"This product broke me out" -- what is actually happening beneath the surface? Recent research indicates that disruption of the skin microbiome (commensal flora) is a major contributing factor.
The Skin's Commensal Flora
Approximately 1,000 species of commensal bacteria inhabit healthy skin. S. epidermidis produces antimicrobial peptides and is also involved in ceramide production. The diversity and balance of this flora being maintained is a condition for healthy skin.
The Mechanism Behind "Doesn't Suit My Skin"
Excessive antimicrobial action from preservatives kills beneficial bacteria along with harmful ones. Overly alkaline cleansing allows pathogenic bacteria to dominate. Surfactant-induced barrier disruption alters the habitat for commensal bacteria.
In other words, "this product didn't suit my skin" in many cases actually means "this product negatively impacted my microbiome".