Acetyltetrapeptide-2 and application thereof in freckle-removing and whitening cosmetics / daily necessities

Abstract

The invention discloses acetyl tetrapeptide-2 and application thereof in freckle-removing and whitening cosmetics / daily necessities, relates to the technical field of cosmetics, and comprises the application of the acetyl tetrapeptide-2 in the freckle-removing and whitening cosmetics / daily necessities, and the freckle-removing and whitening cosmetics / daily necessities comprise facial care, cleaning, body care and sunscreen. The face care type is essence, emulsion, face cream, eye cream, facial masks and toning lotion; the cleaning products are facial cleanser and shower gel; the body care class is body lotion; the sunscreen class is sunscreen cream; according to the acetyl tetrapeptide-2 and the application thereof in freckle-removing and whitening cosmetics / daily necessities, a three-dimensional whitening system is constructed, so that the acetyl tetrapeptide-2, nicotinamide and tranexamic acid have a synergistic effect, and the freckle-removing and whitening effects are more comprehensive and efficient; through step-by-step dissolution and temperature control operation, the biological activity of thermosensitive active substances is effectively protected, and the pH value is accurately regulated to 5.5-6.5 (weak acidity), so that the skin physiological environment is met.

Description

Technical Field

[0001] This invention relates to cosmetic technology, specifically to acetyl tetrapeptide-2 and its application in skin-whitening and freckle-removing cosmetics / daily necessities. Background Technology

[0002] Skin pigmentation, such as melasma, freckles, and post-inflammatory hyperpigmentation, is a common skin problem that plagues consumers worldwide. The root cause lies in the activation of tyrosinase activity in melanocytes under the stimulation of various internal and external factors (such as ultraviolet radiation, hormones, and inflammation). This catalyzes the conversion of tyrosine into dopaquinone, which then undergoes a series of oxidative polymerization reactions to ultimately produce melanin. This melanin is then transferred to keratinocytes, leading to pigmentation and dullness on the skin surface.

[0003] Currently, the active ingredients in skin-whitening and freckle-removing cosmetics on the market mainly focus on tyrosinase inhibitors, antioxidants / reducing agents, and exfoliating agents. Tyrosinase inhibitors are the mainstream whitening mechanism, but these ingredients often have poor stability and are subject to certain irritation or safety controversies. Antioxidants / reducing agents are unstable, easily deactivated, and may irritate the skin at high concentrations. Overuse of exfoliating agents can damage the skin barrier and lead to skin sensitivity. Melanin transport inhibitors have limited efficacy, and some consumers may experience intolerance. Summary of the Invention

[0004] The purpose of this invention is to provide acetyl tetrapeptide-2 and its application in skin whitening and freckle-removing cosmetics / daily necessities, in order to solve the problems of poor stability and certain irritation of existing skin whitening and freckle-removing cosmetics / daily necessities.

[0005] To achieve the above objectives, the present invention provides the following technical solution: acetyl tetrapeptide-2, the structural formula of which is shown below:

[0006] .

[0007] Application of an acetyl tetrapeptide-2 in skin whitening and freckle-removing cosmetics / daily necessities.

[0008] Furthermore, the whitening and freckle-removing cosmetics / daily necessities include facial care, cleansing, body care, and sun protection products.

[0009] Furthermore, the facial care category includes serums, lotions, face creams, eye creams, face masks, and toners; the cleansing category includes facial cleansers and shower gels; the body care category includes body lotions; and the sun protection category includes sunscreens.

[0010] A skin-whitening and freckle-removing cosmetic / daily product containing acetyl tetrapeptide-2, wherein the cosmetic / daily product is an essence, and the ingredients of the essence include, by weight: 0.01-5 parts acetyl tetrapeptide-2, 1-10 parts niacinamide, 0.5-5 parts tranexamic acid, 0.05-2 parts sodium hyaluronate, 2-10 parts glycerin, 1-8 parts butylene glycol, 0.05-0.5 parts carbomer, 0.05-0.3 parts triethanolamine, 0.1-1 parts phenoxyethanol, 0.05-0.2 parts fragrance, and the balance being deionized water.

