Kiehl’s is a brand of body, hair, and skin care products with roots that date back an impressive 167 years. Back then, Kiehl’s was just a single pharmacy in New York’s East Village. Today, Kiehl’s has more than 250 stores worldwide and is a multi-million dollar company. Kiehl’s formulates a variety of different products that treat the most common skin concerns, including acne, dry skin, dull complexion, enlarged pores, sensitive skin, signs of aging, and more. The following discussion will cover Kiehl’s vitamin C products, which can help address dull complexion and signs of aging like fine lines and wrinkles.
Kiehl’s currently makes five products that contain vitamin C, which include the following:
- Clearly Corrective Dark Spot Solution
- Clearly Corrective Brightening & Smoothing Moisture Treatment
- Powerful-Strength Line-Reducing Concentrate
- Powerful-Strength Line-Reducing Eye-Brightening Concentrate
- Facial Fuel Energizing Moisture Treatment for Men
You may have heard that vitamin C is one of the best ingredients to look for in a skin care product due to its ability to brighten and firm the skin. But is this claim true? It turns out there is a plethora of scientific data demonstrating that topically applied vitamin C can improve complexion by protecting the skin from free radicals, stimulating collagen synthesis, and inhibiting melanin production.
Vitamin C exerts potent antioxidant activity. Like other antioxidants, vitamin C is capable of protecting the skin from free radicals and reactive oxygen species (ROS). Specifically, vitamin C donates electrons to neutralize ROS such as the superoxide ion and peroxide that are generated when the skin is exposed to UV light. This is important because the harmful effects of ROS occur as direct chemical alterations of the cellular DNA, the cell membrane, and cellular proteins, including collagen. Damaged collagen manifests as signs of premature aging of the skin, including wrinkles, lines, and sagging skin. Therefore, vitamin C’s ability to protect collagen within skin makes it an ideal ingredient to include in anti-aging skincare products.
Another mechanism behind the capability of vitamin C to reduce signs of aging is through collagen synthesis. Vitamin C serves as a cofactor for two enzymes involved in the biosynthesis of collagen. Once again, by increasing the amount of collagen in the skin, signs of aging will be diminished and the skin will appear more firm.
Lastly, vitamin C can decrease the appearance of dark spots and improve uneven skin tone through inhibition of melanin synthesis. Melanin is a pigment that gives our skin color, but too much of this pigment can lead to undesirable dark spots called hyperpigmentation. Vitamin C inhibits action of the enzyme tyrosinase, which thereby decreases formation of melanin.
In order to understand the key formulation behind Kiehl’s vitamin C products, it’s important to explain the different types of vitamin C that are used in each.
Kiehl’s formulates several of their products with L-ascorbic acid, or pure vitamin C. This is the most chemically active form. It is easily absorbed into the skin and begins working immediately. It is frequently used in anti-aging products to improve radiance and skin texture while diminishing the appearance of fine lines, wrinkles, and crow’s feet. L-ascorbic acid exerts high antioxidant activity, acts as a coenzyme for enzymes involved in collagen synthesis, and inhibits the synthesis of melanin.
Despite these benefits of L-ascorbic acid, there are a few drawbacks to this form of vitamin C.
L-ascorbic acid is actually the least stable form of vitamin C, which means that it oxidizes the easiest. When vitamin C becomes oxidized it loses its potency and ultimately becomes ineffective. Things like sunlight, heat, air, water, and time can all lead to the oxidation of L-ascorbic acid. Additionally, L-ascorbic acid causes the most skin irritation out of all forms of vitamin C. This happens because L-ascorbic acid is an acidic molecule and can only penetrate the skin at a pH of 3.5 or less. Since the normal pH of skin is about 5.5, this low pH can be harsh on the skin. These two factors are important to keep in mind when choosing a vitamin C product from Kiehl’s as their Powerful-Strength Line-Reducing Concentrate uses 10.5% of L-Ascorbic Acid, and it is also found in the Line-Reducing Eye-Brightening Concentrate.
Another form of vitamin C utilized by Kiehl’s is ascorbyl glucoside. This ingredient has a structure in which the C2-hydroxyl group of L-ascorbic acid is masked with glucose. Ascorbyl glucoside has been found to have greater stability in the presence of air, heat, light, and pH changes than L-ascorbic acid. After being absorbed into the skin, ascorbyl glucoside is broken down into L-ascorbic acid. Therefore, ascorbyl glucoside has many of the same benefits as L-ascorbic acid. Kiehl’s uses ascorbyl glucoside in the Powerful-Strength Line-Reducing Concentrate and the Facial Fuel Energizing Moisture Treatment for Men.
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The last form of vitamin C that Kiehl’s uses is called activated C, a next-generation vitamin C derivative that is highly efficacious. According to Kiehl’s, this powerful form of vitamin C penetrates skin and is proven to effectively fade acne marks and age marks, as well as reduce skin discolorations. Activated C is a key ingredient in the Kiehl’s Clearly Corrective Dark Spot Solution and Clearly Corrective Brightening and Smoothing Moisture Treatment.