Why is our Retinol Serum only 96% Natural?

Sometimes we need to use synthetic ingredients to help with the formulation, we never use nasty ingredients, only safe ingredients for skincare. 
 
Ingredients affecting 100% Natural Claims and what they do: 

Phenoxyethanol is a widely used synthetic preservative that has global approval for use in all cosmetic products in concentrations up to 1%. We stick to below this level. 

Ethylhexylglycerin is a synthetic skin-softening agent also used as a preservative, a carrier, or suspending agent for other preservatives such as phenoxyethanol.

Potassium Sorbate is a common synthetic preservative to prevent mould and yeast and has been used at a low concentration.