Published on: 17/01/2025
Liquids are what power the vaporization process and are inhaled during e-cigarette use
Among the main ingredients of e-cigarette liquids, two components dominate the market: propylene glycol (PG) and vegetable glycerin (VG). Both play crucial roles in the vaping experience, but they have very different chemical and physical characteristics.
In this article, we will explore in detail the science behind these two ingredients, their differences, benefits, potential issues, and how they impact the overall vaping experience.
What is Propylene Glycol (PG)?
Propylene glycol (PG) is a chemical substance that belongs to the alcohol category. Used for decades in various industries, from pharmaceuticals to cosmetics, PG is well known for its ability to dissolve many substances, including flavors and nicotine. In an e-cigarette liquid, PG is often responsible for creating the “throat hit” that sharp sensation in the throat that many vapers enjoy, similar to traditional cigarettes.
PG has a lower viscosity than VG, meaning that liquids containing PG are generally more fluid. This makes it easier to use in devices with smaller coils or less powerful systems, as its lower density allows for easier vaporization.
From a chemical perspective, PG is easily absorbable and mixes well with other ingredients. Its ability to produce vapor is lower than VG, but its intensity in carrying flavor is higher. Additionally, being hygroscopic, PG tends to absorb moisture, which can lead to a dry throat feeling, especially noticeable for some users.
What is Vegetable Glycerin (VG)?
Vegetable glycerin (VG) is a natural compound derived from plant oils such as soy, palm, or coconut. It is used in a wide range of products, from cosmetics to food and beverages, due to its ability to act as an excellent humectant and sweetener. In the context of electronic cigarette liquids, VG is the main substance responsible for producing dense, voluminous vapor, which many vapers seek to replicate the experience of smoking a traditional cigarette, but without the tobacco’s harmful effects.
VG has a much higher viscosity than PG. As a result, liquids containing VG are thicker and require vaping devices designed for higher resistance and more liquid supply to avoid issues like “dry hits” or incomplete vaporization.
Chemically, VG is sweeter and less irritating than PG. However, its higher density means it produces a larger amount of vapor, but with a less intense flavor. VG is also harder to absorb, which can lead to a sensation of increased moisture in the mouth and throat. Moreover, its thicker consistency can clog coils more quickly, which may be problematic for users who don’t perform regular maintenance on their devices.
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The Differences Between PG and VG: A Chemical and Physical Comparison
The contrast between PG and VG goes far beyond their viscosity. The two compounds differ significantly in terms of chemical properties, safety, interaction with other ingredients, and their impact on the overall vaping experience. Let’s explore some of the main differences between the two.
Vaping Sensation
One of the most influential factors when choosing between PG and VG is the sensation each substance produces during inhalation. PG is known for delivering a stronger “throat hit” that mimics the act of smoking a traditional cigarette. This makes it a preferred choice for vapers who want a sensation similar to nicotine cigarettes.
On the other hand, VG produces a much larger amount of vapor, creating a dense cloud that some vapers prefer for its smoother throat feel and the production of visible clouds. The “hit” sensation is less pronounced compared to PG, and most vapers seeking a softer feel tend to prefer a VG-rich mix.
Vapor Production
As mentioned, VG is known for its ability to produce a large amount of dense vapor. For this reason, many vapers who enjoy “cloud chasing“—the act of producing large vapor clouds—opt for a liquid with a higher VG percentage. Its density allows the creation of vapor clouds that can remain visible long after inhalation.
PG, on the contrary, produces a thinner, less dense vapor. While not ideal for cloud chasers, it is still suitable for those seeking a lighter and less intrusive vaporization, particularly useful for those looking for an experience similar to traditional smoking.
Flavor and Aroma
PG has a stronger affinity for flavors and dissolves fragrances better than VG. This means that PG-based liquids tend to enhance the flavors, making them more intense. For those seeking a robust aromatic experience, liquids with a higher PG concentration are often preferred.
VG, while not dissolving flavors as effectively, has the advantage of producing a sweeter sensation. However, since the vapor is less concentrated in flavor, vapers who prefer a gentler taste or want to enjoy a mix of soft flavors may prefer a liquid with a higher VG concentration.
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Device Adaptability
VG has a much higher viscosity than PG, so liquids with high VG concentrations may be too thick for smaller devices or low-resistance coils. This could lead to vaporization difficulties and inefficient liquid consumption. Devices suitable for these liquids require more powerful liquid delivery systems and specific coils to handle the increased viscosity.
In contrast, PG-based liquids are much easier to use across a wide range of devices, especially those with simpler liquid delivery systems and smaller coils. This makes PG the ideal choice for users of more portable devices or those with low resistance coils.
Safety and Tolerance
Both PG and VG are generally considered safe for use in e-cigarettes, but there are a few considerations. PG can cause throat irritation or dry mouth in some users, especially when inhaled in large amounts. It is also more likely to cause allergic reactions, although these are rare.
VG, being a natural product, is less likely to cause allergic reactions, but some users might experience coil clogging due to its viscosity. Additionally, VG is sweeter and may cause excessive moisture in the mouth, although this depends on individual preferences.
Conclusion: Which Should You Choose?
The choice between PG and VG largely depends on personal preferences and the type of vaping experience you’re looking for. If you desire a sensation similar to traditional smoking, with a strong throat hit and well-defined flavor, a liquid with a higher PG concentration will be the ideal choice. On the other hand, if you prefer denser, smoother vapor, with larger clouds and a sweeter vaping experience, VG is the right choice.In many cases, e-liquid manufacturers offer customized PG and VG blends, allowing vapers to balance the advantages of both ingredients. Understanding the chemistry and science behind e-cigarette liquids will help you make the best choice for safe, enjoyable, and satisfying vaporization.