[0011] Furthermore, the method for preparing the serum includes the following steps:

[0012] S1. Add deionized water to the reaction vessel, start stirring, and add carbomer, glycerol and butanediol in sequence. Stir until completely dissolved, and stir under heating to form a homogeneous aqueous solution.

[0013] S2. In another reaction vessel, acetyl tetrapeptide-2, nicotinamide, tranexamic acid, and sodium hyaluronate are mixed evenly, and deionized water is added and stirred to dissolve, thus obtaining an active ingredient solution.

[0014] S3. Slowly add the active ingredient solution to the aqueous phase solution and continue stirring for 10-15 minutes to obtain a mixed solution. When the mixed solution cools, adjust the pH value to 5.5-6.5, then add phenoxyethanol and fragrance, stir evenly, and obtain a crude solution.

[0015] S4. Filter the crude solution to obtain a skin-whitening and freckle-removing cosmetic / daily product containing acetyl tetrapeptide-2.

[0016] Furthermore, the heating temperature described in S1 is 70-80℃.

[0017] Furthermore, the stirring time described in S1 is 20-30 minutes.

[0018] Furthermore, the pH-adjusting solution described in S3 is triethanolamine.

[0019] Furthermore, the temperature at which the mixed solution in S3 is cooled is 40–50°C.

[0020] Compared with existing technologies, the acetyl tetrapeptide-2 provided by this invention and its application in skin-whitening cosmetics / daily products achieve multi-target synergistic effects in terms of efficacy, constructing a three-dimensional whitening system: acetyl tetrapeptide-2 inhibits the melanin production instruction from the source; niacinamide blocks the transport of melanin to epidermal cells; tranexamic acid has anti-inflammatory properties and stabilizes melanocytes. The three work synergistically to achieve a more comprehensive and efficient skin-whitening effect; at the same time, ingredients such as sodium hyaluronate and glycerin provide excellent moisturizing, making the skin hydrated and radiant.

[0021] By employing stepwise dissolution and temperature control, the bioactivity of heat-sensitive active substances such as acetyl tetrapeptide-2 is effectively protected. By precisely controlling the pH value to 5.5-6.5 (weakly acidic), it not only matches the skin's physiological environment but also ensures the stability of the carbomer thickening system, resulting in a product with a delicate texture and stable properties. Attached Figure Description

[0022] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this invention. For those skilled in the art, other drawings can be obtained based on these drawings.

[0023] Figure 1 This is a schematic diagram of the preparation process of an essence containing acetyl tetrapeptide-2, provided in an embodiment of the present invention. Detailed Implementation

[0024] To enable those skilled in the art to better understand the technical solution of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings.

[0025] Example 1:

[0026] Acetyl tetrapeptide-2, the structural formula of which is shown below:

[0027] .

[0028] Specifically, acetyl tetrapeptide-2 is a short-chain peptide formed by four amino acids linked by peptide bonds. Its molecular structure is modified by acetylation, which significantly improves its stability and skin permeability. In skin-whitening and blemish-removing cosmetics and daily necessities, it achieves its efficacy through a multi-target mechanism, while also possessing advantages such as high efficiency, safety, and stability.

[0029] The core steps of melanin synthesis depend on the catalysis of tyrosinase. Acetyl tetrapeptide-2 intervenes in this process in two ways: one is by directly inhibiting enzyme activity: its molecular structure binds to the active site of tyrosinase, reducing the enzyme's catalytic efficiency for substrates (tyrosine), thereby reducing the production of melanin precursors (such as dopaquinone); the other is by regulating gene expression: some studies have shown that it may reduce melanin synthesis at the transcriptional level by downregulating the expression of tyrosinase-related genes (such as TYR and TRP-1).

[0030] After melanin is synthesized in melanocytes, it needs to be transported to keratinocytes through dendritic structures to eventually form skin pigment. Acetyl tetrapeptide-2 can inhibit proteins involved in this process (such as PAR-2 ​​and RAB27A), reduce the deposition of melanin in the epidermis, and prevent the formation of age spots.

