• Welcome to Phoenix Rising!

    Created in 2008, Phoenix Rising is the largest and oldest forum dedicated to furthering the understanding of, and finding treatments for, complex chronic illnesses such as chronic fatigue syndrome (ME/CFS), fibromyalgia, long COVID, postural orthostatic tachycardia syndrome (POTS), mast cell activation syndrome (MCAS), and allied diseases.

    To become a member, simply click the Register button at the top right.

Thyroid hormones/ natural production

pattismith

Senior Member
Messages
3,957
it may be useful to have an idea of physiological daily production of T3 and T4

thyroid-axis.png


https://www.straighthealthcare.com/hypothalamic-pituitary-thyroid-axis-illustration.html
 

frozenborderline

Senior Member
Messages
4,405
Interesting! In Ray Peat's recommendations for T3 I thought he said something about ~2-3 mcg T3 an hour which is why he says not to take more than that at once. Will have to look into this more, I may have to start with even smaller doses than I thought.
 

frozenborderline

Senior Member
Messages
4,405
"The brain concentrates T3 from the serum, and may have a concentration 6 times higher than the serum (Goumaz, et al., 1987), and it can achieve a higher concentration of T3 than T4. It takes up and concentrates T3, while tending to expel T4. Reverse T3 (rT3) doesn't have much ability to enter the brain, but increased T4 can cause it to be produced in the brain. These observations suggest to me that the blood's T3:T4 ratio would be very "brain favorable" if it approached more closely to the ratio formed in the thyroid gland, and secreted into the blood. Although most synthetic combination thyroid products now use a ratio of four T4 to one T3, many people feel that their memory and thinking are clearer when they take a ratio of about three to one. More active metabolism probably keeps the blood ratio of T3 to T4 relatively high, with the liver consuming T4 at about the same rate that T3 is used.

Since T3 has a short half life, it should be taken frequently. If the liver isn't producing a noticeable amount of T3, it is usually helpful to take a few micorgrams per hour. Since it restores respiration and metabolic efficiency very quickly, it isn't usually necessary to take it every hour or two, but until normal temperature and pulse have been achieved and stabilized, sometimes it's necessary to take it four or more times during the day. T4 acts by being changed to T3, so it tends to accumulate in the body, and on a given dose, usually reaches a steady concentration after about two weeks. "

Looks like his citation for this is: https://www.ncbi.nlm.nih.gov/pubmed/3830062

Idk if i can find fulltext rn