L-carnitine supplementation for the management of fatigue in patients with hypothyroidism on levothyroxine treatment: a randomized, double-blind, placebo-controlled trial

L-carnitine supplementation for the management of fatigue in patients with hypothyroidism on levothyroxine treatment [Letter to the Editor]

“…We have read with interest the nice article by An et al [1], and thank them for having cited some papers of our team, but not one [2]. That paper [2] not only mentions the wide range of patients who may benefit of L-carnitine supplementation, but also underscores that on some thyroid hormone targets L-carnitine acts as an antagonist, while on others as an agonist.…”

“…First, we continue to confirm that L-carnitine has minimal, if any, side-effects. Second, the formulation of L-carnitine we use (one ampoule of 1 mg given twice a day) is more practical than the one used by An et al (3 tablets of 0.33 g twice a day for a total of 1,980 mg/d) [1].Concerning the relevant comments, we think that the setting or framework for this study is the symptomatology of hypothyroidism which persists despite adequate daily doses of L-T4, and that concerns approxi-2016, 63 (10), [937][938] …”

“…This residual symptomatology consists essentially in physical and/or mental fatigue, and can be addressed by adding L-T3 to L-T4 [3].Within the limits of words and references permitted by the journal and not to give complete details that would preclude publication of a full paper, we would like to give some information in support of the An and colleagues' article [1]. We have a number of hypothyroid patients who have taken 2 g/d L-carnitine even for longer than 12 weeks, and we confirm the benefit in terms of physical and mental fatigue.…”

“…The glucocorticoid-mimetic activity of L-carnitine, resulting from stimulated transcriptional activity of GRα, would have not been predicted by the inhibiting effect of L-carnitine on glucorticoid entry into cells [4]. Now, considering that (i) cytokines are pathogenetically involved in fatigue and other neuropsychological disorders, (ii) GRα-mediated action of glucococorticoids results in "energizing" effects [5], and (iii) glucocorticoids extert a well-known inhibition of TSH secretion, it cannot be coincidental that the improved subgroup had an almost 3-fold lower concentration of TSH compared to the non-improved subgroup [1]. …”

Role and Location of L-Carnitine in Cytoprotection and Correction of Metabolic Processes in Patients With Metabolic Syndrome

“…В исследованиях последних лет отмечены положи-тельные эффекты L-карнитина у пациентов с остеоартро-зом [93], гипотиреозом [94][95][96], вульгарной пузырчаткой (Pemphigus vulgaris) [97].…”