Thyroid UK

T3+T4 combo going down hill now

Hello everyone. Back for some advice. I was put on t3+t4 combo in May by endo and saw amazing improvements. Heavy period, depression gone, energy up, 3stone weight loss. About a month ago I started literally stopping functioning. Can't think straight heavy periods back, heavy eyes. Blood test below. I'd be grateful for any advise. Thank you :-)

T3(20mcg)// T4(100mcg) daily

Test results

TSH <0.02 mu/l [0.30-4.20]

FT4 10.2pmol/l [12.0-22.0]

FT3 4.1pmol/l [3.1-6.8]

Vitamin D 67nmol/l

B12 697

5 Replies




looks to me like your not converting the levothyroxine into t3 probably due to low ferritin

1 like

Thank you for replying. Yes They haven't tested ferritin so I'm taking it and B12. But feeling sluggish each day more.


Brubru, some patients need to increase thyroid meds during the winter. Your FT3 is still quite low so you could try an extra 10mcg of T3.

VitD is less than the optimal 75-200. Supplement 2,000iu vitD3 softgel caps or spray.

B12 looks fine.


Thank you clutter! Would that explain the low t4 or is it fine being low? I'm on the other vitamins but just started.


BruBru, taking oral T3 often causes a drop in FT4 because there's no need for high levels of T4 for conversion to T3. It's not a problem :)


You may also like...