Agaricus Bisporus Cap/Stem Extract: What Is It, Cosmetic Uses, Benefits & Side Effects

Curious about this ingredient? In this article we're explaining exactly what it is and why it's used within cosmetic formulations.
Updated on: June 23, 2025
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All information on this page is verified using The Personal Care Products Council's (PCPC) INCI database. Our ingredient analyses are based exclusively on PCPC's technical data to ensure accuracy and reliability.

What Is Agaricus Bisporus Cap/Stem Extract?

Agaricus Bisporus Cap/Stem Extract comes from the common white button mushroom, one of the most widely eaten mushrooms in the world. The extract is taken from both the cap and the stem, making use of parts that might otherwise be discarded.

Inside the mushroom are skin friendly sugars called beta glucans, small amounts of amino acids, minerals like potassium and phosphorus and a touch of natural vitamins. These compounds are known for holding water and helping to soften rough surfaces, which is why the beauty world took notice.

Mushrooms have been part of traditional skin care in many cultures for years, but the white button variety entered modern formulas in the early 2000s when gentle plant based moisturizers became popular. Labs found that a water or glycerin based soak could pull out the mushroom’s soothing parts without harsh chemicals, giving brands a fresh botanical option.

To make the extract, cleaned caps and stems are chopped, blended with warm water or a water-glycerin mix, then left to steep. The liquid is filtered, sometimes concentrated, and finally preserved so it stays stable in creams and serums.

You will spot Agaricus Bisporus Cap/Stem Extract in hydrating masks, daily moisturizers, anti aging serums, after-sun gels, lightweight lotions and even some calming hair conditioners where its softening effect helps with slip.

Agaricus Bisporus Cap/Stem Extract’s Cosmetic Benefits/Uses

In skin and hair products this mushroom extract is prized for one main job.

As an emollient it fills the tiny gaps between skin cells, leaving the surface smooth and supple. This helps cut down on dry patches, supports the skin barrier and gives formulas a silky glide that makes them pleasant to spread.

Who Can Use Agaricus Bisporus Cap/Stem Extract

This mushroom derived emollient is gentle enough for most skin types. Dry and mature skin may appreciate its moisture holding beta glucans while oily or combination skin can use it thanks to its light water based feel that does not leave a heavy film. Sensitive skin usually tolerates it well because it contains no added fragrance or strong acids. The main group that should be cautious is anyone with a known allergy to mushrooms or mold since the extract comes from the same source.

Because it is obtained from a fungus rather than an animal Agaricus Bisporus Cap/Stem Extract is suitable for vegans and vegetarians. The harvesting and processing steps do not involve animal by products or testing, making it a popular choice in cruelty free and plant based formulas.

Current safety data shows no specific concerns for women who are pregnant or breastfeeding when the extract is used topically in standard cosmetic concentrations. That said this is not medical advice and anyone expecting or nursing should let their doctor review any skin care product they plan to use, just to be safe.

The ingredient does not cause photosensitivity, so it will not make skin more prone to sunburn. It also plays nicely with common actives like vitamin C, niacinamide and retinol so there are no special layering rules to follow.

Potential Side Effects/Adverse Reactions

Responses to topical Agaricus Bisporus Cap/Stem Extract differ from person to person. The effects listed below are possible yet unlikely for most users when the ingredient is properly formulated and preserved.

  • Allergic reaction in people sensitive to mushrooms or mold
  • Mild skin irritation such as redness stinging or itching
  • Contact dermatitis presenting as small rash or bumps
  • Eye irritation if product accidentally gets into the eyes
  • Spoilage related reactions from microbial growth in poorly preserved products

If any adverse effect occurs stop using the product and seek advice from a medical professional or dermatologist.

Comedogenic Rating

Rating: 0 / 5

Agaricus Bisporus Cap/Stem Extract is water soluble and contains hardly any lipids so it does not sit in pores or create the kind of film that can trap oil and debris. It is therefore classed as non-comedogenic and is generally suitable for people who are prone to acne or breakouts. Only the overall formula can change this rating, for example if the extract is blended with heavy plant oils or thick butters.

Summary

Agaricus Bisporus Cap/Stem Extract mainly works as an emollient that smooths skin by filling in surface gaps and locking in light moisture thanks to its beta glucans, amino acids and minerals. It helps products glide, leaves a soft after feel and supports the skin barrier without heaviness.

It is a niche ingredient rather than a blockbuster yet you will spot it more often in clean beauty lines and soothing masks as brands look for mild plant derived moisturizers.

Topical use has an excellent safety record with very low risk except for anyone allergic to mushrooms. As with any new skincare item it is wise to do a quick patch test to rule out personal sensitivities before full use.

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