“Very bad” is too strong. Nicotine is a drug that does not have therapeutic value. It does not cause cancer. It is addictive. It has mild nootropic effects, as well as other effects like appetite suppression. Here’s a good, easy to read rundown:
https://elemental.medium.com/your-brain-on-nicotine-668c0b6a...
We should be careful to differentiate smoking/vaping from nicotine use.
That is false.
> Nicotine in tobacco brings illness and death to millions of people. Yet nicotine in its pure form has the potential to be a valuable pharmaceutical agent. Nicotine fairly specifically binds to the cholinergic nicotinic gating site on cationic ion channels in receptors throughout the body. This action stimulates the release of a variety of neurotransmitters including especially catecholamines and serotonin. When chronically taken, nicotine may result in: (1) positive reinforcement, (2) negative reinforcement, (3) reduction of body weight, (4) enhancement of performance, and protection against; (5) Parkinson's disease (6) Tourette's disease (7) Alzheimers disease, (8) ulcerative colitis and (9) sleep apnea. The reliability of these effects varies greatly but justifies the search for more therapeutic applications for this interesting compound.[1]
Plus, you even said it yourself: "It has mild nootropic effects, as well as other effects like appetite suppression". Sounds like it could pretty much be therapeutic for cognition and weight loss.