What is alpha-glucan oligosaccharide?
Alpha-glucan oligosaccharide, often shortened to AGO, is a short chain of sugar molecules. In skincare it is used as a prebiotic. A 2025 review in Annals of Dermatology lists it alongside inulin and certain plant extracts as an ingredient commonly used this way.
Notice what that sentence says. It tells us the ingredient is used as a prebiotic. It does not report a test of AGO on skin. That distinction matters for the rest of this guide.
What does a prebiotic do for skin?
Your skin carries a community of bacteria, fungi, and other microbes, often called the skin microbiome. A prebiotic is a food source for those microbes. The idea is to support the balance already there, rather than add new bacteria, which is what a probiotic would do.
If you want to compare the two ideas, our guide on prebiotic vs probiotic skincare explains the difference. For the wider picture, see what a prebiotic moisturizer does for the skin barrier.
Why might results differ from person to person?
The same review notes that the makeup of the microbiome varies a lot between people. An ingredient that suits one person's skin community may do little for another's.
This is one reason a single ingredient cannot promise much. A label that mentions a prebiotic is giving you a clue about the formula's intent, not a measured outcome.
What do lab studies tell us, and what do they not?
A 2021 study in Microorganisms tested prebiotic combinations in the lab. The combinations affected two common skin bacteria differently. That suggests prebiotics can act selectively.
The limits are clear. It was a test-tube study, it used a small number of bacterial strains from patients, and it did not test AGO. It cannot tell us what happens on real faces. Here is how to think about it.
| What we can say | What we do not know yet |
|---|---|
| AGO is used as a prebiotic in skincare. | How well AGO works on human skin. |
| Skin microbiomes differ between people. | Who is most likely to notice a difference. |
| Prebiotics can act selectively on bacteria in the lab. | Whether lab results carry over to a cream. |
How does it show up in a daily moisturizer?
Our Protecting Cream includes alpha-glucan oligosaccharide as a prebiotic. It is built to support a balanced-looking skin environment, along with a breathable moisture barrier, argan, sunflower seed, and macadamia oils, peptides, and adenosine. It is made to feel nourishing without a greasy finish.
A few honest notes. The formula contains fragrance, so if your skin is sensitive, patch test first. It also contains seed oils, so if you are prone to breakouts, start on a small area.
It is a cosmetic, not a medicine. And as above, the evidence for AGO itself is weak, so we see it as one part of a barrier-focused formula, not the reason to buy. You can browse more hydrating options in our dehydration collection.
FAQ
Is alpha-glucan oligosaccharide the same as a probiotic?
No. A probiotic contains live microbes, while alpha-glucan oligosaccharide is a sugar meant to feed microbes already on your skin. The two ideas are related but work in different ways.
Can alpha-glucan oligosaccharide fix a damaged skin barrier?
There is not enough evidence to say so. A moisturizer can help skin feel more comfortable, but persistent irritation or a damaged barrier is worth showing to a dermatologist.
How do I know if a product with it suits me?
Check the full ingredient list for fragrance and oils you react to, then patch test on a small area. Add one new product at a time so you can tell what caused any change.
