There are a few misconceptions connected with baby sunblock that I would like to share:
Beyond these misconceptions, the best recommendation when choosing a sunblock for your baby, is to choose a "physical" or "chemical-free" sunscreen made with zinc oxide. This is not only because it is a non-toxic option from all the sunscreen possibilities, but because it provides excellent protection from the UVA rays and the UVB rays and not only the UVB rays. e.g. high SPF and no UVA.
The UVA rays penetrate deeper into the skin layers, potentially causing the DNA damage that not only leads to skin cancer, but the dreaded melanoma. UVB rays are the ones that cause the skin to burn, as well as damage to the DNA. With only protection from the UVB rays, the skin will not turn red and therefore not caution you to get out of the sun. This means you stay out longer in the sun than you would normally without any sunscreen. It also provides confidence that the baby sunblock has worked. But in reality it has allowed the UVA rays a longer time to do their damage.
Most importantly, it is very advisable to keep a baby younger than 6 months out of the sun altogether whenever possible. Their skin is just too fragile for the harsh effects of the sun. However, if it is just not possible to keep out the sun, make sure you protect your young baby's exposed skin with a quality sunscreen, plus good quality sun protective clothing.
A zinc oxide baby sunblock will sit on top of the skin, forming a barrier against the sun's rays, which is far preferable to the chemical sunscreens, which are absorbed into the skin. This also allows you to lather the sunscreen on generously, whereas if it were a chemical sunscreen, I would be extremely hesitant to lather it on that generously knowing that the chemicals will be absorbed into the skin. Sunscreens with a zinc oxide physical barrier start protecting your baby as soon as you put them on. Chemical sunscreens, however, require 15 to 30 minutes in advance of being exposed to the sun, to give the skin time to absorb them first. This also means that when you re-apply when at the beach or such, the baby sunblock will be effective immediately.