Many sunscreens contain ingredients that may be harmful to the delicate skin they are designed to protect. PABA can cause allergic skin reactions in up to 40 percent of users. Ingredients such as benzophenone, octinoxate and homosalate can disrupt hormones. DEA, TEA, padimate-O, avobenzone and titanium dioxide have all been flagged as potential carcinogens.
For breastfed babies, a total of 30 minutes sunscreen-free exposure per week is all that is needed to ensure adequate vitamin-D production. Beyond that, sun umbrellas, hats and light cotton clothing are best. For exposed extremities such as noses and the tips of tiny ears, zinc oxide has proven to be both an effective and safe sunblock.