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The 7 supplements you may need if you’re on a GLP-1

These nutritional supplements could help offset some of the side effects.

By Sarah Z. Wexler|Scientifically reviewed by Kelli Richardson, Ph.D., RDN
Last updated December 23, 2025

When people talk about side effects of GLP-1s, it’s usually uncomfortable G.I. symptoms. But these meds may be causing issues in your body that are less obvious — and certain nutrients can help. While it’s always best to get them from food, supplements can help fill in the gaps. “Because your food intake is decreased while taking a GLP-1, there’s a higher potential risk for micronutrient deficiency,” says Michelle Cardel, MS, RD, Ph.D.

Here are common supplements that can help with a healthier weight-loss journey.

Supplements for bone health: calcium and vitamin D


The most significant, scary, and common impact from losing weight is also losing bone mass, which can set you up for fractures or broken bones. And as you eat less while on the medication, you may not be getting enough calcium and vitamin D from your diet to combat that (strength training can also help reduce bone density loss). Try to get them through dairy products, sardines, dark green leafy vegetables, tofu, and fortified cereals and drinks. Most people on a GLP-1 will still need to take a daily 500 mg calcium supplement, says Cardel, which is often paired with vitamin D.
Learn more about the benefits of strength training on a GLP-1

Supplements for muscle and hair loss: multivitamin and protein


Again, eating less means you may not be getting enough nutrients, which can cause your body to lose not just fat, but muscle mass. A multivitamin helps you maintain at least a baseline. For women at any life stage, go with a prenatal vitamin; men can use any daily multivitamin. Look for at least 400 IU of vitamin D and 18 mg of iron.

Protein can also help reduce both muscle loss as well as temporary hair loss. In addition to eating fish, chicken, eggs, tofu, and legumes, you may need to add a protein supplement, like dairy-based whey protein or plant-based pea protein.

Learn more about the importance of protein on a GLP-1

Supplements for constipation: psyllium fiber and magnesium


The most common long-term gastrointestinal side effect of a GLP-1 is constipation. Make sure you’re drinking enough water and eating enough fiber through fruits and veggies, nuts, seeds, beans, legumes, and whole grains. You can try adding one teaspoon a day of a psyllium husk fiber supplement (like Metamucil), potentially increasing to 2-3 teaspoons per day; if necessary you can also add a magnesium citrate (350 milligrams) powder dissolved in water before bedtime.

Learn more about alleviating constipation on a GLP-1

A thiamine (vitamin B1) supplement for people with a deficiency


While this deficiency isn’t common, if it goes undetected for a long time, it could cause very serious problems — yet if it’s caught early, it's easily treated with a B1 supplement. People who are more likely to be at risk for a B1 deficiency include African Americans, people who already have certain conditions (including hyperthyroidism or liver disease), take certain medications (some diuretics, cardiovascular drugs, and antiseizure medications), or use alcohol heavily. Especially if you’re at higher risk, make sure your doctor does a blood test to check your B1 levels.

This content is for general educational and informational purposes. The content is not medical advice, does not diagnose any medical condition and is not a substitute for professional medical advice, diagnosis or treatment from a healthcare provider. Talk to your healthcare provider about any medical concerns.

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