A skin care composition containing caffeine and a method for preparing and using the same

Abstract

The present application relates to a kind of caffeine-containing skin care composition and its preparation method, application, belong to the technical field of cosmetics.The caffeine-containing skin care composition provided by the present application is composed of water phase and oil phase, wherein the raw materials of water phase include caffeine, nicotinamide, deionized water, the raw materials of oil phase include myrtle geranium oil, aina xiang oil, tulipa gesneriana flower oil, glycerol trioleate, PEG-30-dihydroxy stearic acid ester, each component is reasonably compounded, and multiple skin care levels are synergistically effective, the obtained composition can be stably added in essence oil, massage oil, color cosmetics and other oil cosmetics, realize the comprehensive skin care effect of lightening black eye circle, firming and anti-wrinkle, brightening skin color, soothing and repairing.

Description

Technical Field

[0001] This invention belongs to the field of cosmetic technology and relates to a caffeine-containing skin care composition, its preparation method, and its application. Background Technology

[0002] Caffeine is a natural alkaloid found in over 60 plants, including coffee beans, tea leaves, cocoa beans, and guarana nuts, and is widely used in food, beverages, and pharmaceuticals. Humans have a long history of using caffeine; as early as the 6th century AD, Ethiopian shepherds discovered its stimulating effects by chewing coffee berries, while ancient Chinese people were already brewing tea during the Han Dynasty (2nd century BC). Today, caffeine is widely used in energy drinks, food, and pharmaceuticals through industrial extraction.

[0003] With the continuous advancement of cosmetic technology, caffeine is no longer just a stimulant, but a highly regarded multi-functional skincare ingredient. As a cosmetic ingredient, caffeine has been included in the *Directory of Used Cosmetic Ingredients* (2021 edition) and the *International Directory of Standard Chinese Names of Cosmetic Ingredients* (2010 edition). Thanks to its unique biological mechanism, caffeine, when incorporated into skincare products, can "awaken" and protect the skin, demonstrating significant effects in multiple skincare areas such as anti-oxidation, anti-swelling, and anti-inflammation. It is particularly suitable for addition to eye creams, day serums, sunscreens, and skincare products with brightening and anti-aging claims.

[0004] Although many products using caffeine to improve skin physiological functions have been launched, they still face the following challenges in market application: caffeine is poorly soluble in water, with a solubility of only 2% at room temperature, and it will crystallize at low temperatures; moreover, it does not easily penetrate the stratum corneum of the skin epidermis, hindering the transdermal permeability of caffeine.

[0005] With the rise of the "oil-based skincare" concept, the market demand for caffeine, a raw material suitable for oil-based cosmetics, is increasing. However, caffeine has extremely low solubility in oils, almost being insoluble, which severely limits its application in oil-based products such as facial oils and massage oils. Summary of the Invention

[0006] The purpose of this invention is to provide a caffeine-containing skincare composition, its preparation method, and its application. The caffeine-containing skincare composition consists of an aqueous phase and an oil phase. The raw materials of the aqueous phase include caffeine, niacinamide, and deionized water, while the raw materials of the oil phase include geranium oil, senna oil, Rosa damascena flower oil, triglyceride ester, and PEG-30-dimeric hydroxystearate. The components are rationally combined to work synergistically at multiple levels, such as improving microcirculation, regulating pigment metabolism, inhibiting inflammation, repairing the skin barrier, and promoting transdermal penetration. The resulting composition can be stably added to oil-based cosmetics such as essential oils, massage oils, and makeup to achieve comprehensive skincare effects, including reducing dark circles, firming and anti-wrinkle, brightening skin tone, and soothing and repairing.

[0007] The objective of this invention can be achieved through the following technical solutions: In a first aspect, the present invention provides a skin care composition containing caffeine, wherein the skin care composition is obtained by mixing an aqueous phase and an oil phase in a mass ratio of 1:3-5, the raw materials of the aqueous phase include caffeine, niacinamide, and deionized water, and the raw materials of the oil phase include geranium oil, senna oil, Rosa damascena flower oil, glyceryl trioleate, and PEG-30-dimeric hydroxystearate.

