Developing natural/organic cosmetic products - Balancing consumer expectations versus practical product development. By Lauren Lamont Natural is the new in thing, and that goes for cosmetics as well. In the past, natural cosmetics were only available only in health-food shops and at astronomical prices. But that is now changing as the demand for natural and organic cosmetics has grown rapidly due to an increasing number of consumers opting for these products. The rise of global warming, pollution and illnesses has resulted in consumers growing increasingly concerned about what they're taking into their bodies. This growing concern about what they re taking in internally is leading some consumers to examine what they re applying topically¹. As a result, more people are becoming aware and troubled by the fact that cosmetic products contain ingredients that may be harmful to their health. Controversy surrounding synthetic chemicals such as parabens, petrochemicals, silicones and sulphates has prompted consumers to seek natural and organic alternatives that they perceive to be safer, healthier and better for the environment. In response to this growing demand, more cosmetics producers are targeting the trend toward natural products. Consumers have incredibly high expectations for products that claim to be natural and/or organic. They have been exposed to and are therefore accustomed to the consistent, smooth and elegant texture of synthetic formulations². Consumers expect natural/organic products to be as close to natural and organic as possible (only natural and organic ingredients incorporated in the formulation); perform well, if not better than the synthetic alternatives (more efficacious than synthetic products); match conventional synthetic products with high sensory value; have a shelf life comparative to the synthetic alternatives; are reasonably priced and easily obtainable. The increasing consumer interest in natural and organic cosmetics has led many formulators and cosmetic companies to look at developing syntheticallyclean cosmetics. However, the path leading to pure natural and organic cosmetics is fraught with technical hurdles including several formulation and ingredient challenges³. Imitating nature Several cosmetic companies are attempting to produce natural/organic cosmetics in attempt to meet the overwhelming consumer demand for these products, but still, these companies continue to grapple with ingredient issues³. The availability of natural/organic ingredients remains an issue adequate supply of high-quality raw materials at reasonable costs is a major concern for many companies⁴. Often the ingredients required to produce cosmetics with functional and sensory properties similar to synthetic cosmetics are not available yet: There is a lack of specific raw materials such as UV protection agents, antiperspirant actives, polymers and cationic conditioning agents⁵. Another issue is the high cost of some natural alternatives as opposed to the synthetic analogues for example, alterative natural chelating agents for the well-known and inexpensive Ethylene Diamine Tetraacetic Acid (EDTA), are much more costly⁵. In addition to this, the supply of natural ingredients that are effective is inadequate, resulting in a high demand for these ingredients that in turn leads to these ingredients being marketed at exorbitant prices³. These problems are,
however, not limited to consistency of supply the efficacy and quality of the ingredients are often poor, a factor directly affecting the quality of the final product. In order to bridge the gap between the heavy demand and short supply of natural raw materials, many companies have invested in ethical sourcing projects to guarantee the supply of these materials⁶. Unfortunately for cosmetic companies worldwide, the issues associated with the development of natural cosmetics are not limited to ingredient issues. The introduction of natural and organic ingredients into cosmetic product compositions may lead to new formulation challenges⁵. Natural ingredients or extracts are complicated chemical mixtures. This presents an issue to formulators as they must understand the chemical behaviour and properties of these complex mixtures in order to minimise risk, such that performance, odour, colour, safety, cost and, most importantly, stability and preservation are not compromised. It is often difficult to estimate how natural and organic ingredients will change the stability profile of cosmetic products³. In terms of product performance, several of the natural formulations available in the marketplace lack the high aesthetic value and functional performance found in many synthetic cosmetics. The challenge in formulating natural products is thus to increase the level of natural and organic ingredients in the product composition without compromising the products stability and performance. More ingredient companies are producing high quality, functional natural ingredients such as emulsifiers, surfactants and silicone replacements⁷. As a result there is increasingly less of an issue about natural