Taking a GLP-1? Here Are 5 Side Effects Nobody Warned You About

GLP-1 receptor agonists like semaglutide (Ozempic®, Wegovy®) and tirzepatide (Mounjaro®, Zepbound®) have transformed the way type 2 diabetes and obesity are managed. While most patients are informed about common side effects like nausea and appetite suppression, there are several lesser-known effects that often catch people off guard. As a pharmacist, I regularly field questions about these unexpected reactions.

Let’s take a look at five surprising effects of GLP-1 medications, and what you can do if they happen to you:

1. Food Aversions and Taste Changes

Many people expect to feel less hungry on GLP-1s, but what surprises them is the sudden aversion to specific foods. It's not uncommon for formerly beloved items like coffee, chicken, or eggs to suddenly seem unappetizing. Greasy or sugary foods are frequent culprits too.

This goes beyond appetite suppression; GLP-1s influence the gut-brain axis and may alter dopamine signaling, the pathway associated with reward and pleasure. When dopamine is disrupted, the brain stops associating food with satisfaction, which can explain those abrupt taste changes.

An example not related to GLP-1s would be, disulfiram – a drug that is given to alcoholics which makes them feel sick if they drink alcohol. It’s difficult to derive pleasure from a beer if halfway through you start to vomit, turn red, and your heart is beating a mile a minute.  The bottom line is that when something takes the fun out of a particular activity, such as eating or drinking, it’s generally altering the release of dopamine which would usually accompany that activity.

If you notice your preferences shifting, it’s not all bad news. Use it as a chance to explore lighter, more nutrient-dense foods. Just ensure you're still hitting your protein goals and covering your nutritional bases with the right supplements.

2. Hair Shedding (Telogen Effluvium)

Although not a listed side-effect, I frequently see people dealing with increased hair shedding after significant weight loss. This is likely related to telogen effluvium, a temporary shift in the hair growth cycle caused by stress, nutritional changes, or rapid body transformation.

Maintaining adequate protein intake (about 0.8–1g per pound of ideal body weight) is essential. Nutrients like iron, B12, biotin, and zinc are also key to hair health. Lab work can help identify and address any deficiencies. A well-rounded supplement like GILA Renew can help fill in nutritional gaps, especially for those focusing on hair, skin and nail health during weight loss. I recommend getting your labs checked if shedding is significant or prolonged.

On a personal note, my wife and I struggled to meet our protein targets until we began meal prepping and using protein shakes. We prep a shake mix in the morning with protein powder, collagen, peanut butter, and almond milk - ready to go all day. It’s made a huge difference, and we’re always open to hearing your tips too.

3. Gallbladder Issues

One of the more serious but still under-discussed risks of GLP-1 use is the increased chance of developing gallstones or gallbladder inflammation. Rapid weight loss can cause cholesterol to collect in the bile and form stones, which may result in sharp abdominal pain or nausea.

To reduce your risk, aim for gradual weight loss (1–2 lbs. per week), stay well-hydrated, and don’t skip meals. If you experience upper right abdominal pain or nausea after eating, especially fatty meals, let your healthcare provider know right away.

4. Mood Changes and Brain Fog

Some patients report feeling emotionally flat, anxious, or mentally foggy on GLP-1 medications. Others say they feel more focused and calmer. The difference lies in how these medications affect serotonin and dopamine levels - the same neurotransmitters that regulate mood and cognition.

When starting on any new drug (including the GLP-1 class) pay attention to how you’re feeling mentally, not just physically. If you notice a shift in mood or mental clarity, don’t ignore it.  Reach out to your provider. Sometimes a dosage adjustment or different medication can make all the difference.

 5. Low Resting Heart Rate (Bradycardia)

Here’s one most people haven’t heard of: some patients on GLP-1s develop a lower-than-normal resting heart rate, especially noticeable during sleep. This might show up as fatigue, dizziness upon standing, or unusually low readings on a smartwatch.

While typically not dangerous in healthy individuals, it can be concerning for those on heart medications or with cardiac conditions. A smartwatch can be a useful tool to track your heart rate trends over time. If your resting rate dips below 50 bpm or you're feeling off, bring it up with your healthcare provider.

Final Thoughts

GLP-1 medications are powerful tools, I’m truly grateful to practice pharmacy at a time when we have access to treatments that can make such a difference. But with great tools comes the responsibility to use them wisely. It’s my job not just to dispense medications, but to help people understand how they work in the real world, not just in clinical trials.

We’re still learning about this class of drugs as more people use them, and more data becomes available. If you have questions, or if you’re curious about supplements that can support your health while on GLP-1 therapy, visit our pharmacy forum at MyGlowPure.com. I’m always here to help!

~ Pharmacist Eddie