[0008] Preferably, the mass ratio of caffeine, nicotinamide, and deionized water in the aqueous phase is 1:1.5-10:1-20.

[0009] The caffeine can increase the level of cyclic adenosine monophosphate (cAMP) by inhibiting the activity of phosphodiesterase, thereby promoting capillary dilation, accelerating blood circulation around the eyes and metabolism of venous congestion, thus improving vascular dark circles and eye puffiness caused by morning or fatigue; in addition, caffeine can also effectively combat UV-induced photoaging and inhibit the degradation of collagen by matrix metalloproteinases.

[0010] The niacinamide effectively inhibits the transport of melanosomes from melanocytes to keratinocytes, thereby lightening pigmented dark circles and various blemishes, and brightening the skin tone. Niacinamide also promotes the synthesis of ceramides, strengthens the skin barrier, and enhances the skin's water retention capacity and resistance to external stimuli. In addition, niacinamide can regulate sebum secretion, tighten enlarged pores, and enhance the solubility of caffeine, producing a synergistic effect with caffeine. While improving microcirculation, it repairs damaged skin and makes the skin more delicate and resilient.

[0011] More preferably, the mass ratio of caffeine, nicotinamide, and deionized water in the aqueous phase is 1:3-6:5-12.

[0012] Preferably, the mass ratio of geranium oil, angelica oil, Rosa damascena flower oil, glyceryl trioleate, and PEG-30-dipolyhydroxystearate in the oil phase is 10-15:4-10:1-5:15-60:1-30.

[0013] The geranium oil is rich in citronellol, geraniol, citral, and various phenols and flavonoids, and has excellent anti-inflammatory, antibacterial, and antioxidant effects. It can effectively reduce inflammatory responses and resist oxidative damage caused by ultraviolet rays and environmental stress. In addition, geranium oil can also effectively promote skin microcirculation, regulate skin oil, and tighten pores, thereby improving dullness and brightening skin tone.

[0014] The linalool oil can effectively alleviate cellular oxidative stress and inflammatory responses caused by UVA / UVB by inhibiting the JNK / NF-κB signaling pathway and reducing the expression of matrix metalloproteinases, thereby reducing the degradation of collagen and elastin and protecting the skin and delaying photoaging. In addition, linalool oil can also promote skin microcirculation, downregulate the expression of pro-inflammatory factors, and inhibit skin pathogens, thereby effectively repairing the skin barrier, reducing skin inflammation, and maintaining healthy skin.

[0015] The oil from Rosa damascena is rich in active substances such as nerol, polyphenols, and flavonoids, which can effectively neutralize oxidative stress caused by environmental damage and ultraviolet radiation. By inhibiting the activity of matrix metalloproteinases and tyrosinases, it can delay the skin aging process, enhance skin elasticity, improve dull skin tone, and lighten pigmentation. Rosa damascena contains a variety of amino acids, vitamins, and natural moisturizing factors, which can penetrate deep into the skin to soften dead skin cells, increase skin moisture content, and promote skin cell regeneration and repair.

[0016] The triglyceride is a high-performance, lightweight synthetic oil that can effectively dissolve fat-soluble active ingredients in the formulation and help soften dead skin cells on the skin surface, opening skin channels and thus improving the penetration efficiency of subsequent active ingredients. In addition, triglycerides are chemically stable and not easily oxidized or deteriorated, providing excellent stability to the entire formulation system and ensuring that the active ingredients remain highly effective during storage.

[0017] The PEG-30-dipolyhydroxystearate is a nonionic water-in-oil emulsifier. Its molecular structure uses dipolyhydroxystearic acid as a hydrophobic backbone and connects to a hydrophilic polyethylene glycol chain. It can be precisely positioned at the oil-water interface to form a strong interfacial film, which can efficiently and stably disperse tiny aqueous droplets encapsulating caffeine-cyclodextrin complexes in a continuous oil phase, forming a transparent or semi-transparent water-in-oil microemulsion.

