel fuller).
The effects also occur in the brain as there are areas of the brain that can also send signals to make you feel fuller. It’s a single weekly injection and that’s the case because unlike the GLP-1 hormone itself, the semaglutide drug was developed to have a much longer half life.
Does Ozemic Really Work?
There’s no doubt.
The reason this injection has become so popular is because the drug works and it works well.
20 to 30 pounds of weight loss or 15% of body weight is not uncommon, sometimes less, but sometimes even more.
In a recent 2025 study, subjects lost at average of 21.3% of their starting body weight. (Which is actually kind of crazy).
How Do Ozempic And Other GLP-1 Drugs Work?
This weight loss drug works by making you eat less. You’re simply not hungry and you feel fuller after eating.
This is NOT a thermogenic or metabolism booster which would work on the burning more side. Ozempic works on the eat less side.
That’s probably why Ozempic has been proven so effective, because doing things that make you feel full or simply not feel like eating is the more effective side of the equation.
We’ve also seen thermogenics that have more frequent and potentially more harmful side effects. But ALL drugs have potential side effects, as I’m sure you know if you’ve ever seen the disclaimer section of any pharmaceutical ad on TV.
What Are The Side Effects Of Ozempic?
For Ozempic / semaglutide, the most common side effect is nausea. I saw stats comparing two studies, and in adolescents 65% reported nausea while in adults 33% reported nausea.
Other side effects that are also fairly common (20%-35% of users, according to research) include abdominal pain, vomiting, and diarrhea.
As for more severe side effects, there have been reports of stomach paralysis or intestinal blockage. This is likely associated with the fact that Ozempic slows gastric emptying so much. You see case studies pop up in the news every so often. It does appear rare though.
In the case of Tirzepatide, this is the list of warnings and side effects taken straight from the Eli Lilly website:
Tumors in the thyroid, including thyroid cancer
Inflammation of the pancreas (pancreatitis)
Low blood sugar (hypoglycemia)
Serious allergic reactions
Kidney problems (kidney failure)
Severe stomach problems
Gallbladder problems
Changes in vision
As for the last one on the list, there was recently a report of a patient going blind. As far as I know it was only one case study, but apparently it really did happen and was directly tied to the GLP-1 drug use.
Whether there are serious long term side effects with prolonged use, I’m not sure. I don’t think anyone knows. These drugs haven’t been around long enough to know.
There have been some scare stories about cancer, (thyroid in particular) but from what I’ve seen, most or all were based on rodent studies. In addition, it seems to be associated with the older types of GLP-1 drugs rather than semaglutide.
Also, running counter to this particularly scary side effect are reports that this class of drugs might reduce risk of obesity-related cancers due to the health benefits of the weight loss. But still… it’s on the official side effects list right from the drug companies themselves.
An Alarming Side Effect That’s All Too Common
One side effect of semaglutide that is common, and very concerning to people in the fitness industry is loss of lean body mass.
In one study most of the weight (60%) came from lean body mass and it was commonly over 40%.
Im not sure if there is another mechanism, but a simple explanation is that people on GLP-1 drugs simply may not be eating enough because they’re no longer hungry. That could include not eating enough protein because we know that protein is the most filling / satiating macro.
It’s a real concern, but possibly not as bad as it sounds because the subjects may not have been lifting. I have read countless studies testing a variety of diets (no medications used) where a lot of lean mass was lost simply because people weren’t training.
This would suggest that it’s vital for people on this class of weight loss drugs to lift or do some kind of resistance training.
Unfortunately, a large part of the population of people who are likely to take these drugs are also the ones least likely to lift. This is a demographic of people who just want to lose weight, and they don’t yet understand the importance of resistance training.
And remember, aside from muscle loss causing strength loss and a body that may look “skinny fat” (lacking in athletic muscle), we know from other research that losing lean mass is associated with regaining the weight when the intervention ends.
