What is "Trehalose" and what is its utility?

Known as the "resurrection sugar", trehalose is a compound natural non-reducing disaccharide, in which two glucose residues are linked by an α-1,1-glycosidic bond. Abundant and widely distributed, trehalose is synthesised by many organisms, including bacteria, yeasts, fungi, insects, invertebrates and plants, with the exception of vertebrates, when cells are exposed to unfavourable environmental conditions (extreme dehydration, desiccation, heat, freezing temperatures, etc.). This is possible because trehalose has the unique ability to form a gel around cells, preventing them from dehydrating, which in turn, protects them from damage.

In 1855, a medicine referred to as "Tréhala" was introduced at the International Exhibition in Paris by François DELLA SUDDA. It is used for the treatment of coughs and pulmonary diseases. It is a type of sweet cocoon produced by insects of the genus Larinus that live on various species of Echinops in the Middle East. In 1858, trehalose was isolated from "Tréhala" by Marcellin BERTHELOT, highlighting its physical and chemical properties.

In 1876, it was established that the chemical structure of trehalose, isolated from "Trehala", is similar to the sugar found in ergot of rye (Claviceps purpurea). In 1913, trehalose was also discovered in the plant kingdom, notably in the Jericho rose (Selaginella lepidophylla). It has also been proven that this molecule is present in green algae, mosses, liverworts, and ferns.

Moisturising serums, sun care products, hair masks, eye patches... trehalose is finding increasing applications in cosmetics. In addition to its low toxicity, this is due to the stabilising and protective roles it plays in conjunction with other biomolecules in the body, enabling it to withstand extreme environmental conditions.

Beyond its role as an active ingredient, trehalose has significant potential to enhance stability in cosmetic formulations

• Autophagy Activator: A Study In Vitro Recent research has shown that trehalose can activate autophagy in primary human keratinocytes, a finding supported by the topical application of trehalose-loaded liposomes (In Vivo). This intracellular catabolic mechanism allows the digestion of elements from damaged cells to protect against cellular stress. Thus, by modulating the autophagy process, trehalose exerts protective effects against photodamage by regulating inflammation, oxidative stress, and cell proliferation, and by promoting angiogenesis.

• Coating Agent: The use of trehalose also extends to the formulation of hair care products. In this case, it is adopted as a coating active ingredient that softens hair fibres. This molecule also increases the resistance of hair fibres to various types of damage. However, the mechanism of action responsible for this effect remains to be determined.

• Wound Healing: A recent study on cultured epidermal autografts has shown that highly concentrated trehalose (> 98%) facilitates the healing of skin wounds, by inducing a transient and beneficial state of non-inflammatory senescence in human fibroblasts (cell cycle arrest), through the positive regulation of CDKN1A/p21, for an efficient wound repair process. Indeed, this induction led to the secretion of growth factors that stimulate the proliferation of keratinocytes and the formation of blood capillaries, results that have been confirmed in vivo in mice.

• Protective function: More effective than other sugars, trehalose has the ability to protect DNA, proteins, and lipids from molecular damage induced by various factors. Indeed, results indicate that it helps to maintain cellular integrity by protecting the native three-dimensional structure of cellular bilayers and macromolecules, inhibiting their denaturation, degradation, and aggregation during stress. A widely accepted hypothesis is that trehalose preserves and stabilises macromolecules because its hydroxyl groups form hydrogen bonds with the molecule's surface, which helps to maintain their conformation and thus their activity.

• Humectant: Furthermore, trehalose mimics the effects of the skin's natural hydration factors (NHF). Indeed, it possesses moisture retention properties, superior to those of other disaccharides. This provides the opportunity to maintain and stabilise a water balance, but also to confer optimal comfort to the skin. The result is smooth and hydrated skin.

Trehalose can also be used in cosmetic products to eliminate body odour associated with ageing by neutralising the breakdown of fatty acids to form unsaturated aldehydes.

• Antioxidant Protection: Studies have shown that trehalose inhibits oxidative stress by trapping free radicals, which can otherwise cause oxidative damage in cells. It has been reported that trehalose regulates high levels of free radicals by controlling the expression of antioxidant genes (superoxide dismutase, etc.) and the autophagy pathway. Therefore, trehalose protects the skin from the oxidative and ageing effects of damage caused by environmental stressors.

Comprising 96% natural ingredients, our lip peel contains trehalose for its moisturising properties.

Does the topical application of trehalose pose any health risks?

Trehalose appears to be suitable for all skin types and does not cause skin reactions, such as irritation or redness when used topically. In 2019, the expert group from the "Cosmetic Ingredient Review" deemed that trehalose was a safe cosmetic ingredient in current usage practices and concentration in cosmetics, given that their report covered products containing up to 2%.

Derived from plants, the trehalose present in our lip peel comes from Japan.

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• ELEUTHERIO E. C. A. & al. The role of trehalose and its transporter in protection against reactive oxygen species. Biochimica et Biophysica Acta (2008).

• PAUL P. K. C. & al. Trehalose in hair care: Heat styling benefits at high humidity. Journal of Cosmetic Science (2011).

• WANG Y. J. & al. Trehalose: Current use and future applications. Journal of Pharmaceutical Sciences (2011).

• GU H. & al. Trehalose, sucrose and raffinose are novel activators of autophagy in human keratinocytes through an mTOR- independent pathway. Scientific Reports (2016).

• EMANUELE E. & al. A peel-off facial mask comprising myoinositol and trehalose-loaded liposomes improves adult female acne by reducing local hyperandrogenism and activating autophagy. Journal of Cosmetic Dermatology (2017).

• LUCIA & al. Protective effect of trehalose-loaded liposomes against UVB-induced photodamage in human keratinocytes. Biomedical Reports (2014).

• CAMELI N. & al. Evaluation of the filming and protective properties of a new trehalose and ceramides based ingredient. Cosmetics (2019).

• HELDRETH B. & al. Safety assessment of monosaccharides, disaccharides, and related ingredients as used in cosmetics. International Journal of Toxicology (2019).

• GU H. & al. Trehalose protects keratinocytes against ultraviolet B radiation by activating autophagy via regulating TIMP3 and ATG9A. Oxidative Medicine and Cellular Longevity (2022).

• ZHOU K. & al. Trehalose promotes the survival of random-pattern skin flaps by TFEB mediated autophagy enhancement. Cell Death & Disease (2019).

• SAYAMA K. & al. Highly concentrated trehalose induces prohealing senescence-like state in fibroblasts via CDKN1A/p2. Communications Biology (2023).