# The impact of transcranial magnetic stimulation on serum thyroid-stimulating hormone levels in depressive patients: a systematic review and meta-analysis of randomized controlled trials

## TL;DR

A meta-analysis found that transcranial magnetic stimulation (TMS) does not significantly affect thyroid-stimulating hormone (TSH) levels in people with depression.

## Contribution

This is the first systematic review and meta-analysis to evaluate TMS's impact on the hypothalamic-pituitary-thyroid axis in depression.

## Key findings

- TMS had no statistically significant effect on TSH levels in depressed patients.
- Results were robust in sensitivity and publication bias analyses for the general depression cohort.
- Findings for postpartum depression were inconclusive, suggesting a need for further research.

## Abstract

The findings of current research on the impact of transcranial magnetic stimulation (TMS) on thyroid function are inconsistent. This study investigated the effects of TMS on the function of the hypothalamic-pituitary-thyroid axis (HPT axis) in patients with depression through meta-analysis, with a focus on the thyroid-stimulating hormone (TSH).

From inception to November 27, 2025, we conducted a systematic search of randomized controlled trials investigating TMS therapy for depression across PubMed, Embase, Web of Science, the Cochrane Library, and Chinese biomedical databases. Two independent reviewers screened the retrieved abstracts and full-text articles using our predefined search strategy, in duplicate, to assess eligibility criteria, extract data, and evaluate the risk of bias. Due to the high heterogeneity, a random-effects model was selected. The review protocol was prospectively registered in PROSPERO (CRD420251006441).

Meta-analyses of the 5 randomized controlled trials included demonstrated that TMS treatment had no statistically significant effect on TSH levels in depressed patients (Z = 0.06, P = 0.952). Sensitivity analyses and publication bias tests(Egger’s regression test, t = 1.01, P < 0.386) supported the robustness of the results. TSH levels in postpartum depressed patients were also not statistically significantly modulated by TMS (Z = 1.71, P = 0.087), but the results were not robust.

This meta-analysis indicates that TMS exerts no statistically significant influence on TSH concentrations in individuals with depression, implying a negligible effect on the HPT axis. However, it is important to emphasize that this constitutes only initial preliminary evidence. Although the findings are consistent across the depressive cohort, the data about postpartum depression remain inconclusive, highlighting the necessity for additional investigation. These results enhance our understanding of TMS’s neuroendocrine mechanisms within the context of depressive disorder.

https://www.crd.york.ac.uk/PROSPERO/view/CRD420251006441, identifier CRD420251006441.