Chemistry question: Could propylene glycol cause depression & other symptoms as study suggests

[JamminShaman]

Hello. I was hoping a chemist or someone familiar with the chemistry of propylene glycol could respond to this. Could vapors be ingesting enough pg to significantly increase D-lactate concentrations leading to ailments similar to what the cats in the study experienced: depression, ataxia, encephalopathy, etc.? We must be ingesting exorbitant amounts of pg daily and I wonder if this could lead to depression, etc? I've been vaping on and off since 2011 and love it but I'm concerned with the potential risks associated with inhaling pg. Here is a copy of the study:

Christopher MM, Eckfeldt JH, Eaton JW.

Department of Veterinary Pathobiology, University of Minnesota, St. Paul.

Propylene glycol (1,2-propanediol) is a solvent in numerous pharmaceuticals and a major preservative and source of carbohydrates in processed foods. In mammals, propylene glycol is metabolized similar to ethanol, proceeding via hepatic alcohol and aldehyde dehydrogenases to lactate, which can then enter gluconeogenesis. We observed that cats ingesting 1.6 gm of propylene glycol/kg body weight/day developed increased anion gap. To investigate this further, we measured D- and L-lactate concentrations in these cats; we also measured D-lactate in cats ingesting high doses of propylene glycol (8.0 gm/kg). While L-lactate actually decreased throughout the 35-day course of propylene glycol feeding, D-lactate levels were significantly increased on a dose-dependent basis and correlated positively with anion gap. In cats ingesting the high dose of propylene glycol, D-lactate concentrations were as high as 7 mmol/liter, levels associated with encephalopathy in humans. Indeed, this group of cats developed depression and ataxia, consistent with intoxication by D-lactate. These findings are significant not only for animals ingesting diets which contain propylene glycol, but for humans who receive propylene glycol-containing medications.

PMID: 2296157 [PubMed - indexed for MEDLINE]

Related Articles

* Unusual D-lactic acid acidosis from propylene glycol metabolism in overdose. [J Toxicol Clin Toxicol. 2004]
* Contribution of propylene glycol-induced Heinz body formation to anemia in cats. [J Am Vet Med Assoc. 1989]
* Propylene glycol-induced Heinz body formation and D-lactic acidosis in cats. [Prog Clin Biol Res. 1989]
* ReviewRecognition, treatment, and prevention of propylene glycol toxicity. [Semin Dial. 2007]
* ReviewD-lactic acidosis. A review of clinical presentation, biochemical features, and pathophysiologic mechanisms. [Medicine (Baltimore). 1998]

 

[93gc40]

If inhaling concerns you don't Vape.....

Until vaping is proven more dangerous than smoking. I Just Don't Care.

Worrying about stupid stuff is what cases depression.

Sent from my SCH-I605 using Tapatalk

 

[stols001]

1) It's a mouse study. I don't much care for them when it comes to SOUND conclusions and 1.6 grams of VG is A LOT for a mouse. There are so many mouse studies where they pretty much are forced to EAT their body weight of a substance until they die.

2) Inhalation does not equal ingestion. I'm not saying you *can't( fret about this if you want to you can.

3) I don't ingest that much of anything I am a MTL vaper and only go through a few ml every day.

4) While SOME extrapolation (with a good deal of lack of skepticism in order to work) may be useful, this study defines NOTHING actually.

5) You can always stick to the other compound or ever switch to PEG400 if you are worried. I have a hunch if PEG400 was fed to rats at WAY overdose levels you might find some negatives, although I don't believe that study has been done yet, so you could vape peacefully.

Man I hate mouse studies. I really do.

Best of luck with it all, though.

And finally, I have been vaping and I'm not depressed even slightly and I should be "early" effected because I am bipolar and would be more at "risk" for depression and it's Just Not Happening.
Anna

 

[bombastinator]

Not a chemist but I can read. The key here is that the reaction is similar to alcohol. Severe alcoholics get all these same things as well. One would assume then that the amount of pg you would need to consume daily would be similar to the amount of alcohol one would need to consume daily which is, well, a lot. This is not something I am going to worry about.

 

[denali_41]

theres pg in dogfood,but not catfood.go figure that one out

 

[Rossum]

1) It's a mouse study.

