Kiehl's Powerful-Strength Vitamin C Serum

Kiehl's Powerful-Strength Vitamin C Serum
10.0
/ 10
Moisturizing
10.0 Humectancy icon Humectancy
10.0 Occlusivity icon Occlusivity
2.5Anti-wrinkle icon/ 10
Anti-wrinkle
Rich
in Antioxidants

Review

Results you may expect from using Kiehl's Powerful-Strength Vitamin C Serum:

Based on the ingredient analysis by CreamScan, these are the key benefits you can expect from using Kiehl's Powerful-Strength Vitamin C Serum:

  • Intense moisturizing. It has a moisturizing rating of 10.0 out of 10.
  • Some anti-wrinkle efficacy: Kiehl's Powerful-Strength Vitamin C Serum has an anti-wrinkle rating of 2.5 out of 10 so you may expect some, although limited, effect on wrinkles.
  • Antioxidant protection.

How moisturizing is it?

Maximum hydration: Kiehl's Powerful-Strength Vitamin C Serum has the highest possible moisturizing rating of 10.0 out of 10.

Is it more humectant or occlusive? This is one of the most moisturizing products on the market, with a maximum humectancy of 10 out of 10, primarily due to the substantial concentration of Propylene Glycol (est. ≈22.0%) and Glycerin (est. ≈11.0%), and a maximum occlusivity of 10 out of 10, solely because of the significant content of Dimethicone (est. ≈45.0%).

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

Anti-wrinkle efficacy

According to CreamScan analysis, Kiehl's Powerful-Strength Vitamin C Serum has a slight anti-wrinkle rating of 2.5 out of 10. It contains one ingredient with proven anti-wrinkle efficacy: Ascorbic Acid (est. ≈10.0%), 
 or Vitamin C, a popular anti-wrinkle ingredient, yet with average efficacy confirmed by only one study.
 
Among others, Kiehl's Powerful-Strength Vitamin C Serum also contains contains Ascorbyl Glucoside and Adenosine, two ingredients marketed as effective in reducing wrinkles. However, the studies supporting the anti-wrinkle claims of these ingredients provide insufficient evidence of efficacy according to CreamScan Research Evaluation Standards. Therefore, these ingredients do 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, could deliver additional anti-wrinkle efficacy through its moisturizing action.
 

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

Antioxidant benefits

We estimate that Kiehl's Powerful-Strength Vitamin C Serum is rich (> 3%) in antioxidants, specifically Ascorbic Acid (est. ≈10.0%) and Ascorbyl Glucoside (est. ≈2.0%).

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.

Ingredients

Est. % Ingredient Origin Functions
45
Dimethicone
22
Propylene Glycol
11
Glycerin
10
Ascorbic Acid
4
Cetyl PEG/PPG-10/1 Dimethicone
3
Dimethicone Crosspolymer
2
Ascorbyl Glucoside
1.5
Lauroyl Lysine
1
Boron Nitride
0.3
Hydroxyethylpiperazine Ethane Sulfonic Acid
0.3
Adenosine
0.3
Hydrolyzed Hyaluronic Acid
0.3
Limonene
0.3
Citrus Aurantium Dulcis (Orange) Peel Oil
0.3
Citrus Limon (Lemon) Peel Oil
0.3
Citral
0.3
Pentaerythrityl Tetra-di-t-butyl Hydroxyhydrocinnamate
Est. %
Dimethicone
Function:
Origin:
Propylene Glycol
Function:
Origin:
Glycerin
Function:
Origin:
Ascorbic Acid
Function:
Origin:
Cetyl PEG/PPG-10/1 Dimethicone
Function:
Origin:
Dimethicone Crosspolymer
Function:
Origin:
Ascorbyl Glucoside
Function:
Origin:
Lauroyl Lysine
Function:
Origin:
Boron Nitride
Function:
Origin:
Hydroxyethylpiperazine Ethane Sulfonic Acid
Function:
Origin:
Adenosine
Function:
Origin:
Hydrolyzed Hyaluronic Acid
Function:
Origin:
Limonene
Function:
Origin:
Citrus Aurantium Dulcis (Orange) Peel Oil
Function:
Origin:
Citrus Limon (Lemon) Peel Oil
Function:
Origin:
Citral
Function:
Origin:
Pentaerythrityl Tetra-di-t-butyl Hydroxyhydrocinnamate
Function:
Origin:

