What are parabens in general?
Parabens are derivatives of para-hydroxybenzoic acid, thus their salts and esters. They are used in cosmetics, medicines, tobacco and food. They serve as preservatives and protect against bacteria and fungi.
How are parabens structured?
As mentioned above, parabens are the salts and esters of para-hydroxybenzoic acid , which for a long time has also been called catalpinic acid, since it is found in the plant parts of catalpa spp. (Trumpet tree) occurs. 
The parabens differ in the residue on the carboxyl group (-COO), these may be metal ions, e.g. Be sodium, or organic radicals such as methyl or ethyl esters. Today, methyl and ethyl parabens are mainly used. Less so propyl and butyl esters, and isoethyl, isopropyl, and isobutyl esters have been rarely used for some time.
Why are parabens used at all?
Parabens are cheap preservatives and their antimicrobial and fungicidal effects are highly praised, with a wide range of applications.  They are easy to manufacture and even small amounts are sufficient to allow a regulated performance. They have little competition, as most alternatives are not so close to the skin, or with a proven, more toxic effect than the used parabens.
What is the problem with parabens?
There have been some theories for years that parabens are highly harmful to health, and little has been proven so far. Many statements are so far only speculation and suspicion, whose investigations are often too contradictory for a clear statement. In fact, parabens are similar to the female sex hormone estrogen, which is responsible, among other things, for breast growth. This similarity can cause the tissue to grow unchecked and can lead to breast cancer . In male fetuses and children up to three years, parabens can lead to feminization . However, many of these theses are an eternal back and forth from true to false. There are no conclusive findings on the question "are parabens harmful." 
Are there safe alternatives to parabens?
Yes, nature also preserves some substances that protect the skin, protect it from microbes and fungi, and also bring along vitamins and other substances that have a positive effect on your health. Phytoalexins they are called, plant antibodies.
Flavonoids, alkaloids and terpenoids help conserve cosmetics and have their own otherwise helpful properties. Flavonoids additionally protect against UV rays and other short-wave light, and thus against photo-oxidative destruction . Alkaloids provide better blood circulation to the skin . Terpenoids which have typical, pleasant odors and are regarded as a possible tumor therapy or cancer remedy .
Sources to read:
Articles on Parabens in Cosmetics 
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