[0018] More preferably, the mass ratio of geranium oil, angelica oil, Rosa damascena flower oil, glyceryl trioleate, and PEG-30-dihydroxystearate in the oil phase is 11-13:6-8:2-4:35-45:10-20.

[0019] Secondly, the present invention provides a method for preparing the caffeine-containing skincare composition described in the first aspect, comprising the following steps: A1. Add caffeine and nicotinamide to deionized water and stir until dissolved to obtain the aqueous phase; A2. Mix and stir the geranium oil, senna oil, rose of damascena flower oil, glyceryl trioleate, and PEG-30-dimeric hydroxystearate evenly to obtain the oil phase; A3. Under stirring conditions, the aqueous phase is added to the oil phase, stirred evenly, and then defoamed to obtain a skin care composition containing caffeine.

[0020] Preferably, the stirring in step A1 is carried out at a speed of 200-400 rpm at room temperature, and the stirring in step A2 is carried out at a speed of 100-200 rpm at 30-40°C.

[0021] Preferably, step A3 specifically involves adding the aqueous phase to the oil phase at a stirring speed of 5000-8000 rpm, stirring evenly, and then stirring at a speed of 200-400 rpm for 10-20 minutes to defoam, thereby obtaining a skin care composition containing caffeine.

[0022] Thirdly, the present invention provides the application of the caffeine-containing skincare composition described in the first aspect in the preparation of oil-based cosmetics, wherein the oil-based cosmetics include essential oils, massage oils, and makeup products, and the amount of the caffeine-containing skincare composition added is 0.1%-5% of the total weight of the oil-based cosmetics.

[0023] Fourthly, the present invention provides an essential oil comprising the following ingredients: the caffeine-containing skincare composition described in the first aspect, plant oils, emollients, antioxidants, and synthetic oils.

[0024] Preferably, the vegetable oil is selected from at least one of meadowfoam seed oil, avocado oil, jojoba seed oil, and macadamia nut oil.

[0025] Preferably, the emollient is selected from at least one of squalane, coconut oil alcohol-caprylate / capric acid ester, caprylic acid / capric acid triglyceride, and isononyl isononanoate.

[0026] Preferably, the antioxidant is selected from at least one of ascorbate tetraisopalmitate, triethyl citrate, tocopherol, and coenzyme Q10.

[0027] Preferably, the synthetic oil is selected from at least one of ethylhexyl palmitate, isopropyl myristate, triglyceride (ethylhexanoate), and isopropyl isostearate.

[0028] The beneficial effects of this invention are: This invention provides a caffeine-containing skincare composition in which caffeine and niacinamide exert core effects of "promoting microcirculation metabolism, inhibiting pigment transport, and strengthening barrier repair," forming a synergistic closed loop from improving vascular dark circles and lightening pigmentation to enhancing skin's resistance. Multiple plant essential oils (geranium oil, sage oil, and rosehip oil) build a protective network for the skin from multiple dimensions, including anti-inflammatory, antioxidant, and repairing effects. The addition of triglycerides and PEG-30-dihydroxystearate further constructs a stable microemulsion system, ensuring transdermal absorption of active ingredients and formula stability. The rationally combined components in the composition work synergistically at multiple levels, including improving microcirculation, regulating pigment metabolism, inhibiting inflammation, repairing the skin barrier, and promoting transdermal penetration. The resulting composition can be stably added to oil-based cosmetics such as facial oils, massage oils, and makeup to achieve comprehensive skincare effects such as lightening dark circles, firming and anti-wrinkle, brightening skin tone, and soothing and repairing. Detailed Implementation

[0029] To further illustrate the technical means and effects of the present invention in achieving its intended purpose, the following detailed description of the specific implementation methods, structures, features, and effects of the present invention, in conjunction with embodiments, is provided below.

[0030] Caffeine was purchased with approval from the Shandong Provincial Drug Administration, approval number 233712-15257-4784; nicotinamide was purchased from Hangzhou Weibolai Biotechnology Co., Ltd.; geranium oil, senna oil, glyceryl trioleate, and PEG-30-dimeric hydroxystearate were all purchased from Hubei Shuaiyan Ligao Biomedical Co., Ltd.; and Rosa damascena flower oil was purchased from Wuhan Yuqing Jiaheng Pharmaceutical Co., Ltd.

