That's a good catch about the salt. With your years of being hypothyroid, your adrenals have stepped up to the plate to try to fill in the gap, but by now they've gotten very tired. With better nutrition and your thyroid coming back online, your adrenals get a reprieve. Salt and vit C are very nourishing for adrenals. And when they work well, you'll feel the good effects of your thyroid hormones.