[0031] Inflammation is a significant contributing factor to pigmentation (such as post-acne erythema and melasma). Acetyl tetrapeptide-2 reduces skin inflammation by inhibiting the release of inflammatory factors (such as IL-6 and TNF-α), thereby decreasing melanocyte activity. Furthermore, it may promote fibroblast proliferation, accelerate the repair of damaged skin, and improve skin texture in areas of pigmentation. Ultraviolet radiation or environmental pollution can induce excessive production of free radicals (ROS) in the skin, stimulating melanocyte activation. Acetyl tetrapeptide-2 prevents pigmentation by scavenging free radicals and reducing oxidative stress on melanocytes.

[0032] The application of acetyl tetrapeptide-2 in skin-whitening and blemish-removing cosmetics / daily products has the following benefits:

[0033] High efficiency and targeted action: Its short-chain peptide structure allows it to quickly penetrate the stratum corneum of the skin, directly targeting melanocytes or related signaling pathways. Compared to traditional ingredients (such as hydroquinone, which takes several months to take effect), acetyl tetrapeptide-2 typically shows a fading effect on pigmentation within 2-4 weeks.

[0034] Low irritation: As a natural amino acid derivative, its biocompatibility is better than that of chemically synthesized ingredients (such as hydroquinone, which may cause erythema and peeling), making it suitable for sensitive skin or fragile skin after cosmetic procedures.

[0035] Non-cytotoxic: In vitro experiments showed that even at high concentrations (5%), acetyl tetrapeptide-2 did not produce toxicity to melanocytes or keratinocytes.

[0036] Long-term use is non-addictive: Unlike hormonal ingredients, it will not cause pigmentation rebound after discontinuation.

[0037] Synergistic effects across multiple pathways: A single ingredient can achieve multiple effects such as "inhibiting production + blocking transport + anti-inflammatory repair + anti-oxidation", reducing the need for other ingredients in the formula and lowering the risk of allergies; for example, in spot-removing essences, acetyl tetrapeptide-2 can replace the traditional complex combination of "tyrosinase inhibitor + anti-inflammatory agent + antioxidant".

[0038] Chemical stability: Acetylation modification improves the heat and light resistance of peptides, making them less prone to degradation in formulations and extending product shelf life.

[0039] Dosage form compatibility: Soluble in water or oil phase, suitable for various dosage forms such as serums, lotions, masks, and sunscreens, and does not conflict with common ingredients (such as hyaluronic acid and niacinamide) when compounded.

[0040] Example 2:

[0041] This embodiment provides a technical solution based on Embodiment 1: the application of acetyl tetrapeptide-2 in skin whitening and freckle-removing cosmetics / daily necessities. Skin whitening and freckle-removing cosmetics / daily necessities include facial care, cleansing, body care, and sun protection products; facial care products include serums, lotions, creams, eye creams, masks, and toners; cleansing products include facial cleansers and shower gels; body care products include body lotions; and sun protection products include sunscreens.

[0042] Specifically, in facial care products (serums, lotions, creams, eye creams, masks, and toners): Acetyl tetrapeptide-2 reduces melanin production at its source by blocking the synthesis of tyrosinase. In serums and creams, it can target localized problems such as age spots, sun spots, and melasma, achieving a concentrated fading effect; it inhibits the release of UV-induced inflammatory factors (such as IL-6 and TNF-α), reducing post-inflammatory hyperpigmentation (PIH); in eye creams, it can alleviate darkening of sensitive skin around the eyes caused by friction or irritation; in masks, it quickly brightens skin tone through short-term high-concentration penetration; in toners, as the first step in skincare, it can improve the absorption efficiency of subsequent products; and in lotions, it balances moisturizing and whitening effects, preventing dryness and subsequent darkening.

[0043] Cleansing products (facial cleansers, body washes): Gently exfoliate and metabolize melanin. These products contain a low concentration of acetyl tetrapeptide-2, which helps soften the stratum corneum and promotes the shedding of melanin from dead skin cells. Facial cleansers are formulated with gentle surfactants to prevent barrier damage caused by over-cleansing. Body washes provide targeted care for dull areas of the body (such as elbows and knees), inhibiting inflammatory responses induced by cleansing ingredients (such as SLS) and reducing post-cleansing redness and pigmentation.

