@retiredteacher I've been on thyroid hormones most of my life: I'm now 80 years old, and recall clearly being on it in my 20s and possibly earlier. But years ago I changed from synthetic hormones (Synthroid, Levothyroxine, etc) to Nature-Throid, derived from natural desiccated porcine thyroid. The manufacturer, RLC Labs, has been producing all natural thyroid treatments since the 1930s. Most doctors don't know what I'm talking about, as they've been educated only about the synthetic products. They try to get me to go on the synthetic stuff, but I'm polite and firm in refusing. Do our research!