In this era of general health awareness, pH (acidity/alkalinity) value is a hot issue of concern. A woman friend who is particularly interested in health told me that when she goes to the supermarket to buy a bottle of water, she has to read the product manual for half a day in order to choose a bottle of water that matches the human body’s environment. Because she knows that the normal pH value of the human body is between 7.35 and 7.45, that is to say, it is weakly alkaline, so drinking alkaline water is more beneficial to the human body. Seeing that she was so particular, I asked her whether she should give her skin acidic water or alkaline water. She answered confidently: alkaline water. In fact, this is very wrong. Also as part of our body, the internal environment and the external environment of the human body is not the same acidic and alkaline. A healthy human body is weakly alkaline, but the ideal skin state is weakly acidic. People who may be engaged in skin care work know that the ideal pH of the skin is 5 to 5.6, in this environment, the surface of the skin is weakly acidic, it is difficult for bacteria to reproduce and grow, and the skin looks extra delicate and moist and elastic. If the acidity of the skin decreases and becomes alkaline, it will cause various skin diseases. Therefore, maintaining the weak acidity of the skin is a must for skin care. If you want to avoid alkaline substances in your life, you should first understand what alkaline substances are. The closest relationship with the skin is alkaline detergents, alkaline detergents will not only stimulate the skin, but also accelerate skin aging. The pH of shampoo is 8.5, so don’t let the shampoo stay on your face when you wash your hair. Also avoid using soap in direct contact with the skin on your face, because alkaline detergents like soap are the culprit in destroying the weak acid environment. Our skin is exposed all day, there is inevitably an imbalance of pH, but this is not terrible, because healthy skin in the pH is too high or too low, the skin will automatically balance, so that it returns to its original state. However, if you use alkaline skin care products when the skin is not able to restore itself, the skin condition will occur. Therefore, it is best to consider a weak acidic formula for your skin, so that your skin can say to cosmetics: Do not bother with acid.