PG Sensitivity

PG Sensitivity

Some have questioned PG sensitivity, prompting talk of a shift to VG, although this raises its own difficulties, particularly viscosity concerns.

New e-cig users experiencing throat irritation

It’s also critical to remember that smoking cessation can cause a variety of problems, many of which are exclusively connected to stopping smoking.

Whether they quit on their own or with the help of a counsellor, doctor, or pharmaceuticals, these symptoms are common. They include the Quitter’s Throat and Quit Zits.

Some smokers start by inhaling into their mouths, while others simply breathe straight into the lungs. M2L is a mouth-to-lung draw as a short form, whereas D2L is a direct-to-lung draw.

To begin, make sure that newcomers to e-cigs do not take a direct hit to their lungs, as many smokers do. Hold the vapour in your mouth for a few seconds before breathing it in (if required).

E-cigarettes do not produce smoke, which eliminates the risk of anesthetics/antitussives in tobacco smoke. Despite the fact that vapour is simply a water-based mist, breathing anything other than pure air produces a response, which can be ameliorated by using the appropriate method.

The incorrect technique is the cause of all ‘lung inflammation’ cases, as an e-cigarette isn’t used as a cigarette (in at least one fashion) for a new vaper.

Inhaling to the lungs is a poor technique for novices using an e-cigarette, and it can irritate or cough.

Beginners will be able to use a D2L inhale if they wish (and many do, especially with RBAs, rebuildable atomisers), but any/all modifications of every aspect of e-cig usage may not work for experienced users. In order to transition efficiently, beginners need proper guidance.

Rather than simply admonishing individuals, it’s beneficial to offer professional advice. It is simple to produce terrible outcomes with an e-cigarette by isolating the novice from proper information (or even deliberately withholding it).

This is evident from studies where consumers were deliberately limited in their information intake and product selection, which frequently resulted in failure rates of 10% or worse and complaints such as “lung discomfort,” neither of which has any bearing on correct usage.

Sensitivity to PG

Dry throat

When using high-PG refills, approximately 1 in 10 people are slightly sensitive to propylene glycol, which implies they have a minor degree of upper respiratory tract irritation and/or drying-out while not being severely impacted.

If the symptoms persist, most people will become tolerant of them; 1 in 10 represents individuals who have never smoked or vaped before.

As a consequence, the amount of people with a long-term minor sensitivity to PG in the throat / upper airway area is lower.

Nowadays, it is difficult to quantify since there are so many glycerine-based refills available – those with a PG problem tend to use VG refills, thus the number of reports connected to PG has decreased.

However, it’s vital to remember that virtually all new, unsupervised e-cigarette trialists will experience throat and/or upper respiratory tract discomfort owing to a lack of crucial information: vaporizers are not tobacco cigarettes and should not be used in the same manner.

A vaporizer is not a cigarette and should not be used in the same way as one by a person who has never used an electronic cigarette. With appropriate guidance, there shouldn’t be any irritation. Poor guidance or even a lack of advice is usually responsible for irritation.

Some individuals may experience continual symptoms after quitting, and switching to VG or PEG-based refills could be beneficial. A sore throat is a typical sign of quitting smoking, but it is also experienced by a proportion of people who quit successfully; hence, not all vapers’ experiences are linked to vaping – some are clearly attributable to smoking cessation.

Sore throat

1% of the population is extremely sensitive to PG in this manner, experiencing a severely sore throat when using high-PG refills.

If this is combined with the ‘quitter’s throat’ (see above), an extremely painful throat can develop in rare instances. It was previously difficult to get high-VG or all-VG (all glycerine) refills, but this isn’t an issue anymore for individuals who want to lower the PG content.

Skin problems

1 in 5,000 persons is highly sensitive to PG and develops skin difficulties ranging from dryness to severe itching as a result.

Worsening of tinnitus

One in a hundred thousand people may develop new tinnitus (ringing in the ears) as a consequence of PG-containing refills. Several theories have been proposed to explain this effect, which appears to be linked to the chance that vapour could travel throughout the ENT region. PG has been characterized as having some ototoxic qualities (inadvisable for use in the ears).)

It appears that individuals who have tinnitus should seriously consider using a 90% glycerine or all-glycerine refill liquid.

