Kerstin Florian Clarifying Probiotic Refining Serum Review

Kerstin Florian Clarifying Probiotic Refining Serum
5.0
/ 10
Moisturizing
10.0 Humectancy icon Humectancy
0.0 Occlusivity icon Occlusivity
0.1Anti-wrinkle icon/ 10
Anti-wrinkle
Rich
in Antioxidants
Review

Does Kerstin Florian Clarifying Probiotic Refining Serum Work?

 
According to CreamScan AI's analysis of the ingredient list, here’s what Kerstin Florian Clarifying Probiotic Refining Serum has to offer:
 
  • Strong humectant moisturizing. This lightweight, humectant-rich product, ideal for oily skin, has a moisturizing rating of 5.0 out of 10.
  • Slight anti-wrinkle effect: Kerstin Florian Clarifying Probiotic Refining Serum has an anti-wrinkle rating of 0.1 out of 10, so you may expect a positive, although insignificant, effect on wrinkles.
  • Antioxidant protection.

Key Benefits of Kerstin Florian Clarifying Probiotic Refining Serum

 
These are the key benefits you can expect from using Kerstin Florian Clarifying Probiotic Refining Serum:
 

Lightweight Purely Humectant Moisturizing, Ideal for Oily Skin

According to CreamScan analysis, Kerstin Florian Clarifying Probiotic Refining Serum is quite moisturizing, with a moisturizing rating of 5.0 out of 10.

Is it more humectant or occlusive? It is purely humectant. It has zero occlusivity (we didn't find any occlusive ingredients on the ingredient list) and a maximum humectancy of 10 out of 10, primarily due to the high content of Propanediol (est. ≈6.0%), Butylene Glycol (est. ≈3.0%) and Pentylene Glycol (est. ≈2.0%).

This humectant-rich product, when used alone as a moisturizer, is ideal for oily skin, providing significant hydration in a lightweight, fast-absorbing formula without any occlusive ingredients.

Tip: Certain studies suggest that humectants alone may not effectively moisturize the skin. If you use this product as your only moisturizer, we recommend following it with one that contains at least some occlusive ingredients.

A Humectant Boost for Any Skincare Routine

But it’s not limited to oily skin - such a humectant boost will also positively contribute to the moisturizing efficacy of any skincare routine when used as a step before applying the main moisturizer. This type of formulation is typically used in serums, where a light, fast-absorbing texture is key.

Please refer to the Ratings section below for details of the moisturizing rating calculation.

Slight Anti-Wrinkle Efficacy

According to CreamScan analysis, Kerstin Florian Clarifying Probiotic Refining Serum has a slight anti-wrinkle rating of 0.1 out of 10.

It contains one ingredient with proven anti-wrinkle efficacy: Glycolic Acid (est. ≈0.3%), 
 a highly effective ingredient in peelings but with moderate anti-wrinkle efficacy in leave-on skincare products, as supported by a single clinical study. This study, involving 72 participants (Thibault et al.), demonstrated that a lotion with 5% GA reduced the fine wrinkling score by 6% after 34 days of use, compared to a vehicle (the same formulation without GA).
 
Among others, Kerstin Florian Clarifying Probiotic Refining Serum also contains Copper Gluconate, an ingredient often marketed as effective in reducing wrinkles. However, the studies supporting the anti-wrinkle claims of Copper Gluconate provide insufficient evidence of its efficacy according to CreamScan Research Evaluation Standards. Therefore, this ingredient does not contribute to the anti-wrinkle rating.
 
Moisturizers, when used regularly, are proven to prevent wrinkle formation and even reduce existing wrinkles. Therefore, this product, like any other moisturizer, can deliver some anti-wrinkle effects through its moisturizing action.
 

Please refer to the Ratings section below for details of the anti-wrinkle rating calculation.

