Q&A: Why Do I Feel Fatigued on GLP-1s?

GLP-1 medications are powerful. But "powerful" cuts both ways — and for the 17% of patients who drop out of clinical trials due to side effects, the medication never gets a chance to work.

The difference between patients who push through and those who quit isn't willpower. It's protocol. Our founder, obesity medicine physician Dr. Alexandra Sowa, recently joined the Plus SideZ podcast to answer the questions her patients ask most — from why nausea hits so hard to what's actually driving metabolic dysfunction in the first place.

The answers she gives her patients are the same ones that shaped the SoWell GLP-1 Support System. Here's what she said.

Q: What Causes Nausea and Sulfur Burps on GLP-1s?

GI side effects are the biggest complaint across all GLP-1 medications. In some trials, the dropout rate is up to 17%. But we can treat it, and everyone I start on these medications can tolerate it — because we have a protocol that helps relieve and prevent these side effects.

What's happening with sulfur burps is that there's actually too much food sitting in the stomach. It's your body's way of saying "I can't digest this, I can't take any more food right now." It's because these meds do slow down digestion — my anesthesiology colleagues now want patients stopping Mounjaro a full 10 days before any planned surgery, not just fasting from midnight. It's a very powerful medication.

To help, focus on foods that don't take up too much space in the stomach and are easy to digest. A lot of people will be surprised at this, but vegetables can actually take up a lot of room in the stomach and are harder to break down — so I recommend a focus on protein. You can also wait to drink water until after eating to take up less space in the stomach.

For nausea specifically, I recommend keeping electrolytes by your bed to drink first thing in the morning. Nausea can literally be the body asking for salt. And a B-Complex will really help cut down on nausea and can have a nice effect on reducing a lot of these GI side effects generally.

Q: Why Do People Feel Fatigued on GLP-1s?

Since GLP-1s reduce blood sugar, even a few-point reduction is enough for the body to register as a change. Generally speaking, the fatigue goes away by the end of the first month — and then it hits again when you go up on the dose. I remind patients that this is normal. Once we get you to your maintenance dose, it resolves.

Dehydration plays a role too. Electrolytes are very much your friend. Sodium brings the water you drink to the right places in your body — so even if you're chugging water, if you don't have salts alongside it, you won't get it into the right parts of your body and you'll feel the effects.

The third factor is that when the body is in a weight loss state, it's trying to figure out whether it should conserve energy. People can experience some insomnia and a bit of fight-or-flight activation. That's why we taper up on these medications gradually — and why we can't stress the body too much in the process. Over time, the body adapts to its new state.

Q: What's the Science Behind Metabolic Dysfunction?

A lot of people come to me and say, "I am trying so hard, and the weight keeps coming on. And I know you won't believe me." And I say: of course I believe you. This is all I do.

Fat is the most powerful organ in the body. Metabolic dysfunction is what happens to lead to excess fat — it could be decreased leptin (the satiety hormone), insulin resistance, or any number of hormonal imbalances. And when you put on the weight, there are negative feedback signals that further dysregulate everything. As insulin resistance grows, the body becomes increasingly unable to burn what you're bringing in, and goes into fat storage mode.

For someone to meet the criteria for true metabolic syndrome, they'll show elevated blood sugar, low HDL, high triglycerides, and increased abdominal circumference. When we can identify that dysfunction early — in those early stages when weight is coming on and the patient doesn't understand why — we can stop a lot of disease in its tracks.

Q: Why Do Doctors Miss It?

I long recognized that people would come to me saying, "I ran all the labs and everything looks fine." And I'd look at the same labs and see early insulin resistance. That's a runaway train — for most people, insulin resistance will progress to type 2 diabetes, so we want to catch it early.

Testing fasting insulin is a scientifically validated tool that's not routinely used in clinical medicine — but it allows us to predict pre-diabetes or insulin resistance up to 15 years before we see an increase in average blood sugar markers. I developed the Weight Biology Kit to test for fasting insulin alongside the other markers that make up metabolic syndrome — because what you can measure, you can address.

Q: How Is Diet Culture Damaging to the Metabolism?

If you look at the Biggest Loser studies, you see excessive dieting and exercise that initially produces weight loss — but what does extreme calorie restriction ultimately do? It tanks your basal metabolic rate and puts you at a disadvantage unless you maintain that exact level of deprivation forever. Otherwise, the weight comes back in waves.

Some people conclude from this that you shouldn't lose weight at all. But no — it's the extreme yo-yo that's harmful. Losing weight needs to be done appropriately. The way we titrate GLP-1 medications helps patients do exactly that, losing between 0.5% and 1% of total body weight per week. It shouldn't be more than that.

Overall, the focus needs to be on macronutrients — protein especially — and some form of exercise. Strength training is best because it helps preserve basal metabolic rate during weight loss.

The Bottom Line

Your Questions About GLP-1 Side Effects, Answered

What causes sulfur burps on GLP-1 medications like Ozempic or Mounjaro?

Sulfur burps on GLP-1 medications are caused by food sitting too long in the stomach. These medications significantly slow gastric emptying — which is what makes them effective for appetite suppression — but it also means the stomach becomes overwhelmed more easily. The fix is reducing food volume, eating protein first (which is more efficiently processed than high-fiber vegetables), and delaying liquids until after meals so they don't add to stomach load.

How long does fatigue last on GLP-1 medications?

Fatigue typically resolves by the end of the first month on a given dose — and then returns briefly with each dose escalation as the body adjusts. This is normal and expected. Two key contributors: blood sugar reduction (even modest drops can cause tiredness during adaptation) and dehydration, since electrolyte imbalance prevents water from reaching cells even when fluid intake seems adequate. Electrolyte supplementation addresses the dehydration component and is one of the most effective tools for managing GLP-1 fatigue.

What is the SoWell GLP-1 Support System?

The SoWell GLP-1 Support System is a supplement stack formulated specifically for people on GLP-1 medications, built around the protocol Dr. Alexandra Sowa uses with her own patients. It addresses the most common side effects — nausea, fatigue, GI distress, and electrolyte depletion — through targeted ingredients: electrolytes with B6 for nausea and hydration, B-Complex for GI support, and protein with whey isolate and digestive enzymes for muscle preservation and comfortable digestion.

What is the Weight Biology Kit and who should use it?

The Weight Biology Kit tests for fasting insulin alongside the other markers of metabolic syndrome — a combination not typically ordered in standard clinical lab panels. Fasting insulin testing can identify insulin resistance and pre-diabetes up to 15 years before average blood sugar markers rise, making it a powerful early-detection tool. It's particularly useful for anyone who has struggled with unexplained weight gain, been told their labs are "normal" despite metabolic symptoms, or wants to understand the underlying biology driving their weight before or during GLP-1 treatment.