Vape juice does contain calories, but the amount is so small that it has no meaningful effect on your diet or weight. The two base ingredients in e-liquid, propylene glycol and vegetable glycerin, both contain roughly 4 calories per gram. A typical day of vaping delivers somewhere between 5 and 25 calories total, which is less than a single bite of an apple.
Where the Calories Come From
Nearly all e-liquid is made from two carrier liquids: propylene glycol (PG) and vegetable glycerin (VG). These are the same food-grade ingredients found in packaged baked goods, ice cream, and salad dressings. PG contains about 4 calories per gram, while VG is slightly higher at 4.32 calories per gram. Because VG is denser, a single milliliter of it has around 5.4 calories compared to 4.14 calories for a milliliter of PG.
The flavorings in vape juice are a different story. Most e-liquids use artificial sweeteners like sucralose, saccharin, or aspartame to create their taste. These compounds provide sweetness without adding calories, so the flavor of your vape isn’t contributing anything extra.
Why Those Calories Barely Count
Even though the liquid itself has calories, you’re not drinking it. You’re inhaling an aerosol, which means only a fraction of the liquid’s caloric content enters your body, and what does enter arrives through your lungs rather than your digestive system. Your body absorbs nutrients and calories primarily through the gut. The small amount of vapor that contacts your mouth, throat, and lungs doesn’t get processed the same way food does.
To put the numbers in perspective: a heavy vaper might go through 5 milliliters of e-liquid per day. If that liquid is a 70/30 VG/PG mix (one of the most common ratios), the entire day’s worth of liquid contains roughly 20 to 25 calories before accounting for the fact that most of it is exhaled. That’s fewer calories than a single sugar cube. Even if your body somehow absorbed every calorie from every puff, it would make zero difference to your weight.
Vaping, Weight, and Appetite
If you’re asking about vape calories because you’re concerned about weight gain, the more relevant factor is nicotine, not the liquid itself. Nicotine increases your resting metabolic rate and suppresses appetite, which is why people who use nicotine products tend to weigh slightly less than non-users. Research on smoking cessation shows that people who quit gain a median of about 7 kilograms (roughly 15 pounds), largely because their metabolism slows and their appetite returns to normal levels.
This means nicotine-containing vapes may actually reduce your calorie intake indirectly by blunting hunger, not add to it through the liquid’s calorie content. That said, using nicotine as a weight management tool comes with its own set of health risks, including potential effects on blood sugar regulation. One large study using national health survey data found that e-cigarette users who had previously smoked were about 63% more likely to show signs of insulin resistance compared to people who never vaped, though vaping wasn’t directly linked to higher rates of diabetes or prediabetes.
Will Vaping Break a Fast?
This is a common follow-up question, especially for people doing intermittent fasting. The trace calories in vape aerosol are far too small to trigger a meaningful insulin response or knock your body out of a fasted state. Most fasting protocols consider anything under 50 calories to be negligible, and a full day of vaping falls well under that threshold. Nicotine itself doesn’t contain calories and doesn’t appear to spike blood sugar on its own, though research on its long-term metabolic effects is still mixed.
If you’re fasting for blood work or a medical procedure, the bigger concern isn’t calories but nicotine’s effect on your heart rate and blood pressure. Your doctor’s instructions about fasting before lab tests are about more than just calorie intake.
The Bottom Line on Vape Calories
The base liquids in vape juice contain real calories, about 4 to 5 per milliliter. But the amount you actually absorb through inhalation is trivially small. Vaping won’t contribute to weight gain through its calorie content, won’t interfere with a diet, and won’t break a fast in any practical sense. If nicotine use is affecting your weight, it’s happening through appetite suppression and metabolic changes, not through the calories in the liquid.