Back to Explore | Mary & May / Serums / Citrus Unshiu Fruit + Tremella Fuciformis Serum

Mary & May Citrus Unshiu Fruit + Tremella Fuciformis Serum

Name: Citrus Unshiu Fruit + Tremella Fuciformis Serum
Brand: Mary & May

This brightening serum is formulated around Tremella Fuciformis Extract and Arbutin to brighten dull-looking skin and fade the look of dark spots.

We independently verify ingredients, backed by peer-reviewed research. Suggest an update.

Save

What's inside

Ingredients List

Active Ingredients

Tremella Fuciformis Extract 9.7%

Humectant

Inactive Ingredients

Citrus Unshiu Fruit Extract 83.5%

Antioxidant

Arbutin

Antioxidant

Glycereth-26

Humectant

0 / 0 Helps hydrate Dry Skin Icon

1,2-Hexanediol

Arginine

Carbomer

Ethylhexylglycerin

Caprylyl Glycol

Active Ingredients: Tremella Fuciformis Extract 9.7%
Inactive Ingredients: Citrus Unshiu Fruit Extract 83.5%, Arbutin, Glycereth-26, 1,2-Hexanediol, Arginine, Carbomer, Ethylhexylglycerin, Caprylyl Glycol

Find dupes Discover better matches for your skin

Key Ingredients

Benefits

Ingredients Explained

Citrus Unshiu Fruit Extract

Antioxidant, Emollient, Humectant

Citrus Unshiu Fruit Extract is an antioxidant.

Tremella Fuciformis Extract

Humectant, Skin Conditioning

Tremella Fuciformis Extract comes from the tremella fuciformis mushroom, also known as snow mushroom or white jelly mushroom.

The snow mushroom has moisturizing and antioxidant properties.

Snow mushroom is rich in polysaccharides, giving it moisturizing benefits. As a humectant, snow mushroom helps draw moisture from the air to the skin. Polysaccharides are able to mimic our skin's natural carbohydrates to help the skin retain water.

Snow mushroom has been shown to help with anti-aging due to its antioxidants. It increases the presence of superoxide dismutase in our brain and liver. Superoxide is a by-product of oxygen metabolism. It left unregulated, superoxide causes cell damage. Thus, superoxide dismutase acts as an antioxidant to protect our living cells.

Another study from 2016 showed snow mushroom extract blocks the skin from creating melanin when exposed to UVB. Thus, it may help protect against the signs of aging from sun exposure. However, more studies are needed to confirm this. Another study from 2021 found snow mushroom to protect against UVA damage as well.

This white mushroom is native to Asian countries such as China, Korea, Japan, and Thailand. It is a common ingredient in traditional Chinese cuisine and medicine.

Learn more about Tremella Fuciformis Extract

Arbutin

Antioxidant, Bleaching, Skin Conditioning

Arbutin is a naturally occurring molecule (found in bearberry, cranberry, and blueberry) that is used in skincare as a gentle brightening agent to fade dark spots, melasma, and post-inflammatory hyperpigmentation.

Chemically, it is a sugar-bound form of hydroquinone.

It works mainly by inhibiting tyrosinase, the enzyme your skin uses to make melanin. This means less new pigment gets produced over time.

There are two forms you'll see on labels: beta-arbutin (listed as just "Arbutin") and alpha-arbutin (the more stable and effective of the two).

The evidence behind this is solid: it's less cytotoxic to melanocytes than hydroquinone and comparably effective with kojic acid for hyperpigmentation.

One human study using a 10% solution reduced UVR-induced hyperpigmentation by 43.5% (jumping to 63.3% when paired with aloesin).

More recent clinical work backs it up too; a 2025 study on a 5% alpha-arbutin + 2% kojic acid cream found it comparable to triple combination prescription formulas but with lower recurrence for melasma.

Typical usage in cosmetics serums land in the 1-2% range.

It's a well-tolerated, non-irritating, and non-photoreactive ingredient that also gives some antioxidant benefits too.

Learn more about Arbutin

Glycereth-26

Humectant

Glycereth-26 is a synthetic ingredient and polyethylene glycol ether of Glycerin. Glycerin is already naturally found in your skin and helps keep your skin moisturized.

It is a humectant and helps add texture to products. It can make your product thicker.

As a humectant, it helps draw moisture from the air to your skin. This helps your skin stay hydrated.

Learn more about Glycereth-26

1,2-Hexanediol

Skin Conditioning, Solvent

1,2-Hexanediol is a synthetic liquid and another multi-functional powerhouse.

It is a:

Humectant, drawing moisture into the skin
Emollient, helping to soften skin
Solvent, dispersing and stabilizing formulas
Preservative booster, enhancing the antimicrobial activity of other preservatives

Arginine

Masking, Skin Conditioning

Arginine is a semi-essential amino acid. This just means our bodies can product a bit on its own, but sometimes needs a little boost from food sources.

It is a part of your skin's natural moisturizing factor (NMF), or the water-loving molecules in your outermost layer of skin (stratum corneum) that keeps everything hydrated and happy.

Here's an interesting thing about Arginine: your skin converts it into urea through the Krebs-Henseleit urea cycle. Urea is one of the most effective humectants your skin naturally produces.

A clinical study showed applying 2.5% arginine hydrochloride to atopic dermatitis skin showed significant urea levels in the stratum corneum and improved moisture in just four weeks.

Arginine is also a precursor to nitric oxide; nitric oxide improves microcirculation and supports wound healing and collagen synthesis.

One study found that an amino acid complex containing Arginine reduced skin irritation, improved hydration, and accelerated skin repair in clinical / in-vivo studies.

Arginine itself is an amino acid and not a fatty acid, oil, or ester. On its own, it's not a direct food source for Malassezia, or the yeast that causes fungal acne.

Learn more about Arginine

Carbomer

Emulsion Stabilising, Gel Forming

Carbomer is a synthetic thickening and gelling agent. It's basically the ingredient that gives a lot of serums, gels, creams, and sunscreens their smooth, non-sticky texture.

Although legally permitted at very high levels, carbomers are normally used at concentrations below 1%.

It also needs to be neutralized to actually thicken, and because it is a large molecule, it doesn't really penetrate the skin barrier.

Allergy-wise, the risk is very low. Clinical studies show carbomers have low potential for skin irritation/sensitization even at concentrations up to 100%.

A 2024 UK study patch-tested 1,302 patients and found true allergy to the parent group of carbomer to be rare with no confirmed relevant reactions.

Learn more about Carbomer

Ethylhexylglycerin

Skin Conditioning

Ethylhexylglycerin is created from glycerin. It is a multitasker ingredient that:

The CIR Expert Panel found minimal skin absorption or sensitization of any kind in a safety assessment. Though this ingredient is considered well-tolerated, a small number of cases of allergic dermatitis have been published since 2002. Just be sure to patch test if you are unsure.

Industry-reported use ranges from 8% in rinse-off products and 2% in leave-on formulations.

Learn more about Ethylhexylglycerin

Caprylyl Glycol

Emollient, Humectant, Skin Conditioning

Caprylyl Glycol is a humectant, skin conditioner, emollient, and preservative booster derived from either caprylic acid or synthetically created.

Typical use levels vary from 0.3-1% as a preservative booster and go up to 2% to condition skin.

Because it is not a free-fatty acid, this ingredient is fungal acne safe (there's nothing for Malassezia to feed on).

Learn more about Caprylyl Glycol