Radioiodine (I-131) therapy is of proven efficacy for treatment of differentiated thyroid carcinoma (DTC). However, loss of differentiation in recurrent or metastatic DTC which decrease I-131 uptake may decrease the efficacy of I-131 therapy. Therefore, strategies to improve I-131 uptake are mandatory. This study is an open label clinical study to evaluate the effectiveness of alpha-lipoic acid (ALA) for improving I-131 uptake in recurrent or metastatic of DTC with defective I-131 uptake.

Inclusion Criteria:

1. aged 20 to 75 years

2. under birth control, if fertile women

3. Groups

   • who received radioactive iodine treatment for recurrent and metastatic thyroid cancer, and did not showed any uptake at post-therapeutic whole body scan
   • who planned to receive empirical radioactive treatment due to high expected recurrence

Exclusion Criteria:

• allergic to alpha-lipoic acid
• severe heart failure, lung disease, or end-stage renal disease
• liver function abnormalities (x2.5 above normal limits)
• neuropsychologically unstable patients
• previous history of drug medication such as oral steroid, digoxin, theophylline, carbamazepine, valproic acid, phenobarbital, methotrexate, cyclosporin, tacrolimus within 3 months before this recruitment.
• who is already taking alpha-lipoic acid for other purpose.