Why is Propylene Glycol (PG) Used in E-Liquid?

PG is included in e-liquids to create visible vapor since nicotine and flavorings alone don’t produce any. This vapor serves two purposes:

It helps deliver nicotine to the lungs.
It gives users the feeling of inhaling and exhaling something resembling cigarette smoke.

Both PG and vegetable glycerin (VG) are added to ensure a satisfying vapor cloud. Despite myths, PG isn’t the same as radiator fluid—it’s a widely used substance in food, cosmetics, and even fog machines.

Other Uses of Propylene Glycol

PG that meets BP or USP standards is found in everyday products like:

Cosmetics and toiletries
Food coloring and cake mixes
Salad dressings and soft drinks
Theater and nightclub fog machines

Side Effects of Vaping Propylene Glycol

Some first-time users may experience:

Dry throat: PG attracts moisture, which can leave your throat feeling sore.
Muscle aches: PG converts to lactic acid in the body, potentially causing minor discomfort.
Strong-smelling urine: A temporary side effect.

Drinking more fluids can help alleviate these symptoms quickly. If symptoms persist, it might indicate an allergy.

Signs of PG Allergy

Some people discover an allergy to PG when using PG-based e-liquids for the first time. Symptoms may include:

Night sweats
Body rash
Diarrhea
Sore or irritated throat

If these occur, consult a doctor and switch to VG-based e-liquids.

Vegetable Glycerin (VG)

VG is a thicker, sweeter alternative to PG that produces more vapor. However, higher VG content may slightly reduce flavor intensity. VG is widely used in food and drink additives and is labeled safe by the FDA.

Possible Side Effects of VG:
Rare reactions may include:

Allergies to palm or coconut oil
Skin irritation or respiratory discomfort
Nausea or diarrhea from large quantities

Storage Advice for PG and VG

PG and VG have a shelf life of about two years if stored below 40°C (104°F) in sealed containers away from UV light.