Vegetable glycerine (glycerol) - safety discussion

[Casey C]

I pretty much concluded glycerin was safe to use but I do tend to keep an eye on the vapor.
Just to make myself feel a bit better, I went to the link and read. Now, in English, would someone explain how it's concluded that Glycerin doesn't produce acrolein.

Basically they studied the vapor with an MRI and gas chromatography and didn't find any acrolein...

look fact is, vaporizing or burning things can create carcinogens and harmful chemicals; its a convenient drug delivery system, not a safe one

for peace of mind:
Propylene glycol is a refined glycerol (glycerine, glycerin) used in many food and drug applications. In fact, its used to cut diazepam for injections. You can mainline it. This, however, does not mean its healthy, especially when vaporized.

of course, all is relative - no one worries about vitamins and nutrients in their beer

 

[guting]

ive been sucking on VG + menthol + lorran flavor literally all day everyday for the past month, I don't notice anything wrong or different except ludicrous amounts of vapor and no painful hits that I get from PG.

 

[TropicalBob]

Just don't use it if you're concerned. This bush has been run around too many times.

 

[vapola]

OK, I don't have any agenda pro or con VG. Just trying to decide which one safer and there seems to be a lot of discussions about harmful acroelin that can/may/possibly come off the vaporized VG. Now does anyone know what happens to PG when it is heated? It seems that PG is commonly used all over the place for different purposes. Does anyone have any data on its safety when it's hot?

 

[deuxmachinax]

Hi all,

this is my first post. I just got my 401 yesterday, and it hurts like hell to smoke the liquid that it came with. (Along with whatever was in the cartridges), so I've been looking around to see if it was just me. I really want to try vaping VG now, where would be the best place to order? And from experience, what would be the mildest?

I'm baffled as when I was smoking analogs (2 days ago) I could smoke M/boro reds and I wouldn't feel a thing.

Thanks for the help!

 

[markarich159]

Now that I got back home and I finally received all the e-stuff ordered (2 pens, 2 minis, 2 cigars, 1 cigarillo; all kind of e-liquids) I wanted to start mixing my own stuff. Sadly, in the process, I found out something pretty bad about VG.

You should stop vaping VG now! It's not some theoretical hazard. The first chemist I asked about buying VG for smoking told me instantly I am crazy.

Heated at 280 deg C it decomposes to acrolein. This is not a partial decomposition. It also doesn't need any other chemical component or anything, just heat. This is actually one of the ways of obtaining acrolein.
280 deg C is pretty close of what the atomizer gives now.

Now, about acrolein - it was used as a chemical weapon, it is a suspected human carcinogenic and it is associated with hemorrhagic cystitis.

(from wiki: Acrolein - Wikipedia, the free encyclopedia)



sorry guys, I wish my first message after the long break would have been much more cheerful


the good part is that about PG they couldn't think of anything yet, they said they need more time to study it, so at least it has no obvious connection with something bad


Again, cause I think it's very important: Stop vaping VG! if you are allergic to PG and you can't quit for good then you better go back to cigarettes than using VG. Cigarette smoke does contain acrolein but tens of thousands times less.

Hmm... after some more thought I started again researching and calculating.
Things are not that bad as I thought, but definitely not good.

ADDITION:

First off, I will edit my original message to remove the stupid ‘start smoking again’ stuff . The chemists were absolutely right about the reaction, but they didn’t realized the scale…

So, let me bore you again with some calculations

In the cigarettes smoke there is a quantity of 60-150 micrograms of acrolein per cigarette (references on demand).
From the dehydration of 1g of glycerol @280 deg you get a theoretical 1g of acrolein. From lab tests it was determined that de pyrolisis of glycerol is incomplete, 40-50% of the glycerol is still present in the vapour (references on demand). So, 1g glycerol gives say 0.6 g of acrolein.

Considering 0.1 g of e-liq == 1 cigarette -> 0.06g = 60 micrograms acrolein per equivalent cigarette, if you vape VG only. A more realistic concentration would be max 50% VG and the rest water, alcohol etc. This gives 30 micrograms acrolein per equivalent cigarette – half the minimum amount of acrolein than is contained in the smoke of an ‘analog’ cigarette.

So, it’s still safer than cigarette smoke… but not too healhy.

Sorry for the alarmistic thread, I tend to first react and then think it’s not the first time it happens.

