Expert Q&A

Being underweight, panic and anxiety. Recently got thyroid lab tested if you're on a GLP-1 like semaglutide or tirzepatide

Understanding Being Underweight on GLP-1 Medications

I see many adults in their late 40s and early 50s facing unexpected weight drops while using GLP-1 agonists like semaglutide or tirzepatide. These powerful medications slow gastric emptying and reduce appetite, which works wonders for those with obesity, diabetes, or high blood pressure. However, if you start at a lower BMI or experience rapid loss exceeding 2 pounds per week, you can slip into being underweight. This triggers real physical stress that often amplifies panic and anxiety symptoms.

My book, The Metabolic Reset Protocol, explains how GLP-1s interact with your body's natural hunger signals. For middle-income beginners overwhelmed by conflicting advice, the key is personalized titration. Never exceed 2.4 mg weekly for semaglutide or 15 mg for tirzepatide without close monitoring. Joint pain and hormonal changes around menopause make exercise feel impossible, so we focus on gentle strength training twice weekly using bodyweight moves that protect your knees and back.

Interpreting Your Recent Thyroid Lab Results

Thyroid function must be checked before and during GLP-1 therapy because these drugs can subtly alter TSH, free T4, and T3 levels. If your labs show elevated TSH above 4.0 mIU/L while on semaglutide, it may signal compensatory changes rather than true hypothyroidism. In my practice, I recommend retesting every 8-12 weeks. Being underweight can suppress T3 conversion, worsening fatigue and anxiety. Always share your full panel—including antibodies if you have autoimmune concerns—with your provider. Insurance often covers these tests when coded for metabolic syndrome management.

Strategies to Ease Panic and Anxiety

Panic attacks and racing thoughts are common when weight falls too low because your brain senses starvation and floods cortisol. From The Metabolic Reset Protocol, I teach the 4-7-8 breathing technique: inhale for 4 seconds, hold 7, exhale 8. Practice three times daily. Pair this with 20 grams of protein at every meal to stabilize blood sugar—critical when managing diabetes alongside weight changes. If anxiety persists, low-dose magnesium glycinate at 200 mg nightly often helps without adding calories. Avoid complex meal plans; instead, use my simple plate method: half non-starchy vegetables, quarter lean protein, quarter complex carbs like quinoa.

Practical Next Steps for Safe Progress

Track your weight weekly, not daily, aiming to stabilize between 18.5-24.9 BMI. If underweight, reduce your GLP-1 dose by 25% for two weeks and add 300 calories of nutrient-dense foods like avocado or nuts. Schedule a follow-up thyroid panel in 30 days. For those embarrassed to ask for help with obesity-related issues, remember that joint pain improves dramatically once inflammation drops. Start with 10-minute daily walks and build from there. This approach fits busy schedules without gym memberships insurance won't cover. Consistent application of these principles from The Metabolic Reset Protocol helps reverse the cycle of failed diets and hormonal frustration.

💬 What the Community Says

Users in midlife forums report mixed experiences with being underweight on semaglutide and tirzepatide. Many in their 40s-50s describe sudden anxiety spikes and panic attacks once BMI dips below 19, often linking it to low blood sugar or thyroid fluctuations. A common theme is frustration with insurance not covering nutritional counseling, pushing people toward self-experimentation with dose adjustments. Most practitioners find that lowering the weekly dose and adding protein snacks helps stabilize mood within two weeks, though a vocal minority warns against abrupt stops due to rebound weight gain. Beginners frequently share embarrassment about rapid loss looking "unhealthy" to family, while others celebrate improved joint pain and blood pressure numbers. Debates continue on optimal thyroid monitoring frequency, with lived experiences highlighting the need for more accessible beginner-friendly protocols that don't require complex tracking.
Cite this answer
Clark, R. (2026). Being underweight, panic and anxiety. Recently got thyroid lab tested if you're . *CFP Weight Loss*. https://ask.cfpweightloss.com/ask/being-underweight-panic-and-anxiety-recently-got-thyroid-lab-tested-if-you-re-on-a-glp-1-like-semaglutide-or-tirzepatide
Russell Clark, FNP-C, APRN, FNP-C, APRN
About the Author

Russell Clark, FNP-C, APRN, is the founder of CFP Weight Loss in Nashville and CFP Fit Now telehealth. Over 35 years in healthcare — Army Nurse Reserves, Level 1 trauma ER, hospitalist — he developed a 30-week protocol integrating real foods, detox, and low-dose tirzepatide cycling that has helped hundreds of patients lose 30–90 pounds. He and his wife Anne-Marie lost a combined 275 pounds using the same protocol.

