English is not 1st language, sorry for poor expression if any
I got hyperthyroidism when I was 10 years old (male). I looked at the doctor and he put me on thyroid suppression drugs for few years (till 14 years old). He said my blood test is normal but I never felt good. With these drugs, I gained a lot of weight and my life became **** as well. At that time I was 5'9 and 180lbs, 26% body fat. I suffered from low motivation, weak muscle (i.e. I could not even run for 2 km). Apparently everything shows me I am under hypothyroidism. But the doctor said according to my blood test, my T4 and T3 is still above average. I roughly consume 2000 calories at that time.
At the age of 20, I felt like I have to do things to change or my life quality will remain poor. At that time I got into university and the clinic doctor in university transferred my case to a medical professor specialize in endocrine issues. He looked at my blood test and agreed that my T4 and T3 is actually above average from reference range. He was also unsure what he could do to help me ( he doubt me I might have mild depression).
At that time I learn how to eat clean from bodybuilding forum. I consumed only 1400 calories to cut my weight off (morning with oatmeal and 2 large eggs around 400 calories, lunch with rice and chicken breast also around 400 calories, 2 weight gainer shake with 300 calories each and one multivitamins). Together with cardo and weight training, it still took me 3 months to lose from 180 lbs to 155 lbs with this cutting diet but it stayed steady around 155 lbs. I feel better but still suffer from low motivation etc.
After losing the weight, I did a blood test again. Finally the test showed my T4 and T3 is below average. The medical professor prescribe me synthroid ( I asked if I can get cytomel or thyroid armour but he said no because t3 is kinda dangerous in many doctor's mind). But now with T4 for few years, I can maintain my weight on 140 lbs, 12% body fat eating on 2200 calorie, the most important ting is that I completely feel normal now. I have been taking 50mg synthroid to offload my thyroid half (as thyroid produces ~ 100mg T4 every day).
There is a lot of case people turning from hyperthyroidism to hypothyroidism. Since the thyroid had overload for few years, it may prefer to offload after that. My theory is that if you have symptoms of hypothyroidism with overweight, your test result may show you are normal or above average because you body are forced to burn fat (i.e. avoid more fat storage to protect heart and blood vessel). The preferred under-load thyroid is forced to overload again . You will feel very bad all the time ( this is my personal experience, suffered from no motivation, and this is very easy to diagnose as depression).
Also cardo may help a lot because it stabilizes your cortisol level ( people with thyroid problem is very easy to get nervous). This may affect the conversion from T4 to T3.
I did a lot of research and reading on forum to understanding the potential cause of my health issue. A general doctor solves health issue only according to standard, this is very important to do your own research. I hope the above information could help someone who has similar problems in a day.