Please email us as soon as possible at order@skindiligent.com and describe the problem. We will do our best to help you. If the order has not been shipped, it will be easier for us to help you. Once the order has been shipped, you will need to go through the return procedure.

After your order is shipped, our carrier will send you a tracking number by email.

We prefer to give you the freedom to buy products whenever you need them. But, if you create an account, you will receive discounts for your next order as well as other benefits.

Yes, we regularly deliver within the EU. Outside the EU, the receiving country may impose a tax or duty on the products. These additional costs will be at your expense. You will find all our delivery options here .

If you live in the UK, we strongly recommend purchasing directly from our English site skindiligent.com to avoid any taxes or customs delays post-Brexit.

Your satisfaction is important to us. If you wish to return or exchange an item, you have 14 days from the date you receive your order.

For a return to be accepted, the product must be unused, in its original condition, with its original packaging, and accompanied by proof of purchase (such as your order confirmation email).

To request a return, simply write to us at commande@skindiligent.com with the subject line "Return," stating your order number, your name, and the reason for the return.

Once your request is approved, we will provide you with instructions for returning the product. Return shipping costs are your responsibility, and the package remains under your responsibility until we receive it.

Upon receipt, we will inspect the returned product and inform you by email of the status of your request. If a refund is approved, it will be processed using the original payment method, excluding initial shipping costs.

If the original payment method is no longer available, we may offer you an exchange or store credit of the same value.

Please note that sale items and gift cards are not eligible for return.

For any questions, our team is available at: commande@skindiligent.com

If a product has been damaged during delivery, please write to us at commande@skindiligent.com with the subject "Return", specifying your order number, your name, and attaching a photo of the damaged product.

After verification, we will be able to offer you an exchange or a refund.

Email us at contact@skindiligent.com and we will get back to you as soon as possible.

Yes. At Skin Diligent, all our formulas are developed with particularly high safety requirements. Beyond excluding toxic or controversial ingredients, we have chosen to go further than the usual standards of European regulations.

All our skincare products are tested on their final formula to detect any potential endocrine-disrupting activities of an estrogenic type, using a specific test called OEDT. This very strict formulation charter means that our products are suitable for pregnant and breastfeeding women, as well as women who have had breast cancer.

Only the CEL™ Retinal Serum is not recommended during pregnancy, like all retinoid-containing skincare products.

Yes, all our products are vegan with the exception of our Regulation Serum, which contains propolis.

Yes. At Skin Diligent, we pay extreme attention to the safety of our formulas. Our final formulas are tested for the absence of endocrine disrupting activity, particularly estrogenic and androgenic types.

This requirement is an integral part of our approach and provides a particularly high level of safety for people concerned about the hormonal harmlessness of their skincare products.

Yes, and the two approaches complement each other.

How to combine:

• Before an injection: continue your routine as normal. Stop retinal 3–5 days before if your doctor performs microneedling (mesotherapy).
• After an injection: wait 48–72 hours before reintroducing retinal. Vitamin C Serum and moisturizer can be resumed from D+1.

Botox and fillers act on mechanics (muscle, volume). Epigenetics acts on cellular quality (firmness, density, radiance). These are two distinct levels of action. The combination of both tends to prolong the duration of effect of injections – skin with good cellular health better supports medical treatments.

If in doubt, speak to your practitioner.

DNA methylation is one of the main mechanisms by which your cells regulate gene expression. Specifically, small chemical groups (methyl groups) attach to certain areas of the DNA and act as switches: they can turn certain genes on or off, without ever changing the genetic sequence itself.

In the skin, this mechanism plays a key role in cellular aging. Over time, certain genes involved in collagen production, cellular repair, or antioxidant defense are progressively put to sleep by methylation changes. Epigenetic skincare partly aims to act on this biochemical environment to support more favorable gene expression, and preserve cellular functions longer.

Skin aging is not just a matter of time; it's also a matter of signals. Over the years, due to environmental exposures, stress, chronic inflammation, and endocrine disruptors, skin cells accumulate epigenetic modifications that alter their function.

Skin epigenetics relies on three main mechanisms:

• DNA methylation: chemical "switches" activate or deactivate key genes (collagen, repair, antioxidants)
• Histone modifications: proteins around which DNA is wrapped are modified, changing gene accessibility
• Micro-RNAs: small molecules that regulate the expression of many genes simultaneously

These three mechanisms are influenced by identified external factors: UV radiation, pollution, tobacco, chronic stress, ultra-processed foods, endocrine disruptors present in certain cosmetics, etc.