Rich in Skin-Protecting Antioxidants

We estimate that Kerstin Florian Clarifying Probiotic Refining Serum is rich (> 3%) in antioxidants, specifically Rosa Canina Fruit Extract (est. ≈1.5%), Chlorella Vulgaris Extract (est. ≈1.3%), Saccharomyces/Xylinum/Black Tea Ferment (est. ≈1.0%), and others.

A key benefit of antioxidants is their ability to reduce oxidative stress caused by free radicals and therefore prevent accelerated skin aging. Studies also show that antioxidants can protect against environmental damage such as UV radiation and pollution, and help reduce inflammation and skin redness.

Please note that this is not a complete list of benefits. We are in the process of enhancing our AI model to incorporate anti-pigmentation, exfoliation and anti-acne ratings.

Things to Be Aware Of: Kerstin Florian Clarifying Probiotic Refining Serum

 
CreamScan AI identified a few things to consider before adding Kerstin Florian Clarifying Probiotic Refining Serum to your skincare routine:
 

May Increase Skin Photosensitivity Due to Glycolic Acid

This product contains glycolic acid, a popular AHA known for its ability to exfoliate and brighten the skin. Its action works by removing dead skin cells, revealing new, more delicate skin that is particularly vulnerable to sun damage.

As a result, using products with glycolic acid, regardless of concentration, may increase the skin's sensitivity, making it more prone to sunburn or irritation when exposed to UV rays.

To counteract this increased sun sensitivity, apply a broad-spectrum sunscreen with at least SPF 30 daily to protect your skin during glycolic acid treatment.

Please always check the manufacturer's instructions for using the product, either on their website or product label.

If It’s Your Only Moisturizer, It Needs to Be Paired with Some Occlusives

While humectants are highly effective at attracting water to the skin, studies (J. N. Kraft, C. W. Lynde) suggest they may not be efficient when used alone.

One major drawback of purely humectant moisturization is that the water attracted by humectants to the upper layers of the skin can evaporate completely into the environment through transepidermal water loss (TEWL). Adding occlusive ingredients helps seal this moisture into the skin and prevent further water loss.

If you’re using Kerstin Florian Clarifying Probiotic Refining Serum as your only moisturizer, consider pairing it with one that contains at least some occlusive ingredients, such as oils, butters, or silicones. These work alongside humectants to create a protective barrier, locking in hydration and ensuring longer-lasting moisturization. The amount of occlusive needed depends on your skin type - the drier the skin, the more occlusives it requires.

If this product is used not as a standalone moisturizer but as part of your skincare routine, such as a toner or serum, it should be applied before your main moisturizer (unless it's a sunscreen), which will provide the necessary occlusivity on top of it.

Pros & Cons of Kerstin Florian Clarifying Probiotic Refining Serum

 
Here’s an overview of the pros and cons of Kerstin Florian Clarifying Probiotic Refining Serum to help you decide if it’s the right choice for your skincare routine:
 

Pros:

  • When used alone: Provides humectant-rich moisturizing ideal for oily skin
  • As part of a routine: A humectant moisturizing boost, beneficial for any skin type
  • Lightweight texture
  • Provides slight anti-wrinkle efficacy
  • Rich in antioxidants that combat oxidative stress associated with accelerated skin aging and defend against environmental damage

Cons: 

  • May increase skin photosensitivity due to glycolic acid
  • Only if used as a standalone moisturizer - it needs to be paired with occlusives to seal in humectants

