Thyroid UK

Carnitine, brand name carnitor

type of drug;Thyroid Hormone

Uses;To treat deficiency of Carnitine, a chemical which is vital in the process of changing fat to energy, due to genetic defects or dialysis.

How it works; it helps to transport long chain fatty acids into cells to be burned to produce energy

Caution; to be used with caution if there is impaired kidney function

Thought this would be intresting to post. Would like to hear from anyone who uses it.

I know you can buy it through health stores, eg Holland &Barratt. ,

6 Replies

Can you please provide a link for where you read this information. Especially this bit "type of drug;Thyroid Hormone".


Not at all sure what you were trying to say in the original post.

The abstract below (full paper available by follow the link at the bottom) suggests that l-carnitine might have some role in HYPERthyroidism. It is clear that there is a question over HYPOthyroid people taking it.

Usefulness of L-carnitine, a naturally occurring peripheral antagonist of thyroid hormone action, in iatrogenic hyperthyroidism: a randomized, double-blind, placebo-controlled clinical trial.

Benvenga S, Ruggeri RM, Russo A, Lapa D, Campenni A, Trimarchi F.

Cattedra & Sezione di Endocrinologia, Dipartimento Clinico-sperimentale di Medicina e Farmacologia, University of Messina School of Medicine, 98125 Messina, Italy.


Old studies in animals and unblinded studies in a few hyperthyroid patients suggested that L -carnitine is a periferal antagonist of thyroid hormone action at least in some tissues. This conclusion was substantiated by our recent observation that carnitine inhibits thyroid hormone entry into the nucleus of hepatocytes, neurons, and fibroblasts. In the randomized, double-blind, placebo-controlled 6-month trial reported here, we assessed whether 2 or 4 g/d oral L-carnitine were able to both reverse and prevent/minimize nine hyperthyroidism- related symptoms. We also evaluated changes on nine thyroid hormone-sensitive biochemical parameters and on vertebral and hip mineral density (bone mineral density). Fifty women under a fixed TSH-suppressive dose of L -T(4) for all 6 months were randomly allocated to five groups of 10 subjects each. Group 0 associated placebo for 6 months; groups A2 and A4 started associating placebo (first bimester), substituted placebo with 2 or 4 g/d carnitine (second bimester), and then returned to the association with placebo. Groups B2 and B4 started associating 2 and 4 g/d carnitine for the first two bimesters, and then substituted carnitine with placebo (third bimester). Symptoms and biochemical parameters worsened in group 0. In group A, symptoms and biochemical parameters worsened during the first bimester, returned to baseline or increased minimally during the second bimester (except osteocalcin and urinary OH-proline), and worsened again in the third bimester. In group B, symptoms and biochemical parameters (except osteocalcin and urinary OH-proline) did not worsen or even improved over the first 4 months; they tended to worsen in the third bimester. In both the A and B groups, the two doses of carnitine were similarly effective. At the end of the trial, bone mineral density tended to increase in groups B and A (B > A). In conclusion, L-carnitine is effective in both reversing and preventing symptoms of hyperthyroidism and has a beneficial effect on bone mineralization. Because hyperthyroidism depletes the body deposits of carnitine and since carnitine has no toxicity, teratogenicity, contraindications and interactions with drugs, carnitine can be of clinical use.



Related to the PubMed abstract quoted above, is another PubMed abstract entitled:

Effects of carnitine on thyroid hormone action.

Which states:

" By experiments on cells (neurons, hepatocytes, and fibroblasts) that are targets for thyroid hormones and a randomized clinical trial on iatrogenic hyperthyroidism, we validated the concept that L-carnitine is a peripheral antagonist of thyroid hormone action.

In particular, L-carnitine inhibits both triiodothyronine (T3) and thyroxine (T4) entry into the cell nuclei."


"A very recent clinical observation proved the usefulness of L-carnitine in the most serious form of hyperthyroidism: thyroid storm. Since hyperthyroidism impoverishes the tissue deposits of carnitine, there is a rationale for using L-carnitine at least in certain clinical settings."

You can read the full abstract here


I actually found this listed in a book. Prescription medicines A Practical Guide.

I actually feel quite bad for doing so now . I thought it would be helpful if the GP's would prescribe it to people who would benefit, as alot of people who use this site are unaware of treatments OR have tried diffrent treatments which failed to help them.

Posting the information felt right,if it helps anyone


No need to feel bad, you did nothing wrong by posting, but it's always a good idea to say where you obtained the information.

I was concerned about the apparently misleading statement that carnitine is a thyroid hormone - which it is not.

The important thing to note from the PubMed abstracts quoted above, is that this is not something that will help people with thyroid hormone deficiency, but it might be useful for people whose thyroids are over-active.

It is in theory something that a doctor could prescribe, but it is relatively expensive so I doubt many NHS doctors would be likely to offer this treatment (even if they actually know about it and understand how it works!).


I brought a large container of this and took it for a few weeks, and then i read you shouldnt take it if you take thyoxine and inhibits its absorbtion so i stopped.


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