I started taking 500 mg of acetyl-l-carnitine over a month ago and began to notice a positive benefit in mood, energy, and less muscle weakness. However, these effects lasted for 2-3 weeks, after which I began noticing a drop in energy, needing to sleep more than I did before, and occasional classic hypothyroid symptoms, notably cold hands and feet and feeling cold, as well as constipation. I'm aware of research that documents carnitine's inhibitory effect on thyroid function/uptake into cells, and find it a little strange that the "refuel your mitochondria before tackling thyroid issues" in this case with carnitine apparently means contradictory results, but would it just make sense to increase my thyroid medication dose? I'm currently only taking 50 mcg T4, and had previously tried increasing it to 75 mcg with negative results that definitely weren't hyperthyroid symptoms: worse fatigue and brainfog. (Interestingly, I came across research pointing to thyroid hormone's pretty significant effect on the 2-hydroxyestrone pathway, which DIM also does as well, and when I increased my thyroid dose in the past it was when I was taking a pretty good amount of DIM to control estrogen metabolism.) Would it make sense just to increase my thyroid hormone dose, especially since before I wasn't getting enough thyroid hormone to begin with?