PG and VG are the two base liquids in every e-liquid. PG (propylene glycol) is a thin, nearly tasteless liquid that carries flavor well and produces a noticeable throat hit. VG (vegetable glycerin) is a thicker, slightly sweet liquid responsible for dense vapor clouds. Most e-liquids blend the two in specific ratios to balance flavor, throat sensation, and vapor production.
What PG and VG Actually Are
Propylene glycol is a synthetic compound widely used in food, cosmetics, and pharmaceuticals. The FDA classifies it as Generally Recognized as Safe (GRAS) for use in food products, where it works as a humectant, flavor carrier, and stabilizer. It’s a thin, odorless liquid with almost no sweetness.
Vegetable glycerin is derived from plant oils, typically palm, soy, or coconut. It has a thick, syrupy consistency and is roughly 60% as sweet as sugar, which gives it a faintly sweet taste on its own. Like PG, it shows up in countless food and personal care products as a moisturizer and thickener.
Chemically, the two are close relatives. Both are small, three-carbon molecules. VG has one extra oxygen atom, which accounts for its heavier texture and higher boiling point. PG boils at about 189°C (372°F), while VG requires significantly more heat, boiling at roughly 292°C (558°F). That difference matters inside a vape device: PG vaporizes more easily at lower temperatures, while VG needs more power to produce its characteristic thick clouds.
How They Affect Throat Hit
If you’re coming from cigarettes and want that familiar catch in the back of your throat, PG is the ingredient that delivers it. E-liquids with a higher proportion of PG produce a sharper, more cigarette-like throat sensation. Many former smokers prefer this because it mimics what they’re used to.
VG does the opposite. It smooths things out. Higher VG blends feel softer on the inhale, and at very high VG levels (70% or above), the throat hit can feel mild to almost nonexistent. If throat harshness bothers you or you find yourself coughing, shifting toward more VG in your ratio typically helps.
How They Affect Vapor and Flavor
VG is the cloud maker. Its thicker consistency and lower volatility mean it produces denser, more visible vapor. If big clouds are your goal, you want a VG-heavy blend. PG produces noticeably thinner, wispier vapor by comparison.
Flavor behaves differently with each base. PG is a better flavor carrier, so e-liquids with more PG tend to deliver sharper, more complex flavor profiles. VG’s natural sweetness can slightly mute or round off flavors, though it adds a subtle sweetness of its own. For the most pronounced flavor, a blend with at least 30% PG is a common starting point.
Common PG/VG Ratios and When to Use Them
E-liquid ratios are written as PG/VG (sometimes VG/PG, so check the label). Here are the most common blends and what they’re suited for:
- 50/50 (equal PG and VG): The most versatile ratio. It gives a solid throat hit, good flavor clarity, and a moderate amount of vapor. This is the standard for mouth-to-lung vaping, pod systems, and higher nicotine strengths including nicotine salts. If your device uses a coil with 1.0 ohm resistance or higher, 50/50 is generally what you want.
- 30/70 (30% PG, 70% VG): A popular choice for sub-ohm tanks and more powerful devices. You get thick vapor production with a mild throat hit and rich flavor. This is where many vapers land if they want clouds without completely losing the throat sensation.
- 20/80 (20% PG, 80% VG): Prioritizes maximum vapor density. The throat hit is very gentle, and flavor can be slightly muted compared to higher-PG blends. Common among hobbyist vapers who build their own coils or use high-wattage setups.
There’s no universally “best” ratio. It depends on your device, your nicotine level, and what you enjoy. Higher nicotine concentrations already increase throat harshness, so pairing high nicotine with high PG can feel uncomfortably sharp. That’s one reason most high-nicotine pod liquids use a 50/50 blend or lean slightly toward VG.
Device Compatibility
Your device plays a big role in which ratio works. VG is a much thicker liquid, and small, low-power devices like basic pod kits have tiny wicking holes that can’t absorb it fast enough. Running a high-VG liquid (70% or above) through a device designed for thinner juice can cause dry hits, burnt coils, and poor flavor because the wick can’t keep up.
Larger sub-ohm tanks and rebuildable atomizers have bigger wicking channels specifically to handle thick VG blends. If you’re using one of these more powerful setups, high-VG liquids work well and take full advantage of the extra vapor production. A simple rule: small device, more PG; big device, more VG.
PG Sensitivity
A small number of people are sensitive or allergic to propylene glycol. The most common reaction is skin irritation or dermatitis, particularly on the face. In the context of vaping, PG sensitivity can show up as a sore or unusually dry throat, mild skin rash, or headaches that don’t seem related to nicotine levels.
PG sensitivity isn’t the same as a life-threatening allergy for most people. It’s typically an irritant reaction. If you suspect PG is causing problems, switching to a high-VG blend (80% VG or higher, sometimes called “max VG”) usually resolves the issue. Some e-liquid brands offer 100% VG options, though flavor intensity may be reduced since PG is the better flavor carrier. Keep in mind that propylene glycol also appears in many everyday products like toothpaste, deodorant, and certain medications, so if you’re genuinely sensitive, it’s worth checking ingredient labels beyond just e-liquids.
VG Sensitivity and Side Effects
True VG allergies are rare, but the thickness of vegetable glycerin can cause its own issues. Some vapers notice increased phlegm or a coating sensation in the mouth and throat with very high-VG liquids. VG’s sweetness also tends to caramelize on coils faster than PG, which means coils in high-VG setups may need replacing more frequently. If you’re going through coils quickly and notice a burnt or dulled flavor developing after a few days, the VG content is likely the reason.