Glass Skin: The Rise of the K-Beauty Trend and Why Azelaic Acid and Tretinoin Are Getting So Much Attention

For years, aesthetic medicine has largely focused on reducing wrinkles, restoring volume and addressing visible signs of ageing. More recently, however, there has been a noticeable shift towards something slightly different: skin quality. The goal is no longer simply to look younger. Increasingly, people want skin that looks healthy, smooth, hydrated and naturally radiant, even without make-up. This has helped fuel the popularity of one of the biggest skincare trends of recent years, known as 'glass skin'.

Originating from Korean beauty culture, glass skin has become a global phenomenon, particularly across TikTok and Instagram, where skincare enthusiasts share routines promising a smooth, luminous complexion. Alongside this trend, two ingredients are receiving considerable attention: azelaic acid and tretinoin. Both have been used in dermatology for many years, but their combination is now being widely discussed as a way to improve skin texture, pigmentation and overall clarity.

So what exactly is glass skin, why has it become so popular, and is there any science behind the ingredients being recommended?

What Is Glass Skin?

Glass skin describes a complexion that appears exceptionally smooth, clear, hydrated and reflective, almost as though the skin has a glass-like finish. The idea is not necessarily to achieve completely flawless skin, but rather to improve its overall appearance through hydration, an even skin tone and a healthy skin barrier. Unlike the heavily mattified make-up looks that dominated previous beauty trends, glass skin celebrates a naturally dewy finish, with the emphasis placed on skincare rather than using cosmetics to conceal imperfections.

However, it is important to recognise that glass skin is a beauty description rather than a medical diagnosis or measurable clinical outcome. Skin naturally has pores, texture, fine lines and variations in pigmentation, all of which are normal features of healthy skin. Many of the extremely polished images seen online are also influenced by lighting, make-up, camera settings and digital editing. Real skin does not need to look completely poreless to be healthy.

Where Did the Glass Skin Trend Come From?

Glass skin has its roots in South Korea, where skincare has traditionally placed considerable emphasis on hydration, prevention and maintaining a healthy-looking complexion. Korean beauty, often referred to as K-beauty, became internationally recognised for its multi-step skincare routines, lightweight hydrating products, essences, serums and consistent sun protection. The original philosophy was less about aggressive treatments and more about maintaining skin health through regular care.

As Korean skincare brands gained popularity internationally, the concept of glass skin became increasingly visible across social media. What began as a particular beauty aesthetic gradually evolved into a much broader conversation about achieving clearer, smoother and more radiant skin. Today, the trend has moved beyond Korean skincare products to include prescription ingredients, professional skin treatments and increasingly sophisticated home skincare routines.

Interestingly, the latest approach to glass skin is often less about applying ten different products and more about choosing a smaller number of ingredients that address specific skin concerns.

Why Is Glass Skin So Popular Right Now?

Part of the appeal is that glass skin fits with a wider movement towards natural-looking aesthetic results. Rather than dramatic changes to facial appearance, many people are prioritising skin texture, pigmentation, hydration and overall complexion. Social media has played a significant role in this shift, with close-up skincare videos, before-and-after photographs and detailed product routines making consumers increasingly aware of ingredients that were once mainly discussed in dermatology clinics.

There is also growing interest in what is sometimes described as 'skin longevity', the idea of maintaining healthy skin function and appearance over time rather than simply trying to reverse visible ageing. This has brought ingredients such as retinoids, azelaic acid, niacinamide and ceramides into mainstream skincare conversations. However, while social media can be useful for discovering ingredients, it can also create unrealistic expectations. A skincare routine that works well for one person may be completely unsuitable for someone with sensitive skin, rosacea or an impaired skin barrier. The aim should be healthier skin, not simply chasing a particular appearance seen online.

Azelaic Acid and Tretinoin: The Skincare Duo Everyone Is Talking About

One of the more interesting developments within the glass skin trend is the growing interest in combining azelaic acid with tretinoin. Both ingredients are well established in dermatology, although they work in different ways. Tretinoin is primarily known for its ability to regulate skin cell turnover, treat acne and improve signs of photoageing, while azelaic acid is particularly useful for acne, inflammation, rosacea-related lesions and certain forms of pigmentation.

Used appropriately, they can complement one another, particularly in patients who have several overlapping skin concerns. For example, someone with acne, uneven skin texture and post-inflammatory hyperpigmentation may benefit from a treatment plan that addresses both the acne itself and the marks left behind. However, combining these ingredients is not automatically better for everyone. Both can cause irritation, and introducing them without considering skin type, concentration and tolerance can actually make the complexion look worse.

