It's typical to decrease T4 dosage by ~25 mcg for every 5 mcg T3 added, but that's not always necessary. It depends on what your labs look like -whether Free T4 is too high and Free T3 too low, etc. If you can post your actual lab results, we can be more specific.
Another thing to consider is that there is no biochemical test(s) that can reliably determine your thyroid status. A good thyroid doctor will diagnose and treat based on a full medical history, an evaluation for signs/symptoms typical of hypothyroidism, and expanded testing to include FT4, FT3, cortisol, Vitamin D, B12 and ferritin. TSH is useful as a diagnostic only when at extreme levels typical of primary hypothyroidism. Upon diagnosis as hypothyroidism, the good doctor will test and adjust FT4 and FT3 levels as needed to relieve symptoms, without going so far as to create hyper symptoms. So symptoms are more important than FT4 and FT3 3tests. Which, if any, of the following symptoms do you have?
Increased sensitivity to cold
Elevated blood cholesterol level
Muscle aches, tenderness and stiffness
Pain, stiffness or swelling in your joints
Heavier than normal or irregular menstrual periods
Slowed heart rate
Enlarged thyroid gland (goiter)
Before further discussion, I wanted to ask what time of day do you take your thyroid med? And what time of day was the blood draw for those tests?
I agree with Barb about the Armour. I see no benefit from taking that small amount. I suggest that you just stop the Armour and increase your Tirosint to compensate as well as increasing your T3 to 10 mcg to compensate for the Armour and also add the 5 mcg back. You have a number of symptoms which can be related to being hypothyroid still, along with extremely low iron which can also cause symptoms. With your ferritin/iron as low as it is you might consider asking the doctor for iron infusions to get your level optimal. Ferritin needs to be at least 100 and that would take a lot of supplementing, which you have trouble with.
Everyone is different in the FT4 and FT3 levels adequate for them to feel well. Except when TSH is at extreme levels, there is no lab test(s) that reliably determines an individual's thyroid status. So a good thyroid doctor will treat a hypo patient by increasing FT4 and fT3 levels as needed to relieve symptoms, without being influenced by resultant TSH levels. Symptom relief is the only criterion for success.
It makes no sense that you would gain weight overnight by taking that small amount of T3 med. Weight is mainly a result of our Resting Metabolic Rate (RMR) and our diet and exercise habits. RMR is largely associated with our thyroid status. Hypothyroidism causes RMR to drop. If diet and exercise are constant, for women every drop of 100 calories in RMR results in about 23 pounds of weight gain, over an extended period. This is because every pound ladies gain increases RMR by 4.3 calories per day, so you would have to gain 43 pounds to get your metabolism back to where you were no longer gaining weight.
As I mentioned I can think of no reason why 5 mcg of T3 would cause tht pain within one hour. Only one thought. T3 does have an effect on cortisol and vice versa. Have you ever had a cortisol test done? IF not, the best is a 4 panel saliva cortisol test for Free Cortisol. Doctors usually only order a morning serum cortisol, which is total cortisol and not nearly as revealing as Free Cortisol.
There is a good site I, and several friends have used with great satisfaction. The test you want is diurnal saliva cortisol: 4 tests. It costs $135. I will send you a PM with info. To access, just click on your name and then from your personal page click on messages.