Multifunctional actives for oily skin and scalp disorders

Between 2009 and 2014, there were almost 10,000 product launches that addressed oily skin and oily hair concerns. Shampoos continue to dominate the innovations in hair care in 2014 accounting for more than one third of total launches. Looking at new claims such as ‘brightening/ illuminating’ in the hair care products, we learn that not only the hair care market is following the trends of skin care innovations but also is looking towards more positive functional attributes rather than damage reversal and protection.¹

Based on the data extracted through Mintel, hair care products need to become more segmented not just by hair type but also separated by scalp type with specific formulations for oily scalp and dry scalp. The US alone provided an estimated $5.05 billion dollar shampoo and conditioner market and is projected to grow steadily over the next four years and reach a value of $5.6 bn by 2017.¹ However this growth will likely be driven by the development of new formats and skin care-inspired trends for hair care.¹ Multifunctional claims that bring solutions to several ongoing and interrelated concerns are gaining traction in the US market and driving the growth.

Interestingly, the emerging economies of India and Indonesia offer rapidly developing shampoo and conditioner segments versus the more mature markets such as Japan, France and Italy.1 However scalp care is of extreme importance particularly in Asia where the number of scalp related issues is on the rise. In China, for example, 68% of the consumers suffer from dandruff, 67% have itchy scalp and 56% are afflicted with oily hair/scalp.² In 2014, almost one fifth of the products were formulated for consumers with skin disorders.

The men’s market is a relatively underserved one. Men often do not perceive the additional benefits of using different shampoo and conditioners. This is also due to the fact that most of the men’s products were solely focused on dandruff control. In recent years, men have shown a willingness to pay a premium for products that bring additional value;¹ multifunctionality being considered a real benefit for these consumers.

The Mintel database reveals that almost 8,000 launches between 2009 and 2014 carried the claims of addressing ‘oily skin’. The same research for ‘oily scalp’ remedies revealed 150 launches in those years. Once the two claims of ‘oily hair’ and ‘oily skin’ are juxtaposed, the number of the launches dwindles down to two products. Meanwhile, over 1,800 products were launched to address ‘oily hair’ concerns.

Most of these products are formulated with a wide range of botanicals varying from mostly lemon and citrus to nettle, rose and menthol. The claim of oily hair is often combined with anti-dandruff, pHneutral and anti-inflammatory ingredients or salicylic acid and zinc pyrithione. There were also many other products that have added additional oils to help break the cycle of the skin’s need to over produce sebum. Others claim to have oil added or mineral and vitamin fortified to restore the normal conditions to both hair and scalp. Among these, there were a few dry shampoos that utilised zea mays starch or natural clay to simply soak up the oil. However, very few products launched during the past five years contain ingredients that address the root cause of the sebum over-production.

The physiological role of sebum for skin and scalp

Sebum production has an important function in barrier protection and transepidermal water loss (TEWL). Human sebum produced by sebocytes is composed of triglycerides, saturated and unsaturated fatty acids, wax esters, sterol esters, cholesterol, cholesterol esters, and squalene.3 Epidermis keratinocytes produce ceramides, cholesterol and free fatty acids.4,5 Once the triglycerides are hydrolysed, they then release glycerol, which is an important factor that supports skin elasticity, hydration of the stratum corneum and barrier repair. Sebum in hair lubricates both scalp and hair thus reducing its friction. It also brings dead skin cells in the follicle up to the surface. Sometimes due to hormonal changes, genetics, poor nutrition or environmental stress, sebaceous glands may overproduce sebum. This can result in oily scalp and hair as well as acne and hair loss conditions.

Although oily/hair scalp is considered a cosmetic problem and not a dermatological condition, the absence of adequate scalp care treatment to treat oily scalp disorder, could lead to serious scalp pathology (dandruff, seborrheic dermatitis, alopecia).⁶ Clinical literature provides evidence that the occurrence of such pathologic skin conditions negatively impact individuals’ quality of life.7,8 These pathologies provoke deleterious psychosocial impact on human self-esteem and a healthy self-image.

The oily appearance of scalp is due to an accumulation of sebum on the scalp as a consequence of an excess sebum excretion by sebaceous glands.^9,10 The accumulated ‘sebum’ on the scalp surface is a mixture of sebum produced by sebaceous glands and lipids produced by keratinocytes. This epidermal lipid is very important to skin’s hydration. If this component is disturbed or stripped off though use of harsh detergents, skin’s permeability barrier may become compromised allowing excessive water loss, and as a result of this increase in transepidermal water loss the skin and scalp will face dryness.35 The water contents of the stratum corneum of healthy skin must be greater than 10% and the skin’s lipidic component plays an essential role in maintaining a balanced ecosystem.