It’s worth noting that new research has found that tirzepatide produced less muscle loss than semaglutide. In one study, the subjects lost more than 20% of their bodyweight and 75% of it was fat, while only 25% was lean body mass. I’d rather not lose any lean mass, but that’s not terrible.
The reason for this may be that semaglutide primarily acts as a glucagon-like peptide-1 (GLP-1) receptor agonist, while tirzepatide also activates the glucose-dependent insulinotropic polypeptide (GIP) receptor. That could contribute to better muscle preservation.
But What Happens When You Stop Taking These Drugs? CAN YOU Stop Taking It Or Are You On It For Life?
The latter question is one for a doctor. The drug was originally created as a glycemic control treatment for diabetes.
As a medical issue, this has to be a conversation with a medical professional as whether to take it and for how long. Same thing with questions about A1C or other specific health markers, but improving glycemic control is one of the main benefits touted from the drug makers.
Strictly from a weight loss perspective, everyone can probably guess what happens when you stop taking it…
People regain the weight at about the same rate and percentage as most people when going off any diet or weight loss intervention. Almost everyone regains if they haven’t changed their lifestyle.
Only long term lifestyle change – better nutrition, continuation of weight training and high activity etc, with good adherence and consistency, can guarantee weight loss maintenance.
So, despite how attractive it appears to take a drug that’s been proven highly effective, without committing to lifestyle change, it’s not unfair to say that this is just another quick fix or crutch like any other short term intervention.
We saw the same thing with the old generation of prescription appetite suppressants – they only worked as long as you kept taking them. (And they too had side effects, and many were pulled off the market eventually for safety reasons).
Weight loss drugs might make sense for certain individuals just like bariatric surgery might make sense in some cases. Semaglutide has remained somewhat controversial however for more than one reason….
It’s expensive for one. I think it’s around a thousand a month. Which also brings up the controversy of whether it’s being overprescribed because some people may be making a lot of money off it and eager to continue promoting and selling it.
Novo Nordisk is now one of the most valuable companies in the world. So is Eli Lilly, maker of Mounjaro.
Frivolous Drug Use
It also seems a lot of people take it who are not diabetic and obese, are using these drugs purely for weight loss, and might not have that much fat to lose.
This has also created some controversy and debate because when someone has glycemic regulation issues and is so overweight that it’s a health risk, then it seems a sensible prescription if someone chooses to go down that path and their doctor agrees.
But for someone who is reasonably healthy and is looking to drop a small amount of “vanity pounds” it doesn’t seem as appropriate. It’s certainly not a necessity.
Adding to the controversy, it appears that some bodybuilders and physique athletes (who are not diabetic, obese, or unhealthy) are using GLP1 agonists like semaglutide purely for fat loss (to control the hunger of a contest diet). In my view, that’s pathetic. Lazy too. All-natural bodybuilders who know what they’re doing get shredded with zero drugs.
I know at least one famous You Tube “influencer” who has publicly said he uses GLP drugs. And that’s on top of his steroids, hormones, diuretics, peptides, and god knows what else people are taking these days. I don’t even want to know.
Drugs in physique sports is a whole other can of worms, so I won’t open that one further and we’ll just end on that point for now.
The Bottom Line on Ozempic and Weight Loss Drugs
Injections like Ozempic may have their place for certain individuals under proper medical supervision, (especially diabetics who are very overweight or obese who have tried everything and nothing else worked).
I’ve gotten enough email from readers who told me their success stories and said this medication was nothing short of life changing – even life saving – to believe it. And I replied to them with nothing but congratulations.
But remember… the fundamentals of sustainable fat loss have never changed. The most successful approach remains one that you can maintain for life – not just while you’re taking a medication.
For people looking for effective weight management that doesn’t require taking drugs or supplements and doesn’t require cutting out your favorite foods or following restrictive diets, I’ve created a new, science-based resource that might help…
My “Guide to Flexible Meal Planning for Fat Loss” gives you a framework for sustainable and natural fat loss that works with your lifestyle, not against it.