Ingredients

Est. % Ingredient Origin Functions
70
6
4
3
2
1.5
1.3
1
0.3
0.3
0.3
0.3
0.3
0.3
0.3
0.3
0.3
0.3
0.3
0.3
0.3
0.3
0.3
0.3
0.3
0.3
0.3
0.3
0.3
0.3
0.3
0.3
0.3
0.3
0.3
0.3
0.3
0.3
0.3
0.3
0.3
0.3
0.3
0.3
0.3
0.3
0.3
0.3
Est. %
Water
Function:
Origin:
Propanediol
Function:
Origin:
Lactobacillus Ferment Lysate
Function:
Origin:
Butylene Glycol
Function:
Origin:
Pentylene Glycol
Function:
Origin:
Rosa Canina Fruit Extract
Function:
Origin:
Chlorella Vulgaris Extract
Function:
Origin:
Saccharomyces/Xylinum/Black Tea Ferment
Function:
Origin:
Ulva Lactuca Extract
Function:
Origin:
Phyllanthus Emblica Fruit Extract
Function:
Origin:
Terminalia Bellerica Fruit Extract
Function:
Origin:
Terminalia Chebula Fruit Extract
Function:
Origin:
Spirulina Platensis Extract
Function:
Origin:
Oryza Sativa (Rice) Extract
Function:
Origin:
Leuconostoc Ferment Filtrate
Function:
Origin:
Superoxide Dismutase
Function:
Origin:
Soybean Peroxidase
Function:
Origin:
Heptyl Glucoside
Function:
Origin:
Allantoin
Function:
Origin:
Manganese Gluconate
Function:
Origin:
Ascophyllum Nodosum Extract
Function:
Origin:
Zinc PCA
Function:
Origin:
Copper Gluconate
Function:
Origin:
Glycolic Acid
Function:
Origin:
Lactic Acid
Function:
Origin:
Sodium Magnesium Silicate
Function:
Origin:
Sodium Phytate
Function:
Origin:
Polyacrylate Crosspolymer-6
Function:
Origin:
Leuconostoc/Radish Root Ferment Filtrate
Function:
Origin:
Xanthan Gum
Function:
Origin:
Hydroxyethylcellulose
Function:
Origin:
Sodium Citrate
Function:
Origin:
Biotin
Function:
Origin:
Glycerin
Function:
Origin:
Citric Acid
Function:
Origin:
Potassium Hydroxide
Function:
Origin:
t-Butyl Alcohol
Function:
Origin:
Benzoic Acid
Function:
Origin:
Phenoxyethanol
Function:
Origin:
Sodium Benzoate
Function:
Origin:
Potassium Sorbate
Function:
Origin:
Fragrance
Function:
Origin:
Limonene
Function:
Origin:
Linalool
Function:
Origin:
Mentha Arvensis Leaf Oil
Function:
Origin:
Citrus Limon (Lemon) Peel Oil
Function:
Origin:
Lavandula Hybrida Oil
Function:
Origin:
Mentha Piperita (Peppermint) Oil
Function:
Origin:

Ratings

All humectants
12.5
6
3
2
0.3
0.3
0.3
0.3
0.3
Benchmark
10
All occlusives
0.0
None
Benchmark
20
Moisturizing rating
5.0
Ingredient Est. % Benchmark Raiting
Humectancy All humectants 12.5 10
10.0
6
3
2
0.3
0.3
0.3
0.3
0.3
Occlusivity All occlusives 0.0 20
0.0
None
Moisturizing rating
5.0
Ingredient Est. % Benchmark Humectancy
6
3
2
0.3
0.3
0.3
0.3
0.3
All humectants 12.5 10
10
All humectants
12.5
6
3
2
0.3
0.3
0.3
0.3
0.3
Benchmark
10
Ingredient Est. % Benchmark Occlusivity
None
All occlusives 0.0 20
0.0
All occlusives
0.0
None
Benchmark
20
Ingredient
Ingredient anti-wrinkle power
when present at, %
in this formula est. %
Rating
1.5 /10 5 0.3 0.1
n/a
- 0.3 -
Total
0.1
Glycolic Acid
0.1
Ingredient anti-wrinkle power
1.5 /10
when present at, %
5
in this formula, est. %
0.3
Copper Gluconate
-
Ingredient anti-wrinkle power
n/a
when present at, %
-
in this formula, est. %
0.3
Anti-wrinkle rating
0.1
Ingredient Est. % Benchmark
Rich in Antioxidants
1.5
1.3
1
0.3
0.3
0.3
0.3
0.3
All antioxidants 5.3 3 Rich in antioxidants
All antioxidants
5.3
Rosa Canina Fruit Extract
1.5
Chlorella Vulgaris Extract
1.3
Saccharomyces/Xylinum/Black Tea Ferment
1
Spirulina Platensis Extract
0.3
Superoxide Dismutase
0.3
Soybean Peroxidase
0.3
Manganese Gluconate
0.3
Ascophyllum Nodosum Extract
0.3
Benchmark
3
Ingredient Est. % Benchmark
Rich in Soothing
1
0.3
0.3
All soothing 1.6 5 No
All soothing
1.6
1
0.3
0.3
Benchmark
5