Interpretation accuracy

The following numbers are based on anecdotal evidence and were calculated from the number of reports posted on large vaping communities with 15 million postings, allowing for a lot of material to work with.

The statistics, such as 1 in 1,000, are not precise because they are estimates based on the number of observations.

To get any useable information from clinical trials or RCTs on these topics, we would need CTs on a major scale and at a significant cost, with little practical benefit.

With tens of millions of anecdotes, it’s no longer necessary to do CTs to get basic data; the situation is straightforward.

Of course, anecdotal evidence is a frequent topic of debate, but the scale matters: when a subject is non-contentious and just of informational value, several million answers are a decent resource to work with.

When it comes to uncontroversial themes that are unlikely to be tainted by response bias, conclusions may be seen as having considerable worth even if they haven’t been proved.

It is also worth noting that no medical treatment has ever been proven through clinical trials: CTs and RCTs simply provide evidence, regardless of how solid or frequent; no amount of RCTs can provide any proof, especially outside the limited use of CTs.

(CTs are useless for consumer items, and any conclusions are almost anecdotal – all numerical results for such goods will be unusable.) The evidence is provided by facts like national health statistics.

A fact is a statement that can be verified by observation or, in the health field, when provided by unbiased national health statistics; eventually, enough observations create a fact and when the total number of cases reaches a certain amount, an established position has been obtained.

We’ve amassed a wealth of data, both for and against several elements of these debates (vapers report everything whether it’s good or bad, with an especially vocal reaction to negative effects).

Glycerine sensitivity

1 in 1,000 people is allergic to VG/glycerine/glycerol (glycerol is the most precise of the many names), which means they should avoid it.

However, we don’t know whether these individuals are sensitive to a specific kind of VG or glycerol because there are at least five methods for producing it (single vegetable source, mixed vegetable source, animal source, synthetic source, biodiesel byproduct and more).

If the source type is recognizable, other varieties may be attempted; however, the main issue now is to identify the source kind. Synthetic glycerine should be trouble-free in theory, which is why it’s becoming increasingly popular in many inhalable medications.

It’s worth noting that the phrase “sensitive” is perhaps the most precise way to describe difficulties with these goods, as it is undetermined: “allergic to,” or “intolerant of” can be used, but they may be incorrect.

There are several difficulties with determining if sensitivity is accurately defined as an allergy or intolerance in particular: some people identify allergy as a response to proteins, while others see it as a reaction to plant or animal-derived substances (in “organic” by one definition of the term).

Another base type: PEG

PEG or polyethylene glycol is a viable option, especially since it tastes better than either PG or VG. It has been heavily employed in prefilled cartomizers as a result of this.

However, with DEG, a poisonous glycol manufactured in the same factories using similar feedstocks and thus prone to cross-contamination concerns, it is the most popular base type. When supplied in low-quality grades, it can occasionally be contaminated with MEG (mono)ethylene glycol.

If PEG400 can be found in a high-quality form and tested as absolutely free of DEG or MEG, it’s a fantastic replacement base material.

PG and VG safety issues


In the world of non-food consumer goods, propylene glycol has one of the longest and most extensive research data sets available (i.e. pharmaceuticals, medical supplies, and industrial products with human contact).

It’s been used, consumed, and inhaled for at least 70 years.

The first large-scale clinical trials were conducted in the 1940s when PG was used to mist the air in hospital wards.

PG is one of the most potent bactericidal and viral-cidal aerosols known, according to studies conducted over several years in hospital wards where the air was PG-treated. Communicable illnesses were reduced by 95% when compared to control wards without PG mist, including those spread via a virus (e.g. influenza, acute coryza).

All airborne pathogens are reported killed by a PG level of just 0.5ppm. This effect has still not been explained even today, since at such low levels it is presumed that a PG molecule cannot even come into contact with all the pathogens that are killed.

The glycol family of polymers, which includes DPG, is one of the glycol family. Alcohol rather than oil is a glycol. Some glycols are very dangerous, while others are effectively harmless in the human body and so are unobjectionable.

Diethylene glycol (DEG), is fatal and destroys organ functions by permanently injuring the liver, kidney, and other body organs. The FDA was founded in 1938 as a result of a large-scale poisoning that killed more than 100 people in 1937 due to DEG contamination in medicine.

