Table of Contents

What is A-vitamin and why is it important for the skin

How Retinol works in the skin

Time Controlled Diffusion – the core of modern retinol technology

Benefits of A-vitamin for various skin issues

Who is Retinol suitable for and who is it not

How to start using A-vitamin safely – step by step

Utilizing A-vitamin in salon treatments

A-vitamin and EU legislation – safe use

Combining with other skincare routines

Frequently Asked Questions

A-vitamin is one of the most effective and researched ingredients in skincare. Its ability to influence skin renewal and structure makes it a true cornerstone in modern cosmetics.

Skin Clinic At Kuulaa, we have been using A-vitamin-based products for over 30 years and have guided thousands of customers to find a suitable way to utilize this effective ingredient – safely and effectively.

In this article, we explain what A-vitamin does in the skin, why Retinol is its most effective form, and how Time Controlled Diffusion technology has made it even gentler and more effective.

Different forms of A-vitamin in cosmetics

When talking about A-vitamin in skincare, we practically mean retinoids – different derivatives of A-vitamin. These substances differ in how quickly and strongly they convert into their active form in the skin.

A-vitamin derivatives convert in the skin in stages as follows:

Retinyl esters → Retinol → Retinaldehyde (Retinal) → Active form of A-vitamin.

Each stage requires enzymatic conversion, and the fewer stages needed, the faster and stronger the effect is felt. At the same time, tolerance often decreases. This is why various forms of retinoids are used in cosmetics – the balance between effectiveness and gentleness can be tailored to different skin types.

Modern encapsulation and release technologies, such as Time Controlled Diffusion, have revolutionized the use of retinol: now its effectiveness can be preserved and released in a controlled manner without excessive irritation.

Each step requires enzymatic conversion, and the fewer steps needed, the faster and more potent the effect. At the same time, tolerance often decreases. For this reason, a variety of retinoid forms are used in cosmetics – the balance between effectiveness and gentleness can be tailored for different skin types.

Modern encapsulation and release technologies, such as Time Controlled Diffusion, have revolutionized the use of retinol: now its effectiveness can be maintained and released in a controlled manner without excessive irritation.

How Retinol Works in the Skin

Retinol works at the cellular level in the skin – it doesn't just work on the surface, but guides skin cells to behave more youthfully. When a Vitamin A derivative is applied to the skin, it gradually converts into an active form that the skin can utilize. This active form binds to cell receptors and initiates signaling pathways that directly affect cell function and renewal.

As a result, several simultaneous processes occur in the skin:

• Cell renewal accelerates: old, dull skin cells are replaced with new, healthy ones.
• Collagen and elastin production increases: the skin strengthens and its elasticity improves, resulting in fewer lines and firmer skin.
• The thickness of the epidermis strengthens: retinol improves the skin's structure from deeper levels and increases its resistance to external irritants.
• Melanin production balances: Vitamin A also affects pigment production, brightening the skin tone and reducing dark spots.
• Sebum and moisture balance harmonize: retinol supports the function of sebaceous glands, keeping the skin cleaner and more balanced.

In practice, these changes appear as a more even skin tone, reduction of fine lines, and a more radiant, vibrant skin. Regular use gradually makes the skin stronger, brighter, and more youthful – not by covering, but by supporting the skin's own renewal ability.

Each step requires enzymatic conversion, and the fewer steps needed, the faster and more potent the effect. At the same time, tolerance often decreases. For this reason, a variety of retinoid forms are used in cosmetics – the balance between effectiveness and gentleness can be tailored for different skin types.

Modern encapsulation and release technologies, such as Time Controlled Diffusion, have revolutionized the use of retinol: now its effectiveness can be maintained and released in a controlled manner without excessive irritation.

How Retinol Works in the Skin

Retinol works at the cellular level in the skin – it doesn't just work on the surface, but guides skin cells to behave more youthfully. When a Vitamin A derivative is applied to the skin, it gradually converts into an active form that the skin can utilize. This active form binds to cell receptors and initiates signaling pathways that directly affect cell function and renewal.

As a result, several simultaneous processes occur in the skin:

• Cell renewal accelerates: old, dull skin cells are replaced with new, healthy ones.
• Collagen and elastin production increases: the skin strengthens and its elasticity improves, resulting in fewer lines and firmer skin.
• The thickness of the epidermis strengthens: retinol improves the skin's structure from deeper levels and increases its resistance to external irritants.
• Melanin production balances: Vitamin A also affects pigment production, brightening the skin tone and reducing dark spots.
• Sebum and moisture balance harmonize: retinol supports the function of sebaceous glands, keeping the skin cleaner and more balanced.

In practice, these changes appear as a more even skin tone, reduction of fine lines, and a more radiant, vibrant skin. Regular use gradually makes the skin stronger, brighter, and more youthful – not by covering, but by supporting the skin's own renewal ability.