The epigenetic approach does not solely seek to correct visible signs after the fact. It acts upstream, on the cellular mechanisms that determine how the skin ages: by supporting repair pathways, limiting the accumulation of senescence markers, and helping cells maintain their functions for longer. It is this difference in depth of action that distinguishes epigenetic skincare from classic anti-aging.

Learn more: Dr. Barbara Brockway explores in this foundational article how the microbiome and epigenetics mutually influence each other — and why this double action is at the heart of our approach.

Exosomes are tiny vesicles – a kind of natural “capsule” – secreted by cells to communicate with each other. They transport proteins, lipids, growth factors, and biological information from one cell to another, playing a central role in repair, regeneration, and inflammation regulation processes.

Their size (30 to 150 nanometers, about 1,000 times smaller than a red blood cell) allows them to penetrate the deeper layers of the skin – where large molecules cannot reach. This makes them particularly effective information vectors in cosmetics.

In cosmetics, their interest is twofold: they are capable of efficiently penetrating the deep layers of the skin, and they directly provide cells with targeted repair signals – notably tight junction proteins that strengthen the skin barrier, reduce water loss, and support skin recovery overnight.

In Exosome Advanced Cream, they work to support these tight junctions, the skin barrier, and durably improve skin quality and resilience.

Inflammaging is a term from gerontology research, coined from "inflammation" and "aging." It refers to a state of chronic, low-grade inflammation—silent, persistent, and without apparent symptoms—that gradually develops with age and accelerates cellular aging.

In the skin, this underlying inflammatory state leaves lasting epigenetic imprints: it reduces cells' ability to repair themselves, accelerates their entry into senescence, degrades collagen, and weakens the skin barrier.

Visible signs of inflammaging include: skin that easily reddens without apparent cause, uneven texture, diffuse loss of firmness, progressively developing hyperpigmentation, and increasing sensitivity to external aggressors. These symptoms are often attributed to "age," when they actually reflect an underlying chronic inflammatory state—which can be modulated.

Many factors amplify inflammaging: chronic stress, lack of sleep, ultra-processed foods, exposure to pollutants—and endocrine disruptors present in some cosmetic products.

This is one of the reasons why Skin Diligent has made formulating without endocrine disruptors a non-negotiable commitment: acting on the skin's epigenetic health also means not introducing molecules that fuel inflammaging.

Inflammaging is one of the cellular mechanisms that longevity researchers seek to modulate. Our article on skin biohacking explores the available levers for action.

Retinol, retinal, and tretinoin are three forms of vitamin A with very different levels of efficacy and tolerance.

The conversion chain: your skin must convert retinol into retinal, then retinal into retinoic acid (the biologically active form). Each conversion step results in a loss of efficacy.

• Retinol: 2 conversions needed.
• Retinal: Only 1 conversion. Up to 11x more effective than retinol according to studies - which is why Skin Diligent chose it for CEL™ Retinal.
• Tretinoin: No conversion, immediate action. Prescription-only in France. Can cause significant irritation and peeling.

For sensitive or mature skin, retinal offers the best balance of efficacy and tolerance.

If you have sensitive skin, our comprehensive article explores how to choose the right retinoid and gradually integrate it based on your tolerance.

A classic anti-aging treatment only acts on the symptoms: it hydrates, plumps, and masks wrinkles. The effect stops when you stop using the product.

An epigenetic treatment acts on the surface but also on the cause: it sends signals to cells to modify their behavior and slow down the mechanisms of aging at the gene expression level.

• Classic anti-aging: targets only visible symptoms, filling/hydrating mechanism, effect during application, immediate but superficial results.
• Epigenetic Skin Diligent: targets cellular gene expression, DNA methylation and cell signaling mechanism, progressive results that amplify over time, structural effects.

The Skin Diligent approach does not reject classic active ingredients — it selects them based on their ability to positively influence the skin's epigenome, in addition to their surface action.

The Quintet is Skin Diligent's most comprehensive anti-aging protocol. It combines 5 advanced formulas to target the signs of aging at their source: hydration, antioxidant protection, cell renewal, collagen stimulation and cell longevity.

