I can only find figures for the Expendable configuration - 63.8 metric tons. The Wikipedia article says
The partially reusable Falcon Heavy falls into the heavy-lift range of launch systems, capable of lifting 20 to 50 metric tons into low Earth orbit (LEO), under the classification system used by a NASA human spaceflight review panel. A fully expendable Falcon Heavy may also reach the super heavy-lift category (above 50 metric tons to LEO).
However, this ballpark range has no reference other than a NASA report that makes no mention of Falcon Heavy and is only used to define rocket categories (heavy-lift and super heavy-lift).
Now, I did find this quote on Teslarati, of all places, but it isn't referenced, and as sites that specialize in this area have not named a figure, I'm not sure of its accuracy
...the fully reusable Falcon Heavy has a max payload of about 23,000 kg to LEO and 8,000 kg to GTO.
I do note that the Wikipedia article does have a figure of 8000 kg to GTO, from which the other orbits could be extrapolated, but that gets a different figure than the one mentioned above and is perhaps a bit simplistic. Using Spacex's published payload capacities, that implies 19 tons to LEO.
So how much can the FH Reusable lift?