There are two main reasons why skincare products need to be used at the night:
- The ingredients in skincare products will have photosensitivity.
- The active ingredients in skincare products are easily oxidized and decomposed when exposed to light.
What is photosensitivity?
Photosensitivity refers to certain ingredients that cause skin allergies, dermatitis, rashes, and other adverse reactions under sunlight. In severe cases, it can also cause skin blisters. The damage of photosensitivity to the skin is far more serious than the consequences of direct ultraviolet rays on the skin.
Does the photo-sensitivity component mean that light cannot be seen? Since photo-sensitive ingredients are so easy to cause bad skin, does it mean that skincare products using these ingredients can’t play with mobile phones at night? Can not turn on the lights?
The answer is NO! The “light” in the photo-sensitive component refers to sunlight, ultraviolet rays, etc., but not the light in daily life, mobile phone lights, computer lights, so you really don’t have to apply skincare products in the dark!
Which ingredients need to be protected from light?
Vitamin C
Many people think that vitamin C is photo-sensitive, so they dare not use vitamin C skincare products during the day. In fact, vitamin C does not cause photosensitivity.
The biggest reason why vitamin C needs to be protected from light is its poor stability. The reason for avoiding light is to make it work better. In addition, if you use vitamin C-type skincare products during the day, if you don’t take sun protection, vitamin C will be oxidized. Therefore, the skin will cause dullness and yellowing.
Retinol & tretinoin
Retinol or tretinoin (that is prescribed by the doctor according to the situation, do not use it indiscriminately), and the derivatives of retinol must be protected from light after use.
Although retinol cannot cause skin ulcers and allergies, its stability is very poor. When it encounters the air, ultraviolet rays, and water, it will react and lose its activity.
In addition, vitamin A acid is photo-sensitive. Skincare products containing these ingredients should be used at night.
Kojic acid, alpha hydroxyl acid, and other acids
Like AHA, kojic acid, and salicylic acid, most of them have no photosensitivity, but they can exfoliate the skin. After using these acids, the skin will become very fragile. If sun protection is not done at this time, direct UV radiation on the skin will cause a series of skin problems.
Essential oil
Those who like to use plant essential oils should be careful not to be exposed to the sun if they have applied essential oils! In particular, it is a series of plant essential oils such as lemon, sweet orange, grapefruit, bergamot, bitter orange, verbena, angelica root. They all contain furanocoumarin, which can cause photosensitivity, so it is best not to use them during the day.
The above light-proof ingredients are common ingredients in our daily skincare products, and there are many light-proof ingredients that are not listed. Sincerely hope everyone pays more attention to the instructions when using skincare products, and doesn’t mix them up day and night.