The Difference Between Prebiotics, Probiotics and Postbiotics

Photo Credits: Dennis Kunkel Microscopy/Science Source

This article first appeared in the Winter 2019 issue of NewBeauty. Click here to subscribe.

Probiotics seem synonymous with gut health (and they are), but what they’re also synonymous with nowadays is skin care. We see the word “probiotic” on tons of skin-care products nowadays, but what many people probably don’t realize is that most of the time, it’s actually postbiotics in that cream or lotion instead. It’s for this reason (among others) that the FDA is taking a closer look at how bacteria is being used in beauty, just to make sure the claims are legit and the formulas are safe. To make things a little easier, we’re breaking down the difference between the three types: Here’s how each one works in both gut health and skin care.

PREBIOTICS

Gut Health: Gastroenterologist Will Bulsiewicz, MD tells his patients to think of the gut as a garden: “Prebiotics are the fertilizer, and are almost exclusively found in food—predominantly plant fiber. They are the part of our food that has an effect on our microbiome. Benefiber is actually a prebiotic, and I like to mix it into my morning coffee—it doesn’t change the taste or texture, and improves gut health.” Other prebiotic foods include garlic, asparagus and dandelion greens.

Skin Care: “Prebiotics are types of ‘food’ that bacteria on the surface of the skin can use to do their job,” says Jeff Rosevear, founding scientist and head of product development for SKINSEI, a prebiotic skin-care line. “For example, the microbiome produces fatty acids, which are then used by the skin to maintain barrier health. Emerging science suggests that by giving the right food to the right bacteria, one can support the overall microbiome.”

PROBIOTICS

Gut Health: These are living organisms in foods and supplements that help maintain good bacteria in the gut for a healthy, balanced microbiome. “Probiotics act as the seeds in our gut garden,” says Dr. Bulsiewicz. “You can’t grow a seed without watering it and nurturing it with the right nutrients—in this case, prebiotics. When the two come together, there’s a synergy that creates postbiotics, like short-chain fatty acids.”

Skin Care: In skin-care products, probiotics are either living bacteria, bacteria that has been deactivated (killed), which is called a lysate, or the product of a bacteria, called a ferment. “Live bacteria are very challenging to formulate with in cosmetics, so it’s more common to use lysates and ferments, and there is scientific support to show that they both offer benefits to the skin,” says Rosevear.

POSTBIOTICS

Gut Health: Postbiotics are the byproducts created when prebiotics and probiotics combine. But, “you can’t just take a postbiotic supplement like butyrate because it would get absorbed in the small intestine and never make it to the colon, where it needs to be to work,” says Dr. Bulsiewicz. “The best way to get postbiotics is by eating a diversity of prebiotic-rich plants.”

Skin Care: These are the metabolites, or byproducts of living organisms: “the enzymes, organic acids, polysaccharides, peptides, etc. that further reinforce the skin’s healthy barrier,” says New York dermatologist Whitney Bowe, MD. According to the FDA, 90 percent of cosmetic products that have “probiotic” labels actually contain postbiotics, but are marketed “probiotic,” similarly to the way “natural” and “organic” have been overused in skin care.