Preservatives are used in food and cosmetic products to prevent spoilage and microbial growth. They can be either natural or lab made. Preservatives unfortunately do not have a positive impression and are often considered to be bad and/or harmful, but without them the products go rancid. They are a necessary addition to some skin and hair care products to maintain their efficacy.
In simple words, any product that contains water/aqua needs preservatives to stop microbial growth.
Same is the case with our skin. If we keep our skin moist or wear wet undergarments for a long duration, then our skin observes microbial growth as well. To some extent, our body too, produces natural preservatives to prevent these microbial growth but after continued usage you will see that it deteriorates into fungal or bacterial growth thereby leading to fungal infection. So, we need preservatives.
There are certain preservatives which we consider harmful, like parabens, Benzyl alcohol, Urea etc.
Note: There are many theories debating their safety, but better be safe than sorry.
WE (Bodycafé) use a preservative called Optiphen (Natural Preservative) – inci name – Phenoxyethanol and Caprylyl Glycol and Sorbic acid