After all cigarettes didn't become healthier once the dangers were know (long ago). The government had to step in.
To say nothing of tobacco companies acting like a cartel.
Tobacco smoke is. It has MAOIs (addictive) and possibly other drugs.
[1] https://www.scientificamerican.com/article/is-nicotine-all-b...
It's quite likely that there are useful applications of nicotine (even botox has uses!), but that doesn't mean the drug is safe for general use.
In the absence of government regulation, companies would withhold as much information as possible from consumers, preventing those consumers from making informed decisions about which products and services to consume. There would be overwhelming information asymmetry, which would lead to sub-optimal choices. Such a market would not be free, because companies would have immense power over consumers and would undoubtedly abuse it in order to maximize profits.
Capitalism leads to the most efficient allocation of resources, but government regulation needs to exist in order to ensure the profit motive does not outweigh the need to treat consumers fairly.
Doesn't this provide an opportunity for another business such as Consumer Reports?
The meat industry is a great example of this. Battles are being fought currently between companies and the people who record their operations on video. The former obviously doesn't want consumers to find out the horrendous ways in which they treat animals. The latter have to rely on the legal system (i.e. the government) to ensure that information is available to consumers so that they can make informed decisions.