In response to the flavor question, most juices (quality) are naturally flavored so can't be harmful for you. And generally its just extracted oils or sometimes alcohol based, either way it sure is better for me than tobacco ask my lungs.
Since most people seem to have the opposite experience from what you are having, I hope you've been to a doctor.
It seems to be less about the vapor, and more about something specific to your conditions.
Do you have any similar links for the safety of Propylene Glycol? That could be helpful to new vapers whom have purchased a PG juice.
I find this discussion very interesting. I know it'll be mostly anecdotal, but for those of you who have been vaping for awhile, do you find you can in general breathe easier? I have read the sticky about how vaping is inhaled differently than cigarettes, and am curious if those that don't find it easier to breathe have not chnaged how they inhale for the e-cigs.
The closest hing to anything unhealthy in E-cig vapors is nicotine, which just speeds up your heart rate with no long-term effects.
Did I miss it or did someone mention what the effects of the Flavorings, Sweeteners and Colorants might be?
BTW - Why do they put Colorants in e-Liquids?
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Look, there may be legitimate health questions about vaping, but "we don't know the long term health impact" answers a question that isn't even worth answering. Reject the basic assumption of the question and get on with things.
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