## 3 Results
### Organic Filters  
Several organic sunscreen agents (including PABA and derivatives, cinnates, avobenzene, octocrylene, salicates including homosalate, benzophenones including oxybenzene, and octisalate among others) contain one or more aromatic rings, capable of absorbing and distributing energy from incident UVR [34].  
Organic filters can protect against both UVA and UVB radiation and are the most commonly used [35]. They act by scattering and absorbing radiation through chemical reactions that produce heat and/or degradation byproducts; however, they must be applied more frequently. Many are absorbed through the skin. Organic sunscreens show a higher risk of inducing irritant or allergic contact dermatitis [36].  
Several organic UVFs have been associated with endocrine disruption [37; 38; 39; 40; 41; 42]. Benzophenone-3 (BP-3) seems to have systemic effects on sex and thyroid hormone pathways in animal models [40; 41; 43; 44] and can be absorbed at a rate of 1% to 9% with topical application in some models [45].  
When the skin barrier function is compromised, it may absorb UVFs more rapidly [46]. It is remarkable that UVFs have been found in breast milk [38; 47], placental tissues [48], and urine [49; 50]. During pregnancy an increased incidence of neonatal dysfunction (Hirschprung's disease) due to exposure to BP-3 has been observed [51; 52]. In several studies, possible correlations with uterine leiomyoma formation and increased mobility of breast and lung cancer cells have been found [53; 54; 55; 56].  
UVFs (especially BP-3, avobenzene, OC, amiloxate, and PABA) seem to cause various forms of irritant dermatitis as well as allergic contact and/or photo-allergens [57; 58; 59; 52].  
The most commonly used organic filters [60; 61] and their evaluation by the EWG [62] are described in Table 1.  
In Figure 1 each type of filter and how they act is described.  
\begin{table}
\begin{tabular}{l l l} \hline \hline
**UVB Filters/Risks** & **UVA Filters/Risks** & **Broad Spectrum Filters (UVA and UVB)/Risks** \\ \hline PABA and derivates & Benzophenones (BP-3 or Oxypenzone): & Tinosorb M (Methylene \\ - Octyldimethyl PABA or Padimate O: & EDC effects, bioaccumulative, & bis-benzotriazolyl \\ EDC (estrogenic), liberator of free & photoallergic reactions, absorbed through & tetramethylbutylphenol): Possible \\ radicals, allergic reactions. Always avoid. & the skin, passing into breast milk. & environmental contaminant. \\ Ethylhexyl triazone (octyl triazone): Free & Neurotoxicity. Always avoid & Acceptable/caution. \\ radical liters with sunlight. Prudence. & & \\ \hline \hline \end{tabular}  
* Octinoxate (Octyl Methoxycinnamate, OMC, Ethylhexyl Methoxycinnamate, EHMC): confirmed EDC, persistent and bioaccumulative, absorbed through the skin, appears in breast milk. Always avoid.
- Cinoxate (2-Ethoxyethyl-P-Methoxycinnamate): Avoid. In disuse. Little data on its safety. Avoid as a precaution.  
\begin{tabular}{l l} \hline \hline Salicylates: Better security profile. \\ - Octisalate (ethylhexyl salicate, \\ 2-Ethylhexyl1-Hydroxybenzoate): & \\ Acceptable chemical filter. \\ - Homosalate (3,3,5-Trimethyl-Salicylate \\ Cyclohexanol; 3,3,5-Trimethylcyclohexyl \\ 2-Hydroxybenzoate): Highly Polulting, \\ weak EDC, decomposes with light into \\ oxidizing substances harmful skin. \\ Increases the absorption of other \\ substances. Avoid. & \\ \hline \hline Octocrylene: EDC activity, allergies & Mexoryl SX (Tetraphthalidine sulfonic \\ and/or (photo)allergies. Avoid. & acid dialcamphor): also considered safe. \\ \hline \hline \end{tabular}  
* Ensulizole (2-Pheny 1H-benzimidazole 5-Sulfonic acid, PBSA): produces free radicals (DNA damage and potentially skin cancer. Avoid.  
\begin{tabular}{l l} \hline \hline
**4-Methylbenzylidene Camphor: EDC, \\ persistent and bioaccumulative. Possible \\ thyroid toxicity. Always avoid. \\ \hline \hline \end{tabular}  
* In Figure 1 each type of filter and how they act is described.  
\end{table}
Table 1: The most used organic filters and their possible risks (based on EWG classification).