Hi all, quick question. I am currently taking 25mcg levo and 20mcg t3, and generally feeling better on this than I did on 75mcg levo, and on 20mcg t3 only. But does it matter for my body that my t4 dose is much smaller than t3? I've googled but still confused!
Thank you
Emma
Theoretically our body doesn't need T4 as it's job is to convert to T3. However this is an excerpt:
Dose Selection in T3/T4 Study RCTs The second logical basis for a conclusion
is the actions taken, i.e., the doses given to the subjects. Most subjects received T3 below its adult starting dose of 25 mcg/day.
The subjects in RCTs received T3 in some ratio to the
withdrawn T4. The various RCTs used T4:T3
ratios of 14:1, 10:1, and 5:1. Subsequent
research by the US National Institutes of Health
(NIH) found the therapeutic equivalence was
3:1.
Thus, most of the subjects were under
treated with the T3/T4 combination. In light
of the NIH finding, the conclusion that T3
therapy is never needed is invalid
tpauk.com/images/docs/reduc...
I would think the ratio is, roughly, 3 T4 for 1 T3, i.e. 60mcg of levo with 20mcg of T3. or half these if you take a small dose. Normally if already on levo we drop 50mcg T4 and add 20mcg of T3.
"I am not a medical professional and this information is not intended to be a substitute for medical guidance from your own doctor. Please check with your personal physician before applying any of these suggestions"
Thank you Shaws, that's helpful
Have you seen this? It gives one way to calculate an APPROXIMATE dose: tiredthyroid.com/blog/2014/...
Granted, everyone's optimal dose is different, because it's affected by absorption, enzyme deficiencies, etc., but at least the formula gives you a ballpark dose. The human ratio is about 10:1 T4:T3. Pig ratio is about 4:1. Finding your optimal dose is mostly trial and error, so don't be afraid to add more T4 if you don't feel right!
Thank you for that. Looks like full replacement for me would be 85mcg of levo, which I think my 25mcg + 20mcg t3 is about equivalent to. But I haven't had a thyroidectomy. I feel pretty good apart from sluggish/uncomfortable digestion, I was considering increasing to 25/50 alternate levo but I'm not sure as my bloods are not bad and I don't want to take too much. It's such a mine field!
85 mcg levo is in no way equivalent to 25 T4/20 T3. It is equal to 85 levo. There is no equivalency chart because they have different properties. It's possible that you could have just stayed on your original dose of 75 and added in T3 slowly, raising the T3 5 mcg at a time.
Aha, that makes sense! Such a good job there are people like you out there that understand all this stuff 
I wish that levo worked for me properly, life would be less faffy!
Mountaingoat, 3:1 ratio T3:T4 simply means T3 is 3 x more potent than T4. It doesn't mean that one should take a certain amount of T3 to T4 or vice versa. Take the T4+T3 dose combination which suits you.
Thanks Clutter
Much of the scientific literature says that the human thyroid secretes T4 to T3 in a 14:1 ratio. Many Avant-garde practitioners recommend no less than 10:1 ratio.
I've read it PRODUCES T4:T3 in 15:1 ratio. However it SECRETES it in a 10:1 ratio, because some T4 to T3 conversion is already done in the thyroid gland before actual release.
Thanks for your input. My ratio is way out according to that! But as I feel pretty good I don't want to change things too much.
Mountaingold, could you share your blood results on your current T4+T3 dosage?
Sorry, this is an old thread. I misread it is 1 day old. lol.
I'm sorry, i decided t3 wasn't for me, so I've gone back to levo only.
Thank you! Why have you chosen T4 only?
What are you blood results on T4 only?
I just felt that the T4/T3 mix was not making me feel any better than T4 only, and I started having some chest pain/tingling down my left arm which scared me - I was sent to A&E once. That hasn't happened since I've been back on T4 only. I also didn't like splitting the dose during the day, I felt like I was constantly thinking about how I was feeling, and did I need the next dose yet. I would rather forget I have this disease as far as is possible!
I am now taking 75mcg x 4 days and 100mcg x 3 days. My last blood test in January showed TSH was 0.5. I now know from experience that a) TSH probably is a reasonable indicator for me, b) the window in which I feel ok is really quite narrow and c) lower is not necessarily better - I don't want mine to go any lower than that, but too much higher than 1 isn't great either!
Hope that helps a bit x
Thank you!
Is there a T3 to T4 ratio
T3/T4 ratio dosing query 
T4 to T3 conversion ratio
What's the ratio of T3:T4 in NDT?
is the T4:T3 ratio in NDT wrong?
