GLP-1 medications, including semaglutide (brand names Ozempic, Wegovy) and tirzepatide (brand names Mounjaro, Zepbound), have exploded in popularity due to their ability to promote rapid weight loss and improve blood sugar regulation. These drugs were originally developed to treat type 2 diabetes but are now commonly used as an obesity treatment, as they mimic the hormone GLP-1 (glucagon-like peptide-1), which helps control appetite, insulin secretion, and gastric emptying.
While these medications can be life-changing, especially for folks struggling with obesity and diabetes, it’s important to consider how GLP-1 drugs may impact other aspects of your health. Here’s what to know.
- ABOUT OUR EXPERTS: Dr. Josh Axe, D.C., D.N.M., C.N.S., is a doctor of natural medicine, doctor of chiropractic, and clinical nutritionist. Dr. Jolene Brighten is a board-certified naturopathic endocrinologist. Dr. Ben Winters, D.D.S., is an orthodontist and founder of Something Nice.
How GLP-1 Drugs Work—And Why They’re Effective
GLP-1 is a naturally occurring hormone secreted by the gut in response to food. It regulates insulin secretion and helps to balance blood sugar, acts on hunger centers in the brain to modulate appetite, and slows the rate at which food leaves the stomach (called gastric emptying).
Drugs like Ozempic and Wegovy are synthetic GLP-1 receptor agonists, meaning they amplify these effects. These drugs make people feel fuller faster, reduce cravings, and help stabilize blood sugar, all of which can lead to dramatic weight loss, including in people who haven’t successfully lost weight from other strategies like diet changes and exercise, shares Dr. Josh Axe, D.C., D.N.M., C.N.S., a doctor of natural medicine, doctor of chiropractic, and clinical nutritionist.
The Potential Health Trade-Offs Of Taking GLP-1s
While the weight loss associated with GLP-1 drugs is often seen as a major win, some side effects and risks associated with their long-term use are now coming into focus. Below are seven potential concerns regarding GLP-1s, plus what you can do to mitigate them.
1. Muscle Mass Loss
Studies have shown that up to 40 percent (or possibly even more) of weight lost while on GLP-1s can come from lean body mass. According to Axe, this matters because:
- Muscle is crucial for metabolic health and insulin sensitivity, especially in older age, when it tends to decline.
- Muscle loss can slow your metabolism and increase the risk of rebound weight gain.
- Muscle loss can also impair strength, mobility, quality of life, and longevity.
What you can do about it: Resistance training, such as lifting weights, and adequate protein intake are critical for preserving muscle when using GLP-1 drugs, according to Axe. Aim for about 20 to 30 minutes of strength training two to three times per week to start.
2. Bone Health Concerns
There’s growing concern that rapid weight loss and reduced nutrient intake on GLP-1s could negatively affect bone density, particularly in older adults and postmenopausal women who don’t do resistance training, says board-certified naturopathic endocrinologist Dr. Jolene Brighten.
Research suggests that GLP-1s can reduce appetite and lead to inadequate intake of calcium, vitamin D, and protein, all of which are vital for strong, healthy bones. Meanwhile, falls and fractures may be more likely if bone loss is combined with reduced muscle strength, according to Axe.
What you can do about it: In addition to stimulating muscle growth, resistance training and weight-bearing exercises also support bone formation, Brighten says. You’ll also want to ensure adequate intake of bone-supportive nutrients, such as calcium, vitamin D, vitamin K2, magnesium, and protein, she adds. Bone density monitoring may be a good idea for long-term users if they’re at risk for osteoporosis or fractures.
3. Slowed Thyroid Function
Some studies have linked GLP-1 agonists to thyroid complications, including potential suppression of thyroid hormone conversion, resulting in lower active thyroid hormone levels in some users. Impaired thyroid function can lead to fatigue, hair thinning, constipation, and cold intolerance. People with preexisting hypothyroidism or Hashimoto’s may be more sensitive to thyroid impacts when taking GLP-1s.
What you can do about it: Because thyroid issues while on GLP-1 drugs are relatively common, regular thyroid panel testing (TSH, Free T3, Free T4, and antibodies) may be wise, suggests Brighten. It’s even more important if you have known thyroid issues or are experiencing any symptoms of thyroid dysfunction
Read More: The 5 Worst Foods For Your Thyroid
You can also support your thyroid by eating enough iodine, selenium, and tyrosine—found in seafood (like tuna and shrimp), eggs, dairy products (such as milk and cheese), beef, chicken, beans, and Brazil nuts. Axe recommends avoiding a very low-calorie or low-fat diet, which may further suppress thyroid hormone production.
4. Nutrient Deficiencies
Because these drugs suppress appetite, many users eat less—and sometimes skip meals altogether—meaning they risk running low on certain essential nutrients.
Specifically, some research suggests GLP-1 use can result in lower intake of iron, vitamin B12, magnesium, and protein. Vegans or vegetarians, who may already lack some nutrients, and those with absorption issues like IBS or low stomach acid, may face even greater risk. One recent study found that over 20 percent of GLP-1 drug users had diagnosed nutritional deficiencies within one year of starting treatment.
