T4 is 4 iodine molecules around a ring of tyrosine. Selenium dependent enzymes called deiodinases converts T4 to T3 by removing an iodine atom from the outer tyrosine ring. Selenium is not just pretty good at converting T4 to T3. It's essential! :)
Supplement wise, look for selenomethionine (sometimes called chelated selenium). Dietary wise, the highest source is brazil nuts with between 50 to 90mcg per nut.
In the second month of taking ferrous sulfate there is a markedly diminished bioavailability. And increasing the dosage doesn't increase the bioavailability but increases side effects. The youtube video "Are Chelated Minerals Better Absorbed" explains in detail. I use the brand Swisse. Works great. Chelated = better absorption and less side effects.
The list of ingredients in Swisse Iron...
EACH TABLET CONTAINS:
Iron (from iron amino acid chelate) 20 mg
Vitamin C (as ascorbic acid from calcium ascorbate dihydrate) 16.52 mg
Vitamin B6 (as pyridoxine from pyridoxine hydrochloride) 8.22 mg
Betacarotene 1 mg
Certified Organic Spirulina (Arthrospira platensis cell powder) 200 mg
I find that my FT3 seems more stable when I take selenium, as well. The one I take is made by Solaray, 200 mcg, which is, typically, the recommended dosage.
What was your actual FT4 result?
I'm not quite sure I understand your cytomel dosing. Are you taking 2.5 mcg twice/day, for a total of 5 mcg or are you splitting the pill into quarters taking 1.25 twice/day for a total of 2.5?
Thanks for the suggestions!
Barb-sorry, I'm taking 2.5 total a day, meaning a quarter in the a.m. and a quarter in the afternoon. They did want me to try the full five mcg, which I was slowly building up to. My FT4 was right near the top when I started Cytomel-1.7 out of a range of 0.8-1.8. I just wanted to err on the side of caution for a little while as to not push that since I tend to get hyper symptoms when I'm near the top of the FT4 range.
In case the brand Red_Star mentioned is not available here, here are two types that are good. Ferrous fumarate and ferrous gluconate. One tablet contains about 28 mg of elemental iron. I'm taking 3 tablets daily. My ferritin has gone from 40 up to 80 on this dosage.
Swisse is sold in the US (at Walgreens) but I had a look and found the company only chose the most popular selling products here in Oz for the US market and iron isn't one of them.
But those Aussie products sit upside down on our shelves in the Northern hemisphere and it is harder to read the labels. LOL
Fair dinkum? Streuth! LOL