[0044] Body care products (body lotion): This body lotion provides all-over whitening and evens out skin tone. It contains acetyl tetrapeptide-2, which can target large areas such as the arms and legs to improve uneven skin tone caused by sun exposure. With long-term use, it inhibits melanin transport to the stratum corneum, gradually fading dark spots, promoting hyaluronic acid synthesis, and increasing skin hydration, resulting in a naturally radiant complexion.

[0045] Sunscreen (sunscreen cream): Protective whitening and photodamage repair. The sunscreen contains acetyl tetrapeptide-2, which can neutralize UV-induced free radicals and reduce excessive melanin production caused by DNA damage. By inhibiting the AP-1 (activator protein-1) pathway, it blocks the inflammation-pigmentation cycle under UV stimulation, meeting consumers' dual needs of "sunscreen + whitening", and is especially suitable for repair after outdoor activities.

[0046] Example 3:

[0047] Please see Figure 1This embodiment provides a technical solution based on Embodiment 1: a skin-whitening and freckle-removing cosmetic / daily product containing acetyl tetrapeptide-2.

[0048] The cosmetic / daily product is an essence, and the ingredients of the essence include, by weight: 0.01-5 parts acetyl tetrapeptide-2, 1-10 parts niacinamide, 0.5-5 parts tranexamic acid, 0.05-2 parts sodium hyaluronate, 2-10 parts glycerin, 1-8 parts butylene glycol, 0.05-0.5 parts carbomer, 0.05-0.3 parts triethanolamine, 0.1-1 parts phenoxyethanol, 0.05-0.2 parts fragrance, and the balance being deionized water.

[0049] Specifically, acetyl tetrapeptide-2, in its whitening and spot-removing effects, can inhibit the production and transfer of melanin, reduce the formation of age spots, and help improve dull skin, making the skin brighter and more radiant. 0.01 parts is the minimum effective amount to ensure it exerts a certain level of biological activity; at this dosage, it can begin to regulate skin cells. Five parts is the upper limit set after comprehensively considering factors such as cost, skin absorption capacity, and potential irritation. Using more than five parts not only increases the cost of the product but may also cause adverse reactions such as allergies due to excessive concentration. Furthermore, the skin's absorption of excessive ingredients is limited, failing to further enhance the effect.

[0050] Niacinamide is a multifunctional skincare ingredient that can inhibit the transfer of melanin to keratinocytes, thereby reducing pigmentation and achieving a whitening and spot-removing effect. Niacinamide also enhances the skin's barrier function, improves its moisturizing ability, reduces moisture loss, and makes the skin healthier and smoother. One part is the starting dose for niacinamide to exert its basic whitening effect. Doses below this may not effectively inhibit melanin transfer. The whitening effect gradually increases with increasing dosage, but dosages exceeding 10 parts may cause skin irritation, such as redness and itching. Therefore, the upper limit is set at 10 parts.

[0051] Tranexamic acid is a protease inhibitor that inhibits plasminogen activator, thereby reducing the activity of enzymes required for melanin production, blocking the melanin formation pathway, effectively fading dark spots, and brightening skin tone. Tranexamic acid also has anti-inflammatory properties, reducing skin inflammation and improving overall skin condition. 0.5 parts is the minimum effective amount of tranexamic acid to inhibit melanin production; increasing the dosage to 5 parts achieves a good whitening and spot-removing effect while ensuring safety. Doses exceeding 5 parts may increase the burden on the skin, with less noticeable improvement in effect, and may also pose potential safety risks.

[0052] Sodium hyaluronate is a natural moisturizing factor with a strong water-absorbing capacity. It can form a moisturizing film on the skin's surface to prevent moisture loss and maintain skin hydration. It can also promote skin cell metabolism, enhance skin elasticity, and make the skin smoother and more delicate. 0.05 parts is the starting dose for sodium hyaluronate to exert its basic moisturizing effect, providing the skin with a certain ability to retain moisture; 2 parts is the upper limit for achieving a better moisturizing effect while ensuring a good product texture and feel. Using too much may make the product too sticky, affecting the user experience.

[0053] Glycerin is a common moisturizer that absorbs moisture from the air, replenishing the skin's hydration. It also forms a protective film on the skin's surface to prevent moisture evaporation, keeping the skin moisturized. Glycerin has good skin affinity, binding with the skin's moisture to keep it soft and smooth. Two parts is the minimum amount of glycerin needed to provide basic moisturizing effects, offering some hydration. Ten parts represents the upper limit, considering the overall formula and cost, to achieve good moisturizing results without irritating the skin. Using too much may make the product too oily and affect the skin's breathability.

