6 Supplements to Consider While on a GLP-1

When people talk about side effects of GLP-1s, the ones that get the most air time are uncomfortable G.I. symptoms. But these meds may be causing side effects in your body that are less obvious — namely, losing important muscle mass and bone density that could raise your risk of breaking a bone from a simple fall.

Losing a considerable amount of weight, whether on a GLP-1 or not, means in addition to dropping fat, our bodies naturally shed muscle as well. “The more overall weight loss, the more muscle mass loss,” says Eduardo Grunvald, MD, FACP, Medical Director of the University of California San Diego Center for Advanced Weight Management, though he points out that the benefits of treating obesity outweigh that risk.

So, how are you supposed to mitigate those risks? Lifestyle changes. Adding weight-bearing exercise to your routine and fine-tuning your diet to get the protein, vitamins, and minerals you need can help. And while it’s always best to get these nutrients from food, supplements can help fill in the gaps, especially when your appetite is tamped down.

“It is possible that someone using GLP-1 medications could be meeting the recommended intake for these nutrients. But because your food intake is decreased while taking a GLP-1 medication, there’s a higher potential risk for micronutrient deficiency,” says Michelle Cardel, MS, RD, Ph.D.

Here are common impacts GLP-1 users face and the supplements that can help make for a healthier weight-loss journey.

Calcium
Vitamin D

A significant and scary (and common) impact from losing weight is the impact it can have on your bones. “Loss of bone mass is a concern, especially with getting fractures from falls,” says Grunvald. One reason bone loss can happen is as you eat less on the medication, you may not be getting enough calcium and vitamin D from your diet.

Calcium is the building block of strong bones and teeth, but it’s also necessary for the cellular functions of your muscles and nerves. Your body is crafty — if there’s not enough calcium coming in from your diet, your body will find a source to get it…even if that source is pulling it from your own bones. This calcium cannibalism depletes bone mass and raises your risk of developing osteoporosis. That’s why everyone on a GLP-1 should be cognizant of getting calcium through foods like dairy products, sardines, dark green leafy vegetables, tofu, and fortified cereals and drinks.

Most people on a GLP-1 will need to take a daily 500 mg calcium supplement, says Cardel. It is especially recommended for:

• People with pre-existing low bone mass

• People with pre-existing low vitamin D levels (this is common — due to several complex factors, being overweight is actually a risk factor for vitamin D deficiency)

• People who have had bariatric surgery

• Women in perimenopause/menopause

• Men with low testosterone

• Anyone over 50

Many calcium supplements helpfully come paired with vitamin D, which helps your body absorb the calcium and help maintain your bone density. (Check how much vitamin D you’re getting in your multivitamin as well if you take one — we recommend choosing a multivitamin with at least 400 IU of vitamin D). Testing for vitamin D is straightforward, but checking your calcium levels, not so much. That’s because our bodies are so good at getting enough (even from our bones) that calcium levels tend to show up as normal even when there’s an issue. That’s why it’s important to make sure you’re getting enough through your diet and/or a supplement.

Whey or pea protein
Multivitamin or comprehensive Vitamin B complex vitamin

Strength/resistance training is a key way to hold onto as much muscle as possible, and so is making sure you’re getting enough protein, through sources such as fish, chicken, eggs, tofu, and legumes in your diet. The traditional way to figure out how much protein you need is to take your weight in kilograms (you can always put “X pounds in kilograms” into Google) and multiply it by 1 gram of protein. So for example, someone who weighs 200 lbs (so, 90kg) would need 90g of protein per day. But for people on weight loss medications, you should be more in the range of 1.0-1.6 grams of protein per kilo, so that same 90kg person would need up to 90-144 grams of protein. With reduced intake while on a GLP-1, reaching your protein goals can be harder. To help with this, smaller, more frequently meals that incorporate protein may be recommended to consume throughout the day. If you’re still falling short of your protein target, talk to your Weight Watchers Clinician or Registered Dietitian about adding a protein supplement.

The protein boost will also help you manage another potential side effect — hair loss.  