This customized and flexible approach has helped thousands achieve their goals without expensive medications, without supplements, and without extreme food restrictions.
If you want to to see how you can control your weight naturally while enjoying food freedom, click here to check out my new flexible fat loss guide.
-Tom Venuto,
Author of Burn the Fat Guide To Flexible Meal Planning For Fat Loss
About Tom Venuto, The No-BS Fat Loss Coach
Tom Venuto is a natural bodybuilding and fat loss expert. He is also a recipe creator specializing in fat-burning, muscle-building cooking. Tom is a former competitive bodybuilder and today works as a full-time fitness coach, writer, blogger, and author. In his spare time, he is an avid outdoor enthusiast and backpacker. His book, Burn The Fat, Feed The Muscle is an international bestseller, first as an ebook and now as a hardcover and audiobook. The Body Fat Solution, Tom’s book about emotional eating and long-term weight maintenance, was an Oprah Magazine and Men’s Fitness Magazine pick. Tom is also the founder of Burn The Fat Inner Circle – a fitness support community with over 52,000 members worldwide since 2006. Click here for membership details
Scientific references:
Satoshi Ida, Effects of Antidiabetic Drugs on Muscle Mass in Type 2 Diabetes Mellitus, Meta-Analysis Curr Diabetes Rev, 17(3):293-303.
Look M et al, Body composition changes during weight reduction with tirzepatide in the SURMOUNT-1 study of adults with obesity or overweight, Diabetes Obes Metab,1–10, 2025.
Neeland I et al, Changes in lean body mass with glucagon-like peptide-1-based therapies and mitigation strategies, Diabetes Obes Metab, 26 (Suppl. 4):16–27, 2024
Folks taking these drugs are not hungry because these drugs work on appetite by slowing stomach emptying. The slower your stomach empties, the longer you are not hungry. The delayed stomach emptying is why you can see stomach paralysis, nausea, vomiting and abdominal pain. As a pharmacist, I am not a fan of use for weight loss.
Yes I understand it was originally intended for treatment of type2 diabetes… thus the use for weight loss is quite controversial indeed
The risks of thyroid cancer are greatly increased with these drugs. There is also an over 200% increase in deep vein thrombosis with these drugs.
I judge the character of a corporation from how they advertise on television. Do they use classical conditioning of Ivan Pavlov and B. F. Skinner to associate the image of the drug with syrupy sentimental sounding music and images of families on vacation? This demonstrates their disrespect for their target audience. Do they go out of their way to insult the intelligence of their target audience by going out of their way to look and sound stupid, for instance people grunting, “Oh! Oh!, Oh!,” thereupon demonstrating contempt? If they do, there will be something wrong or even unsafe about the drug.
Sounds like a good criteria for judgement of character. Thank you for posting.
I didn’t know about the lean muscle mass stat, but makes sense knowing the mechanism of action and when you consider most folks on it likely aren’t engaged in a consistent resistance training routine. Would be interesting to see what happens if someone rightly on this drug for obesity let’s say, actively lifted 2-3xs/wk while ensuring they get enough protein daily. I would suspect some lean body mass loss due to the overall weight loss, but perportionally I wonder if it would be significantly less? Sounds like getting the nutrients right is even more vital when on this class of drugs for a healthier outcome…and yes, how many after investing so much money in this will actually end up with sustainable results? Thanks for the article!
Yes good questions. The two most important keys to maintaining lean body mass while in a calorie deficit (with or without medication) are: 1. consistent progressive resistance training and 2. Sufficient protein. Regarding #2, if calories are extremely low, it becomes more difficult to eat enough protein. Also if someone’s appetite is dramatically suppressed, when they DO actually feel like eating, are they more likely to go for the tuna fish, chicken breast, egg whites, etc, or the carbs and fat?