In microbiome skincare, microbiome is not an ingredient

The microbiome is the community of microbes living on your skin. It is already on your face, and it is not a thing sold in a bottle.

So it does not appear in ingredient lists. We read 2,228 Korean labels whose full list we hold, and not one of them prints microbiome as an ingredient.

Two products carry microbiome in the name. Both print a different word in the list.

What that other word is, and how far the evidence behind it goes, is this article.

The word on the front changes name in the list

It becomes a ferment. Microbes are grown in a medium, and what comes out is either filtered or broken open and used. Labels name it one of three ways.

• Ferment filtrate is the culture liquid with the microbial bodies filtered out.
• Ferment lysate is the cells burst open so their contents are released.
• Ferment or ferment extract are looser terms than either.

None of the three is a living culture. Living bacteria almost never go into Korean cosmetics. They do not survive preservation and distribution well, and if they did survive, that would be its own problem.

We read 478 labels carrying something in this family, counting the lactobacillus, bifida, galactomyces and yeast sides together. This is not a rare ingredient class on Korean shelves.

Printing an amount is rare here too

Of the labels in this family, 33 print an amount on the lactobacillus side, eight on the bifida side and four on the galactomyces side.

But this class differs from other ingredients in one way that matters. The disclosed numbers are spread further apart than anywhere else.

• Some labels print parts per billion.
• Some print figures in the nineties as percentages.

Those are numbers on the same ingredient class, separated by orders of magnitude you cannot guess at. In this family, assume nothing before you see the figure.

The reason is what a ferment is. A ferment filtrate is itself mostly water, so it can replace the water phase entirely, and then the figure climbs into the nineties. It can equally be dosed in at a trace. Both uses print on the label as ferment filtrate.

A figure in the nineties does not mean the active is in the nineties. It means the filtered culture liquid is. The same problem of water and extract sharing one name shows up in what a rice toner actually does.

How far has this been shown in people?

The field is filling in quickly, and knowing the exact shape of what has filled in is the useful part.

There is a human trial. Forty two participants with oily skin applied a cream containing 3 percent lactic acid ferment lysate twice daily for 60 days. At day 60, sebum, porphyrins and pore size were reported down and hydration and texture up.

It was a pilot trial with no control arm, and the authors described it that way. Because everyone applied one cream for 60 days, that design cannot separate what the ferment did from what the cream did.

There is a systematic review. A 2026 review of prebiotics, probiotics and postbiotics for acne pooled 33 studies covering 2,112 patients, and reported that safety was favorable throughout. Seven of those studies covered postbiotics.

And there are a lot of cell studies. Bifida ferment lysate raising barrier gene expression in keratinocytes, galactomyces ferment filtrate acting on the junctions between cells. Those results happened in culture dishes. They are not statements about a face.

The summary is this. At the class level, human evidence has started to appear. At the individual product level it is almost all mechanism. And the trial above ran at 3 percent. Take that number to the shelf.

What five labels actually print

Galactomyces Ampoule 97 prints galactomyces ferment filtrate at 97 percent. There are nine ingredients total and no water entry at all, which is what it should look like when a ferment filtrate replaces the water phase. The 97 and the list agree with each other.

Putting the number in the product name is a slightly different act. 97 percent is the proportion of filtered culture liquid, not of active. And the niacinamide in second position and the adenosine in seventh carry no amount at all, which are the figures you would actually want.

PeachMicrobiome 78 PDRN Toner says it uses lactobacillus ferment lysate at 78 percent in place of water, first of 21 entries. The disclosure itself is generous.

Three sentences on the same page do not check out.

• The ingredient marketed as vegan PDRN is hydrolyzed ovum DNA. Ovum means egg, so calling an egg derived ingredient vegan works against the ingredient's own name. It sits last of the 21 at 11ppm.
• Asked whether the product contains fragrance, the brand answers no. Fragrance is printed twentieth on that same page's ingredient list.
• A sentence promising a visibly stronger barrier with consistent use names no duration and no measurement.

Bifida Biome Ampoule Toner prints all three of its figures: bifida ferment lysate at 38ppm, cutibacterium granulosum ferment extract filtrate at 10ppb, and bifida ferment filtrate at 2ppb.

That disclosure is the honest kind. And being honest, it tells you something. 2ppb is a trace. It is a different order of magnitude entirely from the 3 percent in the pilot trial above.

The list also carries fructooligosaccharide, a sugar that feeds bacteria, which is the class these products call a prebiotic. No fragrance and no essential oil appear among the 41 entries.

One gap is worth naming. Lactobionic acid sits twenty sixth. It is a polyhydroxy acid, so the suitable for all skin line does not sit perfectly clean.

Red Apple Lacto Calming Serum prints lactobacillus ferment at 48,950ppm, about 4.9 percent, fourth in the list. Apple water follows at 37,240ppm in fifth.

This is the closest of the five to the concentration the pilot trial used. That does not guarantee a result. The trial used a different ferment lysate and had no control arm, and this is a different product. What is unusual here is simply that you can hold the numbers side by side at all.

The emergency soothing wording promises speed, and nothing measures speed. Panthenol, trehalose and a cooling agent are genuinely on the list.

Galactomy Clearskin Toner prints galactomyces ferment filtrate at 500ppm, which is 0.05 percent.

This is where the category goes wrong most often. The brand copy credits galactomyces with removing dead skin cells. The ingredients doing exfoliating work here are gluconolactone in ninth position and capryloyl salicylic acid in twenty second, a PHA and an LHA. The sentence hands the ferment the acids' job.

Neither acid discloses a concentration, and the mildly acidic wording comes with no pH figure. What those two acids actually do is split out in what PHA actually is and LHA versus BHA.

What to check on a microbiome product

• Skip the word on the front and find the name in the list. It will say filtrate or lysate, and it will say which organism.
• If there is a figure, convert the units. Parts per billion, parts per million and percent all appear inside this one category. Nowhere else makes unit checking this important.
• A figure in the nineties means base, not active.
• Prebiotic means food. Look for an oligosaccharide or inulin entry in the list. Like a free from list, this is something you can confirm on the label yourself, using the method in free from lists versus ingredient lists.

Common questions

Are there cosmetics with live cultures in them?

Almost none on Korean shelves. What gets printed is an already processed form such as a filtrate or a lysate. Recent reviews also lean the same way, treating processed forms as better than live ones on stability and safety grounds.

Does microbiome skincare change the bacteria on my skin?

The pilot trial above reported a shifted microbial composition at 60 days. The authors described that analysis as hypothesis generating. And whether a shifted community is why the skin improved is not something that design can establish.

Should I just pick the highest number?

Within the same organism and the same form, the comparison is worth making. Comparing 97 percent filtrate against 38ppm lysate is not a comparison at all, because they are doing different jobs. One is the base and the other is an addition.

Does it help acne prone skin?

There is a review, and safety came out favorable. But most of the studies it pooled were either oral or, where topical, tested at the ingredient level rather than as a finished product. Carrying that over to a specific bottle goes further than the review does.

Is it fine for sensitive skin?

Ferments themselves are not classed as irritants. But as above, products in this category sometimes carry acids or fragrance alongside. For reactive skin the thing to read is the whole list, not the category on the front.

If you are holding something labelled microbiome and cannot tell which line in the list that word refers to, send us the product page. We will find it with you.