Many people use expired milk for skincare. This method is indeed effective because expired milk produces lactic acid, which is a type of alpha-hydroxy acid (AHA) that can soften the stratum corneum and has a moisturizing effect.
The first to discover that expired milk could be used for skincare was Cleopatra. She, who loved to bathe in fresh milk, found that using spoiled, sour milk left her skin smoother and finer after bathing. In fact, the reason this spoiled milk can be used for skincare is mainly due to the lactic acid in it, followed by the fat in the milk. Therefore, whole milk has a better skincare effect than low-fat milk, the difference being the amount of fat. However, the lactic acid bacteria produced by expired milk are not affected by the fat content.
Expired milk can also be used for a facial mask. Pouring a bottle of expired milk into a bathtub and diluting it may be less effective. Therefore, it is recommended to apply it to the body first, wait for 5 to 10 minutes, and then get into the bathtub for better results. Lactic acid bacteria will not cause urinary tract infections, so there is no need to worry.
As for whether soaking in powdered milk has the same effect, experts say that the components of powdered milk cannot maintain their freshness after being dried, and it contains fewer lactic acid bacteria, so its skincare effect is not as strong as fresh milk. However, it should be noted that if the expired milk has curdled, do not use it, because lactic acid does not curdle; what curdles is the milk protein, which is ineffective for exfoliation or moisturizing. Expired milk has other uses as well:
1. Polish leather shoes--First, use a brush to clean the dirt off the shoe surface, then use a cloth to apply the expired sour milk evenly to the shoes. After it dries, wipe with a dry cloth to make the shoes shine like new and prevent the leather from drying and cracking.
2. Clean floors--Dilute the expired sour milk with water, then sprinkle it on the floor and wipe with a mop.