Sunscreen, antioxidants, and the skin barrier: Dr. Sofia Borges' summer guide.

Have you ever noticed how sometimes a small daily gesture makes all the difference to your skin? That's exactly what we talked to Dr. Sofia Borges , a specialist in Dermato-Venereology, about.

Dr. Sofia is a dermatologist at the MyMoment Clinic in Lisbon, specializing in acne, rosacea, melasma, and skin rejuvenation. She is also the creator of the exclusive My Skin Revive® protocol. But more than her titles, what defines her is how she approaches each patient: with empathy and honesty, without miraculous promises, helping you take care of your skin (and your self-esteem) in a real and sustainable way.

In this interview, Dr. Sofia will tell you everything you need to know to protect your skin this summer: how and when to reapply sunscreen, why it should be part of your daily routine all year round, the role of antioxidants and vitamin C, and also how to repair your skin barrier after a day at the beach or pool.

1. Why is it so important to increase skincare routines during the summer?

Summer is the time of year when we are most exposed to ultraviolet radiation, and therefore, skin care becomes even more important. The sun is one of the main causes of skin aging because it causes direct damage to cells and increases oxidative stress, accelerating the appearance of wrinkles, blemishes, and loss of elasticity.

But the most important thing to remember is that this damage isn't just cosmetic. Excessive sun exposure also increases the risk of skin cancer, which is the most common type of cancer in many countries.

Therefore, during the summer we must reinforce all sun protection measures. It's not just about avoiding sunburn; it's about protecting skin health in the short and long term.

2. Why should sunscreen be part of your daily routine, even when you're not at the beach or pool?

Because ultraviolet radiation is present far beyond just beach days. Whenever we go outside, even for a short walk, to drive, or to go to work, we are exposed to UV rays.

Furthermore, UVA rays, which are the main cause of skin aging, are present year-round. They penetrate clouds and glass, so we remain exposed even inside a car or near a window.

That's precisely why sunscreen should be seen as a daily routine, just like brushing your teeth. It's not just a vacation product; it's a daily preventative habit.

3. How often should we reapply sunscreen?

One of the most frequent questions is whether applying sunscreen in the morning is enough. The answer is: it depends on the sun exposure.

If we are in our daily lives, especially indoors, without significant sun exposure, one application in the morning may be sufficient.

But if we are at the beach, by the pool, walking, doing outdoor sports, or with prolonged sun exposure, sunscreen should be reapplied approximately every two hours. And also always after swimming, sweating a lot, or drying the skin with a towel.

Another very important point is the quantity. Many people use an excellent sunscreen, but apply half the necessary amount and end up not obtaining the protection factor indicated on the packaging.

For the face and neck, the rule of thumb is to use the equivalent of two fingers' worth of product. For the body, an adult needs, on average, about 30 ml, the equivalent of a shot glass, to ensure adequate protection.

4. Are there any other protective measures besides sunscreen?

There's an idea I really like to share: we shouldn't put "all our eggs in one basket" with sunscreen. Sunscreen is essential, but it's part of a photoprotection strategy.

Physical protection remains the most effective. Whenever possible, we should seek shade, wear wide-brimmed hats, sunglasses with UV protection, and lightweight, long-sleeved clothing. Today, there are very breathable fabrics that effectively protect against solar radiation.

I remember a trip I took to China in the summer, with temperatures above 40 degrees Celsius. I was struck by seeing most people completely covered in light-colored clothing, long sleeves, and even umbrellas. At first glance it seems strange, but it makes perfect sense: they were protecting themselves from solar radiation. We often only think about the heat, but the real problem is ultraviolet radiation.

If I could leave one message, it would be this: seek shade whenever possible. If one side of the street is shady and the other is sunny, choose the shade. These are small gestures that, repeated over the years, make a huge difference to skin health.

5. What is the role of antioxidants in skin health?

Antioxidants play a key role in protecting the skin because they help neutralize free radicals, molecules that are naturally produced by the body, but whose production increases with factors such as sun exposure, pollution, and tobacco.

When there is an excess of free radicals, oxidative stress occurs, which contributes to premature skin aging, favoring the appearance of wrinkles, blemishes, and loss of firmness.

Antioxidants help control this process, reducing cellular damage and contributing to healthier, more resilient skin. It's important to understand, however, that they don't work miracles or replace measures like sun protection. They function as part of a comprehensive strategy for preventing and maintaining healthy skin.

6. What is the role of vitamin C and what are its main benefits?

Vitamin C is undoubtedly one of the most studied antioxidants and has the strongest scientific evidence in dermatology. It helps protect the skin against oxidative stress caused, for example, by ultraviolet radiation, but it does not act alone.

In reality, antioxidants work as a team. Vitamin C works in conjunction with other antioxidants, such as vitamin E and glutathione, and this complementary action makes the skin's defense more effective.

In addition to its antioxidant action, vitamin C participates in collagen production and the reduction of melanogenesis (i.e., the appearance of dark spots) by inhibiting the tyrosinase enzyme, thus reducing some blemishes and restoring luminosity to the skin.

Therefore, it's a very interesting ingredient to incorporate into a skincare routine, but it should be considered a complement. It doesn't replace sunscreen or other photoprotective measures, which remain the foundation for preventing skin aging and sun damage.

