THE QUARTET
Achieve beautiful skin with just four products. The Quartet is a complete skincare system that trains your skin like a 2-minute cellular workout morning and night, leaving it healthier—and therefore naturally more beautiful and radiant. It provides everything your skin needs to hydrate, protect, and regenerate, for a smoother, clearer, and visibly healthier complexion.
- A more even and radiant complexion.
- Hydrated, plump, smoother skin.
- Strengthened skin barrier: less dry, less reactive skin.
This kit contains: Triple Action Cleanser 45 ml, Cellular Hydration Serum 30 ml, Vitamin C Serum-in-Oil 30 ml, Exosome Advanced Night Cream 50 ml.
Assets
Ingredients
Triple Action Cleanser 45 ml
Glycerin, Aqua, Sodium cocoyl isethionate, Sodium methyl cocoyl taurate, Helianthus annuus seed oil, Protium heptaphyllum resin, Salicylic acid, Lactobacillus ferment, Menthol, Parfum (100% natural origin and does not contain any of the 26 allergens regulated by the EU).
Preservative-free formula.
Cellular Hydration Serum – 30 ml
Aqua, Propanediol, Glycerin, Inulin, Helianthus annuus seed oil, Protium heptaphyllum resin, Caesalpinia spinosa gum, Sodium hyaluronate, Aloe barbadensis leaf juice powder, Magnesium Chloride, Saccharomyces/Grape ferment extract, Lactobacillus ferment, Coco glucoside, Decyl glucoside, Ethyl lauroyl arginate HCl, Sodium citrate, Sodium benzoate, Perfume (100% natural origin)
Vitamin C Serum-in-Oil – 30 ml
Cannabis sativa seed oil*, Theobroma cacao extract, Brassica napus extract, Camelina sativa seed oil*, Ascorbyl tetraisopalmitate, Punica granatum extract*, Helianthus annuus seed oil, Moringa oleifera seed oil, Protium heptaphyllum resin, Parfum
*Ingredients from organic farming
100% natural fragrance
Exosome Advanced Night Cream 50 ml
Aqua, Balanites roxburghii seed oil*, Glycerin, Camelina sativa seed oil, Propanediol, Simmondsia chinensis seed oil, Butyrospermum parkii butter*, Cetearyl alcohol, Camelina sativa seed extract, Glyceryl behenate, Sodium stearoyl glutamate, Lactobacillus extracellular vesicles, Magnesium chloride, Zinc lactate, Anacardiumouest (cashew) extract*, Rosmarinus officinalis leaf extract*, Sodium hyaluronate, Xanthan gum, Helianthus annuus seed oil*, Glyceryl caprylate, Parfum (100% natural), 1,2-Hexanediol. *Ingredients from organic farming.
Packaging
WHAT MAKES THE DIFFERENCE.
DESIGNED FOR MORNING BIOLOGY.
During the day, skin switches to defense mode. The Duo meets its essential needs first thing in the morning to help it better cope with oxidative stress, UV rays, and external aggressors.
4 NEEDS. 2 FORMULAS.
Hydration, nourishment, antioxidant defense and microbiome balance: two complementary formulas, one aqueous and one oily, to address all four at once. No need for a day cream anymore.
Tested for the absence of estrogenic and androgenic endocrine disruption.
VISIBLE RESULTS, SCIENTIFICALLY VALIDATED.
more hydrated skin*
healthier and more even skin*
prevention of blemishes and breakouts*
reduction of fine lines
*Based on a 28-day clinical study of 20 men and women aged 18 to 60, using Vitamin C Serum-in-Oil once daily.
TESTED TO BE FREE OF OESTROGENIC ENDOCRINE DISRUPTION
Some substances can disrupt the natural functioning of our hormones: these are known as endocrine disruptors. Looking at each ingredient separately is not enough. Once combined in a single formula, they can interact and produce a different effect. This is what we call the cocktail effect.
This is why we test each product in its final formula, exactly as it will be applied to the skin.
DID YOU KNOW?
To truly hydrate the skin, you must act in two stages.
First, provide water to the skin to plump it up and restore its bounce. Then, help retain this water with lipids, in order to limit its evaporation and strengthen the skin barrier.
This is why the DUO combines an aqueous serum with an oil: the former hydrates intensely, while the latter helps seal in moisture while providing antioxidant protection.
Two complementary steps for enhanced, longer-lasting hydration, and skin that is better protected throughout the day.
FAQ - FREQUENTLY ASKED QUESTIONS
What results can I expect, and when?
From the very first applications, skin appears more hydrated, supple, and plump. With daily use, the two formulas work complementarily to support the skin barrier and protect the skin from oxidative stress throughout the day. Our tests, conducted after 28 days of daily use, show an overall improvement in skin quality and health.
Does the Bi-Phase Duo replace a day cream?
Yes. The Cellular Hydration Serum provides water, while the Vitamin C Serum-in-Oil helps retain it thanks to its lipid base.
This combination provides the skin with hydration and comfort without the need for an additional day cream. You simply need to apply your SPF afterward.
Can I use both serums separately?
Yes. Each formula can be used on its own and has its own benefits.
Why use the Bi-Phase Duo in the morning?
During the day, the skin must contend with UV rays, pollution, and oxidative stress. It is also the time when it mobilizes its natural defense mechanisms.
The Bi-Phase Duo was designed with this biology in mind: to hydrate, support the skin barrier, and provide antioxidant protection right from the start of the day.
Can vitamin C be used in the morning?
Yes. Skin Diligent uses a stable, lipidic form of vitamin C, Ascorbyl Tetraisopalmitate, which is resistant to oxidation and is not photosensitive.
It is particularly well-suited for morning use, when the skin is more exposed to oxidative stress.
Can I apply my SPF and makeup over it?
Yes. First, apply the Cellular Hydration Serum to slightly damp skin, followed by the Vitamin C Serum-in-Oil. Once the formulas have been absorbed, finish with your sun protection.
Makeup can then be applied as usual.
Is the Bi-Phase Duo suitable for sensitive skin?
Both formulas have been designed to prioritize efficacy and tolerance. The vitamin C used by Skin Diligent is a non-acidic form, better suited to skin that does not tolerate traditional forms well.
In the case of particularly reactive skin or known allergies, it is always preferable to introduce any new skincare product gradually.