Questions. 1
In the same formula, an oil-controlling ingredient is added in different proportions, and all of them have an oil-controlling effect, can we say that it is caused by this oil-controlling ingredient? Is it necessary to do an oil control test on the base of the formulation (without the oil control ingredient)?
To screen out the efficacy substances, an orthogonal test can be taken if possible. For a simple experimental program, set up three samples, with the active substance, without the active substance, and base with the active substance that has a clear oil control effect.
Because the formula base used is the same, it is best to set up a blank control group, first to determine whether the oil control effect is derived from this raw material, and then set up a control group to determine the different additive amount, the oil control effect strength.
Questions. 2
Oil control efficacy how to do efficacy testing, how to operate the laboratory efficacy test?
According to the effect of time, cosmetics oil control efficacy can be divided into short-term oil control (4 hours, 8 hours, etc.) and long-lasting oil control (14 days, 28 days, etc.), the test method refers to the “T/ZHCA 002-2018 Cosmetic oil control efficacy test method”. At present, the main instrumental test and subject self-assessment are used to evaluate the human efficacy of oil-control skin care products. According to the use of the sample, through the subject’s self-assessment, it can reflect the subject’s self-perceived oil-control effect, which is an evaluation method with a high degree of subjectivity.
When evaluating the efficacy of oil-control skin care products using the instrumental method, it can be evaluated by testing the oil content of the skin and capturing the image analysis method, which is an evaluation method with a higher degree of objectivity.
1、 Skin oil content test
Evaluating the change in skin oil content before and after use is one of the most important methods for evaluating the effectiveness of oil control products. The instrument commonly used to determine the skin oil content is the skin oil tester (Delfin SebumScale), which is based on quartz crystal microbalance technology, the use of quartz crystal sensors to absorb the sebum on the skin, the measurement of the sebum on the sensor will change the frequency of the quartz oscillator, through the amount of frequency changes in the amount of skin oil content is calculated.Delfin SebumScale Skin Sebum Measuring instrument can be used for efficacy testing, skin type, skin research evaluation, skin care and treatment evaluation, claim confirmation work.
2、Image Analysis Test
With the development of fluorescence technology, the study of facial fluorescence in acne patients is increasing. Fluorescence is a photoluminescence phenomenon of matter, and the red fluorescence produced by UV excitation is specifically referred to as Ultraviolet Induced Red Fluorescence (UVRF). Studies on facial UVRF in patients with acne have shown that UVRF is mainly related to the production of porphyrin lipids induced by Propionibacterium acnes, which emit a distinctive red-orange fluorescence when irradiated by UV at a certain wavelength, and thus can be observed on the face of patients with acne. UVRF has been used as a rapid and non-invasive clinical method to assess the severity of facial acne.
You can refer to the Zhejiang provincial group standard, T/ZHCA 002-2018 “Cosmetic oil control efficacy test method”, which is very detailed. It is very detailed, like the temperature and humidity conditions involved, how to screen subjects and so on.
After the use of matte tape to absorb human skin oil, the change in the amount of light transmission reacts to the oil secretion.
Questions. 3
How can oil control products provide long-lasting oil control? What are the methods?
1. The mechanism of skin oil
Simply put [hormone] – [hormone receptors] – [sebaceous glands] path, they are respectively closely related to living habits, dietary routine, genetic factors, temperature and other conditions. Detailed explanation, it is by 5α-reductase enzyme testosterone (androgen) into dihydrotestosterone, and dihydrotestosterone can promote the development of sebaceous glands, but also with the sebaceous glands on the receptor to do the binding, both of which will lead to the increase in our oil, for acne laid the groundwork.
2. About oil control products
The key to oil control is to inhibit 5α-reductase and sebaceous glands The core of the process is to “inhibit 5α-reductase” and “inhibit sebaceous glands”. There are several classic oil control ingredients that work on this step: Vitamin A, azelaic acid, tea polyphenols, zinc PCA, niacinamide, psoralen…. All of these ingredients, can be more root cause to control oil secretion, often some of the more obvious effect of the product, will choose one of the 2~3 ingredients together with the compound, synergistic effect. There are also some new ingredients, such as: red honeysuckle flower extract, silymarin extract and so on.
Starting from the source of oil secretion, apply ingredients that target the sebaceous glands. Attention is also paid to pore cleansing.
The new generation of BHA-containing fruit acid products are oil-soluble, even if the pores are clogged with oil, BHA can still penetrate into the pores to play a role in acne, acne skin is particularly effective in the addition of essential oils to control oil.
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