In your clinical experience, has T3 augmentation been effective for treatment-resistant depression?

I have used T3 as Cytomel for this purpose, after hearing Dr. Lee Cohen describe his research on the subject. However, over time I have found that simply using thyroxine, which I think is a mix of T3 and T4, for augmentation works about as well. The response, as I recall, to either one has been meaningful but subtle. The absence of side effects is a plus for either one, but in older women one must be concerned about accelerating bone loss. These days I am more likely to use an adjunctive atypical antipsychotic when a patient seems treatment-resistant (after trying an SNRI).