Does Levothyroxine cause weight loss?

[Mynx537]

I have recently been put on Levothyroxine at 50mcg, however my doctor now wants me to increase my dose at 100mcg. My symptoms have shown no sign of improving and I have begun to lose weight.

My weight 3 weeks ago was 8 stone or 112 pounds. Now it is 7 stone 6 pounds or 106 pounds. This to me seems like quite a drop and my doctors are now keeping an eye on me about my weight as they do not want me to lose any more.

Is there anything I am doing wrong? I have gradually been removing gluten from my diet and I eat quite a lot anyway so I don't know what is happening and why.

Thank you.

[Mynx537]

Thanks for your reply.

I can ask my doctor at the next appointment if he can order both FT3 and FT4. I only hope he can still do this as the blood test has already been put through and booked. Yes, I have been told labs will not run them too.

I don't think doubling or tripling my dose was a good idea of his as I have had some hyper symptoms earlier today that worried me.

I'm glad that I've got 6 weeks in between tests. :) That's good to know, so thanks.

[Barb135]

If you can, try to get FT3 and FT4 done at the same time.  You can try to talk to your doctor about getting them both and see if he will order them, though we've been told that sometimes, even when ordered by the doctor, the labs won't run them.

Raising your dose was probably okay... what I'm having the problem with is that he's doubling/tripling it without knowing if there's a dose in between that would be better for you. It's never a good idea to make very large changes all at once.

From Feb 12 to March 25, is approximately 6 weeks, which is good for testing.

[Mynx537]

Hi thanks for your reply.

When I had the FT3 done in November I did not have the FT4 tested as well, no.

Doctor wanted to double my dose based on the TSH back in January, I presume. When I called about my symptoms not improving, I think he had no information regarding the TSH done in February as I have been told it takes 3-4 weeks for those results to come through to them.

My next blood draw is 25th March and my last one was done on the 12th February. I think that's ok.

[Barb135]

A drop in dosage from 150 to 50 is huge!!  In my opinion, your doctor is making way too large increases/decreases in your med dosing.   There are a lot of different dosages between 50 mcg and 150 mcg.  Making smaller increases/decreases will allow you to reach a point that's actually right for you, instead of swinging back and forth.

I don't know if you'd have to pay extra for an FT4 test every time you test or not.  That depends on the NHS guidelines.

When you  had the FT3 test in Nov, did you also have an FT4 at the same time?  The results for both really need to come from the same draw, due to differences in the way the tests may be done in different labs, as well as varying reference ranges.  That said, your FT3 was at 64% of its range in Nov and the corresponding FT4 was only at 33%.  I would agree that you're converting adequately, but since FT3 is the hormone that's actually used by the individual cells, it's important to monitor it to be sure levels are staying consistent and where you need them.  Considering the manner in which your doctor is adjusting your dosage, I'm not surprised that you have trouble keeping your weight stable.  

Why does your doctor want to double your dose?  It would be much better to increase to, say, 75 mcg than such a steep increase, especially considering that there is no FT4/FT3 to help guide the decision and your TSH is actually "in range", though a bit on the high side.  Better yet, alternating 50 mcg and 75 mcg, which would average out to 62.5 mcg/day  would give you an even smaller increase, which might be enough.

I notice, also that you've been testing on a monthly basis.  It takes 4-6 weeks for an increase/decrease to take full effect.  You might want to spread your testing out to 5-6 weeks apart in order to let the dosage stabilize better.

[Mynx537]

Hi, thanks for your reply.

When I spoke to my doctor in Jan 2014, this was after the TSH result came back. They decided to drop the Levo as the TSH was back in range and would only increase if it fell out of range again.

Would I need to pay extra to have FT4 tested every time I be tested? I was also tested for FT3. Sorry I did not include this as it was a private result but here it is:

Nov 2013 - FT3: 5.5 (3.1-6.8)

I have been told by the private lab involved I am converting fine.

[Barb135]

Please verify dosage decrease from 150 mcg in Dec 2013 to 50 mcg in Jan 2014.  That's a huge drop, when your levels didn't warrant it.  

First off, it looks as though your doctor is only trying to control your condition by keeping TSH levels "in range", no matter what your other levels might be.  And to make matters worse, your lab is using an outdated reference range for TSH.  Over 10 yrs ago, the AACE recommended that the reference range for TSH be changed to 0.3-3.0.  Many/most labs and doctors have been reluctant to change over.

Secondly, any doctor who adjusts medication, bases solely on TSH results will keep you ill.  We see this a lot with people in U.K. who are living with the NHS guidelines that call for TSH as being the basis for thyroid conditions.  

You need to talk to your doctor about getting the FT4 "every" time you test and also about adding the Free T3 test "every" time you test.  Free T3 is the actual hormone used by individual cells, while FT4 is a storage hormone that must be converted to FT3 in order to be used.  TSH is a pituitary hormone, that's good only for a diagnostic tool and should not be the sole basis for diagnosing a thyroid issue, or adjusting medication.

Increasing dosage by tripling or decreasing by half keeps patients on a roller coaster that's really hard to get off from, since TSH fluctuates greatly over the course of a day and is affected by many things, other than thyroid hormones.

We've had quite a few members who have had to go private in order to get the testing/treatment they need.  

[Mynx537]

Hi, thank you for your reply.

Here are all lab results:

Nov 2011

TSH - 5.2 (0.27-4.2)
FT4 - 16.8 (12-22)
(No medication started)

Feb 2012

TSH - 2.2 (0.27-4.2)
No FT4 as TSH normal

Jan 2013

TSH - 0.69 (0.27-4.2)
Anti-TPO - 84,000 (<34)

May 2013

TSH - 22 (0.27-4.2)
FT4 - 10.9 (12-22)
Levo started at 25mcg, then 50mcg and then 75mcg

Aug 2013

TSH - 4 (0.27-4.2)
No FT4 as TSH normal
Levo increased to 125mcg

Nov 2013

TSH - 4.3 (0.27-4.2)
FT4 - 15.3 (12-22)
Levo increased to 150mcg

Dec 2013

TSH - 4.6 (0.27-4.2)
FT4 - 15.6 (12-22)
Anti-TPO - 41,000 (<34)
Levo not increased

Jan 2014

TSH - 2.7 (0.27-4.2)
No FT4 as TSH normal
Levo decreased to 50mcg

Feb 2014

TSH - 3.6 (0.27-4.2)
No FT4 as TSH normal
Levo doubled to 100mcg

Celiac Disease profile - negative

Thanks :)

[AJWS6]

Hi, although I have not experienced any weight fluctuations on Levo, to much levo can cause weight loss (hyper).  50 to 100mcg is a large increase.  Do you have recent lab results/referance range you can post up, so someone can assist ?  

Diet can contribute to weight loss as well, not familiar with gluten, but low carb can drop the weight.