What Is Azelaic Acid and What Does It Do?

Azelaic acid is a naturally occurring dicarboxylic acid that has been used in dermatology for decades. It has anti-inflammatory, antimicrobial and pigment-regulating properties, making it particularly useful for people dealing with more than one skin concern. One of its main advantages is its versatility. Azelaic acid can help manage acne while also addressing the discolouration that may remain after spots have healed.

It works partly by reducing inflammation, influencing abnormal skin cell build-up within pores and inhibiting tyrosinase, an enzyme involved in melanin production. This makes it especially relevant for people who experience post-inflammatory hyperpigmentation, where acne or irritation leaves behind darker marks. Azelaic acid is also an established treatment for certain forms of rosacea, particularly the inflammatory bumps and spots associated with the condition. It may help reduce some associated redness, although persistent flushing and visible blood vessels often require different treatments.

Another area where azelaic acid may be beneficial is melasma, a pigmentation condition characterised by darker patches, commonly affecting the cheeks, forehead and upper lip. It is generally considered more tolerable than some stronger skincare ingredients, although stinging, dryness and irritation can still occur, particularly when treatment is first introduced. Azelaic acid is available in different concentrations, including cosmetic products and prescription formulations. In the UK, higher-strength preparations used to treat conditions such as acne and rosacea may require a prescription.

Azelaic acid is particularly useful for acne-prone skin, post-acne pigmentation, inflammatory rosacea and certain forms of uneven skin tone. For someone whose main concern is redness, acne marks or pigmentation rather than wrinkles, azelaic acid may be a more appropriate starting point than tretinoin.

What Is Tretinoin and Why Is It So Popular?

Tretinoin is a prescription-strength topical retinoid derived from vitamin A. Unlike cosmetic retinol, which must undergo conversion within the skin to become biologically active, tretinoin is already in its active retinoic acid form. It has been extensively studied for acne and photoageing and is one of the best-established topical ingredients for improving certain aspects of skin texture and appearance.

Tretinoin works by influencing skin cell differentiation and turnover, helping prevent blocked pores and reducing the formation of comedones, including blackheads and whiteheads. With longer-term use, it can also stimulate collagen-related processes and improve some of the visible effects of sun damage, including fine lines, uneven pigmentation and rough skin texture. This is one reason tretinoin has become so closely associated with the pursuit of glass skin.

However, tretinoin does not produce an instant glow. Improvements develop gradually, and the early stages of treatment can involve dryness, peeling, redness and irritation. Some people also experience an initial worsening of acne, although not every breakout after starting tretinoin should automatically be dismissed as purging. Tretinoin is a prescription medicine in the UK and should be used following an appropriate clinical assessment.

Tretinoin is particularly useful for acne, clogged pores, uneven skin texture and certain signs of photoageing, including fine lines and sun-related pigmentation. However, it is not necessarily the best option for everyone. People with very sensitive skin, active eczema, significant rosacea-related irritation or an already damaged skin barrier may struggle to tolerate it. Topical tretinoin should not be used during pregnancy or when planning pregnancy, and anyone who is pregnant, breastfeeding or considering pregnancy should discuss suitable alternatives with their clinician.

Can Azelaic Acid and Tretinoin Be Used Together?

Yes, azelaic acid and tretinoin can be used within the same skincare treatment plan, and the combination may be particularly useful for people dealing with acne alongside pigmentation or uneven texture. The reason they work well together is that they target different aspects of skin function. Tretinoin helps regulate skin cell turnover, reduce blocked pores and improve certain signs of photoageing, while azelaic acid helps address inflammation, acne and pigmentation. For someone with acne and post-inflammatory hyperpigmentation, this can be a useful combination because treating the active acne alone does not always resolve the marks it leaves behind.

However, there is an important distinction between two ingredients being compatible and everyone needing to use them together. Both can irritate the skin, particularly at higher concentrations or when introduced too quickly. Using them simultaneously without considering tolerance can lead to dryness, redness, peeling and a disrupted skin barrier. In some cases, that irritation may worsen pigmentation, particularly in people who are prone to post-inflammatory hyperpigmentation.

There is also less direct clinical research evaluating this particular combination for the cosmetic goal of glass skin than there is supporting the individual ingredients for established dermatological conditions. For this reason, the combination should be viewed as a potentially useful treatment approach rather than a guaranteed shortcut to a flawless complexion.

