Formulation Strategies and Evaluation Techniques for Salicylic Acid-Based Moisturizing Creams: A Comprehensive Review

Abstract

A popular well-known beta-hydroxy acid with keratolytic, comedolytic, and anti-inflammatory qualities is salicylic acid also helps in exfoliation process, making it a significant active component in dermatological products that treat psoriasis, acne, and other hyperkeratotic skin disorders. However, because of its low solubility, sensitivity to pH, and propensity for skin irritation, including it into moisturizing cream compositions presents special hurdles. This article offers a thorough summary of the formulation techniques used to maximize the stability, effectiveness, and skin compatibility of moisturizing creams containing salicylic acid. It talks about choosing the right emulsifiers, emollients, penetration enhancers, and pH modifiers to support the finished product's functional and cosmetic qualities. The evaluation methods utilized to evaluate physicochemical characteristics, medication release, skin hydration, irritation potential, and overall product performance are also examined in the review. This work attempts to assist researchers and formulators in creating salicylic acid-based moisturizing creams that are both effective and consumer-friendly by critically examining current formulation processes and testing methodologies.

Keywords

Introduction

1. Formulation Strategies for Salicylic Acid-Based Moisturizing Creams
   1. Choice of Base and Vehicle

When developing salicylic acid-based moisturizing creams, the choice of the base and the vehicle in which the active ingredient is delivered plays a critical role in determining the overall efficacy of the formulation. Emulsions are among the most commonly used bases, and they can be classified into two primary types: oil-in-water (O/W) emulsions and water-in-oil (W/O) emulsions. Both types of emulsions offer distinct benefits based on skin type and desired product characteristics. ^[11,12] Oil-in-water emulsions are generally the preferred choice for people with oily or acne-prone skin. These emulsions are lighter in texture and are more easily absorbed by the skin. The water phase, which is predominant, provides hydration, while the oil phase helps to deliver salicylic acid deeper into the skin layers. These emulsions have the added advantage of not being greasy, which can be beneficial for individuals who suffer from acne as it minimizes the likelihood of clogging pores. Moreover, these formulations are well-suited for maintaining the skin’s moisture balance without exacerbating oiliness. ^[13,14]

On the other hand, water-in-oil emulsions are better suited for individuals with dry or dehydrated skin. The oil phase in these emulsions is dominant, offering superior hydration and forming a barrier on the skin to lock in moisture. These formulations also provide a higher degree of occlusivity, making them ideal for preventing water loss, which is a common issue in conditions like eczema or psoriasis. The drawback, however, is that these creams can feel heavier on the skin, which may not be suitable for those with oily skin. However, this heavier texture can be beneficial for individuals who need intense hydration alongside the exfoliating action of salicylic acid. ^[15,16]  Gel-based formulations are another common option, especially for acne-prone skin. These are usually clear, lightweight, and often alcohol-free, making them less likely to cause irritation. The gel matrix allows for quick absorption and does not leave the skin feeling greasy, which is a common concern with creams or lotions. Gel-based formulations also tend to be non-comedogenic, meaning they don’t block pores, a crucial feature when treating acne with salicylic acid. This makes them particularly beneficial for users who require the exfoliating properties of salicylic acid but also need a formulation that won’t aggravate their condition further. ^[17,18]

1.2 Incorporation of Salicylic Acid

One of the main challenges in formulating salicylic acid-based creams is its solubility. Salicylic acid, being poorly soluble in water, presents difficulties in its incorporation into aqueous-based formulations. To overcome this, formulators often turn to cosolvents like propylene glycol and ethanol to help dissolve the salicylic acid, ensuring that it can be effectively incorporated into the base without compromising its efficacy. The careful use of surfactants and solubilizers is another strategy to improve the solubility of salicylic acid and create a more stable formulation. ^[19] Advancements in delivery systems, such as liposomes, nanoemulsions, and microemulsions, are providing significant improvements in the effectiveness of salicylic acid-based formulations. Liposomes, which are spherical vesicles made of lipid bilayers, allow for the encapsulation of salicylic acid, protecting it from degradation and enhancing its penetration into deeper layers of the skin. Nanoemulsions and microemulsions, which are fine dispersions of oil in water, can also improve the solubility and stability of salicylic acid while enhancing its delivery into the skin. These advanced systems help to overcome the solubility challenges, ensuring that the active ingredient reaches its target site in the skin without losing its potency.  ^[20] The formulation itself plays a crucial role in how well salicylic acid is absorbed by the skin. For example, the use of permeation enhancers or encapsulation technologies like nanoemulsions helps salicylic acid bypass the skin’s natural barrier, allowing for better therapeutic efficacy. The ability of the active ingredient to penetrate the epidermis ensures that it can exert its exfoliating and anti-inflammatory effects effectively, whether for acne, psoriasis, or other skin conditions. ^[21]