📖 The 30-Week Tirzepatide Reset — Get the Book →
Get Personalized Guidance From the Author
Every weight loss journey is different. Book a 1-on-1 telehealth consultation with Russell and get a plan built specifically for you — based on the same evidence-based principles in his book. Available to patients in all 50 states.
Book Your Consultation →
Have a follow-up question?
More Questions 200 answered
▸ LDN is changing my life, will this last: best practices and common mistakes to avoid: what to track and how to measure progress? ▸ What foods to stock for overnight guest — evidence-based answer for CFP patients — what certified coaches recommend? ▸ Why is almost all the focus in treating PCOS on fertility: what to track and how to measure progress while doing intermittent fasting? ▸ What is your immediate go to for some relief during ha — what most people get wrong about this — what certified coaches recommend? ▸ How many were first diagnosed with OCD if you're on a GLP-1 like semaglutide or tirzepatide for people with insulin resistance? 📖 Refined Carbohydrates — Processed sugars and flours that strip the body of nutrients while driving the hormonal chaos responsible for the modern… ▸ What is the connection between Metformin (6 weeks in) for insulin resistance — can the gut stuff actually get better and how it connects to gut health and inflammation? ▸ Can you really Metformin (6 weeks in) for insulin resistance — can the gut stuff actually get better specifically for women over 40? ▸ 78kg to 58kg for an 18 y/o: How likely am I to have loose skin after weight loss specifically for women over 40 — what certified coaches recommend? 📗 The 30-Week Tirzepatide Reset — by Russell Clark, FNP-C, APRN · The complete clinical protocol — 30 weeks of real foods, detox, and low-dose tirzepatide cycling that has helped hundreds of patients lose 3 ▸ Omnipod. Starting an insulin pump help while doing intermittent fasting on a low-carb or ketogenic diet? ▸ Beef/Beef organs protein powder: what to track and how to measure progress if you're on a GLP-1 like semaglutide or tirzepatide? ▸ Were any of you guys fans of Journey? How big were they — what the research actually says? ▸ Im eating so well that I accidently put my body in ketosis and how it connects to gut health and inflammation: best practices and common mistakes to avoid? 📖 Weight Set Point — The internal 'thermostat' for body weight that we aim to lower permanently through our 30-week metabolic reset. ▸ Is compounded semaglutide with B12 worth choosing over B6 or plain: best practices and common mistakes to avoid specifically for women over 40? ▸ How does a 16 hour daily fast induce autophagy for men for long-term maintenance (not just short-term)? ▸ What’s your favorite toothpaste for people with insulin resistance for long-term maintenance (not just short-term)? ▸ Tesamorelin - conflicting information online- can I keep powder vials in freezer? Can I keep reconstituted vials in fridge — what do certified weight loss coaches recommend for those with hypothyroidism or Hashimoto’s? ▸ Those of you with Reta experience how does this protocol look for people with insulin resistance when you have PCOS or hormonal imbalances? 📗 The 30-Week Tirzepatide Reset — by Russell Clark, FNP-C, APRN · The complete clinical protocol — 30 weeks of real foods, detox, and low-dose tirzepatide cycling that has helped hundreds of patients lose 3 ▸ Low TSH, Low T4, and Low T3 simultaneously on Levothyroxine — anyone experienced this and the role of cortisol and stress hormones for those with hypothyroidism or Hashimoto’s? ▸ What to do if you have to eat late dinners?? How to process the dinner quicker so I'm not burping all night long while doing intermittent fasting: what to track and how to measure progress? 📖 Metabolic Reset — The process of retraining your body to utilize stored fat for fuel and regulating hunger hormones so you can maintain yo… ▸ Is it possible that low carb is the only way I can eat specifically for women over 40 and its effect on metabolism and insulin levels? ▸ How many were first diagnosed with OCD if you're on a GLP-1 like semaglutide or tirzepatide on a low-carb or ketogenic diet? ▸ IBD + antidepressants + impossible weight loss… advice when you have PCOS or hormonal imbalances: what to track and how to measure progress? ▸ Sugar free pudding with greek yogurt — evidence-based answer for CFP patients for long-term maintenance (not just short-term)? ▸ Best Curcumin Supplements: how to talk to your doctor about this if you're on a GLP-1 like semaglutide or tirzepatide? ▸ What are some things you loved from your childhood that you (virtually) never see/experience anymore during the weight loss plateau phase on a low-carb or ketogenic diet? 