[0054] Butylene glycol is also a commonly used humectant. It possesses excellent hygroscopic and moisturizing properties, absorbing and locking in moisture from the air to provide long-lasting hydration to the skin. Butylene glycol also acts as a solvent, helping other ingredients dissolve and disperse better in the formula. One part is the starting dose for butylene glycol to exert its moisturizing and solvent effects, while eight parts represents the upper limit for achieving good moisturizing effects while ensuring product stability and a pleasant user experience. Excessive use may cause irritation and increase costs.

[0055] Carbomer is a commonly used thickener that forms a gel-like structure in water, increasing the viscosity and consistency of products, giving serums a suitable texture for easy application and use. Carbomer also stabilizes product formulations, preventing other ingredients from separating or settling, ensuring product quality stability. 0.05 parts is the minimum amount of carbomer needed to achieve a certain viscosity and stability, while 0.5 parts represents the upper limit for achieving a good texture and stability while considering user experience and cost. Using too much carbomer will make the product too viscous, affecting application and absorption.

[0056] Triethanolamine primarily functions to neutralize carbomer in the formulation. Carbomer is an acidic polymer, and triethanolamine can neutralize it to form a stable gel system, adjusting the product's pH value to be closer to the skin's physiological pH value and reducing skin irritation. 0.05 parts is the minimum amount required for the neutralization reaction between triethanolamine and carbomer to ensure the product's pH value is stable. 0.3 parts is the upper limit for fully neutralizing carbomer while considering the product's safety and stability. Excessive use may cause the product's pH value to be too high, resulting in skin irritation.

[0057] Phenoxyethanol is a widely used preservative that inhibits the growth and reproduction of microorganisms, preventing product contamination by bacteria, mold, and other microorganisms during storage and use, thus ensuring product quality and safety. 0.1 parts is the minimum effective amount of phenoxyethanol to exert its preservative effect, inhibiting the growth of common microorganisms; 1 part represents the upper limit for achieving good preservative effects while considering product safety and efficacy. Excessive use may cause skin irritation and does not comply with relevant regulations.

[0058] The main function of fragrance is to give products a pleasant aroma, enhance the user experience, and provide consumers with a pleasant olfactory experience when using serums. 0.05 parts is the minimum amount required to give a product a noticeable fragrance; 0.2 parts is the upper limit for achieving a good fragrance effect, taking into account the safety of the fragrance and its impact on the overall scent of the product. Excessive use may cause skin allergies or irritation, and an overly strong fragrance may cause discomfort to some consumers.

[0059] Deionized water is the main solvent in serums, used to dissolve and dilute other ingredients, giving the product a suitable concentration and texture for easy application and absorption. It also provides some hydration to the skin. The amount used is adjusted based on the amounts of other ingredients to ensure the total weight of the product meets requirements.

[0060] Please see Figure 1 The preparation method of whitening and freckle-removing cosmetics / daily necessities (serum) includes the following steps:

[0061] S1. Add deionized water to the reaction vessel, start stirring, and add carbomer, glycerol and butanediol in sequence. Stir until completely dissolved, heat to 70-80℃ and stir for 20-30 minutes to form a homogeneous aqueous solution.

[0062] S2. In another reaction vessel, acetyl tetrapeptide-2, nicotinamide, tranexamic acid, and sodium hyaluronate are mixed evenly, and deionized water is added and stirred to dissolve, thus obtaining an active ingredient solution.

[0063] S3. Slowly add the active ingredient solution to the aqueous phase solution and continue stirring for 10-15 minutes to obtain a mixed solution. When the mixed solution cools to 40-50℃, adjust the pH value to 5.5-6.5 with triethanolamine, then add phenoxyethanol and fragrance, stir evenly, and obtain a crude product solution.

[0064] S4. Filter the crude solution to obtain a skin-whitening and freckle-removing cosmetic / daily product containing acetyl tetrapeptide-2.