1.3 Moisturizing Agents and Additives

Salicylic acid’s keratolytic action is what makes it so effective in treating acne and hyperkeratotic conditions, but this action can also lead to dryness and irritation if not properly balanced. Therefore, incorporating moisturizing agents is essential in ensuring that the formulation not only exfoliates but also hydrates the skin, making the treatment suitable for longer-term use. Among the most common moisturizing agents are glycerin, hyaluronic acid, and ceramides. Glycerin is a powerful humectant, meaning it draws water into the skin, helping to keep it hydrated throughout the day. Hyaluronic acid, known for its ability to hold up to 1000 times its weight in water, is another popular choice that helps replenish skin moisture, keeping it plump and hydrated. ^[22,23] Ceramides, which are lipids naturally found in the skin, play an important role in restoring the skin’s protective barrier. They help lock in moisture, prevent water loss, and improve the skin's elasticity, making them particularly useful in formulations aimed at dry, sensitive skin. These ingredients work in synergy with salicylic acid to counteract the drying effects of exfoliation while simultaneously improving the skin’s hydration and resilience. ^[24] In addition to moisturizing agents, soothing agents like aloe vera and chamomile extract are often incorporated to help reduce irritation. Aloe vera is widely known for its cooling and anti-inflammatory properties, making it an ideal choice for calming irritated skin. Similarly, chamomile extract, with its anti-inflammatory and antioxidant properties, can provide additional relief, making salicylic acid-based moisturizers more tolerable for sensitive skin types. These soothing agents help reduce the potential side effects of salicylic acid, such as redness, dryness, or flaking, ensuring that the product remains gentle enough for daily use. ^[25]

1.4 pH Adjustment

Salicylic acid is most effective when formulated at an acidic pH, typically around 3.0 to 4.0, which allows it to exert its keratolytic effects. However, such a low pH can sometimes lead to irritation, especially in individuals with sensitive skin. Therefore, formulators need to carefully adjust the pH to ensure that the cream remains both effective and comfortable to use. pH modifiers like citric acid and triethanolamine are commonly used in these formulations to fine-tune the pH while maintaining the stability of both the salicylic acid and the other ingredients. Maintaining the pH balance not only ensures the efficacy of salicylic acid but also guarantees that the cream remains skin-compatible. A pH that is too high could neutralize the salicylic acid, reducing its exfoliating effects, while a pH that is too low could lead to irritation and discomfort. By using pH modifiers carefully, formulators can maintain the stability of the formulation, ensuring that it provides the desired therapeutic benefits without compromising skin health. ^[26]

2. Evaluation Techniques for Salicylic Acid-Based Moisturizing Creams

2.1 Stability Testing

When formulating salicylic acid-based moisturizing creams, one of the most critical aspects is ensuring that the final product remains stable over time. Stability testing provides a thorough assessment of how well the product can withstand environmental changes, ingredient interactions, and the passage of time. Accelerated stability testing is one of the most commonly used techniques in the industry to predict the shelf life of a product. This test involves exposing the formulation to elevated temperatures, humidity, and light to simulate long-term storage conditions in a short period. By accelerating the aging process, this method helps predict potential degradation, ensuring that the product maintains its efficacy, texture, and appearance when used by consumers. ^[27] Furthermore, freeze-thaw stability testing is employed to evaluate whether the formulation remains consistent when exposed to temperature fluctuations. This test is particularly useful for emulsions and creams, as rapid freezing and thawing can cause separation or phase instability. Ensuring that the formulation can tolerate these changes is crucial, especially for products that may be shipped or stored in varying climates. Both of these tests are fundamental in ensuring that the product performs as intended under real-world conditions, from production to consumer use. ^[28] Environmental conditions, like temperature and humidity, can greatly influence the stability of salicylic acid and other ingredients within the formulation. Salicylic acid, being sensitive to high heat, may degrade under prolonged exposure to high temperatures, reducing its efficacy. Similarly, the pH of the formulation can shift over time due to environmental factors, potentially altering the activity of salicylic acid and making it less effective or even irritating. Therefore, formulating a stable product involves rigorous testing and adjustments to ensure the integrity of both the active ingredient and the supporting elements within the cream. ^[29]

