Is vaping actually bad for you,or is it the liquid?

Regarding the question "Is it the e-cigarette itself that is harmful, or is it the liquid inside the e-cigarette that is harmful?", the most straightforward answer is: The two are inseparable. As a whole, they both pose clear health risks.
Discussing "electronic cigarette devices" and "cigarette liquid" separately is not very meaningful, because the harm of electronic cigarettes precisely stems from the entire process of "the device heating a specific liquid to produce aerosol and then being inhaled".
?? Main Risks and Sources of E-cigarettes
The table below summarizes the main hazards of e-cigarettes and the associated components:
Risk category Examples of specific hazards or diseases Primary associated harmful components
Respiratory system damage Lung damage (such as EVALI), bronchitis, pneumonia, "popcorn lung" (obstructive bronchiolitis) Vitamin E acetate, diacetyl, formaldehyde, acrolein
Cardiovascular system impact Increased risk of heart disease and stroke, damage to vascular function Nicotine
Addiction Highly addictive, damage to the developing brain of teenagers Nicotine (even products labeled as "no nicotine" may contain it)
Carcinogenic risk Contains multiple carcinogens Formaldehyde, acetaldehyde, certain heavy metals
Other risks Contains illegal additives such as etomidate, ketamine, etc. Illegal additives
❗ Common misunderstandings about "e-liquid"
You may have heard the statement that "the main components of e-liquid are edible substances, so it is safe", which is a key misconception:
"Food safety" does not equate to "inhalation safety": The basic components of smoke liquid (such as propylene glycol, glycerin, and food flavorings) are recognized as "generally recognized as safe" (GRAS) in food, but this certification only applies to "eating". When these substances are heated and inhaled into the lungs, their chemical properties and toxicity change, causing irritation and harm to the respiratory tract.
Heating generates new harmful substances: During the heating process, the components of the smoke liquid will react to form new harmful compounds, such as the carcinogenic formaldehyde.
Illegal and unknown additives: The quality of products on the market (especially those from illegal channels) varies greatly. They may contain vitamin E acetate (associated with severe lung damage) or other unknown harmful substances.
?? How to Understand the Hazards of E-cigarettes
For those who have never smoked: E-cigarettes are absolutely unsafe. They expose you to harmful substances and may lead to nicotine addiction. Any form of inhalation is an unnecessary risk.
For smokers: The mainstream public health view holds that a complete switch to e-cigarettes might reduce some risks compared to continuing to smoke, as it avoids the thousands of chemicals produced by tobacco combustion. However, this does not mean that e-cigarettes are safe; it is merely a risk reduction strategy of choosing the lesser of two evils.
The way of use increases risks: The convenience of e-cigarettes may lead to more frequent use, resulting in unintentional intake of more nicotine.
In summary, the risks associated with e-cigarettes are the result of the combined effects of the device, the e-liquid, and the usage behavior.