alternatives for the tried and tested synthetic raw materials. Despite this, the concern regarding how these raw materials will react and constitute the new formulation remains. These overwhelming technical issues have lead formulators and product developers to sacrifice product efficacy and sensory aspects in favour of raw material and stability requirements³. As the natural and organic cosmetics market continues to evolve, an ever growing challenge for formulators and product developers is to produce high quality certified products that match rising consumer expectations. Keeping the balance The issue of stability is a key challenge associated with natural and organic products. For example, many of the natural emulsion stabiliser substitutions do not provide adequate emulsion stability, resulting in low viscosity emulsions that separate with time⁵. The best solution to finding effective natural emulsifiers would be to study how stable oil and water systems are established in nature⁸. The stabilisation of twophase systems in nature usually involves complex combinations of lipids and proteins. A classic natural emulsion is milk, which is a complex mixture of fat suspended in an aqueous solution. This oil in water emulsion, containing approximately four per cent fat is stabilised by complex phospholipids and proteins such as caseins. Natural emulsifiers are available include plant gums, waxes and butters and lecithin. Natural gums that have varying degrees of emulsification, stablilisation and viscosity control and examples of these include xanthum, tragacanth, guar, locust bean, carageenan and the alginates. Natural waxes are used as natural thickeners and emulsifiers. An effective natural wax includes beeswax that has emulsifier, thickener and emollient properties. Lecithin is used as an emulsifier,
thickener, stabilizer, and is also an emollient. Lecithin is a mixture containing phospholipid as the major component and can have varied hydrophilic-lipophillic balance (HLB), depending on the degree of hydrolysis and extraction methods, which can be useful for both water-in-oil (W/O) and oil-in-water (O/W) emulsions. Natural emulsifiers not only serve their function as emulsifiers but also offer many benefits to the skin¹¹. Stability tests are essential and should be run by formulators in order to ascertain the emulsion stability of their natural cosmetics. These tests include: Freeze/thaw testing cycling the product between a freezer at -10oC and an oven at 40oC; ageing programmes constant temperature storage tests; centrifugal force centrifuging the product for 10 minutes; visual assessment using stains to determine the particle size (the smaller the particle size the greater the stability); low shear rate evaluation shaking of the emulsion for a few days²³. Natural oils and exotic butters are widely used in natural and organic cosmetic products. Evening primrose oil and borage oil are very common natural oils, used primarily because of their high content of gamma linolenic acid. Natural butters like shea are among the exotic butters widely used for skin care products. They are rich in symmetrical monounsaturated triglycerides that are solid or semi-solid at room temperature and have appreciable viscosity and emulsion stability. Although these oils, butters and waxes provide many beneficial qualities to natural cosmetic products, they are predisposed to deteriorate through several degradation reactions that occur during long-term storage. The main deterioration processes are oxidation reactions that result in unpleasant rancid odours and decreased sensorial quality¹². The spontaneous reaction of atmospheric oxygen with lipids, known as autoxidation, is the most common process leading to oxidative deterioration. Oxidation may effectively be inhibited by the use of specific additives (antioxidants) that prevent unsaturated oil products from becoming rancid during storage, thus extending the shelf life of the cosmetic product1. Synthetic phenolic antioxidants, butylated hydroxytoluene (BHT) and butylated hydroxyanisole (BHA) are not so well accepted by consumers as there has been growing concern over their possible side-effects¹². The use of these oils and butters in natural cosmetics thus poses yet another challenge for product developers - combating oxidation of natural oils and butters in various cosmetic formulations without the use of synthetic additives. Fortunately for natural cosmetic formulators, natural alternatives to these synthetic antioxidants are available and these include the Vitamins C and E¹² ¹³. Another effective natural antioxidant are tetrahydrocurcuminoids - these are colourless, biologically active curcuminoids extracted from turmeric roots that have been found to offer additional functional antioxidant benefits in protecting fat-based compounds from oxidation. In fact, laboratory studies have found that tetrahydrocurcumins quenched free radicals more effectively than BHT and vitamin E¹³. Natural dyes, such as carmine, caramel, cartenoids and annatto, do not have the same regulatory restrictions as the organic and inorganic dyes¹⁴. These natural dyes pose a great challenge to the natural cosmetic formulator as they have limited stability. At certain ph levels, some natural dyes degrade or shift to a different, lessstable colour: Annatto will precipitate out of solution at a ph less than 4.0, and carmine breaks down at a ph less than 3.5. Carotenoids are susceptible to oxidation and sensitive to light. Use of antioxidants such as tocopherols or Vitamin C can