How to Use Azelaic Acid and Tretinoin in a Skincare Routine

For patients who have been assessed and advised to use both ingredients, a common approach is to use azelaic acid in the morning and tretinoin in the evening. This allows the ingredients to be incorporated into a routine without necessarily layering them together at the same time. A morning routine may include a gentle cleanser, azelaic acid if tolerated, a suitable moisturiser and broad-spectrum SPF 50 sunscreen. An evening routine may involve gentle cleansing, moisturiser and a small amount of prescribed tretinoin applied according to the clinician's instructions.

For those who are new to tretinoin, it is often sensible to introduce it gradually rather than using it every evening from the beginning. Some patients may benefit from using moisturiser before or after tretinoin to improve tolerability. The exact approach depends on the formulation, skin condition and individual response, so there is no single routine that suits everyone. I would generally avoid introducing several other potentially irritating ingredients, such as strong exfoliating acids or additional retinoids, at the same time. The priority should be maintaining a healthy skin barrier while allowing the active ingredients time to work.

How Long Does It Take to See Results?

One of the biggest misconceptions surrounding glass skin is that a dramatic improvement can be achieved within a few days. Hydrating products may make the skin appear temporarily plumper and more luminous quite quickly, but treating acne, pigmentation and uneven texture takes considerably longer. Azelaic acid may begin improving acne within approximately four weeks, although pigmentation and rosacea-related concerns can take several months to respond.

Tretinoin also requires patience. Acne improvement may take several weeks, while changes in fine lines, texture and photoageing often develop over three to six months or longer. Results vary depending on the skin concern, treatment concentration, consistency and individual tolerance. Using stronger products or applying them more frequently does not necessarily produce faster results. In fact, excessive irritation can delay progress.

Is Glass Skin Really About Using More Active Ingredients?

Not necessarily. One of the more positive aspects of the glass skin trend is the growing interest in skin health. However, there is also a risk that people begin using increasingly complicated routines in an attempt to achieve a particular appearance. Healthy skin depends on more than exfoliation and active ingredients.

The skin barrier plays an essential role in retaining moisture and protecting against environmental irritants. When that barrier becomes compromised, the skin may appear dull, red, dry or inflamed, even if someone is using expensive or medically active skincare products. For many people, a consistent routine built around gentle cleansing, appropriate moisturisation and daily sun protection can make a significant difference.

Ingredients such as glycerin, hyaluronic acid and ceramides can support hydration and barrier function, while niacinamide may help with aspects of skin tone and barrier health. Azelaic acid and tretinoin can then be considered where there is a specific indication, rather than simply because they are trending.

Ultimately, the most effective skincare routine is not necessarily the one containing the greatest number of products. It is the one that addresses the individual's concerns without compromising skin health.

My Perspective on the Glass Skin Trend

I think the increasing focus on skin quality is a positive development in aesthetic medicine. For a long time, conversations around facial rejuvenation have focused heavily on injectables and treatments designed to alter facial structure or volume. While these have their place, the quality of the skin itself is equally important. A smooth, well-hydrated and even complexion can make a significant difference to someone's overall appearance without necessarily changing their facial features.

However, I think we need to be careful about turning healthy skin into another unrealistic beauty standard. Pores, texture and natural variations in skin tone are normal. Even the healthiest skin will not look like a filtered photograph under every lighting condition.

Azelaic acid and tretinoin are both valuable ingredients with established medical uses. Their growing popularity is understandable, particularly because they address common concerns such as acne, pigmentation and uneven texture. But they are not miracle products, and combining them is not essential for achieving healthy skin. The most sensible approach is to identify what is actually contributing to someone's skin concerns and choose treatments based on their individual needs.

Glass skin may be the current trend, but good skin health should always be the longer-term goal.

Frequently Asked Questions About Glass Skin, Azelaic Acid and Tretinoin

What is glass skin?

Glass skin is a Korean-inspired beauty trend describing skin that looks exceptionally smooth, hydrated, clear and luminous. It focuses on achieving a healthy-looking complexion with minimal visible unevenness, although completely poreless skin is not a realistic biological expectation.

How do you get glass skin naturally?

A consistent skincare routine is the best starting point. Gentle cleansing, moisturising, daily sun protection and addressing specific concerns such as acne or pigmentation can improve skin quality over time. Good sleep and avoiding smoking also support general skin health. Prescription treatments are not necessary for everyone.

