Hair loss and feeling very cold following T3 therapy? What to do?

A little over a month ago I started on T3 only therapy after trying T4 and natural thyroid hormone for about 2 years (with little long term effects). I have Hashimoto’s with usually low T3 values (lowest within range) and low within range T4 and TSH. Symptoms included weight gain, hair loss, measured low metabolism, low body temperature, extreme fatigue, brain fog, hypoglycemia and Reynaulds syndrome. I also have another autoimmune disease to complicate matters.

I started with 12,5 ug per day (in 2 doses) and worked up to about 50 ug (divided in 4x 12,5 ug). The effect on my energy levels, brain fog, blood sugar levels and overall appearance (less puffy face) has been great. However I have 2 problems. First one is that I get very cold right after taking T3 with also extremely cold hands. It has gotten a little better over time but not much. The second problem is that now after a month I started losing a lot of hair. What am I doing wrong? Is my dose too low or too high? Any tips would be very welcome!!!

8 Replies

  • Springviolet,

    My hair started coming out in clumps when I over medicated T3 and FT3 was over range.

    I think you should order a thyroid test. Blue Horizon Thyroid Plus 6 checks TSH, FT4 and FT3. Don't take T3 before the blood draw or you will get a false high FT3 result.

  • Thank you for your reply :). So in your experience hair loss can happen when you over medicate? I wasn't sure if it is a sign of over or under medicating.

    I am still a bit puzzled as my first dose was only 1/4 of a 25 ug tablet and I still got very cold within an hour (but also got great energy). So I had that negative effect even on a very low dose. I am not sure if hair loss just needs more “time” and was also a result of the low dose or that is was caused by the higher dose.

    I was also wandering if your body perhaps lowers production of T4 or T3 in time causing you to become under medicated (while staying on the same dose). I will order a blood test but not sure how helpful they are. In the past they were often within range even when I felt awful.

  • Springviolet,

    If you are taking T3 only your FT4 will be extremely low. It doesn't matter as long as FT3 is good, but within range.

  • Hi clutter, Do some gp's test the Ft3 & 4 when doing bloods or only private Testing for these?


  • Debbstar,

    Depends on what local agreements CCGs have with labs. Some will test TSH only and if it is abnormal may test FT4 in addition, Some will test TSH and FT4, very few will test FT3 unless TSH is <0.03.

    If your GP practice won't do FT4 and FT3 you can order private thyroid tests via

  • Thank u, I'm going to ask my gp first then maybe order the thyroid plus 6 if they refuse. Silly question alert...but how do I get the blood from myself to do this test 🤔

  • Debbstar,

    Instructions on the postal kits. Write a post asking for tips.

  • If previous FT3 results have been towards the upper end of the lab range and you still have felt under-medicated, then it's a possibility you have a degree of cellular resistance to thyroid hormone. This is an under-appreciated problem, even on thyroid forums, but I can't say whether this is your problem.

    Apart from illness like appendicitis and prolonged flu/bronchitis, the only times I've lost a lot of hair have been when under-medicated for hypo, or when starting to replace with T3 only. My hair growth cycle went a bit awry, so a lot fell out and then it all started to grow back at once. It never grew back into the thick mane of my youth, but it's a lot better than when I was taking T4!

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