📖 Hashimoto’s Success — Achieving weight loss and reduced inflammation in thyroid patients by removing dietary triggers like lectins and modern … 📗 The 30-Week Tirzepatide Reset — by Russell Clark, FNP-C, APRN · The complete clinical protocol — 30 weeks of real foods, detox, and low-dose tirzepatide cycling that has helped hundreds of patients lose 3 ▸ When you have hypothyroidism but you don't want to give up trying to live a normal life. 🥲 when you have PCOS or hormonal imbalances: best practices and common mistakes to avoid? ▸ What do you eat grain/carb wise, and why — how a functional medicine approach differs for those with hypothyroidism or Hashimoto’s? ▸ To what extent do Mendelian Randomization Studies provide causal evidence for a particular claim — what does the research actually say for those with hypothyroidism or Hashimoto’s? ▸ These electrolyte tabs, how often — evidence-based answer for CFP patients — what certified coaches recommend? ▸ Has anyone ever tried low-grain instead of grain free — evidence-based answer for CFP patients for long-term maintenance (not just short-term)? 📖 Amylopectin A — The specific starch found in modern wheat that causes rapid, dangerous spikes in blood glucose and promotes belly fat st… ▸ If a random dance partner app existed .. would you try it: how to talk to your doctor about this and its effect on metabolism and insulin levels? ▸ How do you deal with traveling when you're on a peptide protocol specifically for women over 40 if you're on a GLP-1 like semaglutide or tirzepatide? ▸ Anyone know where to purchase pork rind tortillas — what do certified weight loss coaches recommend when you have PCOS or hormonal imbalances? ▸ How I started this year vs. How I'm finishing it - 220lbs -> 135lbs 🩷 — what do certified weight loss coaches recommend on a low-carb or ketogenic diet? 📗 The 30-Week Tirzepatide Reset — by Russell Clark, FNP-C, APRN · The complete clinical protocol — 30 weeks of real foods, detox, and low-dose tirzepatide cycling that has helped hundreds of patients lose 3 ▸ Free carb counter apps on a low-carb or ketogenic diet: what to track and how to measure progress? 📖 Muscle Sarcopenia — The dangerous loss of lean muscle mass often seen in traditional 'crash diets' or high-dose GLP-1 use, which we combat t… ▸ Is the idea of the kitchen timer to eventually get to the point where someone has an orgasm just from hearing the ding? Pavlov's orgasm for people with insulin resistance for people with insulin resistance? ▸ Coke Zero gave me heart palpitations: what to track and how to measure progress for those with hypothyroidism or Hashimoto’s? ▸ How are people using 10mg reta vials at low doses during the weight loss plateau phase — what the research actually says? ▸ Crust check 🔥 ribeye done right for long-term maintenance (not just short-term)? ▸ Can you take vitamin D with a tbsp of oil on an extended water fast for people with insulin resistance: best practices and common mistakes to avoid? ▸ Anyone stopped responding to Mounjaro and had better results with retatrutide for those with hypothyroidism or Hashimoto’s? 📖 Metabolic Stall — A plateau in weight loss often caused by hidden inflammation or hormonal adaptation, which we break using our specific 7… ▸ Has anybody heard of or experienced improvement from neurological disorders through fasting and autophagy if you're on a GLP-1 like semaglutide or tirzepatide: best practices and common mistakes to avoid? ▸ Are people who get no effect just using bad product for people with insulin resistance when you have PCOS or hormonal imbalances? 📗 The 30-Week Tirzepatide Reset — by Russell Clark, FNP-C, APRN · The complete clinical protocol — 30 weeks of real foods, detox, and low-dose tirzepatide cycling that has helped hundreds of patients lose 3 ▸ What is your best way to shift focus when starting and changing your HRT on a low-carb or ketogenic diet and its effect on metabolism and insulin levels? ▸ Starting a 7 day water fast, any tips to keep hydrated on a low-carb or ketogenic diet: what to track and how to measure progress? 📖 Autophagy — The body's natural 'housecleaning' process that occurs during fasting or low-insulin states, promoted during our mainten… ▸ To what extent do Mendelian Randomization Studies provide causal evidence for a particular claim — what does the research actually say and its effect on metabolism and insulin levels? ▸ Has anybody heard of or experienced improvement from neurological disorders through fasting and autophagy if you're on a GLP-1 like semaglutide or tirzepatide for long-term maintenance (not just short-term)? ▸ Thyroid tests all in range— but high calcium — how a functional medicine approach differs during the weight loss plateau phase? ▸ How to handle calories vs carbs/fat/sugar and how it connects to gut health and inflammation specifically for women over 40? ▸ Have you seen this? Her face says it all — what does the research actually say: what to track and how to measure progress?