Some cool info about PG - from a cosmetic chemist! (self.electronic_cigarette)
by Dancin_Joe ePipe dude
So I was looking around for PG sources tonight, and this article caught my eye: http://www.naturallycurly.com/curlr...the-truth-and-fiction-about-propylene-glycol/
A site on hair care products (and curly hair in general), which repeated some of the same arguments for the use of Propylene Glycol we've already seen (yes it's in antifreeze, but a SAFER antifreeze; it's petroleum-derived, but GRAS/nontoxic/water-soluble; it DOES dehydrate, but is found in a whole bunch of products outside of ejuice)... as for that last one, I've seen an increasing number of body washes and shampoos and all, touting they were glycol and glycerin free as a selling point. It seems these "chemicals" are under fire from groups outside of the ones we deal with regularly, and some education is being done - which is always a good thing.
What stood out to me was both the metabolic breakdown on the site, showing it metabolizing quickly, and almost half never even going through the liver; and the fact that (even though it doesn't bioaccumulate) in high doses that cause neurological and liver effects, the effects are temporary, and go away after the PG is metabolized and excreted! Something new to me, at least...
TL;DR: PG is not only safe for consumption in small amounts, but even if you drink a bunch of it/bathe in it, you'll pee it out and feel better.
Still, DRINK PLENTY OF FLUIDS either way, and stay safe
source: https://www.reddit.com/r/electronic...e_cool_info_about_pg_from_a_cosmetic_chemist/
The Truth About Propylene Glycol, According to a Chemist
by: Tonya McKay 1.12.16
Next Article: How to Moisturize Your Hair in a Very Dry Climate »
An ingredient found in many personal-care products like shampoo, hair conditioner, and styling product, propylene glycol is widely used because of its relatively low cost and versatile nature. Its inclusion in a formula can fulfill a variety of purposes, which makes it a popular choice by the cosmetics chemist. However, some manufacturers have recently made the decision to no longer include propylene glycol in their products.
Do not be alarmed by the term antifreeze or by the chemical, propylene glycol. It is safe at the low concentrations when used in personal care products.
This is possibly due to misinformation and propaganda circulated on the Internet in the interest of marketing "natural" products. I am an avid supporter of using natural products, avoiding putting toxins into our bodies whenever possible or practical. I get frustrated by the dissemination of inaccurate and incomplete information in an attempt to frighten consumers into using different products. In this article, I seek to clear up some misconceptions about this chemical.
The chemical facts about propylene glycol
The FDA has categorized propylene glycol as "Generally Recognized as Safe."
Even with prolonged direct exposure, there is little to no skin irritation or sensitization. It subsides quickly once the area is flushed. The MSDS recommends avoiding direct handling due to potential irritation, which is a smart recommendation for any chemical--this is not an indication of the level of toxicity. Remember: in the chemical industry when a worker is exposed to continuous and large quantities of a chemical in its concentrated form, it is imperative to use the strongest safety precautions possible. This is not relevant to consumers using a product by the teaspoonful, if that.
Propylene glycol is non-toxic when ingested, even in reasonably large amounts.
Unlike its dangerous and frequently lethal cousin, ethylene glycol, PG is easily metabolized by the liver into normal products of the citric acid metabolic cycle, which are completely nontoxic to the body. Approximately 45 percent of any ingested PG is excreted directly from the body and never even comes into contact with the liver. The elimination half-life for propylene glycol is approximately four hours, and there is no bioaccumulation (buildup in the body over time). A few rare incidents have occurred where a person ingested a large quantity of propylene glycol and suffered some liver and neurological effects as a result, but these were short-lived and subsided once the material was metabolized and excreted.
The metabolic cycle for propylene glycol
What "antifreeze" really means for consumers
The word is frequently used to alarm consumers, and is simply a scientific term used to describe the lowering or depression of the freezing point of a liquid. An example is the application of salt to roads and walkways in a snowstorm. This process helps melt snow and ice and prevent development of dangerous icy conditions. The salt accomplishes this by lowering the freezing point of water. This is an example of a "safe" chemical being used as antifreeze. Do not be alarmed by the term antifreeze or by the chemical, propylene glycol. While few chemicals are entirely without risk, propylene glycol is considered to be safe at the low concentrations, used in personal care products and even food products.