2.2 Skin Penetration Studies

Understanding how well salicylic acid penetrates the skin is essential to evaluating the therapeutic efficacy of any topical product. Franz diffusion cells are widely used in skin penetration studies, allowing researchers to measure the rate at which salicylic acid moves through different skin layers. These cells simulate the conditions of the human skin by allowing the formulation to diffuse from a donor compartment through the skin membrane and into a receptor compartment. By measuring the amount of active ingredient that reaches the dermis, researchers can determine whether the formulation delivers salicylic acid effectively and predict its impact on skin health. Another method used to assess salicylic acid’s ability to penetrate the skin is tape stripping, which involves repeatedly removing layers of the stratum corneum, the outermost layer of the skin, to measure how much of the active ingredient remains after each strip. This technique quantifies the residual salicylic acid in the skin and provides insight into how deeply the ingredient has penetrated and whether it stays within the epidermal layers or reaches the dermis. Tape stripping is particularly useful for evaluating the effectiveness of salicylic acid in targeting deeper skin layers, which is essential for treating conditions like acne or psoriasis. ^[30] Additionally, the advancement of delivery systems like liposomes, nanoemulsions, and microemulsions has significantly enhanced the penetration of salicylic acid. These delivery systems act as carriers that encapsulate the active ingredient, improving its solubility and ability to penetrate the skin barrier. Liposomes, for instance, are tiny lipid vesicles that can deliver salicylic acid more effectively to the deeper layers of the skin while also reducing irritation. Similarly, nanoemulsions and microemulsions are more stable and offer finer dispersions of oil and water, which enhances the active ingredient’s ability to bypass the skin’s natural barriers. This is especially important in delivering the desired therapeutic effects while minimizing potential side effects. ^[31]

2.3 Irritation and Sensitization Studies

Salicylic acid, while effective in treating various skin conditions, can be a double-edged sword for some individuals due to its potential for irritation and sensitization. To ensure that salicylic acid-based creams are safe for everyday use, extensive patch testing and Human Repeated Insult Patch Testing (HRIPT) are carried out. Patch testing involves applying a small amount of the cream to a patch that is then placed on the skin for a set period, usually 48 hours. This method helps determine whether the formulation causes any immediate or delayed skin reactions such as redness, swelling, or rash. HRIPT is a more advanced form of testing that involves repeated exposure to the cream over a period of time, allowing researchers to assess the likelihood of sensitization. This is crucial, especially for individuals who may develop an allergic reaction to one or more components of the formulation after prolonged use. To mitigate the irritation associated with salicylic acid, formulating creams with soothing agents like chamomile extract and aloe vera can help calm the skin and reduce inflammatory responses. These ingredients are known for their anti-inflammatory properties and can counterbalance the harsher effects of salicylic acid, ensuring that the product is safe for a broader range of skin types. ^[32] Furthermore, ensuring the safety of the formulation for sensitive skin types requires thorough testing to avoid common side effects like peeling, redness, or stinging. Guidelines for formulating creams for sensitive skin emphasize the importance of selecting non-irritating ingredients and maintaining the right pH balance to prevent disruption of the skin’s natural barrier. ^[33]

2.4 Moisturizing Efficacy

The primary goal of incorporating salicylic acid into moisturizing creams is to provide therapeutic benefits while keeping the skin hydrated. Transepidermal water loss (TEWL) is a key measurement used to evaluate the moisturizing efficacy of a cream. TEWL measures the amount of water that evaporates from the skin’s surface, providing an indication of how well the formulation maintains the skin’s hydration. Salicylic acid-based creams need to balance exfoliation with hydration, as salicylic acid has the potential to increase TEWL by removing the skin’s outermost layers. A good moisturizer should therefore minimize water loss, ensuring that the skin retains its moisture without compromising its barrier function. Evaluating the moisturizing effects of salicylic acid-based creams also involves both subjective and objective assessments. Objective measures, like TEWL, are complemented by subjective assessments, where participants rate their skin's hydration and comfort over time. These combined methods give a comprehensive view of how well a cream hydrates and protects the skin. Long-term use studies are essential to determine the lasting effects of moisturizing agents like glycerin and hyaluronic acid that work in tandem with salicylic acid to deliver both hydration and therapeutic benefits. ^[34]

