It is commonly claimed that you do need to take black pepper with turmeric, but this isn’t quite true. This is largely based on the results of one study which showed that taking black pepper with a curcumin supplement on an empty stomach increased the amount of curcumin in the blood stream. This was done because black pepper contains piperine, which inhibits the action of the enzyme that breaks down curcumin. You can read more about this here.
Curcumin supplements are different to turmeric supplements. Curcumin is an extract of turmeric. Turmeric is a whole food. Many manufacturers seem to interchange the use of turmeric and curcumin, and some even call their product ‘turmeric curcumin’, which is very misleading and confusing (especially when it only contains turmeric).
As a rule, you only need to take black pepper with a curcumin supplement NOT a turmeric supplement. Both are better absorbed and utilised if taken with food.