Did you know non-decolorized whole leaf aloe has been found to cause cancer? And, would you believe the FDA was responsible for the study proving that? So, what's aloe doing in skincare? Well, the aloe in skincare isn't the same as non-decolorized whole leaf aloe... here's why.
In 2002, FDA ruled that aloe laxatives, which used the latex portion of the aloe leaf, were no longer generally recognized as safe. Generally recognized as safe or GRAS ingredients are ones that are deemed as safe for human consumption by FDA.
Because insufficient data was available to support aloe laxatives, FDA removed that classification and perhaps due to backlash undertook a 2-year study that was published in 2012 evaluating the safety of whole leaf non-decolorized aloe in rats. Whole leaf non-decolorized aloe includes both the gel layer and the latex layer of aloe.
In this study, rats ingested non-decolorized whole leaf portion of aloe daily in their diets. The study found that this whole leaf extract of aloe caused a number of different types of intestinal lesions and cancers, which backed the FDA’s original concerns that aloe latex should not be used in laxatives.
If this were the paraben story, fear of aloe would be raging right now. Hopefully, we as a community learned something from the paraben paranoia. Truth is in the nuance. Let’s not throw the baby out with the bath water just yet but instead take a look at the anatomy of an aloe leaf.
Just in case you’ve not seen aloe in real life before, it’s a succulent with thick broad leaves. The healing gel of the aloe resides in its leaves, and you can cut a leaf and slice it open to reveal that gel layer.
Non-decolorized whole leaf extract vs. aloe vera leaf juice (aka aloe gel layer)
Once the gel layer is removed, it’s easy to see the latex layer, a thin yellow layer. Great care is taken not to disturb this layer during gel harvest so as to avoid contaminating the gel layer with the anthroquinone, aloin, which is considered the problematic anthroquinone in the FDA study.
The non-decolorized whole leaf aloe extract contains a compound called aloin along with other anthroquinones from the latex layer of the leaf. Aloin was found to cause cancer in rats when it’s ingested because the rats cannot break it down properly in the intestines. Aloin is yellow-brown in color and you've likely noticed repeated reference to non-decolorized whole leaf aloe extract. The decolorization process removes the aloin along with another anthroquinone, emodin.
The latex layer also contains the phototoxic compound, emodin, as well and is not part of the aloe vera gel used in cosmetics and most food products. Emodin is so rich in color that its used as a natural dye for wool and polyesters and can dye fabrics yellow to red depending on its structure... specifically co-crystals due to different pi-pi interactions and charge-transfer interactions cause variation in the hue. This is beyond the scope of the podcast discussion and well beyond what I researched for this post, so here's a picture to demonstrate pulled from this article in Crystal Growth and Design (linked in reference as well).
One last note on aloe’s safety, despite the single study conducted by the FDA which found whole leaf non-decolorized aloe to cause various types of intestinal cancers in rats, the Cosmetic Ingredient Review has found no evidence supporting that aloe vera gel (also known as aloe vera leaf extract... key point here is aloe vera gel without the latex layer) is in any way carcinogenic, and later in today’s episode, we’ll be talking about a number of studies evaluated and presented in a comprehensive review of aloe’s healing properties.
Harvesting Aloe Vera Leaf Juice
The healing gel of the aloe leaf quickly loses its potency once removed from the plant. This is because the gel quickly oxidizes. In 1964, a pharmacist in Dallas Texas decided to figure out how to stabilize aloe gel. In 1968, Dr. Bill Coates had succeeded in his stabilization attempt and by the 1970s headway was made into the commercialization of aloe so that it could be used anywhere, even in regions too cold to grow your own and also to make it a practical ingredient for skincare products, detergents and as a dietary supplement without concern about the latex layer.
The history of aloe vera in skincare & healthcare
Aloe has been grown by mankind in so many parts of the world for so long that its origin and native land was debated for years. DNA research suggests aloe vera originated in the Arabian peninsula. And, yet, aloe permeates many cultures. Etched into carvings over 6000 years old in Egypt, a burial gift for pharaohs, and regarded a Universal panacea by the Greeks, Aloe has been called the “plant of immortality”. Legends say both Queen Cleopatra and Queen Nefertiti used aloe in their skincare routines.
