Hello – I would really suggest that you explain your concerns to your doctor. Tell him/her that you would rather deal with two different prescriptions of alternating dosages than skipping a day. (Of course, you would need a good system to manage the alternate doses – I’ve used one of those pill boxes that has a compartment for each day of the week).
For someone who is on T4-only therapy, I don’t think this would be a huge deal, as T4 has a fairly long “shelf life”. However, with T3, you are getting a very powerful hormone that does not stay in the body for a long time. Obviously, I’m a fellow patient, not a doc – but it seems to me that your body would likely feel the day of missing T3.
Take care!