As one may know, and CosmeticOBS-L’Observatoire des Cosmétiques has already pointed this point out , there is not a single paraben in cosmetics, but several. They all are still widely used as preservatives. Their different properties, and the potentially undesirable effects that could be linked to them, depend on the various carbon chains' lengths.

Methyl and Ethyl vs Butyl and Propyl

Just as a reminder: the safety of all the parabens used in cosmetics has already been evaluated many times by the sanitary authorities the world over, and, especially, in Europe. The opinions of the European Scientific committees is the basis of the regulation applicable throughout Europe.
Let us make it easy: short carbon-chained parabens (Methylparaben and Ethylparaben) are considered as safe for use in any cosmetic product, as far as they are used at the maximum concentrations allowed in the regulation (0.4% in the finished product, if used alone or 0.8% when blended).

The song is not the same as regard to the long-chained parabens, especially for Butylparaben and Propylparaben, on the one hand, and Isopropylparaben and Isobutylparaben, on the other hand (just to name the most widely used in formulae).
In a 2010 Opinion , the European Scientific …