DrGLP-1 medications can reduce appetite and food intake, making it harder to meet daily nutrient needs. Learn why nutrient depletion happens and what every patient should know before starting their weight-loss journey.
Starting a GLP-1?
Here's What Your Doctor Probably Didn't Tell You Why supplementation isn't optional; it's essential. If you've just been prescribed a GLP-1 medication, whether that's semaglutide (Ozempic, Wegovy), tirzepatide (Mounjaro, Zepbound), or another option first of all, congratulations! You've taken a real step toward reclaiming your health. These medications are genuinely effective, and for many of my patients, they've been life-changing.
But as a triple board-certified physician in family medicine, obesity medicine, and aesthetics someone who has both prescribed these medications and been on a GLP-1 herself here's something I wish more prescribers were telling their patients from day one: GLP-1 medications can quietly deplete the nutrients your body needs most. And if you don't address that, you may find yourself feeling more fatigued, weaker, and worse than you expected even as the weight comes off. Let me explain why.
What GLP-1 Medications Actually Do to Your Body
GLP-1 medications work in a few powerful ways. First, they slow down gastric emptying ,meaning food leaves your stomach much more slowly than it normally would. This is actually intentional. When food sits in your stomach longer, you feel full faster and stay full longer. That sensation of fullness is a big part of why these medications are so effective for weight loss.
On top of that, GLP-1s act on two key hunger hormones: ghrelin (your "I'm hungry" signal) and leptin (your "I'm satisfied" signal). The result? Less cravings, more satiety, and an overall reduced drive to eat. Sounds perfect, right? In many ways it is. But here's what happens next.
The Side Effects Nobody Prepares You For
Because your stomach is emptying more slowly and you're simply eating far less, many patients experience nausea, vomiting, and diarrhea , especially in the early weeks. This is even more pronounced if you eat foods that are greasy, very sweet, salty, or spicy. Some patients go from eating three meals a day to barely managing one. Others are dealing with nausea so intense that eating feels like a chore. And when that happens consistently, your body starts missing out on the micronutrients it needs to function not just for weight loss, but for energy, immunity, muscle health, and everything in between.
This is the nutrient depletion problem.
And it's more common than most people realize. So What Does This Mean for You? Here's the bottom line: when your body is eating significantly less sometimes just once a day food alone cannot cover your micronutrient needs. The combination of reduced intake, nausea, vomiting, and altered digestion creates a perfect storm for nutrient depletion. And most prescribers aren't talking about it.
The good news? It's completely addressable. But you have to know what you're missing before you can fix it.
In Part 2 of this series, we're going to break down exactly which nutrients are most commonly depleted on a GLP-1, what the research says, and what symptoms to watch for. Because understanding what's happening inside your body is the first step to making sure your results actually last.
Coming up in Part 2: The exact nutrients depleted by GLP-1 medications — and why replacing them isn't optional. This is also where we'll talk about what to look for in a supplement that was actually built for this.
The Bottom Line
GLP-1 medications are powerful tools, but they work best when your body has the nutritional support it needs. Understanding how these medications affect appetite, digestion, and nutrient intake is the first step toward protecting your long-term health while losing weight.
In Part 2, we'll discuss the specific nutrients most commonly affected during GLP-1 treatment, the symptoms associated with those deficiencies, and what to look for in a supplement designed to support your journey.
For more physician-led education on GLP-1 medications, nutrition, and wellness, visit the Jealthy Resource Center and follow @jealthylife for weekly insights.
Frequently Asked Questions
Can GLP-1 medications cause vitamin deficiencies?
GLP-1 medications do not directly cause vitamin deficiencies. However, because many people eat significantly less while taking them, they may struggle to consume enough vitamins and minerals through food alone.
Why do some people feel tired on Ozempic, Wegovy, Mounjaro, or Zepbound?
Fatigue can occur for several reasons, including reduced calorie intake, dehydration, inadequate protein consumption, and insufficient vitamin and mineral intake.
Should I take a multivitamin while on a GLP-1 medication?
Many patients benefit from nutritional support while taking GLP-1 medications, particularly when appetite and food intake are reduced. The best supplement plan should be individualized based on your needs and medical history.
What nutrients are most commonly affected while taking GLP-1 medications?
Research and clinical experience suggest that nutrients such as vitamin D, magnesium, B vitamins, vitamin C, and zinc may become inadequate when overall food intake decreases.
About the Author
Dr. Jennifer Mbianda is a triple board-certified physician in family medicine, obesity medicine, and aesthetics,
