Inositol: what are the benefits of carob extract for the skin?

Carob is the fruit of the carob tree, a perennial tree in the legume family that typically reaches between five and ten meters in height. The carob tree thrives in hot, dry climates. Since Antiquity, it has been primarily cultivated along Mediterranean coasts, notably in Morocco, Spain, Italy, etc.... Carob pods are processed into powder, gum, and aqueous extract, depending on the intended use. Carob powder can be used as a substitute for cocoa powder in culinary preparations, while carob gum is used as a thickening agent in cosmetics as well as in the food industry.

Meanwhile, carob extract, and more specifically inositol, one of its main active compounds, is used in cosmetics, particularly for its antioxidant and tanning effects.

Inositol is primarily distinguished by its ability to protect the skin from photoaging. By stimulating fibroblasts, it activates type I collagen synthesis, a fibrous dermal protein that ensures the skin’s firmness and elasticity. This mechanism is especially important because the body’s natural production of collagen declines with age, a process further exacerbated by exposure to UV radiation, which accelerates collagen breakdown. By replenishing collagen stores, inositol helps counteract some of the structural damage induced by the sun, thereby limiting skin sagging and the formation of wrinkles.

The efficacy of this active ingredient has moreover been confirmed by a clinical study that measured the effects of a lotion enriched with inositol, at concentrations ranging from 0.5 to 3%, on a panel of women whose number was not disclosed. After seven weeks of application, instrumental measurements showed an improvement in skin elasticity and an increase in hydration. Even more noteworthy, using an inositol concentration of 1 to 2% helped regulate sebum levels, bringing both dry and oily skin closer to a neutral profile, while visibly reducing wrinkle depth. However, several limitations must be emphasized: in addition to the unknown sample size, the overall composition of the lotion is not provided, which restricts interpretation. Furthermore, the concept of a “neutral profile” with respect to sebum production was not explicitly defined.

While more studies are still needed, these initial results nonetheless suggest that inositol is a promising active ingredient for skin care, whether the skin is dry, oily or mature.

Inositol derived from carob is also useful for intensifying and prolonging the skin’s tan. Unlike self‑tanning products, which color only the surface of the epidermis, inositol acts upstream, at the level of melanocytes, the cells responsible for pigmentation. It works as a trigger for melanogenesis by increasing the availability of phosphoinositols, intracellular messengers that transmit the signal inducing the production of the pigment.

More specifically, the inositol from carob extract regulates the DAG/PKC metabolic pathway. By increasing the amount of diacylglycerol (DAG) in cells, it activates a family of enzymes called protein kinase C (PKC). These then activate tyrosinase, the enzyme that converts tyrosine into melanin, by modifying its structure through phosphorylation. This chain reaction naturally boosts melanin production, allowing for a tan that develops faster, is more intense, and, most importantly, lasts longer after sun exposure.

Note that while inositol optimizes the skin’s pigmentary response, it in no way constitutes a sunscreen protective filter against ultraviolet radiation. The use of a sunblock remains essential to protect the skin from the sun.

Finally, inositol is a valuable ally for skin prone to blemishes, although in this context it is used specifically by oral route and not as a topical application. Its effectiveness is based on its anti-inflammatory and antimicrobial properties, but above all on its ability to regulate hyperandrogenism, that is, an excess of hormones of the male type, and on the sensitivity of hormone receptors. In particular, it works by inhibiting the enzyme 5-alpha-reductase, which is involved in the excessive production of sebum, thus providing a targeted, root-cause approach to treating acne, especially in women with imbalances related to polycystic ovary syndrome (PCOS).

A 24‑week clinical study evaluated the impact of oral myo‑inositol supplementation in women with moderate acne, hirsutism, and irregular menstrual cycles, despite normal blood hormone levels. The results showed a remarkable improvement: as early as the fourth week, a significant decrease in both inflammatory and non‑inflammatory lesions was observed, reaching a 50% reduction in skin imperfections by the twelfth week.

Beyond its effects on the skin, the treatment also helped to regulate menstrual cycles, with the proportion of normal cycles increasing from 10% to 68% in the treated group, without any notable side effects. More specifically, at the beginning of the study, 49% of the women had menstrual cycles longer than 45 days, compared with 3% at the end of the study. Inositol therefore appears to be a promising alternative for improving the appearance of acne-prone skin. However, although the clinical results are encouraging, inositol supplementation must absolutely be discussed in advance with a primary care physician, gynecologist, or dermatologist. It is important to emphasize that this supplementation can in no way replace an established medical protocol, whether for acne treatment or for the management of polycystic ovary syndrome.

Only a healthcare professional can determine whether oral inositol is appropriate for your profile and whether it can be incorporated, as a supplement, into your treatment plan.

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