[0031] Unless otherwise specified, the conditions in the examples shall be performed under conventional conditions or conditions recommended by the manufacturer. Unless otherwise specified, the components of the formulations in the examples are all commercially available products.

[0032] Unless otherwise specified, all other materials, reagents, etc. used in all embodiments and comparative examples of this invention are commercially available.

[0033] The preparation method of the caffeine-containing skin care composition described in Examples 1-5 includes the following steps: A1. Add caffeine and nicotinamide to deionized water and stir at 300 rpm at room temperature until dissolved to obtain an aqueous phase; A2. Mix geranium oil, senna oil, Rosa damascena flower oil, glyceryl trioleate, and PEG-30-dimeric hydroxystearate, and stir evenly at 150 rpm at 35°C to obtain the oil phase; A3. At a stirring speed of 6500 rpm, the aqueous phase is added to the oil phase and stirred evenly. Then, the mixture is stirred at 300 rpm for 15 minutes to defoam, thus obtaining a skin care composition containing caffeine.

[0034] Example 1 A caffeine-containing skincare composition, wherein the mass ratio of the aqueous phase to the oil phase is 1:4, the mass ratio of caffeine, niacinamide, and deionized water in the aqueous phase is 1:4.5:8.5, and the mass ratio of geranium oil, senna oil, Rosa damascena flower oil, triglyceride, and PEG-30-dihydroxystearate in the oil phase is 12:7:3:40:15.

[0035] Example 2 A caffeine-containing skincare composition, wherein the mass ratio of the aqueous phase to the oil phase is 1:4, the mass ratio of caffeine, niacinamide, and deionized water in the aqueous phase is 1:3:5, and the mass ratio of geranium oil, senna oil, Rosa damascena flower oil, triglyceride, and PEG-30-dihydroxystearate in the oil phase is 11:6:2:35:10.

[0036] Example 3 A caffeine-containing skincare composition, wherein the mass ratio of the aqueous phase to the oil phase is 1:4, the mass ratio of caffeine, niacinamide, and deionized water in the aqueous phase is 1:6:12, and the mass ratio of geranium oil, senna oil, Rosa damascena flower oil, glyceryl trioleate, and PEG-30-dihydroxystearate in the oil phase is 13:8:4:45:20.

[0037] Example 4 A caffeine-containing skincare composition, wherein the mass ratio of the aqueous phase to the oil phase is 1:3, the mass ratio of caffeine, niacinamide, and deionized water in the aqueous phase is 0.1:1:1, and the mass ratio of geranium oil, senna oil, Rosa damascena flower oil, triglyceride, and PEG-30-dihydroxystearate in the oil phase is 10:4:1:15:1.

[0038] Example 5 A caffeine-containing skincare composition, wherein the mass ratio of the aqueous phase to the oil phase is 1:5, the mass ratio of caffeine, niacinamide, and deionized water in the aqueous phase is 5:15:20, and the mass ratio of geranium oil, senna oil, Rosa damascena flower oil, triglyceride, and PEG-30-dihydroxystearate in the oil phase is 15:10:5:60:30.

[0039] Comparative Example 1 Compared with Example 1, the only difference is that Comparative Example 1 does not contain caffeine, and the missing amount is made up with an equal amount of nicotinamide. The composition of other raw materials and preparation methods are the same as in Example 1.

[0040] Comparative Example 2 Compared with Example 1, the only difference is that Comparative Example 2 does not contain nicotinamide, and the missing amount is made up with an equal amount of geranium oil. The other raw material composition and preparation method are the same as in Example 1.

[0041] Comparative Example 3 Compared with Example 1, the only difference is that Comparative Example 3 does not contain geranium oil, and the missing amount is made up with an equal amount of geranium oil. The other raw material composition and preparation method are the same as in Example 1.