The skin surface of oily skin and scalp is often characterised by an abnormal lipid composition (decrease in ceramides and sphingolipids content).¹¹ These abnormalities in lipid composition are linked to hyperkeratosis, barrier dysfunction, and weakness of the cell follicle membrane. Consequentially, the weakness of the cell follicle membrane induces the release of digested lipids, which in turn, increase the amount of superficial sebum. Once excreted, the accumulated sebum is spread over the scalp surface and on hair giving it an oily appearance.

The normal scalp has a biotic commensal community (Staphylococcus spp., Propionibacterium spp., and Malassezia spp.)¹² On the dandruff-afflicted scalp, the levels of Malassezia increase by 1.5 to 2 times their normal level.¹³ The presence of these microorganisms (Malassezia restrica, Malassezia furfur and Malassezia globossa)¹⁴ on the oily scalp provide an ideal medium (inflammatory, irritant) which leads to the development of dandruff and/or seborrheic dermatitis.¹⁵ The sebum is degraded by oxygen and microorganisms found on the scalp surface. Once degraded the sebum becomes cytotoxic and irritant due to free fatty acid liberation, thus provoking reactive follicular hyperkeratosis and epidermis alteration marking the onset of scalp disease.

Regulating sebum production with a selected mix of multifunctional ingredients

In this study, we assessed the efficiency of active ingredients (panthenyl triacetate, farnesol, farnesyl acetate) to treat the metabolic origin of scalp disorder by limiting the excretion of sebum at the scalp surface via the modulation of the lipid metabolism process involved in sebaceous gland and in the epidermis.

Concept of this selected mix
Panthenyl triacetate (PTA), farnesol, and farnesyl acetate (FA) were selected for their biological properties. Panthenyl triacetate and farnesyl acetate were respectively synthesised by acetylation of panthenol and farnesol. Panthenol and panthenol derivative (PTA) are converted into pantothenic acid in vivo.¹⁶ Pantothenic acid is categorised as part of the vitamin B complex family and is a characteristic natural by-product of the human metabolism. Pantothenic acid is one of several precursor substances forming coenzyme ^A,17 which is an important cofactor for acylation reactions in numerous biochemical processes in the body. Coenzyme A also plays a decisive part in the cholesterol synthesis (Fig. 1).

Farnesol and farnesol derivatives (FA) are natural substances of high biological potency, which are also found in this form as bioactivators in human skin. Farnesol and farnesol derivatives are widespread in the plant world, in particular in the essential oil plant. The derivatives of panthenol and farnesol were used in order to provide a sustained action. Indeed, their conversion is slower in comparison to panthenol and farnesol into biologically active molecules.

The scalp microorganisms are known to have a limited growth due to the intrinsic antifungal and antibacterial properties of the three active ingredients, panthenyl triacetate, farnesol and farnesol acetate, used in the cosmetic formula. By using the cosmetic formulation, the quality of sebum composition is controlled (by panthenyl triacetate, farnesyl acetate and farnesol) and protected against microorganisms and oxidation.

Clinical investigations

Material and methods
Cream and shampoo formulas
The active ingredients were used in the cream at 5% and in the shampoo at 2%, with the following formulas:

• INCI composition of the cream containing the active ingredient Unitrienol T-27 at 5%: Water, Caprylic/Capric Triglyceride, Beeswax, Lanolin Corona, Safflower Oil, Decyl Oleate, Unitrienol T-27, Sorbitan Sesquioleate, Cholesterol, Trilaurin, Uniphen P-23 (Preservative), Perfume.
• NCI composition of placebo cream: Water, Caprylic/Capric Triglyceride, Beeswax, Lanolin Corona, Safflower Oil, Decyl Oleate, Sorbitan Sesquioleate, Cholesterol, Trilaurin, Uniphen P-23 (Preservative), Perfume.
• INCI composition of the shampoo containing the active ingredient Unitrienol 7-27 at 2%: Water, Sodium Laureth Sulfate, Sodium Lauryl Sarcosinate, Decylglucose, Natrium Hydroxide, Cocamidopropylbetain, PEG 40 Hydr. Castor Oil, Unitrienol T-27, Carbopol ETD 2020, Unigerm G-2, Polyquaternium-10, Perfume.
• NCI composition of the placebo shampoo: Water, Sodium Laureth Sulfate, Sodium Lauryl Sarcosinate, Decylglucose, Natrium Hydroxide, Cocamidopropylbetain, Peg 40 Hydr. Castor Oil, Carbopol ETD 2020, Unigerm G-2, Polyquaternium-10, Perfume.

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