reduce loss of visual colour and natural rosemary extract has antioxidant properties and may be used to improve the oxidative stability of carotenoids. These issues should be taken into consideration when setting formulated product specifications. Natural dyes also exhibit strong odours this should be taken into consideration when selecting fragrances and masking agents. Natural dyes can also be more heat/processing sensitive and thus formulators should be aware of the effect of heat, shear and order of addition will affect the final result and formula reproducibility¹⁵. Flower power Botanical extracts that support the health, texture and integrity of skin, are widely used in natural cosmetic formulations. The use of natural extracts and botanicals, however, presents a myriad of challenges to the natural cosmetic formulator. The deep colouration of several extracts and botanicals available impart a colour to creams and lotions that does not blend well with the currently manufactured personal care products. Extracts may also discolour over time, for example, the ph of a product containing significant levels of Aloe barbadenis leaf extract must be kept below 5.5 or the product will go brown. Several extracts are ph sensitive - in clear products, the incorrect ph can cause precipitation and the incorrect ph could deactivate any extracts in the formulation². Formulators should request information regarding extract/botanical formulation requirements from their suppliers and run stability trials in order to prevent any unwanted formulation problems. Another challenge associated with the use of botanical extracts is their poor solubility in acceptable solvents. Formulators are thus faced with a difficult task that often results in modifications to the entire formulation process. Several factors could be considered to assist solubility of the extracts and these include the order of the addition of ingredients, the type of solvent used, temperature and ph conditions and the mixing process². Skin care products do not last forever. Just like food, all skin care products will eventually deteriorate and go rancid. This natural decaying process can be accelerated by contamination of a variety of organisms such as yeasts, fungi and bacteria such as E. coli, pseudomonas, staphylococci and streptococcus. Cosmetic products that are contaminated by these organisms could be potentially dangerous to the end user. In addition to this, microbial contamination can also lead to product instability such as product separation, cloudiness of originally clear products, loss of viscosity, discoloration, drop of ph and formation of gasses and odours¹⁶. Preservatives are routinely added to skin care products with the intention of preventing and controlling decay, discolouration and microbial growth. These preservatives perform an important function in all cosmetics preparations and are an indispensable ingredient. Chemical preservatives are generally used because they are much cheaper than, and extend the shelf life of the product more than natural alternatives. Although few natural ingredients can adequately match the preservative efficacy of synthetic ingredients, the bad publicity surrounding synthetic preservatives has caused a demand for cosmetics formulated with natural preservatives. As a result many natural cosmetic formulators may wish to formulate with natural preservatives. All natural preservatives must meet the following criteria: Broad spectrum activity (active against all types of microorganisms); effective at low
concentrations; water and oil soluble; compatible with the formulation and other ingredients; does not add colour and/or odour to the formulation; stable under all temperatures and ph; be safe to use and should not be responsible for any irritancy, allergies, sensitivities and other serious reactions; cost effective; and has no impact in the aesthetic/performance of the finished product¹⁷ ²². Unfortunately for cosmetic formulators, the current list of natural preservatives are not nearly as effective or as safe as their synthetic counterparts. Natural preservatives are poor preservatives natural substances that display antimicrobial activity are inadequate for broad-spectrum protection. Most natural preservatives often require high concentrations to be effective; others have offensive odours (neem oil) or unwanted colours (usnic acid) that pose an aesthetic issue in cosmetic products. Other natural preservatives require special handling and are inactivated in certain manufacturing processes. Some do not mix well in emulsions and are not completely compatible with other cosmetic ingredients