I have been doing low carb since January. I take daily levothroxine for hypothroidism. Lost some weight, been doing great, then recently started getting the low thyroid symptoms, hair loss, tired etc. Got my blood tests back today and the thyroid was too low. I thought I would end up having to lower my medicine because of the weight loss and eating healthier. Has anyone else experienced this problem doing LC?

No, but I have never been told by my doctor that I would be able to lower my medication. Low thyroid isn't like hypertension or something where diet can play a significant factor in fixing it. In fact, my doc told me we would probably have to continue to adjust it until it kind of stabilized.

As I get older, I assume I will probably lose more function.

I thought that the amount of thyroid replacement given, weight is a factor in how much is perscribed. Because I lost weight I thought I would end up being hyper, on my current medicine. I am not saying I will cure my hypo thyroid with diet. I know I will have to take replacement for life. I read somewhere in this community that if you eat more protein, you will need more thyroid hormone to compensate. I was just wondering if that's what's going on with me, just so I know what to expect.

I don't think the prescription is based upon weight, but on what your TSH, T3 and T4 levels are. I have actually no idea if those levels are affected by weight gain or weight loss, but in my family the women are kept on their levels regardless of their weight. Those hormones control cellular metabolism-perhaps upping exercise will cause you to lower your medication? What I did do, is ask my doctor to up my levels because I wanted my TSH lowered to be between 1 and 2 because I have seen studies that showed that you will have a hard time losing weight if it is higher.