Re: Kelp / Levothyroxine - T4 levels
Kelp can't take the place of levoT if you are severely hypo or if you have autoimmune hypoT. Kelp provides iodine, which is the raw material the thyroid gland uses to make hormone. It doesn't supply hormone. If you have autoimmune hypoT, the most common type, the gland has suffered damage from that and can't make use of the iodine the kelp provides. Most AI hypoT folks feel worse when they take extra iodine.
If you have an undamaged, but merely sluggish gland... and if you have a low blood level of iodine, the kelp might help your gland produce more hormone.