Thyroid Supplementation Simplified
"The first time I took enough desiccated thyroid to make my heart speed noticeably, there was a pleasurable pushing up from my abdomen through my chest, making me want to smile and laugh." Ray Peat
This will be a supplement to Danny’s “Demystifying Thyroid Supplementation” article, as I think some points could be expanded upon with more detail.
As a general rule, I think starting with a “T3 only” supplement is best since triiodothyronine has a shorter half-life than thyroxine and it’s easier to gauge its effect at a specific dose. A thyroid supplement that contains both “T3+T4” is more nuanced and should be approached with more care. If liver function is impaired and overburdened with things like endotoxin and estrogen, the conversion of T4 to T3 will suffer, causing reverse T3 to increase and lower the metabolism. At night, T4 suppresses the TSH better than T3 and helps to keep the stress hormones down when you’re asleep. Because thyroid supplements are heat sensitive, it is important to find a brand that doesn’t have “dead batches”. I personally use cynoplus and cynomel and find dosing them to be more accurate and consistent than NDTs (Naturally Desiccated Thyroid).
"By stabilizing your glucose and glycogen system, thyroid might be the basic thing that's needed. T3 acts quickly and is excreted with a half-life of about 12 hours. A dose of about 1 to 3 micrograms can have noticeable effects within a few minutes. If your adrenaline is very high (hypothyroid people can secrete it at 30 to 40 times the normal rate), the first doses can make you more sensitive to the adrenaline, so it's good to have the beta blocker, in case you react too strongly to the small dose. The T3 effects are already declining by the second hour, but it will have slightly increased your stored glycogen and reduced your adrenaline sensitivity, so reactions to each following dose should be better, and over a period of 2 or 3 days it should begin to have the calming, relaxing effects that are normal when the adrenaline is lower. Gelatin, sugar, and carbon dioxide have stabilizing, sedating effects, so things like chicken consomme, orange juice, ice cream, and re-breathing in a paper bag for a minute or two at a time might be helpful. Products containing thyroxine, T4, require planning on a longer range, considering that it accumulates in the body with a long half-life of about two weeks. Seafood provides the selenium needed for activation of the thyroid hormone." - Ray Peat (2021)
How much thyroid a person needs is very much context-dependent. During long/warm summer months, a person may find 0.5 grains to be adequate, but during the short/cold months 1-2 grains. People living at a higher altitude naturally have a lower TSH and more thyroid hormones than someone living at a lower altitude so the amount needed to supplement will be different (Alhazmi et al., 2018).
Another factor to keep in mind is protein intake. Broda Barnes found that a high protein diet allowed himself, and his patients to take extra thyroid without becoming hyperthyroid. The metabolism-depressing effect of a high protein diet (due to the anti-thyroid amino acids like methionine/tryptophan) caused them to maintain their weight on an 800-calorie diet (Barnes, 1976). Starting with the lowest dose possible and slowly increasing every two weeks worked best for me and allowed me to fix any deficiencies that arose with less headache.
The most common deficiencies I’ve run into have been that of vitamin B1, B3, vitamin D, and magnesium. Cells retain magnesium under the influence of T3, so when supplementing thyroid there will initially be a need for extra magnesium. Twitching of muscles or the eyelids are common symptoms of a magnesium deficiency. Since a given T4 dose accumulates over 2 weeks, I’ve found that around the two-week mark I need more selenium and vitamin A. Shrimp, lean tuna, and beef liver are good sources.
"I usually take 5 mcg with some milk and cheese, so that it absorbs gradually. If you crush the tablet, doses of 1 or 2 mcg every hour or two will produce very mild effects that you will be able to measure in your pulse rate and temperature. T3 is quick acting and has a half-life in the body of about one day, so it's important to check pulse rate 30 minutes to an hour after a dose of T3, during the first two or three days, until you find the right way to dose. Were you taking the T4 in a single dose per day? Doctors usually give that instruction. If your diet lacks something, such as selenium or vitamin D, that's needed for thyroid to work, T4 can interfere with the effects of T3; if you take 25 or 50 mcg in a single daily dose, the liver will experience a momentary toxic overdose, and over a period of a week or two will adapt its detoxification enzymes to destroy it, with the result that the body will be extremely deficient in thyroid most of the day, with a short period of toxic excess." - Ray Peat (2018)
I’ve found that using a pill crusher and a milligram scale to measure the amount of thyroid has been more useful than eyeballing it.
References
Ayman S Alhazmi., et al. “Effect of High Altitude on Thyroid and Thyroid Stimulating Hormones Levels in Taif City”. Acta Scientific Nutritional Health 2.12 (2018): 11-13.
Barnes, B. O., & Galton, L. (1976). Hypothyroidism: The Unsuspected Illness. Crowell.