The first and most critical difference between baby skin and adult skin is the surface-to-weight ratio. On average, the surface-to-weight ratio of an adult is 0.025m 2 /kg, while the baby has a surface-to-weight ratio of 0.065m 2 /kg, meaning that ingredients are 2.6 times more available for the baby. Thus, ingredients that will not irritate an adult can be problematic for babies.
Although anatomically the skin of a baby is the same as an adult, the skin renewal is much higher for a baby. The skin of a baby renews every two weeks, twice as fast as adults. Because of this reason, skin cells have less time to maintain the skin barrier and therefore it is underdeveloped. Hence, the trans-epidermal water loss is higher for babies, and ingredients can penetrate much faster, which is why ingredients can be experienced more aggressively for babies.
Thirdly, babies are real adventurers; they like to explore their surroundings. They crawl over the beach and try how their favourite toy tastes. So, their immune system is much more challenged. Moreover, their immune system is not so experienced, making the skin very sensitive. One of the most sensitive areas of the baby is the nappy region, a region that is occlusive, warm, humid, and has an elevated pH because of the urine and feces. Together, you have an area of the skin that is highly challenged causing ingredients to penetrate even easier than other parts of the baby’s body.
Another difference is that there is a of lack knowledge about the blood-brain barrier of a baby up to four months. The blood-brain barrier acts as a filter to strictly regulate which molecules can reach the brain. In addition, the skull of a baby has still separated fontanelles, structures that form gaps between the baby’s cranial bones. For this reason, there is a chance that ingredients can reach the baby’s brain and it is so important to respect the safe strategy in baby cosmetics.
Fifth, the melanocytes are just as inexperienced as all the other parts of the baby’s body. These cells have never seen sunlight and they will make mistakes during the first summer, like melanin of low quality or they produce not enough melanin. The melanocytes are becoming active in their second summer, but still do not produce enough melanin. It takes a couple of years until the melanocytes are fully trained. So, the baby is less protected from UV light, which means that the first three years require special care to protect the baby's skin from UV damage.
The main difference between the baby’s skin and adult skin is their skin microbiome. The skin microbiome is a huge discovery in cosmetics. However, research is mainly focused on the adult’s skin microbiome. The baby’s skin microbiome is very immature and does not offer protection from invaders. The baby’s skin microbiome has not recruited all the protective microbes that make us love the skin microbiome so much; it only consists of the microbes that the baby inherited from the mother, which are primarily Lactobacillus bacteria from the vagina. It will take almost eighteen years until the skin microbiome has reached its full potential and for this reason, the baby is so prone to skin conditions. It is for this reason that prebiotics are so successful. Prebiotics make the skin microbiome stronger and more resilient, which is especially important for a baby.
Listing all these key differences shows that baby cosmetics need safer ingredients because they are more available to the baby’s body and brain. Second, the skin is more sensitive due to the immature immune system and melanocytes. So, now you know why you must care for your baby's cosmetics just as much as you love babies.