[0042] Comparative Example 4 Compared with Example 1, the only difference is that Comparative Example 4 does not contain Ena oil, and the missing amount is made up with Rosa damascena flower oil. The other raw material composition and preparation method are the same as in Example 1.

[0043] Comparative Example 5 Compared with Example 1, the only difference is that Comparative Example 5 does not contain Rosa damascena flower oil, and the missing amount is made up with caffeine. The composition of other raw materials and preparation methods are the same as in Example 1.

[0044] Comparative Example 6 Compared with Example 1, the only difference is that the mass ratio of caffeine, nicotinamide and deionized water in the aqueous phase of Comparative Example 6 is 8.5:1:4.5, while the composition of other raw materials and preparation methods are the same as in Example 1.

[0045] Comparative Example 7 Compared with Example 1, the only difference is that the mass ratio of geranium oil, angelica oil, Rosa damascena flower oil, glyceryl trioleate, and PEG-30-dihydroxystearate in the oil phase of Comparative Example 7 is 7:3:12:40:15. The composition of other raw materials and the preparation method are the same as in Example 1.

[0046] Comparative Example 8 Compared with Example 1, the only difference is that the mass ratio of geranium oil, angelica oil, Rosa damascena flower oil, glyceryl trioleate, and PEG-30-dihydroxystearate in the oil phase of Comparative Example 8 is 12:7:3:10:45, while the composition of other raw materials and preparation methods are the same as in Example 1.

[0047] Note: The total weight of the compositions in each example and comparative example is equal.

[0048] Test Example 1: Antioxidant Test Using the caffeine-containing skincare compositions prepared in Examples 1-5 and Comparative Examples 1-8 as samples, they were dissolved and diluted with 60% v / v ethanol aqueous solution to prepare sample solutions with a concentration of 1 mg / mL. Sample and control groups were set up. In the sample group, 100 μL of sample solution and 100 μL of DPPH solution were added to each well of a 96-well plate; in the control group, 100 μL of 60% v / v ethanol aqueous solution and 100 μL of DPPH solution were added to each well of a 96-well plate. The plates were incubated at room temperature in the dark for 30 min, and the absorbance was measured at a wavelength of 517 nm. The DPPH free radical scavenging rate was calculated using the following formula: DPPH radical scavenging rate (%) = (1 - absorbance of sample group / absorbance of control group) × 100%; Each group was set up with three parallel groups, and the results were averaged and recorded as shown in Table 1 below.

[0049] Table 1 Example 1 94.8 Example 2 94.2 Example 3 93.1 Example 4 91.5 Example 5 89.6 Comparative Example 1 78.3 Comparative Example 2 64.1 Comparative Example 3 68.7 Comparative Example 4 71.5 Comparative Example 5 74.9 Comparative Example 6 59.4 Comparative Example 7 47.6 Comparative Example 8 44.2 As shown in Table 1, the caffeine-containing skincare composition prepared by the present invention can effectively scavenge free radicals and has good antioxidant effects.

[0050] Test Example 2: Melanin Inhibition Test Take 1g of each of the caffeine-containing skin care compositions prepared in Examples 1-5 and Comparative Examples 1-8 as samples, and dissolve the samples in 10mL of physiological saline to obtain different sample solutions.

[0051] Two hundred and twenty zebrafish were randomly divided into 13 groups of 20 each, and placed in different sample solutions. After incubation for 15 minutes, the heads of the zebrafish were photographed, and the melanin signal intensity in the heads was analyzed using the advanced image processing software Lightroom. Next, each group of zebrafish was added to 5 volumes of PBS solution and homogenized using a homogenizer. Tyrosinase activity was then measured.

