There’s always excitement with products like Clarins Double Serum ($85, amazon.com), which promises to smooth, strengthen, and brighten skin. But what really counts is whether the ingredients can live up to that promise. In their self-reported studies, 197 women reported a more even skin tone and less visible pores in four weeks. And out of 50 women, 90% said they preferred Clarins Double Serum to their regular serum.

But it’s the ingredients that count and exactly how proven they are. Many of Clarins ingredients aren’t as well-researched as the well-known classics. That doesn’t mean they won’t work. It just means we need more research to understand exactly how they work and what effects they have.

Katafray Extract

Clarins’ katafray extract comes from a tree found in Madagascar known as Cedrelopsos grevei, and is sometimes called katrafray (Clarins, Natural Product Communications). Whether this bark does make skin soft and strong hasn’t been backed by data. It’s used in traditional medicine for a variety of reasons, most notably on wounds and skin infections (Timbers I).

Clarins, along with several publications, claim that katafray bark works to hold in moisture and improve skin barrier function, but there’s little actual scientific evidence to back these claims (Clarins, Cosmetics & Toiletries). And don’t let the idea that it grows in dry, sub-arid climates make you think it will impart these qualities onto your skin. We definitely need more research on this one.

Kiwi (Fruit)

Kiwifruit, found in China and New Zealand, is often used in cosmetics for its scent, but also because it serves as an emollient with high essential fatty acids (Omega-3 from alpha-linoleic acid) and antioxidants (A Consumer Dictionary of Cosmetic Ingredients). In fact, the fruit has been touted recently for purportedly having more antioxidants than green tea, which has been proven to have a beneficial effect on skin (Cosmetics Design). The only fruits with more antioxidants are strawberry, plum, orange, and red grapefruit (Agricultural and Food Chemistry).

Because there’s limited research, we don’t know exactly what kiwi will do for skin. Like katafray, it’s possible that it’s the wonder fruit many claim it to be, but that awaits the research and testing. Most studies have been devoted to increasingly common kiwi allergies (Clinical & Experimental Allergy, Pediatric Allergy Immunology). For this reason, it’s important to patch test this product on your skin.

Pistachio Nuts

Pistachio nuts are generally found in Central and West Asia, as well as in the Mediterranean basin. It’s considered one of the 50 foods with the highest antioxidant potential (Biochimie). These nuts have a high level of phenolic compounds, have good free-radical scavenging capabilities, and also contain beta-carotene and tocopherol (Science Daily). The skins in particular are antioxidant-packed. When applied topically, pistachios have a photoprotective effect, reducing UVB-induced erythema (Fitoterapia).

Nut allergies are one of the most common food allergies, and if you have an allergy to other kinds of nuts, you might be sensitive to pistachio nuts as well (Clinical and Experimental Allergy, Clinical and Experimental Allergy). Be sure to patch test to be sure that this serum won’t cause allergic reaction.

Musk Rose

Musk Rose is an emollient that has good antioxidant properties (Natural Product Radiance). It’s known for having a high proportion of fatty unsaturated acids, such as linoleic, oleic, and linolenic acids, along with carotenes, tocopherols, and tretinoin (Tocopherol Treatment of Psoriasis). Ideally, this helps the skin to increase production of elastin and collagen, improving the texture and appearance of skin.

A study don’t at the University of Conception in Chile found that oil from the musk rose helped to heal skin and reduce signs of aging in the 180 participants, all of whom had premature aging, scarring from UV damage, burns, surgery, or trauma (Healthy Beginnings Magazine). At first it was assumed that this was because of the fatty acids, but another study uncovered the presences of tretinoin.

Though there aren’t many studies on the musk rose, those that do exist show excellent results.

Green Banana

Banana’s have fewer antioxidants than kiwi, but still enough to be rated one of the top fruits (Agricultural and Food Chemistry). They have a healthy dose of vitamins A, C, and E, as well as beta-carotene, selenium, and lutein. And bananas, particularly unripened, green ones, have been shown to help heal ulcers faster and better (Indian Journal of Experimental Biology, British Journal of Pharmacology).

The one downside is that bananas — like kiwis and nuts — can be an allergen, particularly for those who already suffer from latex allergies (Journal of Clinical Immunology). For this reason, you should consider patch testing this product before using it.

Bottom Line

Clarin’s Double Serum has plenty of promising ingredients. They’re not as well tested as some of the classics, but further research will help us understand what they do and how well they work. There are quite a few potential allergens in this product, so it’s important to patch test before regular use. Otherwise, if you like to be the first of your friends to try something new, this might just be a product that you want to try.