The place I have bought from before is no longer carrying T3, they say it is no longer being produced

They do have another product they sugested to me called T4, said it was the same exact thing but a diffrent name. Strange they wouldnt sell it as T3 if that was true.
T4 is it worth buying and does it have the same effects as T3? And if i were to purchase it do i take the same doses as i would for T3?
The T3 came in tabs of 25mcg the T4 is 50mcg (not sure if you needed that).
If T4 is not worth the effort, is T3 often faked? Theres another site id chance using but i dont want to get riped off and waste my time if T3 was a big time faked.... you know what i mean.