Maybe I'm missing something, but reading the summary in the OP's post made me think it was a cat study.

Cats have substantially different physiology than humans do, and cats' physiology is well known to be far more sensitive to PG than humans'.

Then there's the "1.6 gm of propylene glycol/kg body weight/day" thing. A comparable amount in a human of smaller than average build would be around 100 grams a day. That's a LOT of PG.

 

[Rossum]

theres pg in dogfood,but not catfood.go figure that one out

Cats are known to be hyper-sensitive to PG for some reason.

 

[Opinionated]

Basic math is a positive thing.

When that vet put those cats on high PG ostensibly to see what happened he put them on 8 grams per kilogram of body weight.

Your average person weighs 150 pounds.. (just a guess.. )

At 8 grams per kilogram of body weight that is ingesting 544 grams of PG..

544 grams is more than a POUND!

A higher PG ejuice is mixed at 50% PG and 50% VG..

A vaper who vapes a LOT might vape 20ml of ejuice in a day..

That 20 ml of 50/50 ejuice = 9 grams of PG..

That's nowhere near what the vet gave those cats to make them sick! Not even in the same ballpark.. not even on the same planet!

So no..vaping won't make you depressed.

 

[denali_41]

Cats are known to be hyper-sensitive to PG for some reason.

well that was my point

 

[Rossum]

A vaper who vapes a LOT might vape 20ml of ejuice in a day..

That 20 ml of 50/50 ejuice = 9 grams of PG..

Right, and most of that is exhaled.

 

[Opinionated]

Right, and most of that is exhaled.

Yep.....

The only real moral we can glean from that study is don't sit around feeding cats PG..

As if anyone would anyway apart from that vet..

 

[Rossum]

Honestly, if the OP is worried about PG making him depressed, it would be fairly straightforward for him to vape PG-free liquid for a while to see if it makes a difference. Personally, I doubt it will, but you never know, because people are different.

 

[Fidola13]

1) It's a mouse study. I don't much care for them when it comes to SOUND conclusions and 1.6 grams of VG is A LOT for a mouse. There are so many mouse studies where they pretty much are forced to EAT their body weight of a substance until they die.

2) Inhalation does not equal ingestion. I'm not saying you *can't( fret about this if you want to you can.

3) I don't ingest that much of anything I am a MTL vaper and only go through a few ml every day.

4) While SOME extrapolation (with a good deal of lack of skepticism in order to work) may be useful, this study defines NOTHING actually.

5) You can always stick to the other compound or ever switch to PEG400 if you are worried. I have a hunch if PEG400 was fed to rats at WAY overdose levels you might find some negatives, although I don't believe that study has been done yet, so you could vape peacefully.

Man I hate mouse studies. I really do.

Best of luck with it all, though.

And finally, I have been vaping and I'm not depressed even slightly and I should be "early" effected because I am bipolar and would be more at "risk" for depression and it's Just Not Happening.
Anna

Same with me- I’m Bipolar 2 and have been DL vaping for 7 months now. Anywhere between 25-40 mls a day and it hasn’t had any effect on my mental health.

But if you’re really concerned then maybe vaping isn’t for you and try some other smoking cessation device just NOT Chantix which is PROVEN to cause depression and suicidal ideations.

Good Luck with whatever you choose to do though.

 

[Doctorvapes]

I'm schizo affective bipolar type 1 and my psychiatrist encourages me to vape . I think if he thought there was a danger for depression or really anything that would upset me, he'd be the first lecturing me to stop.

 

[stols001]

I know of no cases of exacerbated depression caused by vaping. I know and have interacted with a fair number of vapers and well, NOPE.

It's really not a known effect, this is MOUSE STUDIES. By all means don't vape if you are concerned.

I rather think the mice might have been depressed because they were ingesting 0MG nic.

If I based my life on mouse studies, I'd be dead right now. Mouse studies fed their body weight in ANTIDEPRESANTS would ALSO die.

Seriously, don't pursue this, and if vaping is working for you you'd be crazy to try anything else (based on this STUDY alone). Just my opinion as always, although if you want a reason to stop vaping, I'm sure you can find an irrelevant study to do it with.