Supposedly, Alexander the Great was persuaded by Aristotle to capture an island in the Indian Ocean because of aloe was extensively available on that island and could be used to treat wounded soldiers.
Native Americans used aloe for its emollient and rejuvenating powers. The Chinese treatment book of Shi Shen describes aloe as the “method of harmony”. Russians call aloe vera “the elixir of longevity”.
In Japan, aloe was known as the “royal plant” and drank by the samurai as an elixir. Hindu people named it the “silent healer”. Arabian traders called it “Desert Lily” and used it to treat internal and external conditions. Ayurvedic texts refer to aloe as ‘vera rasayana’, the rejuvenator of the organism, a balancing plant for the three doshas: pitta, vata, and kapha. Ayurveda also assigns four of the six flavors to Aloe: sweet, sour, bitter, and astringent.
The healing properties of aloe
More than 75 compounds have been identified in aloe vera leaf gel including vitamins A, C, E and B12, a number of enzymes, minerals like selenium and zinc, a variety of sugars, fatty acids, salicylic acid, and others including antioxidant and anti-inflammatory compounds such as sterols.
A major review of aloe looking at research conducted between 2014 and 2019 found evidence suggesting aloe has a number of therapeutic properties including antioxidant & anticancer properties and may help reduce diabetic tendencies and control hyperlipidemia. This review even found cardioprotective effects for some of the constituents in aloe and antimicrobial and prebiotic effects for some of aloe’s constituents.
One study covered by this review paper found that aloe reduced swelling and pain in people who had their molars removed. Aloe was found to alleviate inflammation of the mucosal membranes in patients undergoing radiation therapy for head and neck cancer treatments.
This extensive review paper also looked at studies using aloe for skin protection and found that aloe’s antioxidant and anti-inflammatory properties improved wound healing, and exhibited remarkable antioxidant properties protecting skin cells from DNA damage, lipid peroxidation, and reactive oxygen species generation by prompting superoxide dismutase activity in the skin and increasing glutathione levels. One study covered in this article found that some of those sugars in aloe may be beneficial in treating psoriasis flare-ups.
Mankind continues a long love affair with aloe and for good reason. The inner gel of this plant exhibits great benefits in skincare and also in healthcare. What are your feelings on aloe? Do you love it or feel ambivalent towards it? Email me at firstname.lastname@example.org with your feelings on this skincare ingredient.
And, would you take a minute to rate this podcast and share it with a friend? Your time in doing so means the world to me and helps so much with getting the word out.
P.S. If you or someone you know is in the small group of people who have an allergic contact dermatitis to aloe, would you be interested in being a tester for some new product formulations at Rain Organica? Send an email to email@example.com to learn more about the tester application process.
FDA study regarding evidence of carcinogenic activity by a whole leaf extract of Aloe barbadensis miller (aloe vera) in F344N rats
Pharmacological update properties of aloe vera and its major constituents: A comprehensive review
In vitro studies on the photobiological properties of aloe emodin and aloin A
Cosmetic Ingredient Review: Final report on the safety assessment of Aloe barbadensis Miller (aka aloe vera leaf juice)
Effects of ingesting aloe vera aqueous leaf extract on testicular weight, sperm count, and motility of adult male Sprague-Dawley rats
Semen characteristics and sperm morphological studies of the West African Dwarf Buck treated with aloe vera gel extract
Aloe vera: A review of toxicity and adverse clinical effects
Emodin and Dermocybin: Natural antraquinones used as dyes for wool and polyesters
Fine-Tuning the Colors of Natural Pigment Emodin with Superior Stability through Cocrystal Engineering
Disclaimer: The information provided in this post and throughout Rain Organica's site is not intended to treat or cure any disease or illness and is provided for information only and not a substitute for medical advice, diagnosis, or treatment by your own healthcare practitioner.
About the Author
Brandy's a formulation scientist and self-proclaimed health geek who loves hiking, gardening, bird-watching, and body boarding.
Her struggle with acne during her teens and 20s led to a holistic and healthy approach to skincare, embracing skin as an organ to be loved and cared for rather than a canvas to wage war on.
Since 2008, she's been developing all-in-one products for a simple routine at home, & Rain Organica started when her backpacking friends asked for a portable skincare routine to keep their skin healthy & happy on and off the trails.
You can try Rain Organica for yourself with The Essentials Kit, a complete skincare routine in just 3 steps.
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