Like muscle loss, hair loss isn’t a side effect of the medication per se, but more from any kind of significant weight loss, including GLP-1s and bariatric surgery. “Hair loss usually lasts for six to 12 months and then tends to stop,” says Grunvald. “It’s not going to keep progressing until you’re bald.” 

When you’re losing weight, your body tries to slow down a lot of the processes in your body that require energy, including energy for your hair follicles. “The number one thing to reduce hair loss is to make sure that you're getting enough high-quality protein,” he says.

Along with a high protein diet with a big variety of fruits and vegetables, you also want to make sure you’re consuming an adequate number of calories to prevent rapid hair loss. It may also help to take a good-quality multivitamin or a comprehensive Vitamin B complex vitamin.

If adding in a protein supplement, whey protein, made from dairy, has the best bioavailability, which just means your body is better able to break it down and use it. If dairy doesn’t work for your system or you don’t eat animal products, the next best thing is pea protein. WeightWatchers makes keeping track of macronutrients like protein simple. On the GLP-1 Success Program — a nutrition plan that complements your GLP-1 medication — when you track your meals in the app, it automatically tracks your protein, along with other macros like carbs, fats, fiber, and sodium.

Psyllium fiber
Magnesium

While nausea may be the top G.I. side effect of using a GLP-1 as your body adjusts, the most common long-term gastrointestinal side effect is constipation, says Grunvald. If that’s happening for you, the first step is to make sure you’re drinking enough water. The GLP-1 Success Program guides members in drinking 64 fluid ounces (or 8 cups) of water per day. If you’re feeling constipated, try increasing this to 72 ounces per day (or adding an additional cup of water) to help soften the stool.

You also want to make sure you’re eating enough fiber; guidelines recommend that women consume at least 25 grams of fiber per day, while men should consume at least 38 grams per day. Generally, you want to get 14 grams of fiber for every 1,000 calories you eat. Yet more than 90 percent of women and 97 percent of men in the U.S. aren’t hitting those numbers. If you’re falling short of the recommendations, increase fiber gradually, one meal or snack at a time (or by ~5 grams over the course of a few days). The best way to add fiber is by making sure there are plenty of fruits and veggies, nuts, seeds, beans, legumes, and whole grains in those mini-meals you’re consuming.

If you’re unable to meet your fiber goals through food alone, consider psyllium husk. This natural fiber supplement that comes in powder form you can dissolve in water (bonus: you also get those ounces in!) or take as a tablet. You can also add magnesium citrate (350 milligrams) powder dissolved in water before bedtime. It helps soften stool by drawing water into the small intestine, making it easier to go when you get up in the morning. 

In addition to fiber, gentle movement, such as walking, can also encourage natural bowel movements.

If you’re taking a GLP-1, the above intel gives you a good idea of the supplements you may want to take. But both Grunvald and Cardel agree that your specific supplement routine should be personalized and guided by a doctor or dietitian. Sadly, most people aren’t getting that guidance from an MD or RD, says Grunvald.

“Sitting down with a healthcare provider to go over your labs is ideal. Then you can see if there are deficiencies and discuss areas of concern in your life, such as being vegetarian or being in menopause; existing medical conditions; or family history that is concerning. Then together, you can make a plan of what to monitor and what foods or supplementation to prioritize,” says Cardel.

Cardel recommends meeting with WeightWatchers dietitians to be “your support partner through this journey and really help personalize your nutrition and supplements to ensure that you're not just getting that nutritional adequacy, but nutritional optimization.” In many cases, you’re going to need to be your own advocate to ask your prescriber about what testing and supplements make sense for you.

There are lots of positive health benefits from using a GLP-1 to eat less and lose weight, but there are also a few challenges, especially losing bone density and muscle mass. Food is the first line of defense for your body to ensure you’re getting enough fiber, protein, calcium, magnesium, and vitamin D — but thankfully daily supplements are an easy way to fill in nutritional gaps if needed. Talk to your doctor or Registered Dietitian about your risk factors, blood test results, and diet to see if these supplements are right for you.