Benefits of Vitamin A for Various Skin Problems

Vitamin A balances skin function, brightens, and firms. It supports the skin's natural repair ability and prevents premature aging. Regular use helps to reduce lines, diminish pigment changes, and improve skin texture.

Who is Retinol Suitable For and Who Is It Not

Retinol is suitable for almost everyone who wants to improve skin texture and tone. Encapsulated retinol is particularly suitable for sensitive skin and those who want effectiveness without irritation.

However, the use of Vitamin A is not recommended during pregnancy and breastfeeding.

How to start using vitamin A safely – step by step

1. Start with a low concentration and use the retinol product initially 1–2 times a week.
2. Gradually increase the frequency as your skin gets used to it.
3. Always apply to dry skin and add a moisturizing cream on top.
4. Use sunscreen during the day (at least SPF 30).

Utilizing vitamin A in clinic treatments

The best results are achieved when a home vitamin A routine is combined with a professional treatment. Skin Clinic At Kuulas, we offer treatments that utilize different forms of vitamin A safely and effectively – always according to the individual needs of the skin.

DELTA Quadraction Retinol Peel

An effective yet gentle peeling treatment that utilizes 3% retinol and Time Controlled Diffusion technology. The treatment renews the skin in two phases: first, liposomal retinol activates cell renewal, and then delayed release continues the effect for several hours. The result is brighter, smoother, and firmer skin with almost no recovery time.

DELTA A Vitamin (Age Reverse) Skin Supplement

This supplement enhances the effects of vitamin A and boosts skin renewal. It contains Time Controlled Diffusion retinol, vitamins C and E, and peptides that support the skin's protective functions and brighten the skin. After the treatment, the skin is calm, radiant, and more receptive to home care products.

Vitamin A and EU legislation – safe use

The EU cosmetics legislation defines the safe concentrations of vitamin A derivatives. All approved products undergo comprehensive safety assessments to ensure they can be used long-term without adverse effects. Therefore, it is advisable to purchase vitamin A products from a knowledgeable online store or clinic that can guide their proper use and select the appropriate concentration according to skin type.

Combining with other skincare routines

Vitamin A works best when it is part of a deliberate skincare routine. Traditionally, retinol has been used in the evenings, but with encapsulated retinol, it is also possible to use it in the morning. Time Controlled Diffusion technology releases retinol evenly over several hours, preventing sudden irritation and allowing the skin to tolerate vitamin A much better.

Evening routine

Evening use is still the safest and most effective way to start. Cleanse the skin thoroughly, let it dry, apply the encapsulated retinol product, and add a moisturizing cream on top. Niacinamide, hyaluronic acid, peptides, and ceramides are well-suited to support the skin's barrier and prevent dryness.

Morning routine for advanced users

Once the skin is accustomed to vitamin A (usually after 6–8 weeks of regular use), encapsulated retinol can also be used in the morning. This supports skin renewal and provides additional protection against oxidative stress during the day. In the morning routine, retinol is always followed by sunscreen (at least SPF 30) – it is the most important part of using vitamin A regardless of the season.

Frequently Asked Questions

How quickly will I see results?
The first changes are visible in 4-6 weeks, significant results after about three months of use.

Can I use retinol in the summer?
Yes, you can – as long as you remember sun protection. Previously, the use of retinol was often avoided during the summer season, but modern encapsulated retinol has changed the situation. Its Time Controlled Diffusion technology releases vitamin A slowly and controlled, so the skin does not become sensitive to the sun in the same way as with traditional retinol products. Encapsulated retinol can be used both in the morning and evening, as it works evenly in the skin for up to 8 hours and is very well tolerated. Morning use supports skin renewal and protects against daily stress, while evening use enhances the repair process that occurs overnight. If you are a beginner, start cautiously: use the product initially in the evenings 1-2 times a week and gradually increase the frequency as your skin gets used to it. Once the skin has adapted (usually within 6-8 weeks), you can switch to regular morning and evening use. Sun protection (at least SPF 30) is always essential during the day – even in cloudy weather.

Is retinol suitable for sensitive skin?
Yes, especially encapsulated retinol is suitable for most skin types.

Why might the skin peel initially?
It is a sign of cell renewal – the skin's adaptation phase is temporary.

Can I combine retinol with other active ingredients?
Yes. Retinol works well together with ingredients like niacinamide, peptides, and hyaluronic acid, which help strengthen the skin's barrier and maintain moisture balance. However, be cautious with exfoliating acids (such as AHA, BHA, and PHA acids) – use them on different nights to prevent excessive irritation.

Can I use retinol during pregnancy?
Vitamin A is not recommended during pregnancy or breastfeeding.