[0065] The specific implementation method is as follows: S1. Preparation of the aqueous solution: Accurately weighed deionized water is added to a cleaned and sterilized reaction vessel. The stirrer is turned on, and the stirring speed is set to 150-200 r / min. Carbomer is slowly added to the reaction vessel while stirring to prevent clumping. After stirring for 10-15 minutes, the carbomer is initially dispersed in the deionized water. Glycerin and butylene glycol are added sequentially, and stirring is continued for 20-30 minutes to ensure that all components are completely dissolved. At this point, the solution should be uniform and transparent, without visible particles. The heating device is turned on, and the solution in the reaction vessel is heated to 70-80℃. Stirring is maintained at this temperature for 20-30 minutes. During the heating process, the temperature change should be closely monitored to ensure that the temperature is uniform and stable, promoting the full swelling of carbomer and its integration with other components.

[0066] S2. Preparation of the active ingredient solution: In another clean and sterilized reaction vessel, accurately weighed acetyl tetrapeptide-2, nicotinamide, and tranexamic acid are added to a clean container. The mixture is gently stirred with a glass rod until homogeneous. A small amount of deionized water is slowly added while stirring continuously to initially wet the active ingredients. Then, the remaining deionized water and sodium hyaluronate are added. The stirrer is turned on, and the stirring speed is set to 200-250 rpm. The mixture is stirred for 30-40 minutes until all active ingredients are completely dissolved, resulting in a homogeneous and transparent active ingredient solution.

[0067] S3. Mixing and pH Adjustment: Slowly add the active ingredient solution to the stirred aqueous solution through a pipe, maintaining a constant stirring speed during the addition process to prevent localized high concentrations and uneven composition. After the addition is complete, continue stirring for 10-15 minutes to ensure thorough mixing and a homogeneous solution. Stop heating and allow the solution to cool naturally. Continue stirring during cooling to prevent separation. When the solution cools to 40-50°C, measure its pH value using a calibrated pH meter.

[0068] Based on the measurement results, triethanolamine was slowly added dropwise while the solution was continuously stirred, and the pH value was closely observed. The pH value of the solution was adjusted to between 5.5 and 6.5, which is close to the physiological pH value of human skin and can reduce skin irritation. Phenoxyethanol and fragrance were added sequentially, and stirring was continued for 15-20 minutes to ensure that the preservative and fragrance were evenly dispersed in the solution, thus obtaining the crude solution.

[0069] S4. Pass the crude solution through a 0.45μm or 0.22μm filter membrane to remove any small particles, impurities and insoluble substances that may be present in the solution, to obtain a clear and transparent essence.

[0070] Example 4:

[0071] This embodiment provides a technical solution based on Embodiment 3: In this embodiment, relevant performance tests were conducted on a skin-whitening and freckle-removing cosmetic / daily product (essence) containing acetyl tetrapeptide-2, and the tests are as follows:

[0072] 1. Viscosity testing:

[0073] Pour the filtered essence into the viscometer's measuring container, ensuring the sample volume covers the rotor to a certain height (the specific height depends on the instrument's requirements). Slowly immerse the rotor in the sample, avoiding the formation of air bubbles. Start the viscometer and, once the reading stabilizes, record the viscosity value. Similarly, to obtain accurate results, multiple measurements (3-5 times) can be performed, and the average value can be taken as the final viscosity test result.

[0074] After multiple measurements and averaging, the viscosity of the serum was found to be 500 mPa·s, which meets the product design requirements.

[0075] 2. Microbiological index detection:

[0076] On a sterile operating table, use a sterile pipette to draw 1 mL of the filtered essence and add it to a test tube containing 9 mL of sterile physiological saline. Mix thoroughly to prepare a 1:10 sample homogenate. Then, following the tenfold incremental dilution method, prepare sample homogenates of different dilutions such as 1:100 and 1:1000 in sequence.

[0077] Select 2-3 suitable dilutions of sample homogenate, and add 1 mL of each to a sterile petri dish, making two parallel dishes for each dilution. Simultaneously, add 1 mL of sterile physiological saline to a sterile petri dish as a blank control. Pour approximately 15-20 mL of preheated nutrient agar medium (46℃) into each petri dish, and quickly rotate the dish to thoroughly mix the sample homogenate with the medium. After the medium has solidified, invert the petri dishes and incubate them in a 37℃ incubator for 48 h ± 2 h.

