Most people experience some nausea early on because GLP-1 slows how quickly your stomach empties. The good news is that it almost always improves as your body adjusts to the dose. Eating smaller meals, staying hydrated, avoiding heavy foods during dose increases, and not lying down right after eating is usually all it takes. 

GLP-1 slows the entire digestive process, which can cause constipation, especially at higher doses. Drinking at least 2 to 2.5 liters of water daily, getting fiber from vegetables rather than just supplements, and staying physically active is usually enough to keep this from becoming an issue.

Because GLP-1 slows how quickly the stomach empties, some people experience increased reflux, especially those who already had mild heartburn before starting. Avoiding food 2 to 3 hours before lying down, reducing heavy or spicy meals, and eating smaller portions is usually all it takes. Most people on GLP-1 never experience this at all.

Feeling a little tired in the first few weeks is completely normal — your body is adjusting to eating less, and your energy systems are recalibrating. For most people, it passes quickly on its own. Making sure you are eating enough, even with a reduced appetite, keeping protein high, and doing some light resistance training makes a noticeable difference.

Dizziness most often shows up when someone is not eating enough or not drinking enough water, both of which can happen when appetite drops significantly on GLP-1. It is your body's way of telling you to fuel up. Hitting your calorie and fluid targets consistently through the day typically resolves this within days.

Some people find that foods they used to enjoy no longer appeal to them — this is actually the medication doing its job, reducing the reward response to food. It tends to settle over time. Focusing on foods that are nutrient-dense rather than trying to force meals you are not interested in helps most people move through this phase comfortably.

Headaches in the first few weeks are almost always a hydration or nutrition issue rather than a direct medication effect. When appetite drops, people often drink and eat less without realizing it. Increasing water intake, making sure meals are not being skipped, and adding a small electrolyte supplement if needed usually clears this up within days.

If you notice some hair thinning, it is almost always because of how fast the weight is coming off — not because of the medication directly. Rapid weight loss puts physiological stress on the body and protein intake often drops when appetite does. Keeping protein at or above 1.2 grams per kilogram of bodyweight and not skipping meals even when you are not hungry is the most effective protection.

When you are eating less, you are also taking in less water from food than you normally would, and that adds up. Combined with any nausea in the early weeks, dehydration can sneak up on you faster than expected. Keeping a water bottle with you and aiming for at least 2.5 liters daily, more if you are active, is usually all it takes.

When weight comes off quickly without enough protein to support it, some of what you lose can be muscle rather than fat. This is the most underestimated risk of GLP-1 use — and also the most preventable. With a structured food plan built around your protein targets from the start, you protect your muscle and make sure what you are losing is actually fat. This is exactly what Yossi builds with every client before the first dose.

Weight coming back after stopping GLP-1 is real, but it is not inevitable. It happens when the medication stops and nothing has changed about how a person eats. The clients who keep the weight off are the ones who used the time on the medication to build lasting habits. That is the whole point of working with a dietitian alongside it, not just taking it and hoping for the best.

Some people choose to stay on GLP-1 medications long term, and that is a completely valid decision. Others use it as a starting point to build habits they can sustain without it. Either path works. What matters is going in with a plan so you are in control of that decision, rather than just defaulting to staying on it indefinitely because nothing else has changed.

Rapid weight loss of any kind, not just from GLP-1, slightly increases the risk of gallstones, and GLP-1 is no exception. This is rare, and most people never experience it. If you have a history of gallstones, it is worth discussing with your doctor before starting. Sharp pain in the upper right abdomen, nausea, or fever are signs to contact your doctor right away. Do not try to manage this at home.

Pancreatitis is rare, but it is a serious condition and worth knowing about before you start. People with a personal or family history of pancreatitis should discuss this risk with their provider before beginning GLP-1. If you experience persistent severe pain in your upper abdomen that radiates to your back, stop the medication and contact your doctor immediately.