There are two terms in vaping that you will always encounter. These are PG and VG. To a new vaper, these may be confusing — so we've summed up pretty much everything you need to know about PG, VG and their differences in this handy guide.
What Are PG and VG?
PG stands for propylene glycol and VG is vegetable glycerine. Both are odorless liquids that makeup two of the key components of most vape juices. They are also used in lots of other consumable products like flavorings and additives. When heated, they produce vapor, which vapers inhale and result in specific mouth and throat sensations.
Though in many ways similar, PG and VG have a different consistency and taste differently as well.
While you will find both 100% PG and 100% VG e-liquids, most vape juices use a combination of both ingredients in different ratios. Choosing the right PG/VG ratio is essential for getting the right experience out of your vaping session.
Now, let's take a look at PG and VG individually — and in a bit more detail.
What Is Propylene Glycol?
Propylene Glycol is a petroleum by-product. It is a colorless and almost odorless alcohol and its "official" chemical name is propane-1,2-diol. PG has a number of useful properties: it is a humectant, a preservative, and a solvent. Because of these properties, it has a wide range of applications: PG is a popular component in cosmetics, pharmaceuticals, human and pet foods, flavorings and even asthma inhalers.
Is PG Safe?
Research has shown that PG is safe to ingest orally and it has been "generally recognized as safe" by the FDA. With that, it is worth noting that most studies that have looked into the safety of propylene glycol looked into the ingestion of PG rather than inhaling it. The only long-term experiment on inhaling PG was held back in 1947 and resulted in the conclusion that inhaling propylene glycol was "harmless".
What is Vegetable Glycerine?
Just like propylene glycol, vegetable glycerine is alcohol. It's colorless, odorless and has a slightly sweet taste. Its chemical name is propane-1,2,3-triol.
Just like PG, VG has lots of applications: it is both a solvent and a preservative. VG is widely used in pharmaceuticals (cough syrups, creams, etc.), cosmetics, baked foods, food flavorings, and colorings.
Is VG Safe?
VG is "generally recognized as safe" by the FDA and has been proven to have low toxicity (when consumed). As VG is widely used in medicine and cosmetics, it is also an indication that it is safe for human consumption. With that, just like with PG, there are very few comprehensive long-term studies on the effects of inhaling vegetable glycerine.
What Are The Differences Between PG And VG?
PG and VG have a lot of similar properties — but a lot of differences as well. Here are 5 key differences between PG and VG.
PG will give you a stronger throat hit
The throat hit is important for most vapers (check out our Ultimate Guide to Throat Hit). And e-liquids that are high in PG offer a stronger, more cigarette-like throat hit. Basically, it makes vaping more like smoking — and this is what a lot of ex-smokers are looking for.
VG based e-liquids, on the other hand, come with a smoother feeling on the throat and is more suitable for those who prefer a gentler throat hit.
VG will give you more clouds
Where VG lacks in throat hit, it makes up for it in vapor production. Vape juices that are high in VG produce denser and thicker vapor — and this is what makes them a favorite among cloud chasers.
This may not be something that new vapers are particularly interested in — but you still have to find the right balance. If your e-liquid is too low on VG, the vapor production will be weak and your vape may not be as satisfying as you hope for it to be.
PG has no flavor of its own
Both PG and VG are odorless. But VG does have a light sweet flavor undertone, that may affect the taste of your e-liquid. In most cases, this will not be noticeable at all — but you might feel a difference between identical flavored e-liquids that are high in PG and high in VG.
VG may affect the lifespan of your kit
E-juices that are high in VG tend to be thicker and more viscous. Thus, they leave more residue in the tank and can affect the lifespan of your vaping device. This means that you may need to tend to your kit more often cleaning your coils and tank. Vape juices that are high in PG don’t have the same effect.
Some people may be allergic to PG
It is estimated that about 4% of the population are allergic to propylene glycol. Vapers who are allergic to PG are typically recommended to switch to 100% VG e-liquids. Learn more about PG allergy below.
What are the symptoms of a PG allergy?
One in ten people say that they experience a certain level of sensitivity when vaping a PG- based e-liquid and PG allergy symptoms may range from a light dry throat feeling to hives and severe coughing. Some of the most common allergy symptoms include:
Dry throat: 1 in 10 new vapers report being slightly sensitive to PG and will experience a soft irritation or dryness of the throat. In most cases, this will not be severe and the symptoms should subside and, ultimately, go away within a few days. However, if you continue to suffer from throat irritation for a longer period, this may be a sign that you are allergic to PG
Sore throat: if you experience a sharp throat pain when vaping e-liquids, this may be related to a PG allergy. Try stopping vaping for some time and see if the pain goes away.
Swollen gums: If you have swollen, painful gums while vaping a high PG e-juice, you may have a PG allergy.
Rashes and skin problems: 1 in 5,000 people who are highly sensitive and allergic to PG and will experience skin problems that can range from light dryness to severe itching as well as rashes and hives. If you start to notice rashes on your face, lips, and neck you should stop vaping PG immediately and consult a medical professional.
Sinus problems: if you are having sinus problems and discomfort while vaping a high PG e-liquid, this is a common sign of a PG sensitivity — especially if you are experiencing a burning or tingling sensation in the nose/sinuses that gets worse as you vape.
While the symptoms listed above are common indicators of a PG allergy, there may be other reasons for them as well. Before diagnosing yourself with a PG allergy, consider if the symptoms you are experiencing may be related to what is known as "a smoker's flu", a set of temporary symptoms associated with smoking withdrawal. These typically include headaches, nausea, sore throat, dizziness, and even mouth ulcers. These can also be the signs that you are using an e-liquid with a very high nicotine content — if this is the case, try lowering your nicotine intake. Dehydration is another common side effect of vaping — try drinking more water to compensate for PG and VG e-liquids attracting moisture.
What should you do if you are allergic to PG?
Just because you are sensitive or allergic to PG e-liquids does not mean that you have to stop vaping. All you need to do is find a 100% VG e-liquid and you can continue exploring the advantages of vaping over smoking further. Thus, here's is the generally recommended course of action:
What VG/PG Ratio Should You Use?
It all depends on what you want to get out of the experience.
So, there you have it. In this guide, we have tried to sum up some key facts about PG and VG without burdening you with too much detail. Stay tuned for our next mini-guide on choosing the right PG/VG ratio, where you will be able to find more on balancing the two ingredients.