Is it a sin to vape?
A question about the body that Scripture never takes up directly

In short
Nothing in the Bible addresses tobacco or nicotine, which did not reach the writers' world. The case is made from stewardship of the body and from the danger of being mastered by a habit. Most Christians treat it as unwise rather than as sin, and few treat it as a matter of salvation.
What the text says
What? know ye not that your body is the temple of the Holy Ghost which is in you, which ye have of God, and ye are not your own?
Colossians 2:23 was the verse of the day on July 26, 2023. See that day
Often brought in1 Corinthians 6:12
All things are lawful unto me, but all things are not expedient: all things are lawful for me, but I will not be brought under the power of any.
Paul's own test for a disputed liberty: not whether it is permitted, but whether it has come to own him. Nicotine gives that test something to bite on.
The counterweightColossians 2:23
Which things have indeed a shew of wisdom in will worship, and humility, and neglecting of the body; not in any honour to the satisfying of the flesh.
A caution against rules that look like devotion. Paul is wary of prohibitions invented in the name of holiness, which is worth remembering when a habit becomes a marker of who is serious.
What Christians agree on
Addiction is a genuine concern in Christian ethics, and deliberately damaging your health needs a reason. Nobody claims vaping is good for you, and nobody claims it sends you to hell.
Where they disagree
Those who apply the temple passage directly
Knowingly harming your body is a failure of stewardship. That it is legal and common changes nothing about what it does to you.
Those who see a matter of wisdom, not sin
Scripture is silent, and inventing a prohibition where God left one out is its own error. Unwise and sinful are not the same word.
Those who focus on mastery
The question is not the vapour but the dependence. A habit you cannot put down has already answered the question about who is in charge.
Questions worth asking
- Do I choose this each time, or does it choose for me?
- What happens in me when I cannot have it for a few hours?
- Am I honest with the people close to me about how much?
If you came here hoping for a verdict, the honest answer is that Scripture leaves this one to you and gives you good questions to take into it. That is less satisfying than a rule and considerably more use.