It's a unknown. Personally, I think it seems to become less effective later into a bottle of it than at the start. I also get more stomach upset later than sooner.
I tried the: low-dose-while-on years ago because I had some left that had been making me want to

Puke!.
I wanted to use it before it expired, so I did it like 300iu. I was surprised it had a good effect at the low dose.
If I dont use it for a while - I become more sensitive to a small dose again.
I'm leery of using it non-stop as part of a HRT method. I just dont think thats a good idea.
Lets hear results and personal impression to the low dose/ on protocol.