Ingredients explained

Water
Est. %70
Function
Origin
WaterThe most used ingredient in skincare. Its concentration defines the product texture: rich creams may have about 50% of water while a light jelly about 90%. Water doesn’t moisturize the skin by itself and is used in skincare as a solvent for other ingredients.
Propanediol
Est. %6
Function
Origin
PropanediolAn excellent solvent capable of mixing water with normally water-insoluble ingredients. It also functions as a humectant due to its water-loving alcohol groups. Propanediol can control the viscosity of a product by reducing its thickness.
Lactobacillus Ferment Lysate
Est. %4
Function
Origin
Lactobacillus Ferment Lysate
Butylene Glycol
Est. %3
Function
Origin
Butylene Glycol

A clear, colorless liquid humectant that draws moisture to the skin. The humectancy of butylene glycol, owed to its two hydroxyl groups, is quite considerable, although not as powerful as glycerin, which contains three hydroxyl groups.

Pentylene Glycol
Est. %2
Function
Origin
Pentylene Glycol

A naturally or synthetically derived preservative that exhibits effective antifungal and antibacterial traits. It also acts as a booster for more traditional preservatives. Pentylene glycol can also serve as a moisturizing humectant and solvent.

Rosa Canina Fruit Extract
Est. %1.5
Function
Origin
Rosa Canina Fruit ExtractAn extract from the fruits of the Rosa canina, better known as rosehip. It contains carotenoids, which give it its bright, orange-red color, as well as high amounts of antioxidant vitamin C, flavonoids, tannins, and organic acids.
Chlorella Vulgaris Extract
Est. %1.3
Function
Origin
Chlorella Vulgaris ExtractA dried mass of tiny, single-cell green algae. It is widely used as a food source or dietary supplement since it is rich in proteins, amino acids, minerals, and vitamins. This dark green extract is used as an antioxidant agent in skincare.
Saccharomyces/Xylinum/Black Tea Ferment
Est. %1
Function
Origin
Saccharomyces/Xylinum/Black Tea FermentThis is what you probably know as kombucha. It contains various B vitamins, organic acids, and phenolic compounds that have antioxidant, anti-inflammatory, and antimicrobial properties.
Ulva Lactuca Extract
Est. %0.3
Function
Origin
Ulva Lactuca Extract
Phyllanthus Emblica Fruit Extract
Est. %0.3
Function
Origin
Phyllanthus Emblica Fruit ExtractAn extract from the fruits of the Indian gooseberry, also called Amla, which is rich in acids, vitamin C, astringent tannins, and humectant moisturizing sugars.
Terminalia Bellerica Fruit Extract
Est. %0.3
Function
Origin
Terminalia Bellerica Fruit Extract
Terminalia Chebula Fruit Extract
Est. %0.3
Function
Origin
Terminalia Chebula Fruit Extract
Spirulina Platensis Extract
Est. %0.3
Function
Origin
Spirulina Platensis ExtractA dark green emollient and antioxidant extract derived from spirulina - a dried mass of tiny blue-green algae. It is rich in proteins, amino acids, minerals, and vitamins (namely B1 and B2).
Oryza Sativa (Rice) Extract
Est. %0.3
Function
Origin
Oryza Sativa (Rice) ExtractAn abrasive rice extract rich in various emollient fatty acids, amino acids, and vitamin E.
Leuconostoc Ferment Filtrate
Est. %0.3
Function
Origin
Leuconostoc Ferment Filtrate
Superoxide Dismutase
Est. %0.3
Function
Origin
Superoxide Dismutase
Soybean Peroxidase
Est. %0.3
Function
Origin
Soybean Peroxidase
Heptyl Glucoside
Est. %0.3
Function
Origin
Heptyl Glucoside
Allantoin
Est. %0.3
Function
Origin
AllantoinA fluffy, white powder that acts as a humectant due to its water-loving chemistry and as an exfoliant that helps to remove dead skin cells. It has also been shown to be very soothing to irritated and inflamed skin.
Manganese Gluconate
Est. %0.3
Function
Origin
Manganese Gluconate
Ascophyllum Nodosum Extract
Est. %0.3
Function
Origin
Ascophyllum Nodosum ExtractAn extract from brown sea algae, a rich source of gel-forming algae polysaccharides such as fucoids, alginate, and ascophyllan, as well as some antioxidant phenolic compounds and minerals.
Zinc PCA
Est. %0.3
Function
Origin
Zinc PCAA two-part ingredient: Zinc helps to control sebum and bacteria in acne-prone skin, while skin-identical PCA is a moisturizing humectant. Zinc PCA may even boost collagen production and so is researched as a potential anti-wrinkle ingredient.
Copper Gluconate
Est. %0.3
Function
Origin
Copper GluconateAn organic salt of copper that can aid in the wound healing process. The manufacturer claims it also has soothing and anti-inflammatory properties, although this has yet to be confirmed. Copper gluconate is also a perspective anti-wrinkle ingredient.
Glycolic Acid
Est. %0.3
Function
Origin
Glycolic Acid