In the morning:
The Hydration and Vitamin C Serums in the morning will provide the 3 essential elements for your skin's health: hydration, the right antioxidants and the maintenance of your skin microbiome.

1. Cellular Hydration Serum over the entire face. It hydrates the skin, helps maintain its comfort and supports the skin microbiome.
   
2. Vitamin C Oil Serum over the entire face. It provides antioxidant protection, helps restore radiance and improves comfort.
   
3. Sunscreen if exposed to the sun during the day
   

In the evening:
The evening products, the cleanser, the CEL Retinal serum and the Exosome Advanced cream will directly address the signs of aging, namely elasticity, firmness and reduce the depth of wrinkles.

1. Triple Action Cleanser: cleanses the skin without stripping it. In the evening, it removes residue accumulated during the day while respecting sensitive or fragile skin.
   
2. CEL™ Retinal Serum: this is the most relevant serum to act on the visible signs of aging. It helps support skin renewal, skin quality, firmness and the appearance of wrinkles.
   
3. Exosome Advanced Cream: it complements the retinal by providing comfort, repair and support for the skin barrier. It helps the skin recover better overnight.
   

This protocol supports skin health in the morning with hydration and antioxidants, then acts in the evening on longevity, more directly on firmness, elasticity, wrinkles and overall skin quality.

Discover the protocol: Link

If you want to start simply, we recommend the following first:

Evening

1. CEL™ Retinal Serum
2. Exosome Advanced Cream
   

This is the most relevant duo for targeting visible signs of aging, particularly wrinkles, sagging, and loss of skin quality, while also broadly supporting cellular longevity.

For acne-prone skin, we recommend a simple, regular, and non-aggressive routine that helps rebalance the skin without over-burdening it.

ACNE KIT Routine

Morning

1. Skin & Stress: take 3 capsules once a day, preferably with breakfast, with a large glass of water
   
2. Triple Action Cleanser: apply a pea-sized amount to damp skin, gently massage for about 30 seconds, then rinse thoroughly
   
3. Regulation Serum: apply locally to pimples and the surrounding area, then let dry for 1 minute before the rest of the routine
   
4. Sun protection if exposed to sun during the day
   

Evening

1. If you wear heavy makeup, first use a gentle makeup remover
   
2. Triple Action Cleanser
   
3. Regulation Serum on affected areas, then let dry for 1 minute
   

Why this routine?

• Skin & Stress acts from within to support the skin in a more holistic way, especially when imperfections are linked to stress or an inflammatory condition.
  
• Triple Action Cleanser cleanses without aggressing or stripping the skin, which is essential for acne-prone skin often weakened by overly aggressive routines.
  
• Regulation Serum targets imperfections, excess sebum, post-acne marks, redness, and localized irregularities.
  

The idea behind the ACNE KIT is to act 360°, both from the inside and the outside, while remaining compatible with sensitive skin.

If your acne is hormonal, our article explains in detail how hormonal fluctuations trigger breakouts and how to address them sustainably.

The duration depends on many factors. The most important is the regularity of use. You should use the care products morning and evening and take the dietary supplements every day. If you use sunscreen or heavy makeup, we recommend using a gentle makeup remover before starting the routine.

On average, you should expect to use the Acne-Prone Skin kit for 2 to 4 months to see results. But it can be quicker or slower depending on your case. Simply put, the duration of use is directly proportional to the severity of the acne and how long it has been on your skin. You can see the photos of our testimonials here to get an idea.

Other factors that will affect the speed of progress include an anti-inflammatory diet (choose foods rich in antioxidants like green vegetables), your stress level, moderation of bad habits (avoid snacks like chips or cookies or sugary bars), the quality of your sleep and your lifestyle while using the kit.

The kit is effective for both young people and adults.

To learn more about the differences and similarities between juvenile acne and adult acne, click here .

For skin prone to rosacea, we recommend a complete routine designed to act on several levels: soothe inflammation, rebalance the skin microbiome, limit water loss, and support skin barrier repair.

Morning:

1. Regulation Serum on affected areas
2. Wait approximately 1 minute
3. Cellular Hydration Serum on the entire face
4. Vitamin C Serum-in-Oil on the entire face
   

Evening:

1. Regulation Serum on affected areas
2. Wait approximately 1 minute
3. Cellular Hydration Serum on the entire face
4. Exosome Advanced Cream on the entire face
   

Why this routine?