But, I am NOT signing on to vaping CAUSING depression, I haven't seen it, mice are not MEN despite Dickens book combining the two, and it's just a FLAWED study.

And yes stay away from Chantix there are actual, human, real documented homicides and suicides.

Anna

 

[Opinionated]

I know of no cases of exacerbated depression caused by vaping. I know and have interacted with a fair number of vapers and well, NOPE.

It's really not a known effect, this is MOUSE STUDIES. By all means don't vape if you are concerned.

I rather think the mice might have been depressed because they were ingesting 0MG nic.

If I based my life on mouse studies, I'd be dead right now. Mouse studies fed their body weight in ANTIDEPRESANTS would ALSO die.

Seriously, don't pursue this, and if vaping is working for you you'd be crazy to try anything else (based on this STUDY alone). Just my opinion as always, although if you want a reason to stop vaping, I'm sure you can find an irrelevant study to do it with.

But, I am NOT signing on to vaping CAUSING depression, I haven't seen it, mice are not MEN despite Dickens book combining the two, and it's just a FLAWED study.

And yes stay away from Chantix there are actual, human, real documented homicides and suicides.

Anna

Cat...

Cat studies...


Yes.. my type A is coming out.. lol.. you'll have to forgive me.

 

[Asbestos4004]

I'm too sad to respond.

 

[bombastinator]

For those taking issue with the use of the term “mouse study”:
It doesn’t necessarily refer only to mice but to any animal used in a study which really isn’t that appropriate but is convienient. Cats for example are free when they are being euthanized. Horrible but true.

 

[stols001]

Cats would be even worse then given what is being said about cats and how they respond, etc.

Yes, "mouse studies" do refer to any animal study etc. They're one step DOWN from petri cells of human tissue in a lab. Or equal or whatever.

But perhaps the cats were depressed that there were no mice enrolled in the study as well?

Anna

(Still not depressed, OR SMOKING and my mom is here. I'm thinking I'm pretty safe, LOL).

Anna

 

[HauntedMyst]

I remember wanting to end it all. Everything looked bleak..even the weather...no point in going on. So I was out on the ledge, enjoying my last few cigarettes before jumping. Pretty soon people were gathering and yelling "don't jump!!!" Even that big bass turd next door, Jimmy Phillips who borrowed my hedge clippers and never returned them. I hoped I'd land on him and take him out with me. The police showed up. One brave sargent joined me on the ledge. I could tell he was new at this. Since it was like my 14th time on the ledge, I thought I'd help him out. I talked him through talking someone down and gave him a cigarette to calm his nerves. Me and Stan sat there together for 30 minutes or so before until I was down to my last smoke. Just as I took it out of the pack, it broke off at the filter. Dang it! That settled it, I was jumping!!! Just then another cop handed Stan his vape through the window and Stan told me to try it. It was fantastic!!! It was like I was seeing colors for the first time! Each puff brought out a new fruity flavor! The sun came out!!! This was the hope I was looking for!!! Stan said, "Lets go in!" I said "No, we can just slide down the pole I put up after my 6th jumping attempt." We were only a floor and a half off the ground so we slid down the pole next to house like firemen to the cheers of the crowd. I was arrested but the cop let me keep his vape. I was so grateful because it was great for vaping and I had to use it to shank a guy in the hospital. Ever since then I've been vaping happily, joyfully. Vaping causes depression? No sir, no sir indeed. The thorn bush at the bottom of the pole I forgot to take out, that causes depression.

 

[Opinionated]

Cats would be even worse then given what is being said about cats and how they respond, etc.

Yes, "mouse studies" do refer to any animal study etc. They're one step DOWN from petri cells of human tissue in a lab. Or equal or whatever.

But perhaps the cats were depressed that there were no mice enrolled in the study as well?

Anna

(Still not depressed, OR SMOKING and my mom is here. I'm thinking I'm pretty safe, LOL).

Anna

That is why the cats thing is bugging me. Cats are already super sensitive...

.... the kitty curled up beside me isn't helpful though..

But this was literally a study on how it affects extremely sensitive cats to sit around and drink pg..

Answer.. don't feed them PG.