[0052] Tyrosinase activity assay: Take 0.5g of homogenate from each sample, centrifuge at 12000rpm for 15min at 4℃, and collect the supernatant for later use. Using bovine serum albumin as the standard protein, determine the protein content of the supernatant using the Coomassie brilliant blue method. Transfer the supernatant containing 100μg of protein per well to a 96-well plate, add 100μL of 1mL dopamine solution and 100μL of PBS solution to each well, and incubate at 37℃ in the dark for 1h. Measure the absorbance (A490) at 490nm. Set the melanin signal intensity and tyrosinase activity of Example 1 as 100%. The melanin signal intensity and tyrosinase activity of other groups are expressed as relative percentages of the melanin signal intensity and tyrosinase activity of Example 1. The relative percentages of skin melanin signal intensity and tyrosinase activity reflect the melanin removal effect of the samples.

[0053] Table 2 Example 1 100 100 Example 2 126 117 Example 3 141 134 Example 4 160 153 Example 5 187 176 Comparative Example 1 384 359 Comparative Example 2 293 271 Comparative Example 3 329 305 Comparative Example 4 345 320 Comparative Example 5 368 342 Comparative Example 6 321 283 Comparative Example 7 306 298 Comparative Example 8 285 264 As shown in Table 2, the caffeine-containing skincare composition prepared by the present invention can effectively inhibit melanin production and accelerate melanin degradation, thereby achieving a good melanin removal effect.

[0054] Test Example 3: Anti-inflammatory Test Using the caffeine-containing skincare compositions prepared in Examples 1-5 and Comparative Examples 1-8 as samples, the concentration of mouse macrophages Raw 264.7 (Hunan Fenghui Biotechnology Co., Ltd., catalog number: CL0266) was adjusted to 6×10⁻⁶. 5 Cells were seeded at 100 μL / well in 96-well plates and cultured overnight. The supernatant was discarded, and cells were divided into groups: blank control (BC) with LPS-free cell culture medium; model group (NC) with LPS (1 μg / mL) cell culture medium; sample group with LPS (1 μg / mL) and 0.1 wt% sample culture medium; positive control (PC) with LPS (1 μg / mL) and dexamethasone (1 μM) culture medium; each group had three replicates. After culturing for 24 h, the supernatant was collected, centrifuged at 1000 rpm for 5 min, and the IL-6 content in the supernatant was measured according to the mouse IL-6 ELISA kit instructions. The average value of each group was taken. The IL-6 inhibition rate was calculated using the following formula: ; Among them, C 模型组 C 样品组或阳性对照组 C 空白对照组 The values ​​represent the average IL-6 levels in the model group, sample group or positive control group, and blank control group, respectively. A higher IL-6 inhibition rate indicates a more significant soothing and repairing effect of the composition in inhibiting the inflammatory response. The results are recorded in Table 3 below.

[0055] Table 3 Positive control group 79.3 Example 1 66.4 Example 2 65.8 Example 3 64.9 Example 4 63.7 Example 5 62.1 Comparative Example 1 53.5 Comparative Example 2 47.2 Comparative Example 3 48.6 Comparative Example 4 49.9 Comparative Example 5 51.3 Comparative Example 6 44.5 Comparative Example 7 45.8 Comparative Example 8 42.4 As shown in Table 3, the caffeine-containing skincare composition prepared by this invention can effectively inhibit the expression of TNF-α inflammatory factors and has good anti-inflammatory properties.

[0056] Test Example 4: Anti-aging Test Using the caffeine-containing skincare compositions prepared in Examples 1-5 and Comparative Examples 1-8 as samples, HaCaT cells (Hunan Fenghui Biotechnology Co., Ltd., catalog number: CL0114) were injected at a rate of 2×10⁻⁶. 5Seeds were inoculated per well in 6-well plates and incubated at 37°C for 24 h. After incubation, the original culture medium in each well was discarded, and the plates were divided into sample and control groups. The sample group contained 0.5 wt% of the sample in DMEM culture medium containing 10% v / v fetal bovine serum, while the control group contained an equal volume of DMEM culture medium containing 10% v / v fetal bovine serum. Each group had three replicates, and the plates were incubated for 24 h. After incubation, the supernatant was discarded, and the plates were analyzed using 30 mJ / cm² water. 2 After 1 hour of UVB irradiation, the expression level of the collagen-related gene MMP-1 was detected using qRT-PCR. Higher MMP-1 mRNA expression levels indicate more MMP-1, making the skin's collagen and elastin fibers more susceptible to damage, and increasing the likelihood of wrinkles and aging. The average results are shown in Table 4 below.