Interestingly, some of the most common symptoms experienced by GLP-1 drug users—including nausea, fatigue, mood changes, hair loss, and brain fog—could be attributed to the nutrient deficiencies associated with these medications, Axe says.
What you can do about it: “Prioritize nutrient-dense meals and supplements, including a high-quality multivitamin,” says Axe. “In particular, focus on eating plenty of protein, fiber, and healthy fats.” If your appetite is very low, smoothies or nutrient-rich soups may be easier to tolerate.
5. Mental Health Changes
Although weight loss and improved blood sugar may initially benefit mood, some people on GLP-1 medications report mental health issues, such as brain fog or fatigue (possibly from very low caloric intake or nutrient deficiencies) or anxiety or mood shifts (likely related to blood sugar changes, hormonal shifts, or low serotonin).
Read More: Ways To Boost And Balance The “Feel-Good” Hormone Serotonin
That said, there’s some evidence that GLP-1s can promote cognitive health and even protect the brain from issues like cognitive decline by lowering oxidative stress and inflammation.
What you can do about it: Support brain health with nutrients such as omega-3s, B vitamins, and magnesium, suggests Brighten. Eating consistent meals, minimizing added sugar and refined carbs, and emphasizing protein and healthy fats can also support stable blood sugar and more balanced moods, Axe and Brighten agree.
6. Digestive Upset
GLP-1 drugs are known to slow gastric emptying, which means they delay how quickly food leaves your stomach. While this contributes to feeling fuller longer (a key reason they help with weight loss), it can also lead to uncomfortable gastrointestinal side effects for some users.
Common digestive issues include:
- Nausea and bloating after meals
- Early satiety (feeling full after just a few bites)
- Constipation or slowed bowel movements
- Acid reflux or GERD, due to slow gastric emptying
- Gastroparesis (extreme gastric slowing), which can cause vomiting or abdominal discomfort
What you can do about it: To ease symptoms, eat smaller, more frequent meals, stay hydrated, and avoid eating large amounts of fat or fiber in one sitting, which may further slow digestion, recommends Axe. Taking digestive bitters or drinking ginger tea before meals can also help by stimulating digestive enzyme production. If symptoms persist, speak with your doctor about dosage adjustments or alternative therapies.
7. Dental and Oral Health Issues
While dental problems aren’t listed as official side effects on GLP-1 drug labels, many dentists and patients are noticing a concerning trend among users.
A growing number of people taking GLP-1s are experiencing dry mouth (reduced saliva production) and enamel changes. “There isn’t anything officially on the labels, but these drugs are new, and dentists are hearing from patients—and seeing firsthand—symptoms like decreased saliva and more enamel erosion,” says Dr. Ben Winters, D.D.S., an orthodontist and founder of Something Nice.
So what’s going on? Winters believes that dry mouth happens because GLP-1 users eat and drink less overall, and less fluid intake means less saliva. This matters because saliva protects your teeth, acting like a natural mouthwash that rinses away bacteria, food particles, and debris throughout the day.
Additionally, the vomiting that many folks experience while taking GLP-1s exposes the teeth to stomach acid, which can weaken and erode enamel, Winters notes. (Brushing right after instances of vomiting can actually make things worse, as the acid exposure temporarily softens enamel, meaning brushing immediately can cause more wear and tear.)
Similarly, some GLP-1 users experience GERD (gastroesophageal reflux disease) or acid reflux due to delayed gastric emptying, says Winters. In this case, acid can creep up overnight and slowly damage the enamel while you sleep.
When combined, these effects can lead to increased tooth sensitivity, bad breath, cavities, gum disease, and accelerated enamel erosion, he suggests.
What you can do about it: For people taking GLP-1s, staying hydrated is vital for maintaining natural saliva production, Winters says. (Folks can also chew sugar-free gum to stimulate saliva.) He also suggests using a remineralizing toothpaste to protect enamel. If you experience bouts of vomiting or reflux, rinse your mouth with water and wait at least 30 minutes to brush your teeth.
The Bottom Line
Choosing to take a GLP-1 medication is a major decision that should be made with the utmost care. There’s no doubt these medications are useful for those with obesity-related conditions, insulin resistance, or type 2 diabetes who have not responded to other interventions, Axe says.
GLP-1 drugs can be powerful tools for weight loss and blood sugar control, but they’re not without drawbacks. If you’re considering one, make sure to talk to a knowledgeable provider about your risks and goals. Should you decide to go for it, support your muscle, bone, and hormone health with intentional lifestyle habits like strength training and supplementation. It’s essential to understand that these medications work best when paired with movement, nutrition, and stress support. (The WHO’s recent recommendations around these drugs emphasize that medication alone won’t resolve the obesity epidemic.)
If you’re not ready to take the drug route, you can still make significant improvements in metabolic health naturally with the right tools, consistency, and support.