Weight loss medications affect everyone differently. Some side effects are mild and temporary, while others are your body’s way of telling you that something about your treatment may need to change.

Some nausea, fatigue, or GI symptoms can happen when you first start a medication or increase your dose. But you don’t need to tolerate severe symptoms in the name of progress.

Your provider should be looking at how you feel alongside how the medication is working — not weight loss alone. That's why actively working with a provider when on a weight loss medication is so critical.

Let your provider know about:

• Persistent or worsening nausea, vomiting, diarrhea, or constipation
• Difficulty eating or drinking enough
• Significant fatigue
• Abdominal pain
• Rapid weight loss
• Symptoms that appear or worsen after a dose change

Weight loss medication side effects: what to expect from each type

Side effects are a normal part of starting many medications, and weight loss medications are no exception. Knowing what to expect can make the first few weeks feel more manageable and help you recognize when something is worth bringing up with your provider. GI side effects are common across many weight loss medications. But these aren’t one-size-fits-all treatments. Your diagnoses, other medications, health history, and even prior surgeries can affect which medication, and which dose, is right for you.

Here's a look at the most common side effects of the medications Visana prescribes, along with tips for easing them.

Side effects of Metformin

Common metformin side effects include diarrhea, nausea, vomiting, gas, bloating, and a metallic taste. Stomach issues often improve with time. Taking metformin with food can help, and extended-release metformin (the type Visana prescribes) may be easier to tolerate. Long-term use can also lower vitamin B12 levels in some people.

Side effects of Naltrexone-bupropion

Common side effects of naltrexone-bupropion include nausea, constipation, headache, trouble sleeping, dizziness, and dry mouth. Nausea and constipation may be most noticeable during the first few weeks while your dose is gradually increased.

Side effects of GLP-1 medications

Common side effects of GLP-1 medications include nausea, vomiting, diarrhea, constipation, stomach pain, bloating, headache, fatigue, and injection-site reactions. Digestive symptoms are often most noticeable when you start treatment or increase your dose.

Why your weight loss medication dose may stay the same

A higher dose isn’t automatically a better dose.

Your provider is looking at the whole picture: how well you’re tolerating your medication, how quickly you’re losing weight, your nutrition, other health conditions, and your long-term goals.

That means you may stay at the same dose longer than expected — or decide together that increasing it doesn’t make sense at all.

Visana isn’t a prescription-first weight loss service. Your care may include labs, nutrition and lifestyle changes, health coaching, treatment for hormonal or metabolic conditions, and medication when it makes sense.

The goal isn’t simply to get you to the next dose. It’s to find an approach you can tolerate, sustain, and build on for the long term.

How to alleviate mild side effects

For nausea or other GI symptoms, try smaller meals, avoid greasy or very heavy foods, stay hydrated, and stop eating when you feel full.

For constipation, fluids, fiber, movement, and over-the-counter options like a stool softener may help.

For fatigue, look at how much you’re actually eating — especially protein. When your appetite drops, it's easy to unintentionally under-fuel and then try to make up the difference with caffeine or quick carbohydrates.

For headaches, start with adequate food and fluids. Over-the-counter medications such as acetaminophen or ibuprofen may be appropriate depending on your health history.

Prescription anti-nausea medication can help when needed, but if you need it frequently just to tolerate your weight loss medication, tell your provider. That can signal that your dose or treatment needs another look.

Nutrition and hydration while on medication 

The goal of weight loss medication isn’t to make eating impossible. It’s to help you eat less while still giving your body what it needs.

Prioritize protein, fiber, healthy fats, adequate fluids, and smaller, more frequent meals if larger meals are difficult. Eating enough protein and getting adequate nutrition can help protect muscle and support your long-term health while you lose weight.

If you’ve had gastric surgery or have a condition such as diabetes or congestive heart failure, generic nutrition or hydration advice may not be right for you. Your provider and health coach can help you figure out what is.

What to tell your provider about weight loss medication side effects

You don’t need to diagnose the problem yourself, but specifics can help your provider figure out what’s going on faster:

• Your medication name and exact dose
• When your symptoms started
• Whether you recently changed doses
• Whether symptoms are improving, staying the same, or getting worse
• What you’ve been able to eat and drink
• Any vomiting, diarrhea, constipation, fever, or abdominal pain
• Your last bowel movement
• Any missed or changed doses
• Other medications or supplements, including anything new or over the counter
• How symptoms are affecting your sleep, work, movement, or daily activities

If you have them, measurements like your blood pressure, pulse, blood sugar, or approximate fluid intake can also be useful.

When to contact your provider about weight loss medication side effects

Mild nausea, fatigue, headache, or a change in bowel habits may improve as your body adjusts.

Check in with your provider if symptoms:

• Persist for about 3 days
• Are getting worse instead of better
• Make it difficult to eat or drink enough
• Aren’t improving with basic at-home strategies
• Feel outside of what you and your provider discussed

You don’t have to wait until a side effect becomes severe to bring it up.

For non-urgent portal messages, expect a response within 48 business hours. If you need help the same day, call Visana at (612) 217-4967 instead.

When to seek urgent or emergency care

Telehealth has limits: we can’t physically examine you, take your vital signs ourselves, or run immediate testing. Seek immediate in-person care for:

• Severe or persistent vomiting
• Inability to keep down food or fluids
• Moderate to severe abdominal pain
• Constipation lasting several days with abdominal pain
• A rapid heart rate or significant drop in blood pressure
• A significant drop in blood sugar
• Severe weakness or fatigue that keeps you from normal daily activities

You don't have to navigate side effects on your own

Some side effects are a normal part of starting or adjusting a weight loss medication, and many ease as your body adapts, but feeling unwell isn't the price of progress. The right treatment is one you can tolerate, sustain, and build on, and finding it is a team effort. 

At Visana, your provider looks at how you feel, not just how much weight you're losing, and adjusts your plan as your needs change. With health coaching, nutrition guidance, and care for related hormonal and metabolic conditions, you'll have support at every step.

If you're ready to explore a weight loss plan built around you, book your Visana appointment today.