Objective and background: Hashimoto's
thyroiditis (HT) is both a B cell- and T cell-mediated, organ-specific
autoimmune disease. No current treatment for underlying pathological mechanisms is available for HT and once diagnosed it requires long-term
levothyroxine (LT4) treatment in most patients. The aim of our study was to evaluate the effects of
photobiomodulation (
PBM) on HT patients regarding thyroid functions, thyroid
autoantibody levels, and decrease in
hormone replacement needs. Methods: A total of 350 patients, who were diagnosed with Hashimoto`s
thyroiditis, were included in our study. Patients were classified into two groups. Group 1 (n = 210) received
PBM and dietary supplementation such as
vitamin D,
iron, and
selenium. Group 2 (n = 140) received dietary supplements only. Patients' needs for LT4 replacement levels,
triiodothyronine (T3),
thyroxine (T4), and TSH levels, T3/T4 ratio, and thyroid
autoantibody levels were evaluated. Results: As we compare both groups, the increase in T3 levels and T3/T4 ratio was markedly superior in Group 1 (p = 0.0001). The decrease in
thyroid peroxidase antibody (TPO Ab) levels was also significantly different between both groups (p = 0.0001).
Hormone replacement needs were also significantly decreased in Group 1 compared with Group 2 (p = 0.03).
Low-level laser therapy (
LLLT) is 70 times more effective in increasing T3/T4 ratio (p = 0.001) and 15 times more effective in decreasing
levothyroxine dosage. Conclusions: Our results are encouraging and
PBM seems to be very effective in increasing T3/T4 ratio and decreasing TPO Ab levels and weekly dosages of LT4 replacement
therapy. Anti-inflammatory properties of
PBM are greatly responsible for these changes and
PBM causes major improvements in HT-related symptoms of the patient.