3. Challenges in the Formulation of Salicylic Acid-Based Moisturizing Creams

Formulating salicylic acid-based moisturizing creams may seem straightforward on the surface, but it comes with its own set of challenges. These challenges arise mainly from the need to balance the active ingredient’s exfoliating power with its potential for irritation and dryness. Salicylic acid, while beneficial for skin health, is also known for its ability to cause irritation and skin sensitivity, especially when used in higher concentrations or over extended periods. The keratolytic effect of salicylic acid, which helps to shed dead skin cells and unclog pores, can sometimes disrupt the skin's natural barrier, leading to dryness, redness, and irritation. This issue is particularly troublesome for individuals with sensitive skin, who may experience heightened irritation, making the formulation process tricky for those consumers. To minimize these effects, formulators often need to balance salicylic acid with ingredients that have soothing or hydrating properties, such as aloe vera, chamomile extract, or glycerin. Beyond irritation, formulation instability is another key challenge when working with salicylic acid. Salicylic acid is sensitive to heat, light, and air, which can cause the compound to degrade over time, losing its effectiveness. This creates a significant hurdle for manufacturers who need to ensure that the active ingredient retains its potency throughout the product's shelf life. The instability is exacerbated when salicylic acid is combined with other ingredients, especially in emulsions, where phase separation can occur if the formulation is not properly balanced. This is particularly concerning for consumers who rely on the active ingredient for therapeutic purposes like acne treatment or psoriasis management. Therefore, testing the formulation for accelerated stability and ensuring the proper packaging, such as opaque containers or airless pumps, becomes a crucial part of the formulation process. ^[35] The formulation of salicylic acid-based creams requires a delicate balance between the exfoliating and moisturizing actions. While salicylic acid’s primary role is to exfoliate, its drying effect can be counterproductive if not appropriately addressed. The challenge is in crafting a cream that exfoliates effectively while also providing sufficient moisture to the skin. Moisturizing agents like hyaluronic acid and ceramides are often included in these formulations to provide hydration and restore the skin's barrier. However, if the moisturizer does not provide adequate hydration, the skin can become dry and irritated, counteracting the intended benefits of the salicylic acid. On the other hand, too much moisturizer may prevent the salicylic acid from working effectively. It is this fine line that formulators need to walk – ensuring that the salicylic acid can exfoliate effectively while the moisturizer maintains skin hydration and prevents moisture loss. ^[36]

Moreover, creating a formulation that works for different skin types presents its own set of difficulties. Oily skin, for instance, may benefit from lighter, non-greasy formulations that can effectively exfoliate without adding extra oil or clogging pores. These formulations tend to favour oil-in-water emulsions or gel-based systems which offer lightweight hydration without the risk of making the skin feel greasy. On the other hand, dry skin requires more intensive hydration, making water-in-oil emulsions or thicker, cream-based formulations a better fit. These formulations provide more substantial moisture and create a barrier that helps lock it in, which is crucial for dry or compromised skin. For sensitive skin types, the challenge becomes even more pronounced. Sensitive skin is more prone to reactions from salicylic acid, so careful selection of additives and stabilizers is necessary to avoid irritation. A formulation designed for sensitive skin must strike a balance between providing the therapeutic effects of salicylic acid and ensuring the product is gentle enough for daily use without exacerbating irritation. ^[37] In conclusion, the formulation of salicylic acid-based moisturizing creams is not a one-size-fits-all approach. The challenges lie in ensuring that the cream works effectively for various skin types while maintaining stability and minimizing irritation. The need to balance exfoliation and hydration, coupled with the sensitivity of salicylic acid to environmental factors, means that formulators must navigate a complex landscape to create an effective and safe product. Continued research into advanced delivery systems, such as liposomes and nanoemulsions, along with the careful selection of ingredients and their concentrations, will help in overcoming these challenges and optimizing the use of salicylic acid in skincare. By addressing these hurdles, the cosmetic and pharmaceutical industries can create salicylic acid-based creams that offer both therapeutic benefits and skin comfort. ^[38]

