I have lost nearly 50lbs with untreated hypothyroidism

You should probably call your doctor and ask him. Good luck!

I'm hypo as well but I was on Armor Thyroid. I didn't gain weight from my meds, but I didn't lose any either. Since I quit taking them and just started focusing on eating clean and exercising a lot, I've lost 25 lbs. your thyroid controls a lot more than just your metabolism, so if you're experiencing other symptoms that need treatment, such as the mood disorders, you should take the meds. If you're just concerned about your metabolic rate and you're obviously having success without medication, then I don't see a reason to take it.

I struggled for a year to get doctors to take my complaints seriously because all insisted I could not be having thyroid issues since I was not struggling to lose weight. Finally diagnosed with Hashimoto's in January. I've also had to have a sonogram and uptake/scan and will be meeting with the endo again next month to discuss treatment as he wanted to wait to see the results of the scan before medicating.

If the hypothyroidism is caused by Hashimoto's (the autoimmune form of hypothyroidism), it could explain the weight loss. Hashimoto's, it being an autoimmune disease, can often result in fluctuating levels - which can end up leaving you hypothyroid at some times and HYPERthyroid at others, at least in the earlier stages of disease. Eventually the thyroid tissue will 'eat itself' out and 'die' and you will be hypothyroid plain and simple.

Also, I have heard that sometimes people LOSE instead of gain with hypothyroidism, but more often you will gain weight. I don't know if the reason for some people's loss is different than what I wrote above.

But we don't know if you have Hashimoto's (it is the most common form of hypothyroidism, though), so you should ask your doctor. Were you tested for antibodies?

I lost 30 lbs very quickly from mid-September to mid-November while taking 50 mcg Synthroid. It seemed to be working well because I felt excellent and was finally able to lose weight (a little too much weight - I could have and should have been eating a few hundred more calories per day)! Toward the end of November I started feeling off again and by January I was so ill that my hair was falling out, my skin was pale and painfully dry, every joint in muscle was in pain, I was severely depressed, I had ZERO energy to speak of (sleeping 13 hours a day and unable to do much more than lay around the rest of the day), I couldn't focus or think clearly, was very confused, scared, and emotional, and over the course of two months I had gained 50 LBS!!! I was also severely deficient in vitamin D. Needless to say I was very sick and I had to go home from my ballet school in Russia because I was too ill to wait it out until the summer break. Now I'm a lot better but still not 100%. My point in sharing this was to say that hypothyroidism deals with a lot more than just weight, and it can feel unpredictable and out of your control at times. But maybe it will be different for you - it's different for everyone, really! It will probably take some time until you settle on the right dose and combination of meds, and even then you may find what worked for you some time ago is no longer appropriate at another point in time. I myself am no longer on Synthroid. I am taking 10 mcg Cytomel, 150 mg Bupropion HCL XL, and high-dose vit D. I still feels my Cytomel needs to be increased but my endocrinologist has been doing it only 5 mcg at a time. We may have to add the Synthroid back in to the mix in the future.

You'll get it all straightened out, but you have to be patient! The biggest lesson I have learned from all this is to be patient (I'm still learning how to do that!) I know now that I have an illness and I need to let my body heal. You can't let it blow you down, but you HAVE to get well again before you tackle the world! ;-) I don't know if you're struggling with as many physical symptoms as me - I hope not - but it does get muuuuch better with the proper treatment. Good luck! Keep us updated.

I think you mean untreated hyperthyroidism.

Nope. TSH is thyroid stimulating hormone, it's elevated because her body was trying to force her thyroid to make more thyroid hormone. She has hypothyroidism.