It looks like the FDA puts safety limits on what percentage of each blocking chemical can be put in sunscreen but allows mixing the maximum allowed of each (I p

It looks like the FDA puts safety limits on what percentage of each blocking chemical can be put in sunscreen but allows mixing the maximum allowed of each (I presume to achieve higher SPF?). This study might be looking into this. > (a) Aminobenzoic acid (PABA) up to 15 percent. (b) Avobenzone up to 3 percent. (c) Cinoxate up to 3 percent. (d) Dioxybenzone up to 3 percent. (e) Ensulizole8 up to 4 percent. (f) Homosalate up to 15 percent. (g) Meradimate9 up to 5 percent. (h) Octinoxate10 up to 7.5 percent. (i) Octisalate11 up to 5 percent. (j) Octocrylene up to 10 percent. (k) Oxybenzone up to 6 percent. (l) Padimate O up to 8 percent. (m) Sulisobenzone up to 10 percent. (n) Titanium dioxide up to 25 percent. (o) Trolamine salicylate up to 12 percent. (p) Zinc oxide up to 25 percent. > "(1) Two or more sunscreen active ingredients identified in §§ M020.10(a), (c), (d), (e), (f), and (g) through (p) may be combined with each other in a single product when used in the concentrations established for each ingredient in § M020.10. The concentration of each active ingredient must be sufficient to contribute a minimum SPF of not less than 2 to the finished product. The finished product must have a minimum SPF of not less than the number of sunscreen active ingredients used in the combination multiplied by 2." [1] [1] https://www.accessdata.fda.gov/scripts/cder/omuf/index.cfm?event=NewMonograph&ID=1245EB7DED1F08847DCC4EDB3991C18DE39AF98AA3629BD7F1184B2F58850C5E&OMUFID=OTC000006 https://www.accessdata.fda.gov/scripts/cder/omuf/index.cfm?e...