Any hard proof (pretest/post-test) that Low Carb increases TSH and whether it is bad or not?

Answered on August 19, 2014
Created September 20, 2012 at 2:12 PM


I am male, 39, 5???10??????, 178 and I have been on semi-strict (coffee, rare cream or cheese) Paleo for about a year. When I started, I had really low energy for about 6mts partly I think because of the low fat that I was taking (I was eating everything lean) and luck of exercise. After routine blood test I discover that I have low testosterone (150) and my TSH was 3.15. I was referred to endocrinologist and he put me on clomid to raise my testosterone levels. After few months my endo tested me for TSH and my vitamin profile; my TSH was 3.75 (proper pale diet with plenty of fats) and I was low on B12 and D3. Doctor put me on synthroid, B12, and D3.

I now exercise regularly (4-5 times a week, HIIT + Oly lifts) and eat right (veggies, some grass fed meats, ect, no fruits or nuts). After retesting for TSH it only came down to 3. I requested to be put on natural med like Armour, however, after reading a wealth of information out there regarding low carb and increased TSH levels I think that my doctor and I might be jumping a gun here. It seems that with low carb TSH naturally goes up and thyroid function goes down due to lessened load. Plus my TSH numbers are borderline and I am not sure that I should be messing with it. Without pretest (prior to paleo diet) there is no way to say with confidence that it is a low cab diet that is driving TSH levels, on the other hand, based on evidence out there, it is quite possible that THS levels go up with low carb but it is just a normal process.

My questions are:

What should individual on a low cab (>50g) do if TSH levels goes higher than normal?

Should I get off the Armour and see how I feel for about a week?

Should I keep taking Armour?

Should I kick Clomid as well?

Any response, be it personal or not, will be appreciated. If you have similar story please share. For now I am thinking to log how I feel with the meds and then how I feel without them and make a decision after that, but I would very much appreciate any comments as they will definitely will help to solve this little problem of mine.

Thank you very much.

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on September 20, 2012
at 07:48 PM

I got the feeling that the answers to Dr. Cate's query were not definitive. I'm not sure that there's solid evidence that low carbing causes hypothyroidism. Thyroid downregulation may even be a normal adaptive response to lowering carbs, not necessarily a problem. Or it could be (my theory) that we tend to ingest fewer calories on low carb, and that causes the thyroid to downregulate.

In my N=1 experiment, I had a TSH of 5.49. My doctor assured me that nothing I could do dietwise would improve this. But I looked at my diet and saw that many days I was eating only 900 or so calories--way too low. So I increased my calories to about 1300/day while remaining very low carb. My TSH went down to 3.0. No medication. And, throughout all of this I feel fine--not sluggish or tired, not cold (I'm warm all the time, actually), sleeping well. I think my TSH is continuing to improve simply from eating sufficient calories.



on September 20, 2012
at 05:04 PM

I don't have a lot of experience with this but there's a good write up of thyroid effects from low carb at this blog, some good conversation in the comments, and links to some thyroid studies that might help you at the bottom of the post.

Also in the comments of this post by Dr. Cate there's lots of stories similar to yours, she encourages people to share their thyroid numbers. I think she's researching for her next book which should have some good info when it comes out.

Good luck Dino! I hope this helps you out some.

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