Kiehl's Powerful-Strength Vitamin C Serum Review

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

Does Kiehl's Powerful-Strength Vitamin C Serum Work?

 
According to CreamScan AI's analysis of the ingredient list, here’s what Kiehl's Powerful-Strength Vitamin C Serum has to offer:
 
✅ Intense moisturizing. It has a moisturizing rating of 10.0 out of 10.
✅ Modest 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

  

Key Benefits of Kiehl's Powerful-Strength Vitamin C Serum

 
These are the key benefits you can expect from using Kiehl's Powerful-Strength Vitamin C Serum:
 

🔵🔵🔵 Exceptionally Rich Moisturizer Perfect for Dry to Very Dry Skin

According to CreamScan analysis, Kiehl's Powerful-Strength Vitamin C Serum is exceptionally moisturizing, with 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%).

This type of moisturizer is ideal for people with dry to very dry skin who want intense hydration. It combines a high concentration of humectants with an exceptional level of occlusive ingredients to provide effective dual-action moisturizing specifically for very dry skin.

The occlusive profile of Kiehl's Powerful-Strength Vitamin C Serum suggests a rich, thick texture, making it perfectly suited for very dry skin.

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

🟣 Modest Anti-Wrinkle Efficacy

According to CreamScan analysis, Kiehl's Powerful-Strength Vitamin C Serum has a modest level of anti-wrinkle efficacy, rated 2.5 out of 10.

It contains one ingredient with proven anti-wrinkle efficacy: Ascorbic Acid (est. ≈10.0%),
 or Vitamin C, a popular ingredient, yet with moderate anti-wrinkle efficacy, as confirmed by a single clinical study involving 20 participants (Humbert et al.). This study showed that a cream with a relatively high concentration of 5% ascorbic acid reduced the average wrinkle depth by 7% after 6 months of use, compared to a vehicle (the same formulation without ascorbic acid).
 
Among others, Kiehl's Powerful-Strength Vitamin C Serum also contains contains Ascorbyl Glucoside and Adenosine, two ingredients often 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.
 
While this does not categorically rule out the possibility that these ingredients may reduce wrinkles, their efficacy is not supported by convincing, vehicle-controlled, double-blind clinical studies - at least none that were available to the CreamScan team at the time of publication.
 
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, can deliver some additional 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 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.

📌 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: Kiehl's Powerful-Strength Vitamin C Serum

 
CreamScan AI identified a few things to consider before adding Kiehl's Powerful-Strength Vitamin C Serum to your skincare routine:
 

⚠️ Best for Very Dry Skin - May Be Too Thick for Other Skin Types

With exceptional occlusivity, this product is optimal for moisturizing dry and very dry skin but may be too thick for other skin types, including normal, and especially combination and oily skin.

If you have oily, combination, or normal skin and are considering purchasing this product for the first time, it might be a good idea to try a sample before buying.

Pros & Cons of Kiehl's Powerful-Strength Vitamin C Serum

 
Here’s an overview of the pros and cons of Kiehl's Powerful-Strength Vitamin C Serum to help you decide if it’s the right choice for your skincare routine:
 

🟩 Pros:

✅ Very rich moisturizer perfect for dry and very dry skin: exceptionally occlusive and humectant-rich
Offers modest anti-wrinkle efficacy
✅ Rich in antioxidants that combat oxidative stress associated with accelerated skin aging and defend against environmental damage
 

⭕ Cons: 

⚠️ May feel too rich and thick on skin types other than dry
   

Summary: Kiehl's Powerful-Strength Vitamin C Serum

 
Based on the ingredient list analysis, CreamScan AI suggests that Kiehl's Powerful-Strength Vitamin C Serum
 is an ideal moisturizer for dry to very dry skin, combining a very high concentration of humectants and occlusive ingredients in a rich, thick texture.
 
Kiehl's Powerful-Strength Vitamin C Serum contains ingredients with proven evidence of anti-wrinkle efficacy that may provide a modest anti-wrinkle effect. As a result, you can expect a positive, though not very significant, impact on wrinkles.
 
With its high antioxidant content, Kiehl's Powerful-Strength Vitamin C Serum helps protect against free radical damage and offers multiple benefits for all skin types, including preventing premature aging, defending against environmental damage, and calming inflammation.
 
That said, there are some things about Kiehl's Powerful-Strength Vitamin C Serum worth noting.
 
With its high occlusivity, Kiehl's Powerful-Strength Vitamin C Serum is ideal for dry skin but may feel too thick on other skin types. If you have oily, combination, or normal skin, it’s a good idea to try a sample before purchasing.
 
❗️ Fact check. At CreamScan, we are committed to accuracy and fairness. If you spot any errors or something that doesn’t seem right, please click here to let us know. We regularly update the ingredient lists and monitor the latest research on ingredient efficacy to ensure that our information remains as complete and precise as possible.

 

Ingredients

Est. % Ingredient Origin Functions
45
22
11
10
4
3
2
1.5
1
0.3
0.3
0.3
0.3
0.3
0.3
0.15
0.3
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
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.

Citrus Aurantium Dulcis (Orange) Peel Oil
Est. %0.3
Function
Origin
Citrus Aurantium Dulcis (Orange) Peel Oil

An 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 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.

Citral
Est. %0.15
Function
Origin
Citral

A 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.