On a GLP-1? Use caution with supplements, especially those that can trigger low blood sugar or nausea.Fiber supplements, appetite suppressants and others may worsen side effects of your GLP-1.Check with your health care provider before using supplements with your prescribed GLP-1.
More and more people are taking GLP-1 medications for weight loss and blood sugar control. These medications work by mimicking a hormone in the body called glucagon-like peptide-1 (GLP-1), which slows digestion, increases feelings of fullness and lowers blood sugar by stimulating the release of insulin.
On their own, GLP-1s often cause side effects like nausea and diarrhea. But what many people don’t realize is that combining a GLP-1 with some common supplements could cause additional side effects and may even interfere with how the medication works. If you’re taking a GLP-1 and considering adding a new supplement into the mix, it’s crucial to work with a health care provider or registered dietitian to better understand which ones could potentially be problematic.
Here, registered dietitians tell us which supplements you may want to avoid, or at least be mindful of, when taking a GLP-1, and why they can be an issue.
High-Dose Fiber Supplements
Large amounts of psyllium, inulin and other fiber supplements may not be the best idea when you’re taking a GLP-1. Fiber is definitely a nutritional win given that it plays a powerful role in supporting digestion, helping you feel full, regulating blood sugar levels and a whole lot more. But in large amounts, it can sometimes lead to uncomfortable symptoms like bloating, gas and nausea. While on a GLP-1, the side effects may be worse—especially because GLP-1s are also known to cause gastrointestinal symptoms like nausea even when taken on their own.
“GLP-1 medications also slow stomach emptying and digestion,” says Kayley George, RDN. “Adding a fiber supplement on top of this can significantly worsen gastrointestinal side effects, including bloating, nausea, abdominal discomfort and constipation.”
Meridan Zerner, M.S., RDN suggests trying to get enough fiber through food sources first and then slowly add in fiber supplements as needed to address constipation or other health challenges.
Appetite Suppressants
Appetite suppressants often contain natural stimulants like caffeine, green tea extract and bitter orange extract. Stacking appetite suppressants with a GLP-1 can increase the risk of side effects like nausea, shakiness and undereating, Zerner says.
“Since GLP-1 users are already likely to experience appetite suppression from the medication, the addition of these supplements could lead to further restricted caloric intake,” says Maria Sylvester Terry, M.S., RDN.
Additionally, GLP-1 medications increase the risk of dehydration, and many stimulant supplements further increase this risk., This could lead to electrolyte imbalances, fatigue, cramping and headaches, Terry says.
Berberine and Chromium
Commonly referred to as “nature’s Ozempic” or “nature’s GLP-1,” berberine is a supplement commonly taken for weight loss, blood sugar control and heart health. Chromium is similarly used for blood sugar control and metabolic health.
Since one of the primary goals of taking a GLP-1 is to improve blood sugar regulation and lower high blood sugar, taking another supplement that affects blood sugar—such as berberine or chromium—could cause blood sugar to drop too low, George says, adding, “This can lead to symptoms such as dizziness, shakiness, fatigue or lightheadedness.”
Magnesium
Diarrhea and cramping are common side effects when taking a GLP-1, especially when the medication is new to you or when you’re increasing the dose.
“If that is the case, then I recommend decreasing any magnesium supplements they might be taking or have them consider switching the form of magnesium from a magnesium citrate or oxide to a glycinate or threonate,” Zerner says.
But there’s a caveat: Since magnesium is key in supporting bone health and other areas of health, these factors should also be considered when deciding if a magnesium supplement is needed.
Other Considerations When Taking a GLP-1
Make sure you’re eating enough protein: “Weight loss can cause muscle loss if you are not eating enough protein, so I recommend starting each meal with protein,” says Ana Reisdorf, M.S., RD.
Do regular resistance training: Strength training is important for building and preserving muscle.
Eat small, frequent meals: “Eating smaller, intentional meals more often can help with the reduced appetite,” Zerner says.
Hydrate consistently: GLP-1 medications can cause you to become dehydrated, so pay attention to hydration and make sure you’re drinking 2 to 3 liters of water each day.
Make sure you’re eating enough: GLP-1 users need nutrient-dense meals to support their nutritional needs and long term-health, Reisdorf says. “Consistently consuming too few calories can increase the risk of fatigue, muscle loss and nutrient deficiencies,” adds George.
Simple 7-Day GLP-1-Friendly Meal Plan for Beginners, Created by a Dietitian
Our Expert Take
GLP-1s are increasingly prescribed to help people with weight loss and blood sugar control. If you’re taking a GLP-1, it’s important to be careful with supplements, especially those that can cause uncomfortable side effects like low blood sugar or nausea. Before taking a supplement, talk with your health care provider to learn more about whether it’s a good fit alongside your prescribed GLP-1. And if you’re feeling worried about leaving your supplements behind, remember that a diverse, nutrient-rich diet can be highly effective in supporting your long-term health.
