What amount nicotine is too mich?

How about any??: There is no safe amount of nicotine, mainly because the data show that an individual who smokes more than 7 cigarettes in their life has a 90% chance of becoming a regular smoker. There are people who will smoke one or two cigarettes on a rare basis, and it is unlikely that that causes serious harm (unless they have asthma or unusual sensitivity). Even 1-2 cigarettes per day increases health risks.