EDITED TO ADD:

uh, my math skills are failing me. I need to check my results with someone else...
until then I'm back to where I started : I confused somewhere micrograms with milligrams. This means that the acrolein in vapour is 1000 times more than what I said in the edit. this is pretty bad.

Personally, for now, I'll just skip adding glycerine to my mix:


0.1 g of glycol will yield 60 mg acrolein = 60000 micrograms........

Dude, settle down, there is no way ur producing acrolein in an atomizer. First of all, this again(as has been an issue in other threads), is a problem of units.(I guess being a pharmacist I'm just more sensitive to unit analysis) you're confusing celcius temp scale with farenheit temp scale. 280 degrees celcius is EXTREMELY hot(way hotter then any atomizer could produce). 280 celcius is 536 degrees farenheit. to give you a sense of how hot that is, 212 degree F is boiling point of water, 451 degree F is the kindling point of wood, paper etc..., so your talking almost 100 degree F hotter then kindling temp: I'm sorry atomizers don't get that hot.

Also, think about it, if this was true, how many thousands of people would be dead already. Everyone who vaped Glycerine would be dead.

 

[Casey C]

Also, think about it, if this was true, how many thousands of people would be dead already. Everyone who vaped Glycerine would be dead.

well glycerin is used to keep cigarette/pipe tobacco moist, and cigarettes burn at around 500-700 degrees celsius, and acrolein has been found in cigarette smoke.. so I'm sure you can breath some without dying

found a great study on glycerin in cigarettes, but can't post links..

 

[markarich159]

well glycerin is used to keep cigarette/pipe tobacco moist, and cigarettes burn at around 500-700 degrees celsius, and acrolein has been found in cigarette smoke.. so I'm sure you can breath some without dying

found a great study on glycerin in cigarettes, but can't post links..

That's correct, but the amount of Acrolein in Cig smoke is miniscule due to the realtively minor amounts of Glycerin in them. I beleive the OP was worried because of the relatively large amounts of Glycerine in VG based eliquid. If all or most of the Glycerine in VG eliquid(which can be up to 70% Glycerine) were converted to Acrolein in the atomizer, then my last point would occur(everyone would be dead). Of course, since the atomizer does not reach anywhere near 280 degree celcius, that does not occur.

Good info, however, It shows that analog cigs do contain a deadly poison that was used as a chemical weapon at one time.

 

[Casey C]

That's correct, but the amount of Acrolein in Cig smoke is miniscule due to the realtively minor amounts of Glycerin in them. I beleive the OP was worried because of the relatively large amounts of Glycerine in VG based eliquid. If all or most of the Glycerine in VG eliquid(which can be up to 70% Glycerine) were converted to Acrolein in the atomizer, then my last point would occur(everyone would be dead). Of course, since the atomizer does not reach anywhere near 280 degree celcius, that does not occur.

Good info, however, It shows that analog cigs do contain a deadly poison that was used as a chemical weapon at one time.

your argument is that a vaporizer does not reach the boiling point of the vaporized liquid

just sayin'

 

[Casey C]

since i can't link the article I'll post excerpts

"The Effect of the Humectants Glycerol and Propylene Glycol on Mainstream and Sidestream Smoke Deliveries of Acrolein, Formaldehyde, Acetaldehyde, Acetone and Propionaldehyde"



"It was found that glycerol, added at a level of 3% to the filler, contributed about 8.5% of the total mainstream smoke (MS) acrolein. A more recent investigiation (2) showed that after spiking cigarettes with glycerol, a small increase in MS acroleim delivery was noted, however a significant increase in sidestream smoke (SS) delivery was found. In order to confirm these findings a more extensive project was commissioned. "


"For MS the addition of glycerol and/or propylene glycol to the filler had no significant effect on the acrolein delivery. In fact, acrolein deliveries at high humectant content, ( 5%) were lower than for the reference cigarette. This is probably due to a lower weight of tobacco in the filler. For SS the addition of glycerol to the filler had a significant effect on the acrolein delivery e.g. 5.4% glycerol gave a 50% increase in acrolein delivery. The acrolein does not appear in the MS smoke in significant quantities perhaps due to-filtration by the filler rod or the filter itself. Approximately 1% of the available glycerol was converted to acrolein during smoking. Propylene glycol had no effect on SS delivery of acrolein. The cigarettes containing both humectants also showed increased acrolein deliveries which were directly proportional to the glycerol content of the filler."

from what I'm reading, propylene glycol appears much safer, the OP was quite correct

 

[Casey C]

