Sunscreen is the most important step in skincare. Skincare without sunscreen is useless. In order to achieve the best sunscreen effect, it is very important to choose the appropriate sunscreen and the correct use method.
Sunscreen is generally divided into physical sunscreen and chemical sunscreen. The main components of physical sunscreen are titanium dioxide and zinc oxide. It achieves the purpose of sunscreen by reflecting and refracting ultraviolet rays. It is more suitable for people with fragile skin, but it feels greasy; Chemical sunscreen is mainly composed of chemical synthetic sunscreen. It is refreshing and suitable for most skin types. The sunscreen durability is shorter than that of physical sunscreen.
The sunscreen effect is also related to PA and SPF
SPF value is the ability to isolate UVB. UVB energy is relatively strong. It can destroy the epidermal layer of the skin in a short time, redden and sunburn the skin, and even cause skin cancer.
PA is the ability to protect against UVA. Although UVA energy is weak, it has strong penetration. It can penetrate the epidermal layer of the skin and reach the dermis.
The package of sunscreen will be marked with PA and SPF. PA means delaying the time of skin tanning. The more plus signs of PA + means the longer the time of delaying tanning; SPF is the sun protection factor. Common ones include SPF30, spf50, etc. the number indicates the duration of sun protection. For example, SPF30 indicates 30 * 15 = 450min, that is, the duration of sun protection is 7.5 hours.
When purchasing sunscreen, you should not only look at the sun protection factor, that is, the PA and PPD index of UV UVA protection and the SPF index of UV UVB protection, but also look at the sun protection ingredients, so as to ensure safe and effective use.
| Product Name | Basic Introduction | Main Application |
Cosmetic active ingredients and raw materials | Avobenzone | UVA sunscreen can absorb UVA320-400nm band and hardly absorb visible light. It has the advantages of high absorption rate, nontoxicity, no teratogenicity, good stability to light and heat, etc | Suitable for light–colored transparent products, widely used in sunscreen cream, lotion, and other cosmetics. |
Isooctyl p-methoxycinnamate | It is a good absorber for UVB ultraviolet rays, which can effectively prevent UVB 290-320nm ultraviolet rays, with a high absorption rate, no irritation to the skin, and good safety | It can effectively absorb ultraviolet rays from the sun and prevent human skin from being sunburned and tanned. It is also a treatment for photodermatitis |
Propranolol | UVB sunscreen is a colorless and transparent liquid, insoluble in water, can absorb ultraviolet rays in UVB295-315nm band, and is suitable for a water-resistant formula | Protect the skin from UVB exposure and reduce the long-term harmful effects caused by exposure to sunlight |
Octyl | The new sunscreen ingredient has the advantages of high absorption rate, non-toxic, no teratogenic effect, good light, and thermal stability, and can absorb UVA and UVB at the same time | It is often used together with other sunscreen agents to achieve a high SPF |
Isooctyl salicylate | The weaker UV UVB sunscreen，can absorb uvb280-320 band, which is safer and less toxic than most other sunscreen agents | Used as a UVB absorbent, it is suitable for sunscreen cosmetics |
Why do you get sunburned after applying sunscreen?
Both physical sunscreen and chemical sunscreen need to form a uniform and dense sunscreen film, which takes time. Don’t put on powder and make-up before it is formed. So after applying sunscreen, wait 5-10 minutes, and then apply something else to your face.
How to apply sunscreen is the most effective?
If the sunscreen is applied unevenly, it will leave a small hole in the skin and cannot form a complete sunscreen film. And light is pervasive. If there are holes, they will irradiate or even penetrate the epidermal layer, stimulate the skin and melanocytes, and cause sunburn and tanning.
So don’t put on makeup and powder after applying sunscreen. The sunscreen just applied hasn’t formed a film yet. If you put on makeup at this time, you may make the sunscreen just applied full of holes, but it won’t play the role of sunscreen.
Chemical sunscreen absorbs ultraviolet rays and decomposes itself, so after a period of time, the sunscreen itself slowly decreases and the sunscreen effect becomes weaker. Therefore, it needs to be painted every two or three hours.