Can azelaic acid and tretinoin be used together?

Yes. They can be used in the same skincare routine when appropriate, particularly for acne and post-inflammatory hyperpigmentation. However, both can cause irritation, so it is important to introduce them carefully and follow professional guidance.

Should I use azelaic acid before or after tretinoin?

There is no universal rule because the best approach depends on the formulation and skin tolerance. Some people use azelaic acid in the morning and tretinoin at night, which can be easier to tolerate than applying both together.

Is azelaic acid or tretinoin better for pigmentation?

Both may help, but the most suitable ingredient depends on the cause of pigmentation. Azelaic acid can be particularly useful for post-inflammatory hyperpigmentation and melasma, while tretinoin may help with acne-related marks and certain forms of sun damage. Some patients may benefit from both under medical supervision.

Is azelaic acid good for rosacea?

Yes. Azelaic acid is an established treatment for inflammatory rosacea and can help reduce the bumps and spots associated with the condition. It may also improve some persistent redness, although it is less effective for flushing and visible blood vessels.

Can tretinoin help achieve glass skin?

Tretinoin can improve acne, uneven texture, fine lines and certain pigmentation concerns, all of which may contribute to a smoother-looking complexion. However, it does not guarantee a glass skin appearance and may initially cause dryness or irritation.

Does tretinoin make your skin thinner?

Tretinoin can initially affect the outermost layer of the skin and cause dryness or peeling. However, longer-term use has been shown to improve aspects of the skin's structure, including collagen-related changes in the dermis. The idea that tretinoin simply thins and damages the skin is misleading.

Can azelaic acid and tretinoin cause purging?

Tretinoin may cause an initial increase in acne lesions in some people as treatment begins. Azelaic acid can also cause irritation or temporary changes in the skin. However, not every breakout is purging. Persistent worsening, significant redness, burning or swelling should prompt a review of the routine.

Can I use azelaic acid and tretinoin every day?

Some people can tolerate daily use once their skin has adjusted, but this is not appropriate for everyone. Tretinoin is often introduced gradually, while azelaic acid frequency depends on the formulation and individual tolerance. Follow the instructions given by your prescribing clinician.

How long does azelaic acid and tretinoin take to work?

Acne may begin improving within four to eight weeks, although some people take longer. Improvements in pigmentation, fine lines and texture often require several months of consistent treatment. Results depend on the skin condition and how well the products are tolerated.

Can I use azelaic acid and tretinoin with vitamin C?

It may be possible, but combining multiple active ingredients increases the risk of irritation. For many people, a simpler routine is preferable, especially when first starting tretinoin. Additional products should be introduced only when there is a clear benefit.

Is tretinoin stronger than retinol?

Tretinoin is a prescription retinoid that acts directly on retinoic acid receptors in the skin. Retinol must first be converted into active retinoic acid, so it is generally less potent and often better tolerated. Stronger does not automatically mean more suitable.

Can I use tretinoin during pregnancy?

No. Topical tretinoin should be avoided during pregnancy and when planning pregnancy. Azelaic acid is often considered a suitable alternative for certain skin conditions during pregnancy, but any treatment should be discussed with an appropriate healthcare professional.

Do you need a 10-step Korean skincare routine for glass skin?

No. Although multi-step routines helped popularise K-beauty internationally, there is no evidence that using ten products is inherently better than a simpler routine. A gentle cleanser, moisturiser, sunscreen and carefully selected active ingredients may be sufficient.

What is the difference between glass skin and glazed donut skin?

Both trends focus on a luminous complexion. Glass skin generally refers to smooth, clear and evenly hydrated skin, while glazed donut skin places more emphasis on a glossy, moisturised finish. Neither term is a medical classification.

Is glass skin possible for oily or acne-prone skin?

Yes, oily and acne-prone skin can look healthy, smooth and radiant. However, the skincare approach should focus on managing excess oil, preventing clogged pores and treating inflammation rather than layering heavy products to create shine.

Is SPF necessary when using azelaic acid and tretinoin?

Yes. Daily broad-spectrum sun protection is important, particularly when treating pigmentation or using tretinoin. SPF 30 is a minimum commonly recommended by dermatologists, with SPF 50 often a practical choice for facial use. Sun protection also helps preserve improvements in skin tone and reduce further photoageing.

This article is intended for general education and does not replace individual medical advice. Prescription skincare should be selected following an appropriate clinical assessment, particularly for those with sensitive skin, existing skin conditions or pregnancy-related considerations.