History and Origin
Discovered by Swedish chemist Carl Sheele in 1779 and further refined by subsequent chemists, glycerin is a wonder child of sorts. Also known as glycerol, it is a colorless, odorless, and non-toxic liquid that boasts a wide array of applications. Its versatility is grounded in its unique chemical makeup, making it an indispensable ingredient in both scientific and natural remedy communities. It’s even one of the main ingredients in vaping liquid for e-cigarettes.
A popular ingredient in vegan health products, glycerine is a naturally occurring substance in all plants and animals, both as fats and oils and in the intracellular space as lipids (fats). It is considered a neutral substance for anything used in the medical, homeopathic, and cosmetic industries. It is a sugar alcohol, just like xylitol. Anyone who has studied the ingredients label of an organic natural toothpaste has seen xylitol there and perhaps questioned its presence. That’s a topic for another day, but rest assured that xylitol is safe for oral care.
Chemistry
Glycerine is a simple polyol compound with the molecular formula C3H8O3. It is essentially a trihydroxy alcohol, possessing three hydroxyl groups that contribute to its ability to absorb moisture from the air, known as hygroscopy. This attribute underpins many of its applications. This structure facilitates solubility in water and alcohol. However, it remains insoluble in oils, pivotal for its use in various emulsions and solutions.
At the molecular level, glycerine’s properties are a testament to the complexity of organic chemistry. Its boiling point is relatively high, at 290°C (554°F) and a melting point of 17.8°C (64°F). This makes it liquid at room temperature, enhancing its practicality in numerous applications. Its chemical stability and non-reactivity make it safe for use in food, pharmaceuticals, and cosmetic formulations.
Glycerine results from the hydrolysis of fats and oils, which may be organic or synthetic. The US Food and Drug Administration (FDA) notes that glycerin is a byproduct of biodiesel fuel produced from the Jatropha species of plant, a family of chemicals known as glycerides grants fat cells their structure.
Types of Glycerine
Most modern uses of glycerine are vegan. However, there are non-vegan sources.
- Plant-based (vegetable oil): derived from oils and fats of coconut and palm. The plant oils are subjected to a combination of pressure, temperature, and water to form glycerin. Because of its organic composition, vegetable glycerin has a texture similar to syrup. This type of glycerin is useful in vegan formulations.
- Animal-based (fat): Tallow (beef or mutton fat) is combined with water and heated to a thick consistency over medium to low heat. The mixture is then chilled overnight in the refrigerator. The hardened mixture is boiled to remove excess water or strained to remove impurities. Historically, soapmakers have mixed lye with animal-derived glycerine for homemade products.
- Synthetic: Petroleum-based and produced from cane syrup or corn syrup sugar, or propylene. Its debut usage in the early decades of automobiles as the precursor to antifreeze discourages confidence that it is safe in beauty products. Yet, it remains an effective ingredient in skincare. Worry not, automobiles use a more modern and more affordable antifreeze. Furthermore, petroleum is the priciest way to make glycerin so is less common than its plant and animal cousins.
Pros and Cons
- Moisture Retention: Among its most celebrated benefits is its ability to attract and slow the evaporation of moisture, i.e., it is hygroscopic. This makes it popular in the personal care, cosmetic, haircare, and skincare industries as a great emulsifier for products. This water absorption, however, means that it should be used with restraint, between 1.5-2% of the product. Over 5% may result in oily skin and damp hair because it retains the water too well. If overdosed on skincare products it can lead to skin dehydration in arid conditions.
Used in the recommended dosage, it is an invaluable component in skin care formulations, where it functions as a humectant, drawing moisture into the skin and a cornerstone ingredient in creating hydrating serums and lotions that soothe dry, irritated skin.
- Sweetening Agent: Academia and pharmaceutical research use glycerine as a solvent and a sweetening agent in cough syrups, toothpaste, and other oral care products. Note that anyone with sugar sensitivity should be careful with formulations containing this very sweet ingredient. Most orally-delivered glycerine is incorporated into body fat or brought into glycolysis principally in the liver. It generally is metabolized within 2.5 hours.
- Oral Care: Mixed reviews here, but very similar to xylitol. In 1997, a chemist named Gerald F Judd, in a “treatise” he called “Good Teeth from Birth to Death” claimed that glycerine toothpaste and products create a barrier of glycerine on the teeth which require 20+ rinses to get rid of. If true, this prevents “re-mineralization”, the natural process of the teeth’s enamel regenerating itself. This happens when the acids on the teeth’s surfaces are neutralized by brushing and cleaning. Countering this, Doctor Gerry Curatola states that glycerine has probiotic qualities like bacteriostatic – which prevent bacteria from reproducing and is water-soluble, which means it dissolves easily and wouldn’t coat the teeth. Certainly, toothpaste approved by the American Dental Association (ADA) is recommended to have a humectant such as glycerine to prevent the toothpaste itself from drying out.
- Laxative: used to relieve occasional constipation. Glycerin belongs to a class of drugs known as hyperosmotic laxatives. It works by drawing water into the intestines. This effect usually results in a bowel movement within 15 to 60 minutes. As with any laxative, it is only to be used for a short time.
- Preservative: Glycerin’s efficacy as a preservative is leveraged in both food and herbal preparations, used to extend the shelf life of homemade extracts, tinctures, and even cosmetic products by preventing microbial growth and maintaining the solubility of active ingredients. Note, however, that it is a weak preservative.
Because our bodies naturally produce glycerin, it is generally safe for consumption and application.
We All Have Drawbacks
Herbalists and DIYers are conscious of the environment and want to source products sustainably, ethically, and responsibly. Unfortunately, palm oil is found in almost everything we use in our daily lives, from toothpaste to biscuits. Most of it (90%) originates in the forests of Indonesia and Malaysia. The demand has led to destructive levels of deforestation and climate change, it is also the main cause behind the looming extinction of orangutans. You can take action. Email the manufacturer of your product and ask where they have sourced their palm oil.
For those who live in humid climates, glycerin is only effective as a moisturizer when the humidity in the air is less than 65%. This is because it sucks the moisture from the dermis, the inner layer of the skin. As a result, your skin will continue to look healthy and hydrated on the outside, but the hydration levels will be lacking on the inside.
Its sugary, sticky texture can make your epidermis feel and look sticky. This poses a risk as it makes it easier for dust and pollution to stick to it, putting your skin at greater risk of damage.
Conclusion
Most evidence points to glycerin being safe. It is primarily used in moisturizing products such as lotions but is also prominent in soaps, toothpaste, laxatives, and sweetening agents. It’s possible to make your own at home (typically done with animal-rendered lard). That is messy, so purchase it if you prefer.
https://www.thankyourbody.com/all-natural-homemade-toothpaste/
https://lovelovething.com/homemade-diatomaceous-earth-toothpaste
https://www.breathmd.com/how-to-make-toothpaste.php
https://wellnessmama.com/natural-home/squeezable-homemade-toothpaste
