Decreased muscle mass as a side affect of levothyroxine

@radinski
I am also on levothyroxine after lobectomy (have Hashimoto’s and hypothyroidism).

Here is what I found:
Levothyroxine is a medication commonly prescribed for hypothyroidism, and while it helps regulate thyroid hormone levels, some individuals report changes in muscle mass or strength. Here are some insights regarding the potential effects of levothyroxine on muscle mass and strategies to address muscle loss:
Potential Effects of Levothyroxine on Muscle Mass
Thyroid Hormone Regulation: Thyroid hormones play a crucial role in metabolism, including muscle metabolism. An imbalance, whether from hypothyroidism or the treatment itself, can affect muscle mass and strength.
Muscle Protein Synthesis: Some studies suggest that thyroid hormones influence muscle protein synthesis. If levothyroxine levels are not optimized, it may lead to decreased muscle protein synthesis, impacting muscle growth and recovery.
Exercise Response: Individuals on levothyroxine may experience changes in how their muscles respond to exercise. This could be due to hormonal fluctuations or other factors related to thyroid function.
Strategies to Address Muscle Mass Loss
Optimize Thyroid Levels: Ensure that your thyroid hormone levels are within the optimal range. Regular check-ups with your healthcare provider can help monitor and adjust your levothyroxine dosage if necessary.
Strength Training: Incorporate a structured strength training program that focuses on progressive overload. This means gradually increasing the weight or resistance to challenge your muscles.
Nutrition: Ensure adequate protein intake to support muscle repair and growth. Aim for a balanced diet rich in whole foods, including lean proteins, healthy fats, and complex carbohydrates.
Hydration: Staying well-hydrated is essential for overall health and can aid in muscle recovery.
Rest and Recovery: Allow sufficient time for muscle recovery between workouts. Overtraining can hinder muscle growth and lead to fatigue.
Consult a Professional: Consider working with a fitness trainer or a nutritionist who can tailor a program to your specific needs and help you regain muscle mass effectively.
If you continue to experience issues with muscle mass despite these efforts, it may be beneficial to discuss your concerns with your healthcare provider for further evaluation and potential adjustments to your treatment plan.

I have been taking levothyroxine combined with liothyronine (generic Cytomel) for about 18 years. I have always been thin from running, but my strength has been steady over time, and I haven't lost any muscle mass. But things might be different for someone with more muscle mass than me.

I have been on those as well for years but have not experienced loss of muscle mass. It may be your diet - are you getting enough protein that is needed for muscles? I also have been adding creatine to my smoothies which is touted as helping. Overall, diet is incredibly huge to our health in many ways. I strongly recommend finding a nutritionist who is knowledgeable about health issues and recommending foods that will aid you in growing muscle mass. There are also foods to look at that are good for the and thyroid issues. It's finding the right person to help you with that. And your loss of muscle mass could very well be due to something else. Perhaps you are not absorbing the nutrients you eat from foods and supplements.

Thank you @jeff97.

Thank you @gigi4. Those are all factors to consider.

I'm 71, been on hypothyroid meds (Levothyroxine) for 25 years and haven't noticed any loss of muscle mass. I offset age-related loss of muscle mostly by weight lifting and other resistance exercise. Gardening and woodworking also help. If you don't currently lift weights then it would be good to get an experienced personal trainer because technique are critical for strengthening muscle groups. I started weight training 35 years ago. Resistance training is also very important for retaining bone mass (minimizing risk of osteoporosis). Regarding diet, most people get all the protein they need and it won't add muscle unless one is working out muscles. Creatinine is not recommended for someone with kidney disease, for example. Mediterranean and similar diets are better for us than most the processed food out there.

@radinski Welcome to Mayo Clinic Connect! You’ve quickly gotten some responses! Have you spoken to your doctor about this? What recommendations do they have?

Thank you for your response @becsbuddy. I have not spoken to my doctor. It’s the holiday weekend and I just noticed the issue. But I suppose it’s an easy ask.

Thank you @kayabbott. I have a Total Gym that I have been using for about 20 years. Currently, I use it 3-3 times a week and I walk 20-30 minutes 3 times a week. I just noticed recently that my muscles are not responding. Perhaps it is age related…New to me…

I have been recently diagnosed with eosinophila fasciitis. I was prescribed prednisone, methotrexate, and sol metro infusions. I’m having very bad muscle spasms in my back. I’ve read this is a side effect to the infusions. Has anyone experienced this!! Thank you
Darlene