Side effects of topical application of probiotics?

Numerous studies have been conducted on the topical use of probiotics, and the majority have reported no side effects. Indeed, the use of probiotics has not resulted in redness, irritation, itching, or swelling following their application. There is a fairly widespread fear that probiotics, being microorganisms, could disrupt the natural skin flora. At present, there is no scientific evidence to support this claim.

However, this does not prevent some researchers from believing that the current understanding of the microbiome is incomplete and that the use of such cosmetics is imprudent. Indeed, they argue that applying live probiotics to the skin could potentially disrupt the skin microbiome and lead to the proliferation of "bad" bacteria. This is why, today, in cosmetics, most products claiming to contain probiotics in their formula actually only contain "dormant" probiotics. These are microorganisms that are unable to grow but still retain their metabolic activity. More specifically, the molecules they contain remain active and can therefore be beneficial to the skin. The topical application of such probiotics then presents no danger to the skin.

Important : Even though probiotics are generally very well tolerated, including by those with sensitive skin, it is always a good idea to perform a tolerance test the first time you use a new product.