Whenever you think of combining energies including Cosmic Serums, you can always read about them individually.
The BRAIN SERUM article mentions in point 3 that it should not be given together with TOTAL WEALTH SERUM.
There is no incompatibility between these serums, it only that energies will get divided, so it is recommended to give them separately.
Hope you are reading the articles too. Sharat Sir has taken lot of efforts to write in detail in each of his article including all 30 COSMIC serums.
There is a lot to explore in these articles.
GOLDEN SUNRISE