However, certain family members are entirely safe: Non-toxic glycols include PG and PEG.

It’s not really inactive, since the body sees it as a carbohydrate and some are metabolized to lactic acid, which is all excreted.

It is said to have one-third the intoxicating effect of ethanol, the alcohol in alcoholic beverages; nevertheless, because the doses inhaled via vaping are so low, this result cannot be seen (usually about a teaspoon daily – clearly too little to produce any altering effects)

Because PG is non-toxic and has a low freezing point (like all glycols), it is used as an antifreeze in human-contact and animal-contact applications rather than the less expensive, more poisonous DEG, which is utilized where toxicity isn’t an issue.

It is used instead of the toxic, but less expensive glycols in RV and boat toilet systems, where human contact is possible. It’s safe, non-toxic, and its pathogen-destroying capability is quite useful: farmers may use it to water troughs over the winter since it deters the troughs from freezing, allowing pathogens to be destroyed while remaining harmlessly edible if consumed in quantity.

Because PG is inert and one of the most effective excipients available (a diluent, solvent, or carrier for other substances), it’s used in a variety of medications for inhalation and injection.

It has been taken by millions of people for years in asthma inhalers and other types of breathing machines; it’s even used as a solvent in liquid medications that are immiscible (they won’t mix with water). It is also contained in diazepam and phenytoin, two drugs that are administered via injection.

If one considers that PG is non-toxic and can be injected in high amounts, is breathed by patients with the most severe lung diseases and the worst health, is ingested by animals without consequences, and has been used for medical purposes for 70 years, there are few if any reasons to consider its usage as posing any measurable risk.

There are, of course, plenty of people who aren’t aware of these facts or will make things up for money.

The most frequent usage of PG is in air-conditioning plants. Because it fulfils all the criteria and, in fact, performs effectively, it’s employed as the treatment substance in both cooling water and condensate return systems. It’s non-toxic, inert, acts as an antifreeze, is highly dispersive as an aerosol, and is a very efficient airborne pathogen killer.

This is why Legionnaires’ Disease does not exist in well-maintained, big structures: the air conditioning plant’s PG-treated water destroys all airborne and water-borne pathogens. Because PG is so effectively dispersed as an aerosol, it acts in both the water and aerosol phases.

Because PG has such a low freezing temperature, it prevents the rooftop water treatment facility from icing up.

Because the Legionnaire’s Disease virus is dispersed in a building’s air and can infect everyone there, and because PG spreads readily as an aerosol, it is logical to believe that everyone in large structures has been breathing PG at tiny doses for decades. Hospitals, for the most part, are probably well-kept in terms of hygiene.

PG has no health concerns regarding its use in any form, whether ingested, inhaled or injected. Some people find it dries out the upper airway tract, especially when newly exposed; this generally recedes with familiarity.

Slight reactions are typical with any/all materials, as might be anticipated with any/all substances. They may experience skin issues as a result of heavy usage. Of course, we can’t know the long-term effects of high-volume inhalation on health, which could lead to COPD stage 1 problems or similar issues.

When compared to the stated certain mortality of perhaps half or more of all continuing smokers, and the reported eight-year average life expectancy loss, this would be a practically non-existent issue.

Only one real PG-related health issue is known to us: cats have unusual blood chemistry, and high-volume ingestion of PG has been reported to damage the blood cells.

This is why cat food does not contain PG, whereas dog food does (PG is a strong humectant that keeps the food moist and prevents drying out).

On the other hand, tens of thousands of vapers with hundreds of thousands of cats in their homes have stated that ‘2nd-hand vapour’ has had no negative influence on their pets; therefore we can reasonably conclude that the tiny amount of PG in exhaled vapour has no health impact for cats.

It’s also a checkmark for PG and vapour safety: even if a typical animal’s blood can theoretically be harmed by a vapour component, there is so little of it in any case that it isn’t an issue, and this has been demonstrated by the millions of user-years.


Glycerine, or glycerol as it may perhaps be better termed, to reflect the fact it is an alcohol and not an oil (see the suffix -ol), can be obtained from multiple feedstocks.

The best available now is the pure synthetic pharmaceutical-grade glycerol form, which comes from plants (e.g. Dow Optim), rather than vegetable-based glycerine, palm oil, or a mix.

