The dosage of TUDCA supplementation you need will depend on the benefits you are seeking from its use.

The liver protective benefits can be had for as little as 500mg/day, which the extrapolated numbers from an animal study show a 4,000mg dosage for neuroprotection from age-related memory loss and 1,750mg for muscular and liver insulin sensitivity.

A dose calculated at 15-20mg/kg of bodyweight can be used to improve overall bile salt composition in the body. [1]

Most users of tudca normally take a dose around 500mg a day, although it common to go higher than this to 1000mg+.

[1] http://examine.com/supplements/Tauroursodeoxycholic+Acid/#main_clinical_results