If all or most of the Glycerine in VG eliquid(which can be up to 70% Glycerine) were converted to Acrolein in the atomizer, then my last point would occur(everyone would be dead)

and just to nip this response early:

heating glycerol is a very inefficient way of attaining acrolein, consider that cigarettes reach 700 degrees celsius and only 1% of the glycerol in the study was converted to acrolein so even if your liquid is 70% glycerol, you're not using much liquid in the first place, and the yield of acrolein is quite low

glycerol actually breaks down into acetaldehyde and propionaldehyde as well, while propylene glycol boils at a much lower point and doesn't release these chemicals - so from whats known, it is much safer

my original point still stands tho, if you're allergic to PG or prefer the more substantial smoke or sweeter taste created by glycerol, thats your call, just know its a skin and respiratory irritant, although they haven't proved its carcinogenic.. like the 40 chemicals in cigarette smoke

 

[markarich159]

Casey, I don't quite understand your argument. Your basically agreeing with me that there is no danger in vaping Glycerine(which has been discussed to death in other threads), but continuing to show studies on cigarette data. Can you please show a study on acrolein production in an e-cigarette, or a case history of a patient harmed by acrolein poisoning from vaping VG. None of us in this forum care about cigarette studies anymore(we know the dangers, that's why we're now vaping and in this forum). The point is e-cig atomizers do NOT reach anywhere near the temp required to produce acrolein from glycerol. The OP's initial post was a reaction to something that someone he knew(who knew nothing about e-cigs or the function of the atomizers) combined with a bit of data on acrolein that any can wiki. That is my final word on the issue. Continue to post as many unrelated cig studies, pulled out of context, as you wish. I have no more time to defend a position that has logically and practically been proven. Do you even know what the LD50 of Acrolein is? Do you know what an LD50 is without google or wiki?

Just sayin'(what are you 16)

 

[Casey C]

Casey, I don't quite understand your argument. Your basically agreeing with me that there is no danger in vaping Glycerine(which has been discussed to death in other threads), but continuing to show studies on cigarette data. Can you please show a study on acrolein production in an e-cigarette, or a case history of a patient harmed by acrolein poisoning from vaping VG. None of us in this forum care about cigarette studies anymore(we know the dangers, that's why we're now vaping and in this forum). The point is e-cig atomizers do NOT reach anywhere near the temp required to produce acrolein from glycerol. The OP's initial post was a reaction to something that someone he knew(who knew nothing about e-cigs or the function of the atomizers) combined with a bit of data on acrolein that any can wiki. That is my final word on the issue. Continue to post as many unrelated cig studies, pulled out of context, as you wish. I have no more time to defend a position that has logically and practically been proven. Do you even know what the LD50 of Acrolein is? Do you know what an LD50 is without google or wiki?

Just sayin'(what are you 16)

a heat based vaporizer works by boiling liquid into a vapor, I'm sensing you don't know this - now granted there is new technology that uses ultrasonic frequencies, but that's not what we're debating

liquid touches the hot coil, boils into a vapor, and fresh liquid hits the coil, rinse repeat

don't call me a child because you fail to grasp the basic concept

oh and the ruyan report does admit to having found trace levels of acrolein, again can't link

 

[Angela]

...and Ecopure (which is a VG-based liquid) was specifically tested for Acrolein because of people's concern over this and none was found in the vapour.

 

[Casey C]

Casey, I don't quite understand your argument. Your basically agreeing with me that there is no danger in vaping Glycerine(which has been discussed to death in other threads), but continuing to show studies on cigarette data. Can you please show a study on acrolein production in an e-cigarette, or a case history of a patient harmed by acrolein poisoning from vaping VG. None of us in this forum care about cigarette studies anymore(we know the dangers, that's why we're now vaping and in this forum). The point is e-cig atomizers do NOT reach anywhere near the temp required to produce acrolein from glycerol. The OP's initial post was a reaction to something that someone he knew(who knew nothing about e-cigs or the function of the atomizers) combined with a bit of data on acrolein that any can wiki. That is my final word on the issue. Continue to post as many unrelated cig studies, pulled out of context, as you wish. I have no more time to defend a position that has logically and practically been proven. Do you even know what the LD50 of Acrolein is? Do you know what an LD50 is without google or wiki?

