by Tonya Mckay
What is Aloe Vera?
Aloe vera is a perennial succulent plant that has been treasured throughout the history of mankind for its many beneficial properties. Evidence of its use are found in ancient Egyptian and Greek histories. Once introduced to southern Europe in the early 17th century it quickly became an accepted medicinal plant. It can be grown easily in most climates, and is well-suited for patio and indoor habitats, making it a species found in many homes.
Several of the properties attributed to aloe vera gel include facilitation of wound healing (especially burns and abrasions), mitigation of damage from ultraviolet radiation, anti-microbial activity (antibacterial and antifungal), anti-inflammatory action, skin moisturization, digestion aid, as well as potential applications as an anti-cancer agent and a targeted, controlled release drug delivery agent. Investigation is being done to increase our understanding of the composition of aloe vera and of the mechanisms by which it achieves it extraordinary accomplishments.
Aloe Vera in Hair Products
Given its ready accessibility and apparently gentle and healing nature, it is unsurprising that aloe vera gel is also popular in cosmetics and hair care, particularly as a kitchen-chemist or home herbalist ingredient. The claims made for what it can do for hair are fairly broad, and some should probably be viewed with a healthy degree of skepticism. The frequently touted aloe vera gel benefits to hair include improved detangling, moisturization, scalp healing, remediation of dandruff, restoration of pH levels, decreased frizz, enhanced cellular regeneration, anti-inflammatory action for the scalp and generation of hair growth.
Many people report excellent results when aloe vera gel is applied on the hair after washing and conditioning, and before a styling gel is applied. Some curlies enjoy using aloe vera gel as a stand-alone styling agent, while for others, this does not supply sufficient hold or curl retention.
There have also been testimonies of aloe vera gel being drying to hair, that it contains protein which makes low-porosity hair stiff and dry, and many questions of whether or not it behaves as a humectant. Finally, inconsistent results have been obtained when using aloe vera gel from different sources. A quick peek at the complex chemistry of this wonderful plant should provide some insight into these observations and questions.
The aloe vera plant stores water in its leaves, which allows it to thrive during arid periods in climates where rainfall is sporadic. “Gel” is the terminology used to describe the mucilaginous material obtained from the parenchyma tissue of the plant. This slimy substance is approximately 99.0 – 99.5% water. The remaining 0.5-1.0% is comprised of a highly complex mixture of many components consistently mainly of a number of polymeric carbohydrate molecules called polysaccharides which contain building blocks of different small molecule sugars (monosaccharides). While a number of polysaccharides are present, the primary ones are acetylated mannan and pectin substance. These polymers provide the physical structure to this highly aqueous system which gives it its mucilaginous character. Mannans are also responsible for binding cellulose and for acting as signaling molecules for plant growth. Pectin substance includes several closely-related polysaccharides such as pectin, pectic acid, and arabinogalactin.
Polysaccharides have many hydroxyl groups pendant to the chain, available for hydrogen bonding, and for this reason are very hydrophilic and water soluble. This hydrophilicity also means that polysaccharides attract water from the atmosphere and bind it to the polymer surface, which is classic humectant behavior. This can have important ramifications for curly hair especially.
Aloe vera gel also contains small amounts of the protein lectin, as well as various amino acids. These can be absorbed into the cortex of hair, to greater extents by hair with greater porosity, where they can add structural integrity to the hair. However, some hair types become overly stiff and brittle or dry when protein accumulates on or in it, so it is wise to be aware of the presence of these materials in anything applied to the hair. The balance of the components in aloe vera gel include several vitamins, organic fatty acids and triglycerides, minerals, enzymes, amino acids, proteins, simple sugars and other compounds.
Key Ingredients in Aloe Vera
- Polysaccharides (carbohydrates): mannan, acetylated mannan (also: acemannan), pectic substance, cellulose, galactan, galactogalacturan, arabinogalactan, xylan.
- Fatty acids: γ-linolenic acid, arachidonic acid, salicylic acid, uric acid.
- Vitamins: α-tocopherol (vitamin A), B vitamins including folic acid, ascorbic acid (vitamin C), β-carotene, choline.
- Protein: lectin, lectin-like substance.
- Inorganic elements and minerals: chromium, calcium, magnesium, manganese, sodium, copper, iron, phosphorous, potassium, zinc.
- Various organic molecules: monosaccharides (sugars), enzymes, amino acids, anthroquinones, chromones, miscellaneous.
Aloe vera gel has both emollient and moisturizing properties, meaning that it smoothes the cuticle surface and also attracts and seals in moisture. Despite having a relatively low amount of active ingredients on a molecular or weight basis (less than 1.0%), the specific combination and type of ingredients enable it to pack a significant punch.
It imparts detangling and conditioning by forming a polymer film on the surface of the hair, thereby smoothing the cuticle. This film can also provide mild hold, but significant curl retention based on application of aloe alone is unlikely. The pectin and sugar molecules can deliver moisture to the hair, and the amino acids and trace amounts of protein present can strengthen the cortex of damaged hair. It can act as a humectant as well, which can be beneficial in certain climates for specific hair types, but can also be a detriment in others.
Finally, aloe vera gel contains minerals such as iron, calcium, potassium, magnesium, and other micronutrients which may be beneficial to the hair and scalp. For many users, aloe vera makes an excellent leave-in conditioner to be used underneath applied styling products to provide extra protection for delicate tresses. It is completely water soluble, so can be used regardless of the preferred cleansing regimen.
Aloe Vera Gel Variations
Investigators have observed that there is significant variation in the polysaccharide content and composition of aloe vera gel. This has been found to be dependent upon many factors. Extraction and processing methods have a huge impact on the polysaccharide content of the gel. Polysaccharides are highly susceptible to degradation from temperature and shear forces. Season of growth and location create variations also. There have even been differences observed from leaf to leaf of the same plant. This is a potential explanation for variability in performance noted by different users. As with many things in nature, some degree of flexibility may have to be acceptable.
As documented below, most “100% pure Aloe vera gel” available for purchase is a mixture containing some aloe, polymers for viscosity modification, preservatives and other additives. These additions will necessarily change the impact of the aloe vera on your hair as well.
Fruit of the Earth Aloe Vera Gel: Aloe Vera (Aloe Barbadensis) Gel, Triethanolamine, Tocopheryl Acetate (Vitamin E), Carbomer 940, Tetrasodium EDTA, DMDM Hydantoin, Diazolidinyl Urea
Buying Aloe Vera Gel
Many health food stores should carry a product that is more pure than this. However, the fact that aloe contains high amounts of water means that it is highly susceptible to microbial growth and thus, must be preserved if packaged for commercial sale. In order to achieve proper suspension of the preservative, it is probably necessary to add the viscosity-modifying polymer. For these reasons, the optimal way to obtain truly pure Aloe vera gel would be to grow it at home and extract what you need from your own plants. Gardening can be fun and rewarding in its own right anyway. There is something very satisfying about growing, nurturing and harvesting your own supplies.