• Regulation Serum: anti-inflammatory + antifungal + antibacterial.
  The combination of several acids - shikimic acid, cinnamic acid, lactic acid, and a tiny amount of salicylic acid - acts on fungal and bacterial skin issues (demodex and others). It also contains a cocktail of powerful anti-inflammatories.
• Cellular Hydration: regulates the skin's microbial barrier + anti-inflammatory.
  Hyaluronic acid hydrates and soothes the damaged skin barrier. Encapsulated probiotics help regulate the skin microbiome.
• Vitamin C Serum-in-Oil: anti-inflammatory + antioxidant.
  Vitamin C is an important ingredient in rosacea treatment, and the lipid form of our serum helps decrease trans-epidermal water loss, which is very high in rosacea-prone skin. Vitamin E and punicic acid also act as anti-inflammatories and antioxidants.
• Exosome Advanced Night Cream: repairs + regenerates.
  Ideal for repairing the skin barrier thanks to exosomes, rich in tight junction proteins. These proteins improve the quality of the skin barrier as well as the excessive water loss typical of rosacea-prone skin. The cream is also rich in anti-inflammatory ingredients such as zinc, magnesium, hyaluronic acid, and a small amount of shea butter.

If a simpler system is desired, you can remove the Cellular Hydration Serum (you will also find hyaluronic acid in the cream). Thus, the morning and evening routine will be the same: Regulation Serum, Vitamin C, and Exosome Advanced Cream.

The use of cold metal tools can also provide relief to the skin.

Regarding nutrition, it is recommended to prioritize all anti-inflammatory foods and foods that strengthen the immune system.

Yes. The CEL™ Retinal Serum has been formulated to offer the effectiveness of retinal with optimal tolerance, even for sensitive skin.

The retinal it contains is encapsulated in a natural resin of Protium heptaphyllum.

This encapsulation acts as a vegetable shield: it protects the molecule from oxidation, allows for progressive release into the skin and helps reduce the risk of irritation. The result is a highly bioavailable active ingredient, more effective than classic retinol, while remaining particularly well tolerated, even by sensitive skin. This slow diffusion helps limit the overstimulation often associated with more classic retinoids.

The formula is also enriched with CEL™ Complex, to support the skin, promote its tolerance, and preserve its balance. This is what makes the serum particularly suitable for sensitive skin, including acne-prone skin.

Yes! In addition to avoiding toxic products, at Skin Diligent, we have exceeded the standards of European regulations. We have tested all our skincare products to detect endocrine disruptions of the estrogenic type, thanks to a test called EMCDDA. A strict formulation charter, which makes our products safe for pregnant women, breastfeeding women and women affected by breast cancer.

We recommend storing the serum in a cool, dry place, away from direct sunlight. It does not need to be refrigerated.

Yes, Skin Diligent skincare is unisex. The preservative-free formula and lightweight texture that absorbs quickly without leaving a greasy finish make it ideal for all seasons and all skin types, including blemish-prone and sensitive skin!

Our Vitamin C serum contains a rare form of lipid-soluble vitamin C, Ascorbyl Tetraisopalmitate. This form is effective at 1-2%; at Skin Diligent, we have formulated it at 3%.

Unlike pure vitamin C in an aqueous base, which often requires higher concentrations to be effective, this form is less acidic and therefore generally better tolerated by the skin, including sensitive skin.

Yes. The Vitamin C Serum-in-Oil uses a rare form of lipid-soluble vitamin C, Ascorbyl Tetraisopalmitate, chosen because lipophilic derivatives are more stable and better suited to the skin barrier than pure vitamin C in an aqueous base. Conversely, classic L-ascorbic acid is hydrophilic, penetrates the skin less easily, and generally needs to be formulated at a pH below 3.5 to properly penetrate the skin, which can be more irritating for sensitive skin.

This is precisely why we chose an oil-based form, which is gentler and more comfortable to apply, while remaining effective.

If your skin is very reactive, you can still introduce it gradually, for example by mixing it with your cream for a few days.

To learn more about the benefits of vitamin C and how to choose a stable formulation suited to your routine, our complete guide gives you all the keys.