4. Advancements and Future Directions

4.1 Novel Delivery Systems

The field of salicylic acid-based moisturizing creams is seeing significant advancements in delivery systems that promise better skin penetration and enhanced efficacy. One of the most promising innovations is the use of nanoemulsions, liposomes, and microneedles. Nanoemulsions, which are fine dispersions of oil and water, have been gaining popularity for their ability to enhance the solubility of poorly water-soluble compounds like salicylic acid. These nano-sized particles allow for a more stable formulation and improve the penetration of the active ingredient into the skin, providing deeper, more effective treatment. Unlike traditional emulsions, nanoemulsions are able to deliver the active ingredient to the dermis without being affected by the skin’s natural barriers. ^[39] Liposomes have also become a game-changer in drug delivery systems. These small, spherical vesicles encapsulate the active ingredients, allowing for controlled release and better stability. Salicylic acid encapsulated in liposomes can be delivered more effectively to the targeted skin layers, bypassing the outer skin barrier, which can otherwise limit the penetration of topical treatments. This method reduces irritation while improving the therapeutic effects, making it particularly beneficial for sensitive skin. Another novel approach, microneedles, is also showing great potential in dermatology. These tiny needles create microchannels in the skin, allowing active ingredients like salicylic acid to be delivered directly into the dermis. The microneedles provide a minimally invasive method of delivering a high concentration of the active ingredient with fewer side effects compared to traditional methods. ^[40]

Moreover, supramolecular salicylic acid formulations are gaining attraction due to their ability to enhance skin penetration. These formulations leverage the unique properties of molecular interactions to improve the solubility and stability of salicylic acid, allowing for a more efficient and targeted delivery. Such advancements in nanotechnology and delivery systems significantly increase the dermal bioavailability of salicylic acid, ensuring that it reaches the deepest layers of the skin where it can exert its full therapeutic effects. ^[41]

4.2 Personalized Skincare

As the field of dermatology continues to evolve, personalized skincare is becoming increasingly important. One key factor driving this shift is the growing understanding of the skin microbiome and its role in skin health. The skin microbiome, which consists of trillions of microorganisms living on the skin's surface, influences everything from skin conditions like acne to the skin’s response to different treatments. Personalized skincare solutions are now being developed with this in mind, aiming to tailor products to the individual’s unique microbiome composition. By analyzing a person’s microbiome, dermatologists can create customized treatments that not only target specific skin conditions but also balance the skin’s natural flora, ensuring better results with fewer side effects. ^[42] Another important aspect of personalized skincare is the role of genetic variations. Advances in genomics and bioinformatics are allowing researchers to identify specific genetic markers that affect how individuals react to certain skincare ingredients. For example, some individuals may have genetic variations that make their skin more sensitive to salicylic acid, while others might require a higher concentration to achieve the same effect. By incorporating these genetic insights, skincare formulations can be optimized for better tolerance and effectiveness. Future trends in dermatological care will likely include personalized products that not only consider the individual’s skin type but also genetic predispositions, paving the way for treatments that are more tailored and efficient. ^[43] The development of personalized skincare is set to revolutionize how we approach skin health. It will likely lead to more precise, effective treatments that take into account an individual's specific needs, making skincare more science-driven and less about broad-spectrum solutions. As the industry embraces these advancements, we can expect a more customized approach to treating a wide range of skin conditions, with products that are fine-tuned to deliver the best possible results. ^[44]

4.3 Exploration of Combination Therapies

Another exciting avenue of research in the field of salicylic acid-based creams is the exploration of combination therapies. Combining salicylic acid with other active ingredients, such as retinoids, benzoyl peroxide, or hyaluronic acid, can enhance the therapeutic effects and provide a more comprehensive treatment for skin conditions like acne, psoriasis, and other inflammatory skin disorders. ^[45] Retinoids, for instance, are commonly used to treat acne and are known to promote skin cell turnover. When combined with salicylic acid, which also promotes exfoliation, the two act synergistically to improve the overall appearance of the skin. While salicylic acid clears pores and reduces inflammation, retinoids help to normalize skin cell production, further preventing acne breakouts. Similarly, benzoyl peroxide, another common acne treatment, can be paired with salicylic acid to target different aspects of acne. Benzoyl peroxide works by killing acne-causing bacteria, while salicylic acid helps to exfoliate and reduce inflammation. The combination of these two ingredients provides a more robust defence against acne, addressing both bacterial and clogged pore issues at the same time. In addition to these actives, hyaluronic acid is often included in salicylic acid formulations to counterbalance the drying effects of exfoliation. Hyaluronic acid helps to retain moisture in the skin, improving hydration and preventing the skin from becoming overly dry or irritated during treatment. This combination is particularly beneficial for individuals with acne-prone skin who also struggle with dryness or irritation from other acne treatments. By integrating these various actives into a single formulation, the benefits of each ingredient are maximized, offering a comprehensive treatment that addresses multiple skin concerns at once. ^[46] As dermatological science continues to advance, the future of combination therapies seems promising. By understanding the synergistic effects between salicylic acid and other active ingredients, researchers can develop more powerful, multi-functional skincare solutions that offer enhanced results in managing chronic skin conditions. With the right combination, these therapies can not only improve skin health but also help in achieving faster, more noticeable results without the side effects that often accompany the use of individual active ingredients. ^[47]