The second most used AHA (after lactic acid) known for its potent exfoliating and smoothing effects. It increases skin cell turnover, which is beneficial for treating acne. When used in peels, glycolic acid has confirmed anti-wrinkle efficacy, though it is less effective in leave-on products like creams and serums.

Lactic Acid
Est. %0.3
Function
Origin
Lactic AcidThe most popular AHA in skincare and less irritating than glycolic acid. It can be naturally found in sour milk. It is a humectant moisturizing, pH stabilizing, and gently exfoliating ingredient, able to soften dry, cracked, and peeling skin.
Sodium Magnesium Silicate
Est. %0.3
Function
Origin
Sodium Magnesium Silicate
Sodium Phytate
Est. %0.3
Function
Origin
Sodium PhytateSodium phytate is a chelating agent that serves to remove heavy metal ions from water. Removing metal ions helps other ingredients, such as antioxidants and preservatives, to perform better and keep products from separating.
Polyacrylate Crosspolymer-6
Est. %0.3
Function
Origin
Polyacrylate Crosspolymer-6A polymeric ingredient that works best in water-based formulas to create gel textures. It helps to stabilize emulsions and control viscosity.
Leuconostoc/Radish Root Ferment Filtrate
Est. %0.3
Function
Origin
Leuconostoc/Radish Root Ferment FiltrateA biotechnological fermentation ingredient that is created by feeding radish root to Leuconostoc kimchii. It allegedly contains organic acids and a mixture of peptides known as bacteriocins – which have antimicrobial activity.
Xanthan Gum
Est. %0.3
Function
Origin
Xanthan GumA natural multi-functional ingredient that originates from fermented sugars. Xanthan gum acts as a viscosity-building agent to thicken skincare products. It is also an excellent stabilizer and works well to hold other ingredients together.
Hydroxyethylcellulose
Est. %0.3
Function
Origin
HydroxyethylcelluloseA naturally-derived thickener that can form clear gel textures without the slimy feeling, unlike some other natural gel-formers.
Sodium Citrate
Est. %0.3
Function
Origin
Sodium CitrateA salt of citric acid that has a salty and tart flavor and is used as a fragrance. It is mildly basic, meaning that its addition to a skincare product can adjust the pH upward.
Biotin
Est. %0.3
Function
Origin
BiotinBiotin is an important nutrient that can cause weak hair and nails if deficient. Unfortunately, while biotin supplements have promising studies, topical biotin in creams and serums doesn’t have a large body of evidence to support its use.
Glycerin
Est. %0.3
Function
Origin
Glycerin

The most popular moisturizing ingredient in the world. It is a powerful humectant – cheap yet very effective.

