This is going to sound a bit kooky, but please keep an open mind.
I think what may have happened, is that your gut bacteria profile changed from one that was working for you, to one that's causing your symptoms.
One of the clues ... other than the obvious one which is you your weight gain... that points in this direction is that you've got high levels of T4... which is what you're putting into your body when you take Synthroid, or generic(aka levothyroxine).
And that you've got low levels of T3.
Its seems as if your liver and gut bacteria aren't doing a good job converting your medication to T3... which is why you need Cytomel.
As I mentioned in my other reply, T3 is made from T4. This is done by an enzyme called de-iodenase, which contains selenium. So its a good idea to eat some every day, particularly if your are on a diet that doesn't contain a lot of whole grains.
I've found fortified nutritional yeast to be a good source of selenium, ( I use Kal brand)as well as of B vitamins for trace minerals like chromium. Alternately a brazil nut a day provides adequate selenium. Its like everything else, though, you don't want to overdo, too much isn't better, its excess.
What you may want to try is:
1. A source of probiotics. I use Kefir... this is a probiotic drink you can grow at home. There's two types, milk and water. IMO the water kefir is super easy to grow and with its apple juice taste, can be put in smoothies or chilled with a meal.
2. A source of gelatin and minerals... bone broth is great for this. Sounds exotic, but its simply about stewing a chicken (preferably organic) until the meat falls off the bones, with vegetables like onion, garlic, celery and carrot and taking a cup or so of this gelatinous broth per day. If you can't watch it all day an alternative is a crock pot.... or Knox unflavored gelation. Gelatin is a rich source of glycine and proline, two amino acids we don't get much of in our contemporary diets. The calcium and minerals in the chicken bones are easily absorb-able.
3. Greens like Kale (organic)... which can be chopped and put in the broth.. for fiber and nutrients.
4. Make sure you're getting some iodine, 150 mcgs per day.
Stay away from sugars, refined carbs and starches, soda, artificial sweeteners, fast foods. Choose organic whenever you can... those with thyroid problems seem to be more sensitive to chemicals than normals.
Why not try this for the 4 weeks while you are taking the Cytomel/Synthriod combination and see if anything changes?
Hey we all can relate here about carrying extra weight. 18 pounds is a lot of extra work for your heart, plus fat puts out hormones of its own which makes things worse.
| current weight: 146.0