7. Skin hydration and post-sun exposure care

In reality, many people even feel their skin is more comfortable in the summer because the ambient humidity is usually higher and sebum production increases with high temperatures, which reduces the feeling of dryness. However, this does not mean that the skin barrier is healthier or more hydrated, because sun exposure causes significant changes in the skin barrier. UV radiation induces oxidative stress and inflammation, alters the organization of lipids in the stratum corneum (such as ceramides, cholesterol, and free fatty acids), and increases transepidermal water loss (TEWL). In other words, although the skin may appear oilier, its barrier function may be compromised.

Furthermore, the sun is usually not the only aggressor. Chlorine from swimming pools and seawater also contribute to weakening the skin barrier.

• Chlorine: removes some of the protective lipids from the skin's surface, alters the skin's pH, and can increase irritation and dryness.
• Seawater: due to its high salt concentration, it exerts an osmotic effect, promoting water loss from the skin. Furthermore, when the salt dries on the skin's surface, it can further increase the feeling of dryness and irritation.

Therefore, a very simple gesture makes all the difference: taking a freshwater shower right after leaving the beach or pool, removing salt, sand, and chlorine residue before it remains in contact with the skin for too long.

8. How to repair the skin barrier?

The first step is always to prevent damage. It makes no sense to continually try to repair a barrier that continues to be damaged. This means: avoiding times of peak UV radiation; using sunscreen in adequate amounts; and reapplying as needed.

After sun exposure, care should focus on restoring the skin's barrier function. After-sun products can provide a pleasant feeling of freshness and temporarily relieve discomfort. However, on their own, they cannot rebuild the skin's barrier.

In practice, I like to maintain pretty much the same moisturizing routine that I use during the winter, using bath oil and emollient right after showering.

Why do you prefer bath oils? Unlike many shower gels, which use more detergent surfactants and remove some of the skin's natural lipids, bath oils contain much gentler cleansing agents and emollient ingredients. They effectively cleanse without depleting the skin's surface as much, better preserving the barrier and reducing water loss.

Which moisturizers should I choose? I prefer repairing formulas, many of them similar to those we use on atopic skin or even on babies, because they are usually fragrance-free and rich in ingredients that restore the skin barrier.

The ingredients with the best evidence include:

• Ceramides replenish the main lipids in the barrier.
• Cholesterol and essential fatty acids help rebuild the architecture of the stratum corneum.
• Glycerin - a humectant that attracts water to the outermost layer of the skin.
• Panthenol - with calming and restorative action.
• Niacinamide - stimulates ceramide synthesis, reduces inflammation, and improves barrier function.
• Shea butter and other emollients reduce water loss and leave the skin more comfortable.

Reinforcement: more than looking for a miracle product to repair skin after a day at the beach, the most important thing is to minimize the damage from the start.

9. Are there any ingredients that should be avoided during the summer?

The answer isn't a simple "yes" or "no." The most important thing is to distinguish between potentially irritating ingredients and ingredients that actually increase photosensitivity.

The ingredients that most frequently cause irritation during the summer are retinoids (such as retinol, retinal, or tretinoin) and some alpha-hydroxy acids, especially glycolic acid, because they accelerate cell renewal and can leave the skin temporarily more sensitive, particularly if the skin barrier is already weakened by sun exposure.

However, this does not mean that they should be suspended for the entire summer. On skin that is already adapted, that has been using them for months or years and that maintains adequate sun protection, there is no benefit in interrupting these active ingredients for three or four months. On the contrary, this interruption can lead to the loss of some of the results obtained and force a new adaptation period when they are reintroduced.

What makes sense is to adjust the routine, not necessarily stop the treatment: reinforce hydration, rigorously protect the skin from UV radiation and, if there is increased sensitivity after a day at the beach or pool, temporarily reduce the frequency of application or take a break of one or two days.

The main recommendation is different for those who have never used these ingredients. Summer is generally not the best time to start retinoids or exfoliating acids, precisely because the skin has not yet developed tolerance and there is a greater risk of irritation. Whenever possible, I prefer to start these treatments in the months with less sun exposure, allowing the skin to gradually adapt over the following months.

10. For those who want to maintain a simple and effective routine this season, what are the essential steps that should never be skipped?

For most of my patients, I don't change their routine from winter to summer. Many ingredients need an adaptation period, and constantly changing skincare routines ends up compromising long-term results. What I do is reinforce some fundamental pillars: in the morning, an antioxidant combined with sunscreen; and at night, a good moisturizer to help repair the skin barrier. At this stage, I also like to include soothing and repairing ingredients, such as niacinamide, ceramides, ectoine, or centella asiatica, which help reduce inflammation, strengthen the skin barrier, and minimize sun irritation.

11. Dr. Sofia Borges' 3 tips for this summer?

1. Seek shade. It remains the most effective form of sun protection. Sunscreen is essential, but it doesn't replace avoiding direct sun exposure, especially during peak sun hours.
2. Simplify sun protection. Don't follow trends or myths from social media. The sunscreens currently available, whether with organic filters, inorganic filters, or a combination of both, are safe and effective, and the best choice is always the one you can use correctly, every day.
3. If you like a tanned look, choose self-tanners. A tan is a sign that the skin has been damaged by UV rays. Although ideally we should value healthy skin rather than a tanned one, for those who like this effect, self-tanners are undoubtedly the safest alternative.