Citric Acid
Est. %0.3
Function
Origin
Citric AcidA gently exfoliating AHA that helps to remove the top layer of dead skin cells. In comparison to other AHAs, citric acid has been shown to be one of the least effective. It is also very commonly used as a stabilizing and pH-controlling agent.
Potassium Hydroxide
Est. %0.3
Function
Origin
Potassium HydroxideA very alkaline ingredient, meaning that it has a high pH. Potassium hydroxide is therefore useful in bringing a low pH in a cosmetic product up to a more neutral, skin-safe level.
t-Butyl Alcohol
Est. %0.3
Function
Origin
t-Butyl Alcohol
Benzoic Acid
Est. %0.3
Function
Origin
Benzoic AcidA preservative effective against fungi, yeast, and some bacteria. It is commonly paired with phenoxyethanol to create a broad spectrum preservation system. Benzoic acid can also serve as a pH adjuster, fragrance, and bulking agent.
Phenoxyethanol
Est. %0.3
Function
Origin
PhenoxyethanolThe most frequently used preservative in skincare. It is a clear, oil-like liquid synthetic substance that protects products from harmful bacteria and yeast, whilst still leaving skin microflora unharmed. It is confirmed by research to be harmless.
Sodium Benzoate
Est. %0.3
Function
Origin
Sodium BenzoateA preservative that usually works in combination with other preservatives. It has to be at low pH (<5.5) to be effective.
Potassium Sorbate
Est. %0.3
Function
Origin
Potassium SorbateA preservative widely used in food and personal care products, available from natural sources or synthetically produced. Potassium sorbate works by inhibiting the growth of yeasts, molds, and some bacteria.
Fragrance
Est. %0.3
Function
Origin
FragranceUnder trade secret law, manufacturers have the right not to disclose what exactly went into the fragrance and use the unspecific word Fragrance or Parfum instead. Many fragrances are highly allergenic.
Limonene
Est. %0.3
Function
Origin
Limonene

One of the most used fragrances in skincare products. It is produced from the peels of citrus fruits and has a fresh, pleasant, citrusy smell. People who are sensitive to citrus should try to avoid it, or at least do a patch test before using it.

Linalool
Est. %0.3
Function
Origin
LinaloolA fragrant, volatile compound naturally present in many essential oils. It has a pleasant scent and is often used in skincare products as a fragrance. People with sensitive skin should try to avoid it, or at least do a patch test before using it.
Mentha Arvensis Leaf Oil
Est. %0.3
Function
Origin
Mentha Arvensis Leaf OilSimilar to peppermint oil, this fragrant wild mint essential oil contains menthol, mentone, and other compounds responsible for its cool, fresh, minty scent.
Citrus Limon (Lemon) Peel Oil
Est. %0.3
Function
Origin
Citrus Limon (Lemon) Peel Oil

A fragrant essential oil extracted from the rind or peel of a lemon. It is mainly comprised of limonene (up to 70%) and has a fresh, citrusy scent. Lemon peel oil may cause a sun-induced skin rash in people with a sensitivity towards citrus fruits.

Lavandula Hybrida Oil
Est. %0.3
Function
Origin
Lavandula Hybrida OilA fragrant essential oil distilled from a lavender hybrid of the two most common lavender species: true lavender and spike lavender. It contains linalool and linalyl acetate as well as eucalyptol and camphor, which altogether give it a cooling, lavender scent.
Mentha Piperita (Peppermint) Oil
Est. %0.3
Function
Origin
Mentha Piperita (Peppermint) OilAn essential oil distilled from peppermint leaves that is used as a fragrance and for its cooling effect on the skin. It contains up to 50% of menthol, which interacts with heat-sensitive nerve endings upon application to the skin, producing a cold sensation.