The Study
Usefulness of L-carnitine, a naturally occurring peripheral antagonist of thyroid hormone action, in iatrogenic hyperthyroidism: a randomized, double-blind, placebo-controlled clinical trial.
This study gave some women a supplement and others a sugar pill without telling them which was which, then watched what happened. It found that the supplement seemed to help with symptoms, but we can't be 100% sure because we didn't see the full details of how the study was done.
Analysis score
Maximum 90 for a randomized controlled trial.
Where the score came from
Women taking too much thyroid medicine got a supplement called L-carnitine to see if it could help stop the side effects.
Where does this study sit?
Reviews of RCTs (Meta-analyses)
Max 100Randomized Trials
Max 90Reviews of Cohort Studies
Max 85Cohort Studies
Max 72Reviews of Case-Control Studies
Max 63Case-Control Studies
Max 58Cross-Sectional & Case Series
Max 50Expert Opinion
Max 548 / 100
Quality score
Participants are randomly assigned to treatment or control groups, minimizing bias. The gold standard for testing whether an intervention causes an effect.
Key takeaways
Summary
Based on the study abstract and findings.
- 1Yes — it may help prevent shaky hands, weight loss, and bone thinning caused by too much thyroid medicine, without side effects.
- 2Two doses (2g and 4g per day) both worked equally well over 6 months to reduce symptoms and protect bones.
- 3When they stopped taking it, symptoms came back.
Score breakdown, methodology, conflicts of interest, evidence analysis & raw study data
Publication
Journal
The Journal of clinical endocrinology and metabolism
Year
2001
Authors
S. Benvenga, R. Ruggeri, A. Russo, D. Lapa, A. Campenní, F. Trimarchi
Related Content
Claims (5)
Taking 2 or 4 grams of L-carnitine daily for six months stops and reverses the symptoms and biochemical changes caused by levothyroxine-induced hyperthyroidism in women, and both doses work equally well.
Taking 2,000 to 4,000 milligrams of L-carnitine per day reduces the amount of thyroid hormones entering cells, which lowers the metabolic activity driven by these hormones.
In women with thyroid-related bone loss due to medical treatment, taking 2 or 4 grams of L-carnitine daily for six months is linked to a slight increase in bone density at the hip and spine.
In women with thyroid-related bone loss due to medical treatment, taking 2 or 4 grams of L-carnitine daily for six months does not change levels of osteocalcin or urinary OH-proline, which are markers of bone breakdown.
L-carnitine has not been associated with harmful effects, birth defects, medical contraindications, or interactions with other drugs in people with hyperthyroidism caused by medical treatment.
Not medical advice. For informational purposes only. Always consult a qualified healthcare professional before making health decisions.