For some persons, the makers of inhalable medicines (such as asthma inhalers) have chosen to utilize glycerine in addition to or instead of PG.

It’s anticipated that the same health effects apply: essentially zero. Glycerine is metabolized and excreted by the body like a carbohydrate. When using the pure pharmaceutical grade, no lung problems have been reported in people using it for medical purposes.

Pulmonary Oedema

Oedema, or “wet lung,” was initially reported as a risk among VG users, who presumably were unaware that inhalable medicines are moving over to this excipient instead of PG.

Dr Polosa states that while there has never been a case of this condition linked to vaping, it isn’t being discussed as a potential concern any longer.

Of course, if these problems are not discovered in patients exposed to chemicals like PG that include these materials for decades (such as used in asthma inhalers), it’s reasonable to expect they won’t be.

General safety issues

The molecular formulas of propane 1,2-diol and glycerol (propane 2,3-triol) are alcohols that are not significantly different. The version of their real chemical names given above demonstrates this (there are a plethora of such names for each molecule; e.g., everything).

As has been claimed by the chemically ignorant, inhaling alcohols cannot induce lipoid pneumonia.

However, there is evidence that inhalation of glycerol might exacerbate a propensity to (ordinary) pneumonia in individuals who have emphysema as a result of smoking.

Because of this, individuals with irreparably damaged lungs and an increased risk of pneumonia, such as emphysema sufferers, should avoid high-VG refill fluids with their e-cig. In fact, they should strongly consider using Snus as their main THR product.

PG, VG (and all similar commonly-used chemicals) have a number of levels:

  • Industrial grade
  • Agricultural grade
  • Food grade
  • Pharmaceutical grade

The main distinction is the quantity of pollutants, although the feedstock type can play a part.

Although it appears obvious that only pharmaceutical-grade PG or glycerine should be inhaled, as other grades are assured to be tainted, this has not percolated down to some e-liquid producers.

A new warning has been issued in the case of glycerine: biodiesel by-product glycerine should not be used for refill liquid manufacturing.

This is due to the increasing amount of jatropha plant glycerine in these feedstocks, which is hazardous: phorbol esters from the jatropha plant are carcinogenic.

Unfortunately, although this issue has been widely publicised with regard to pharmaceutical glycerine products, it is difficult to see how jatropha glycerine can be absolutely excluded from the supply chain unless only synthetic glycerine is used (as, realistically, it should be exclusively now – this is not the 19th century).

Glycols and glycerol are alcohols

The materials with the -ol suffix are alcohols and not oils. They are not oils, no matter how ‘oily’ they appear (especially when undiluted glycerine is concerned) or how viscous, thick, gloopy they may be.

Glycerine viscosity

The notion that VG is “thick,” which is to say gloopy or more accurately too viscous, is mistaken: it means the solution has not been sufficiently diluted.

Before it’s suitable for vaping, glycerine must be diluted with 10% to 20%. Before flavours are added, they may be diluted with 5% to 20% distilled water.

The final viscosity of a correctly-made glycerine-based refill liquid (also known as “e-liquid“) is comparable to that of PG e-liquid – if not, it has been improperly blended and must be redone. It should be diluted further if it is too thick.

For example, a properly-made VG liquid can be used in a cartomizer tank system, which is the most demanding of correct viscosity because of the tiny feed holes in the cartomizer wall within the tank system.

The precise viscosity of the finished mix determines the size of the cartomizer’s feed hole, just as it does for a PG-only or PG/VG combination.

It’s important to note that the hole size might vary based on the specific liquid. For example, if you’re playing with a ‘PG’ juice containing 80 per cent VG and 20% PG (commonly known as an “80/20 mix”), it may be necessary to make adjustments in order for your hits to not flood or dry out; this is typical.

It’s also why no-button pulls are sometimes required: To draw more liquid through a system with a feed hole that is too small for the refill viscosity, suck on the drip tip without operating the on/off switch.

If no-button pulls are frequently needed, the liquid viscosity is too high and it needs diluting, or the feed hole needs to be enlarged.

A suitable diluent can be anything thinner than the VG component of the liquid and maybe alcohol, PG, or distilled water. There are no drawbacks to adding 10% water or even more; it is still effectively nebulized.


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OZ Vapour Team
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