Propylene glycol in personal care products
How propylene glycol affects hair
Propylene glycol is a completely water-soluble material that will not build up on the hair. It is also important to note that it is a diol with low volatility, meaning it will not evaporate easily and cause dry hair in the manner of low molecular weight alcohols such as SD alcohol and isopropyl alcohol.
Curl Chemist's conclusion: Don't fear propylene glycol
Propylene glycol should not be a feared ingredient. If product manufacturers are finding replacement ingredients to fulfill the same purposes in their formulas served by propylene glycol, I see no harm in that. However, I hesitate to support marketing materials that use this as a selling point.
As a curly, it would be wise to be aware if you are using products that contain this ingredient, just in case you observe increased frizz or dryness. Use plenty of moisturizing products to help lock moisture into your hair shaft, which can help prevent any potential problems caused by a humectant.
Writer Tonya McKay Becker is a curly-haired polymer scientist and cosmetic chemist whose academic and industrial research experience have provided her with expertise in the fundamentals and applications of polymer science and colloid chemistry.
References
"Case Studies in Environmental Medicine (CSEM), Ethylene Glycol and Propylene Glycol Toxicity"
What is Propylene Glycol?
Gaunt, IF, Carpanini, FMB, Grasso, P and Lansdown, ABG, "Long-term toxicity of propylene glycol in rats, Food and Cosmetics Toxicology," April 1972, 10(2), pages 151-162. Dow
McKay, T. "Humidity, Humectants and Hair", online publication, Aug. 2007
by Dancin_Joe ePipe dude
So I was looking around for PG sources tonight, and this article caught my eye: http://www.naturallycurly.com/curlr...the-truth-and-fiction-about-propylene-glycol/
A site on hair care products (and curly hair in general), which repeated some of the same arguments for the use of Propylene Glycol we've already seen (yes it's in antifreeze, but a SAFER antifreeze; it's petroleum-derived, but GRAS/nontoxic/water-soluble; it DOES dehydrate, but is found in a whole bunch of products outside of ejuice)... as for that last one, I've seen an increasing number of body washes and shampoos and all, touting they were glycol and glycerin free as a selling point. It seems these "chemicals" are under fire from groups outside of the ones we deal with regularly, and some education is being done - which is always a good thing.
What stood out to me was both the metabolic breakdown on the site, showing it metabolizing quickly, and almost half never even going through the liver; and the fact that (even though it doesn't bioaccumulate) in high doses that cause neurological and liver effects, the effects are temporary, and go away after the PG is metabolized and excreted! Something new to me, at least...
TL;DR: PG is not only safe for consumption in small amounts, but even if you drink a bunch of it/bathe in it, you'll pee it out and feel better.
Still, DRINK PLENTY OF FLUIDS either way, and stay safe
source: https://www.reddit.com/r/electronic...e_cool_info_about_pg_from_a_cosmetic_chemist/
The Truth About Propylene Glycol, According to a Chemist
by: Tonya McKay 1.12.16Next Article: How to Moisturize Your Hair in a Very Dry Climate »
An ingredient found in many personal-care products like shampoo, hair conditioner, and styling product, propylene glycol is widely used because of its relatively low cost and versatile nature. Its inclusion in a formula can fulfill a variety of purposes, which makes it a popular choice by the cosmetics chemist. However, some manufacturers have recently made the decision to no longer include propylene glycol in their products.
Do not be alarmed by the term antifreeze or by the chemical, propylene glycol. It is safe at the low concentrations when used in personal care products.
This is possibly due to misinformation and propaganda circulated on the Internet in the interest of marketing "natural" products. I am an avid supporter of using natural products, avoiding putting toxins into our bodies whenever possible or practical. I get frustrated by the dissemination of inaccurate and incomplete information in an attempt to frighten consumers into using different products. In this article, I seek to clear up some misconceptions about this chemical.