Just sayin'(what are you 16)

since post count will allow me to eventually link things I'll keep going,

I'm not interested in the lethal dosage of acrolein, I pointed out that the amounts produced would be small, its long term exposure to a tissue irritant that produces effects at 2ppm that I'm worried about. Throat irritation, respiratory problems, secondary infections, although cancer is ruled out by it not being a carcinogen, it is something you'll be sucking into your lungs repeatedly and regularly

I am quoting cigarette reports as they are quite relevant; they show the effects of heating glycerol and data on "e-juice" is quite limited. There is also the point to be made that as this is a 'healthier' alternative to smoking that this would be the light to show it in, as opposed to having no risks at all, which would be disengenuous as nicotine itself is not 'healthy'

 

[markarich159]

a heat based vaporizer works by boiling liquid into a vapor, I'm sensing you don't know this - now granted there is new technology that uses ultrasonic frequencies, but that's not what we're debating

liquid touches the hot coil, boils into a vapor, and fresh liquid hits the coil, rinse repeat

don't call me a child because you fail to grasp the basic concept

oh and the ruyan report does admit to having found trace levels of acrolein, again can't link

These are different physical processes at work. Vaporization is different from Boiling(evaporation). One is a physical phase change(requiring a specific enthalpy). The other is a radical change in particle size. In an atomizer (as well as a fog machine) the glycerin or PG assists the water present to vaporize(this is not steam(gas), rather a mixture of PG/VG/water that has been tranformed from a liquid to a very small particulate vapor- particle size of about 0.04micron). The nicotine(and any other flavors/excipients present in the initial liquid) are taken "along for the ride", so to speak, dissolved within the microparticles. This is why it takes less energy to create vapor then it does steam , and also why the atomizer can function at lower temperatures. This property of glycerine/PG/water solutions has been known for some time. It is a similar principle used in a nebulizer machine(that delivers albuterol/cromolyn/ipratropium solutions to asthmatics). I went to Pharmacy School for 6 years to learn about things such as this. I'm sorry, I did not mean to offend you. I just don't want information that is patently false distributed on these forums to cause hysteria among us fellow vapers. We already have enough to worry about with the FDA, PayPal etc... Ok that's my final word.

 

[Casey C]

...and Ecopure (which is a VG-based liquid) was specifically tested for Acrolein because of people's concern over this and none was found in the vapour.

can't speak to their results, but the test itself states the injection temp on the chromatography was 300 degrees celcius, above the boiling point of glycerol

These are different physical processes at work. Vaporization is different from Boiling(evaporation). One is a physical phase change(requiring a specific enthalpy). The other is a radical change in particle size. In an atomizer (as well as a fog machine) the glycerin or PG assists the water present to vaporize(this is not steam(gas), rather a mixture of PG/VG/water that has been tranformed from a liquid to a very small particulate vapor- particle size of about 0.04micron). The nicotine(and any other flavors/excipients present in the initial liquid) are taken "along for the ride", so to speak, dissolved within the microparticles. This is why it takes less energy to create vapor then it does steam , and also why the atomizer can function at lower temperatures. This property of glycerine/PG/water solutions has been known for some time. It is a similar principle used in a nebulizer machine(that delivers albuterol/cromolyn/ipratropium solutions to asthmatics). I went to Pharmacy School for 6 years to learn about things such as this. I'm sorry, I did not mean to offend you. I just don't want information that is patently false distributed on these forums to cause hysteria among us fellow vapers. We already have enough to worry about with the FDA, PayPal etc... Ok that's my final word.

quite
except the glycerol or PG is added to create a heavy vapor, not merely facilitate the boiling of water

if the only point was to cut the nicotine for vaporization it could be done with alcohol or another fluid - the glycerol is added to create a heavy vapor that creates a 'throat hit' and a visible cloud upon exhale - much like it is used in fog machines to create the heavy visible fog

oh - and steam is vaporized water.

 

[RIMP]

Thank you. There is WAY too much hysteria. Until we get a thorough analysis of exactly what is produced when you vape vg or pg or peg we need to chill! Most of us feel it is still a safer alternative to smoking. My little soapbox.

 

[Casey C]

These are different physical processes at work. Vaporization is different from Boiling(evaporation).

oh - and evaporation is a type of vaporization

 

[Casey C]

oh and mark, since you obviously can't look things up on your own

Boiling, a type of phase transition, is the rapid vaporization of a liquid


A vapor is a substance in the gas phase at a temperature lower than its critical temperature. This means that the vapor can be condensed to a liquid or to a solid by increasing its pressure, without reducing the temperature.

Vaporization of an element or compound is a phase transition from the liquid phase to gas phase. There are two types of vaporization: evaporation and boiling.