[0057] Table 4 control group 3.51 Example 1 1.98 Example 2 2.06 Example 3 2.11 Example 4 2.23 Example 5 2.37 Comparative Example 1 3.34 Comparative Example 2 3.06 Comparative Example 3 3.12 Comparative Example 4 3.23 Comparative Example 5 3.28 Comparative Example 6 2.91 Comparative Example 7 3.01 Comparative Example 8 2.83 As shown in Table 4, the caffeine-containing skincare composition prepared in this invention can inhibit the expression of MMP-1 mRNA and improve the damage to collagen and elastic fibers of the skin under ultraviolet induction, thereby exerting a good anti-aging effect.

[0058] Application Example 1 and Blank Application Example The caffeine-containing skincare composition of Example 1 was added to the essential oil at a concentration of 3 wt% to obtain the essential oil of Application Example 1. In addition, a blank application example without the addition of the skincare composition was prepared. The formula of the essential oil is shown in Table 5.

[0059] Table 5. Essential Oil Formulas

[0060] Application Example 1: The preparation method of the essential oil described in Application Example 1 specifically includes the following steps: At 50°C, synthetic oils, antioxidants, and emollients are mixed and stirred evenly. The mixture is then cooled to 40°C, plant oils are added, and the mixture is stirred evenly. The mixture is then cooled to room temperature, and a skincare composition containing caffeine is added. The mixture is stirred evenly and filtered to obtain the essence oil.

[0061] The preparation method of the essential oil described in the blank application example specifically includes the following steps: At 50°C, synthetic oils, antioxidants, and emollients are mixed and stirred evenly. The mixture is then cooled to 40°C, plant oils are added, stirred evenly, and filtered to obtain the essence oil.

[0062] Example 1 of efficacy test: Human patch test Referring to the relevant requirements and testing methods of "Human Skin Patch Test" in the "Cosmetic Safety Technical Specifications (2015 Edition)" issued by the Ministry of Health, the essential oils of Application Example 1 and Blank Application Example of this invention were tested. Skin reactions were observed at 0h, 6h, 12h, 24h, and 48h. The test results of all volunteer subjects were negative, and no adverse skin reactions were observed. This indicates that the essential oil prepared by adding a skin care composition containing caffeine to this invention will not cause allergic reactions, is non-irritating, and has high safety.

[0063] Example 2 of the performance test: Stability test The essential oils prepared in Application Example 1 and the blank application example were poured into test tubes, sealed, and placed at 2-8℃, 25±2℃, and 48±2℃ respectively for one week, and the appearance of the products was observed.

[0064] The experimental results showed that the essential oils prepared in Application Example 1 and the blank application example did not undergo significant changes in appearance after being placed at 2-8℃, 25±2℃, and 48±2℃ for one week, and remained transparent or semi-transparent, indicating good stability.

[0065] Example 3 of efficacy test: Human efficacy test Based on the principles of human efficacy evaluation in the "Cosmetic Safety Technical Specifications (2015 Edition)," 30 participants (healthy men or women aged 25-55) were selected according to the subject inclusion criteria. The participants were randomly divided into two groups of 10 each. The test product sample group (essence oil prepared in Example 1 and the blank application example) applied one pump (approximately 1g) of the sample evenly to the entire face each time and gently massaged until fully absorbed. Follow-up visits were conducted on day 0 and day 28 to test various indicators, evaluating the melanin removal function, skin barrier repair function, anti-inflammatory function, wrinkle improvement function, and skin elasticity improvement function of the test product. On days 0 and 28, subjects did not apply any skincare products. After cleansing, they sat quietly for 30 minutes in a constant temperature and humidity room (21±1℃, 50±10%). Melanin content (MI), TEWL, a*, wrinkle count, and skin elasticity coefficient (R²) were measured in the same area using an MX18 melanin analyzer (CK, Germany), a Tewameter®™ Hex transdermal water loss probe, a Colorimeter CL400 (CK, Germany), a VISIA® high-precision skin image analysis system, and a Cutometer® skin elasticity analyzer. The improvement rate of each indicator was calculated using the following formula: MI value improvement rate (%) / TEWL value improvement rate (%) / a* value improvement rate (%) / wrinkle number improvement rate (%) = [(value on day 0 - value on day 28) / value on day 0] × 100%; R2 improvement rate (%) = [(value on day 28 - value on day 0) / value on day 0] × 100%; The results, after being averaged, are recorded in Table 6 below.