The chemical facts about propylene glycol
- It is water-soluble.
- It is synthetic.
- It is non-toxic.
- It is easily metabolized.
The FDA has categorized propylene glycol as "Generally Recognized as Safe."
Even with prolonged direct exposure, there is little to no skin irritation or sensitization. It subsides quickly once the area is flushed. The MSDS recommends avoiding direct handling due to potential irritation, which is a smart recommendation for any chemical--this is not an indication of the level of toxicity. Remember: in the chemical industry when a worker is exposed to continuous and large quantities of a chemical in its concentrated form, it is imperative to use the strongest safety precautions possible. This is not relevant to consumers using a product by the teaspoonful, if that.
Propylene glycol is non-toxic when ingested, even in reasonably large amounts.
Unlike its dangerous and frequently lethal cousin, ethylene glycol, PG is easily metabolized by the liver into normal products of the citric acid metabolic cycle, which are completely nontoxic to the body. Approximately 45 percent of any ingested PG is excreted directly from the body and never even comes into contact with the liver. The elimination half-life for propylene glycol is approximately four hours, and there is no bioaccumulation (buildup in the body over time). A few rare incidents have occurred where a person ingested a large quantity of propylene glycol and suffered some liver and neurological effects as a result, but these were short-lived and subsided once the material was metabolized and excreted.
The metabolic cycle for propylene glycol
- Propylene glycol → lactic acid → pyruvic acid → CO2 + water
What "antifreeze" really means for consumers
The word is frequently used to alarm consumers, and is simply a scientific term used to describe the lowering or depression of the freezing point of a liquid. An example is the application of salt to roads and walkways in a snowstorm. This process helps melt snow and ice and prevent development of dangerous icy conditions. The salt accomplishes this by lowering the freezing point of water. This is an example of a "safe" chemical being used as antifreeze. Do not be alarmed by the term antifreeze or by the chemical, propylene glycol. While few chemicals are entirely without risk, propylene glycol is considered to be safe at the low concentrations, used in personal care products and even food products.
Propylene glycol in personal care products
- It is an effective humectant.
- It is a solvent for fragrances and preservatives.
- It can be used as an emulsifier or co-surfactant.
- It is used as a solvent for pigments in cosmetics.
- It can be used as a preservative due to its antifungal and antimicrobial properties.
- It is frequently used in deodorants and antiperspirants.
- It is found in hand cleansers and disinfecting gels.
- It is a common additive in shaving creams and gels.
How propylene glycol affects hair
- It applies like a humectant (attracts water to the hair).
- It won't cause build-up.
- It will not evaporate easily (which may cause dry hair).
Propylene glycol is a completely water-soluble material that will not build up on the hair. It is also important to note that it is a diol with low volatility, meaning it will not evaporate easily and cause dry hair in the manner of low molecular weight alcohols such as SD alcohol and isopropyl alcohol.
Curl Chemist's conclusion: Don't fear propylene glycol
Propylene glycol should not be a feared ingredient. If product manufacturers are finding replacement ingredients to fulfill the same purposes in their formulas served by propylene glycol, I see no harm in that. However, I hesitate to support marketing materials that use this as a selling point.
As a curly, it would be wise to be aware if you are using products that contain this ingredient, just in case you observe increased frizz or dryness. Use plenty of moisturizing products to help lock moisture into your hair shaft, which can help prevent any potential problems caused by a humectant.
Writer Tonya McKay Becker is a curly-haired polymer scientist and cosmetic chemist whose academic and industrial research experience have provided her with expertise in the fundamentals and applications of polymer science and colloid chemistry.
References
"Case Studies in Environmental Medicine (CSEM), Ethylene Glycol and Propylene Glycol Toxicity"
What is Propylene Glycol?
Gaunt, IF, Carpanini, FMB, Grasso, P and Lansdown, ABG, "Long-term toxicity of propylene glycol in rats, Food and Cosmetics Toxicology," April 1972, 10(2), pages 151-162. Dow
McKay, T. "Humidity, Humectants and Hair", online publication, Aug. 2007