[0078] After incubation, remove the petri dishes and visually inspect the colony count. Select petri dishes with colony counts between 30-300 CFU for counting. If two dilutions have colony counts within this range, use the ratio of the two dilutions to determine the calculation method: if the ratio is less than or equal to 2, report the average; if the ratio is greater than 2, report the colony count from the petri dish with the lower dilution. Finally, calculate the total number of colonies in the sample based on the dilution factor.

[0079] After testing, the total bacterial count of the whitening and freckle-removing essence was 50 CFU / g. No total mold or yeast was detected. No pathogenic bacteria such as thermotolerant coliforms, Staphylococcus aureus, or Pseudomonas aeruginosa were detected. It meets the relevant microbiological standards for cosmetics.

[0080] The foregoing has only described certain exemplary embodiments of the present invention by way of illustration. Undoubtedly, those skilled in the art can modify the described embodiments in various ways without departing from the spirit and scope of the present invention. Therefore, the foregoing drawings and descriptions are illustrative in nature and should not be construed as limiting the scope of protection of the claims of the present invention.

Claims

1. Acetyl tetrapeptide-2, characterized in that, Its structural formula is shown below: 。 2. The application of acetyl tetrapeptide-2 as described in claim 1 in skin-whitening and freckle-removing cosmetics / daily necessities.

3. The application according to claim 2, characterized in that, The whitening and freckle-removing cosmetics / daily necessities include facial care, cleansing, body care, and sun protection products.

4. The application according to claim 3, characterized in that, The facial care category includes serums, lotions, face creams, eye creams, face masks, and toners; the cleansing category includes facial cleansers and shower gels; the body care category includes body lotions; and the sun protection category includes sunscreens.

5. A skin-whitening and freckle-removing cosmetic / daily product containing acetyl tetrapeptide-2, characterized in that, The cosmetic / daily product is an essence, and the ingredients of the essence include, by weight: 0.01-5 parts acetyl tetrapeptide-2, 1-10 parts niacinamide, 0.5-5 parts tranexamic acid, 0.05-2 parts sodium hyaluronate, 2-10 parts glycerin, 1-8 parts butylene glycol, 0.05-0.5 parts carbomer, 0.05-0.3 parts triethanolamine, 0.1-1 parts phenoxyethanol, 0.05-0.2 parts fragrance, and the balance being deionized water.

6. The whitening and freckle-removing cosmetic / daily product containing acetyl tetrapeptide-2 according to claim 5, characterized in that, The method for preparing the serum includes the following steps: S1. Add deionized water to the reaction vessel, start stirring, and add carbomer, glycerol and butanediol in sequence. Stir until completely dissolved, and stir under heating to form a homogeneous aqueous solution. S2. In another reaction vessel, acetyl tetrapeptide-2, nicotinamide, tranexamic acid, and sodium hyaluronate are mixed evenly, and deionized water is added and stirred to dissolve, thus obtaining an active ingredient solution. S3. Slowly add the active ingredient solution to the aqueous phase solution and continue stirring for 10-15 minutes to obtain a mixed solution. When the mixed solution cools, adjust the pH value to 5.5-6.5, then add phenoxyethanol and fragrance, stir evenly, and obtain a crude solution. S4. Filter the crude solution to obtain a skin-whitening and freckle-removing cosmetic / daily product containing acetyl tetrapeptide-2.

7. The whitening and freckle-removing cosmetic / daily product containing acetyl tetrapeptide-2 according to claim 6, characterized in that, The heating temperature described in S1 is 70-80℃.

8. The whitening and freckle-removing cosmetic / daily product containing acetyl tetrapeptide-2 according to claim 6, characterized in that, The stirring time described in S1 is 20-30 minutes.

9. The whitening and freckle-removing cosmetic / daily product containing acetyl tetrapeptide-2 according to claim 6, characterized in that, The pH-adjusting solution described in S3 is triethanolamine.

10. The whitening and freckle-removing cosmetic / daily product containing acetyl tetrapeptide-2 according to claim 6, characterized in that, The temperature at which the mixed solution described in S3 is cooled is 40–50°C.

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