and others are not entirely safe for use due to potential irritation (limonene) or allergic reaction (cinnamon oil)¹⁸. Protect and preserve Many companies use a variety of natural preservatives in combination to ensure broad spectrum protection, as few new natural preservatives on the market work very well used in isolation. Natural preservatives that are available to cosmetic manufacturers include essential oils, plant extracts and vitamins. Formulators also tend to combine natural preservatives with synthetic preservatives because they are easier to use with other ingredients and are less expensive⁵. For formulators striving to use only natural preservatives, several options are available, but most of these only provide a shelf life of six months. Essential oils, such as tea tree and thyme have antiseptic properties and are shown to kill bacteria and fungi. The disadvantage of essential oils is that they need to be used in high quantities to be effective and also can create sensitivities to the skin and they also can break down or evaporate if left exposed to the atmosphere. Commonly used extracts include rosemary, grapefruit and lemon peel extract. Potassium Sorbate can be considered natural since it comes from a natural source and is used often as a food preservative. It is most effective as a preservative at a ph of 6.5¹⁶. This ingredient is very rarely used alone because it supports only the prevention of mold and yeast as it will not stop bacterial growth. It is possible to preserve products by lowering to product ph to 4.0 4.8. Citric acid from a suitable source may be used to adjust the ph. Maintaining the ph of a product at a low level is, however, insufficient to ward off all strains of bacteria, yeast and moulds. It is thus necessary to incorporate a preservative that is stable at such a low ph. Both Benzoic acid and potassium sorbate may be used at this ph; benzoic acid is more effective against bacteria than potassium sorbate but less effective against yeast and moulds.2 The combination of potassium sorbate and benzoic acid, coupled with the low ph, serve as quite an effective preservative system. Citric acid, as a ph adjuster, also appears to act in synergy to improve the microbial action of these two materials² ¹⁹. As mentioned, few natural preservatives work well in isolation and thus more often than not, one or more varieties must be used in combination to attain broad spectrum
coverage. Despite the many effective natural preservative substitutes available, their stability in formulations are less established than the synthetic varieties and thus may cause unintended stability problems. It is thus evident that natural preservation required a great deal of experimentation. Formulators must experiment with the different preservative systems available in order to obtain a preservative system that is not only robust, but is safe for to use for extended periods (will not cause any skin reactions). Formulators must ensure the robustness of their preservative systems by running preservative efficacy tests on the actual finished formulation²². The test will assist the formulators in ascertaining which preservative system to use against strains of micro-organisms to which the product may be exposed and also the preservative concentration which will preserve the product throughout manufacture and in use²². Consumers expect natural/organic products to be made entirely of natural and organic ingredients; be as efficacious as synthetic products; match conventional synthetic products with high sensory value; have a shelf life comparative to the synthetic alternatives; be reasonably priced and easily obtainable. This benchmark is difficult for cosmetic formulators to attain due to several ingredient and formulation restraints. Several of the ingredients necessary to produce cosmetics with functional and sensory properties similar to synthetic cosmetics are not available yet, and the natural ingredients that are available often lack the same efficacy and quality found in their synthetic counterparts. The high cost of natural ingredients is also a limiting factor for formulators worldwide. Furthermore cosmetic manufacturers are bombarded with several formulation issues and these include stability and preservation issues. The former involves preventing emulsion breaks, oil rancidity, foul odours, unwanted colour, viscosity and ph changes. The latter involves preventing and controlling decay, discolouration and microbial growth, thereby ensuring a safe product with a reasonable shelf life. With the use of the correct ingredient combinations, carefully selecting formulated product specifications and running stability and preservative efficacy trials on the final product, cosmetic manufacturers may be able to overcome the myriad of technical issues they face when formulating natural and organic cosmetic products and thus may be able to provide consumers with high quality natural cosmetic formulations that match their synthetic counterparts in terms of efficacy, aesthetic vale, shelf life and price. References available on request.