[0066] Table 6 Blank application example 2.1 2.7 3.8 2.2 1.9 Application Example 1 32.5 29.8 27.6 30.7 29.3 As shown in Table 6, the essential oil prepared using the caffeine-containing skincare composition of the present invention can effectively reduce skin melanin content, repair the skin barrier, relieve inflammation, reduce wrinkles, and improve skin elasticity, showing good application prospects.

[0067] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present invention. Any indirect modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A caffeine-containing skincare composition, characterized in that, The skincare composition is obtained by mixing an aqueous phase and an oil phase in a mass ratio of 1:3-5, based on parts by weight. The raw materials of the aqueous phase include caffeine, niacinamide, and deionized water, and the raw materials of the oil phase include geranium oil, senna oil, Rosa damascena flower oil, glyceryl trioleate, and PEG-30 dihydroxystearate.

2. The caffeine-containing skincare composition according to claim 1, characterized in that, The mass ratio of caffeine, nicotinamide, and deionized water in the aqueous phase is 0.1-5:1-15:1-20.

3. The caffeine-containing skincare composition according to claim 2, characterized in that, The mass ratio of caffeine, nicotinamide, and deionized water in the aqueous phase is 1:3-6:5-12.

4. The caffeine-containing skincare composition according to claim 1, characterized in that, The mass ratio of geranium oil, angelica oil, Rosa damascena flower oil, glyceryl trioleate, and PEG-30-dihydroxystearate in the oil phase is 10-15:4-10:1-5:15-60:1-30.

5. The caffeine-containing skincare composition according to claim 4, characterized in that, The mass ratio of geranium oil, angelica oil, Rosa damascena flower oil, glyceryl trioleate, and PEG-30 dihydroxystearate in the oil phase is 11-13:6-8:2-4:35-45:10-20.

6. A method for preparing the caffeine-containing skincare composition according to any one of claims 1-5, characterized in that, Includes the following steps: A1. Add caffeine and nicotinamide to deionized water and stir until dissolved to obtain the aqueous phase; A2. Mix and stir the geranium oil, senna oil, rose of damascena flower oil, glyceryl trioleate, and PEG-30-dimeric hydroxystearate evenly to obtain the oil phase; A3. Under stirring conditions, the aqueous phase is added to the oil phase, stirred evenly, and then defoamed to obtain a skin care composition containing caffeine.

7. The method for preparing the caffeine-containing skincare composition according to claim 6, characterized in that, The stirring described in step A1 is stirring at a speed of 200-400 rpm at room temperature, and the stirring described in step A2 is stirring at a speed of 100-200 rpm at 30-40℃.

8. The method for preparing the caffeine-containing skincare composition according to claim 6, characterized in that, Step A3 specifically involves adding the aqueous phase to the oil phase at a stirring speed of 5000-8000 rpm, stirring evenly, and then stirring at a speed of 200-400 rpm for 10-20 minutes to defoam, thereby obtaining a skin care composition containing caffeine.

9. The application of the caffeine-containing skincare composition according to any one of claims 1-5 in the preparation of oil-based cosmetics, characterized in that, The oil-based cosmetics include essential oils, massage oils, and makeup products, and the amount of the caffeine-containing skincare composition added is 0.1%-5% of the total weight of the oil-based cosmetics.

10. An essential oil, characterized in that, The essential oil comprises the following ingredients: a caffeine-containing skincare composition according to any one of claims 1-5, plant oils, emollients, antioxidants, and synthetic oils.

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