Just to clarify for anyone reading. 20mcg of T3 is not a supra physiological dose. >=50 is however.
Here is the reference that proves what GH said, yes, the supraphysiological dosage for someone who has mild degree Hypothyroidism"25mcg"... I sinned in saying that it was 20mcg. (more, it's better to use less than more since we don't suffer from Hypothyroidism.