How many different chemical substances are there (on the average) in a human cell?
I saw of an estimation of ~ 1 billion (10^9) in sci-pop books.
Is there any reliable estimation rooted in the scientific community?
There is this question, but it does not have any answer. It only states that modern researches use (model) only a very limited number of chemicals within a cell. But what is the estimation of the real complexity of a problem.