Ratings

All humectants
33.3
22
11
0.3
Benchmark
10
All occlusives
45.0
45.0
Benchmark
20
Moisturizing rating
10.0
Ingredient Est. % Benchmark Raiting
Humectancy All humectants 33.3 10
10.0
22
11
0.3
Occlusivity All occlusives 45.0 20
10.0
45.0
Moisturizing rating
10.0
Ingredient Est. % Benchmark Humectancy
22
11
0.3
All humectants 33.3 10
10
All humectants
33.3
22
11
0.3
Benchmark
10
Ingredient Est. % Benchmark Occlusivity
45
All occlusives 45.0 20
10.0
All occlusives
45.0
45.0
Benchmark
20
Ingredient
Ingredient anti-wrinkle power
when present at, %
in this formula est. %
Rating
2.5 /10 5 10 2.5
n/a
- 2 -
n/a
- 0.3 -
Total
2.5
Ascorbic Acid
2.5
Ingredient anti-wrinkle power
2.5 /10
when present at, %
5
in this formula, est. %
10
Ascorbyl Glucoside
-
Ingredient anti-wrinkle power
n/a
when present at, %
-
in this formula, est. %
2
Adenosine
-
Ingredient anti-wrinkle power
n/a
when present at, %
-
in this formula, est. %
0.3
Anti-wrinkle rating
2.5
Ingredient Est. % Benchmark
Rich in Antioxidants
10
2
0.3
0.3
All antioxidants 12.6 3 Rich in antioxidants
All antioxidants
12.6
Ascorbic Acid
10
Ascorbyl Glucoside
2
Hydrolyzed Hyaluronic Acid
0.3
Pentaerythrityl Tetra-di-t-butyl Hydroxyhydrocinnamate
0.3
Benchmark
3
Ingredient Est. % Benchmark
Rich in Soothing
None
All soothing 0 5 No
All soothing
0
None
Benchmark
5

Ingredients explained

Dimethicone
Est. %45
Function
Origin
DimethiconeThe most common silicone in skincare. It forms a silky, smooth film on the skin’s surface and can help to prevent water loss. It also aids in wound healing and can treat and soften scars. Dimethicone is considered to be very safe for use.
Propylene Glycol
Est. %22
Function
Origin
Propylene GlycolA clear, thick, odorless liquid of synthetic origin. Its main function is to stabilize cosmetic products exposed to varying temperatures. It is also a moderately strong humectant with similar properties to glycerin.
Glycerin
Est. %11
Function
Origin
Glycerin

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

Ascorbic Acid
Est. %10
Function
Origin
Ascorbic Acid

Also known as vitamin C, this multi-benefit ingredient has proven anti-wrinkle, antioxidant, and anti-pigmentation efficacy. It degrades easily when exposed to air and light, so it requires proper packaging to maintain its stability.

Cetyl PEG/PPG-10/1 Dimethicone
Est. %4
Function
Origin
Cetyl PEG/PPG-10/1 DimethiconeA silicone-based powerful emulsifier that helps to create lightweight and pleasant feeling lotions and creams.
Dimethicone Crosspolymer
Est. %3
Function
Origin
Dimethicone CrosspolymerA group of ingredients that are typically added to skincare products to adjust the formula. Dimethicone Crosspolymers stabilize a formula, regulate its thickness and consistency and give the product a velvety feel.
Ascorbyl Glucoside
Est. %2
Function
Origin
Ascorbyl GlucosideA derivative of vitamin C. It is more stable and less irritating than ascorbic acid. There are unfortunately no clinical studies on ascorbyl glucoside’s anti-pigment or anti-acne efficacy alone.
Lauroyl Lysine
Est. %1.5
Function
Origin
Lauroyl LysineA synthetic insoluble powder that improves the texture of a product, leaving the skin silky smooth and absorbing oils and sweat.
Boron Nitride
Est. %1
Function
Origin
Boron NitrideA synthetically made compound that has several functions. As an opacifier, it can provide a range of appearances, ranging from translucent to completely opaque. It is also an excellent absorber and is capable of high oil absorption.
Hydroxyethylpiperazine Ethane Sulfonic Acid
Est. %0.3
Function
Origin
Hydroxyethylpiperazine Ethane Sulfonic AcidA pH buffer that secures the pH around 7.5.
Adenosine
Est. %0.3
Function
Origin
Adenosine

A key molecule responsible for energy transportation, signaling, and enzyme activity. Adenosine is a popular anti-wrinkle ingredient, however, the key study about its anti-wrinkle efficacy (1) does not meet CreamScan Research Evaluation Standards as it is not double-blind.

Hydrolyzed Hyaluronic Acid
Est. %0.3
Function
Origin
Hydrolyzed Hyaluronic AcidA smaller-molecule version of the regular hyaluronic acid. It is a powerful humectant that absorbs into the skin and offers moisturizing, smoothing, and anti-wrinkle effects. It is also slightly anti-inflammatory and displays subtle antioxidant properties.
Limonene
Est. %0.3
Function
Origin
LimoneneOne 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.
Citrus Aurantium Dulcis (Orange) Peel Oil
Est. %0.3
Function
Origin
Citrus Aurantium Dulcis (Orange) Peel OilAn essential oil derived from the peels of the sweet orange. It is commonly used as a fragrance because of its pleasant, citrusy scent. The main constituent of the essential oil is limonene (up to 96%).
Citrus Limon (Lemon) Peel Oil
Est. %0.3
Function
Origin
Citrus Limon (Lemon) Peel OilA 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.
Citral
Est. %0.3
Function
Origin
CitralA fragrant compound found in many essential oils (especially lemon myrtle and lemongrass essential oil). It has a sweet, lemon-like scent. People with sensitive skin should try to avoid products with citral, or at least do a patch test before using.
Pentaerythrityl Tetra-di-t-butyl Hydroxyhydrocinnamate
Est. %0.3
Function
Origin
Pentaerythrityl Tetra-di-t-butyl HydroxyhydrocinnamateAn antioxidant that protects vulnerable ingredients from the damage caused by ultraviolet radiation, which can also lead to the generation of damaging free radical species.