At time when the Confucians were in power no official would have thought it wise to confess that he practised alchemy.
It is to be noted, however, that even the greatest of Confucians, Chu Hsi (died 1200 A.D.) wrote a commentary on the Ts'an T'ung Ch'i. But he wrote it under the Taoist pseudonym Tsou Hsin. [A.W.]