CONCLUSION:

In summary, the formulation of salicylic acid-based moisturizing creams involves a careful balance of several complex factors. From the choice of base and vehicle to the incorporation of the active ingredient, every step must be meticulously planned to ensure both therapeutic efficacy and skin safety. Emulsions, such as oil-in-water or water-in-oil, offer different benefits depending on skin type, while gel-based formulations cater to those with oily or acne-prone skin. The incorporation of salicylic acid, although effective in treating various dermatological conditions, presents challenges due to its solubility issues. These challenges are overcome by using advanced delivery systems like nanoemulsions, liposomes, and microneedles, which enhance skin penetration and stability. The importance of balancing salicylic acid’s exfoliating effects with the skin's need for hydration cannot be overstated. Including moisturizing agents such as glycerin, hyaluronic acid, and ceramides helps mitigate the drying and irritating effects of salicylic acid, making these formulations suitable for prolonged use. ^[48] Evaluation techniques, from stability testing to skin penetration studies, further ensure that the final product performs as expected while remaining safe and effective for various skin types. Stability testing, including accelerated and freeze-thaw stability, helps assess how the product holds up over time, while skin penetration studies with tools like Franz diffusion cells and tape stripping provide insight into how well the active ingredient is delivered into the skin. These methods are essential for guaranteeing that the salicylic acid reaches its target sites and delivers the desired therapeutic results without causing unwanted side effects. Moreover, irritation and sensitization studies, such as patch testing and HRIPT, play an essential role in ensuring that the product can be safely used by individuals with sensitive skin. These evaluation techniques, when executed properly, ensure that salicylic acid-based moisturizing creams are both effective and safe. ^[49] Looking toward the future, the outlook for salicylic acid-based moisturizing creams is incredibly promising. As technological advancements in nanotechnology and personalized skincare continue to evolve, the ability to create products tailored specifically to individual skin types and conditions will significantly improve. The use of advanced delivery systems such as nanoemulsions and liposomes will allow for even deeper penetration of salicylic acid, enhancing its effectiveness while minimizing irritation. Additionally, the integration of genomic and microbiome research will allow dermatologists and formulators to develop more personalized skincare solutions, ensuring that products can be tailored to address unique skin conditions based on an individual’s genetic makeup and skin flora. ^[50] Furthermore, the exploration of combination therapies offers exciting opportunities. By combining salicylic acid with other active ingredients like retinoids, benzoyl peroxide, or hyaluronic acid, formulators can create multifaceted products that address several skin concerns simultaneously. These combination therapies are particularly beneficial in treating complex conditions like acne or psoriasis, where multiple therapeutic mechanisms are required. In the future, salicylic acid-based creams may not only become more effective in treating existing conditions but also more versatile, offering additional benefits for skin rejuvenation, hydration, and barrier repair. ^[51,52] In conclusion, the development of salicylic acid-based moisturizing creams is a rapidly advancing field that shows great promise in dermatological and cosmetic applications. With ongoing research and technological innovations, these products will continue to evolve, offering more effective, safer, and personalized solutions to a variety of skin concerns. The future is bright for salicylic acid-based moisturizers, and as we continue to explore new delivery systems, combination therapies, and personalized skincare approaches, we can expect even greater improvements in skin health and consumer satisfaction. As these advancements unfold, we will undoubtedly see an increase in the availability of skincare solutions that not only treat specific skin issues but also enhance the overall quality of life for users. ^[53,54].

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