Key points:

UVA and UVB radiation have different effects
Most sunscreens protect from UVB only, look for broad-spectrum labels
There are two categories: chemical and mineral sunscreens
Chemical ones might cause hormonal disruptions
Mineral ones are better, but nanoparticles are potentially problematic
Retinol is one of the best-known skincare ingredients to treat wrinkles

As the Northern hemisphere is approaching the peak of summer, many are just about to embark on their highly anticipated holidays. In the last week’s article, we discussed how tanning works and highlighted the fact that you should build up your tan gradually if you are planning an extended sun exposure.

Most people put on sunscreen for protection from harmful UV radiation and to reduce the risk of cancer. At least that’s the popular belief.

Let’s explore how safe sunscreen use is, what types are out there and how to use it.

UVA and UVB

Just a quick recap on the two UV wavelengths that affect our skin and consequently our health. The two types we usually talk about are UVA and UVB. The easy way to remember is A is for ‘ageing’ and B is for ‘burning’. The former will give you a nicer tan but penetrate deeper and make your skin wrinkly, the latter will give you sunburn and cancer much quicker. However, we need them both for our health, the key is in the dose.

When we talk about sunscreen’s SPF (sun protection factor) we are talking about blocking the UVB radiation. They actually measure this on humans. They would expose volunteers under the UVB light and see how long it takes to turn red (a scientifically objective measurement), explains oculofacial plastic surgeon Brett Kotlus, M.D.

Applying an SPF 30 sunscreen, for example, means it takes 30 times longer to get a sunburn. SPF 30 gives you around 96 per cent protection from UVB rays in that period, while SPF 50 offers 98 per cent protection. The lower you go on the SPF scale the more drastic the differences are.

Sunscreen might not be as effective as you’d think

Sunscreen can successfully block the penetration of UVB rays which can damage your collagen, alter your DNA, and cause cancer. Unfortunately, they do little to protect you from lower frequency UVA rays which penetrate the skin much deeper. According to the University of Iowa Health Care (UIHC), there are approximately 500 times more UVA rays in the sun’s light than UVB rays!

Although they don’t have enough power to damage your DNA directly, UVA rays do interact with the polyunsaturated fats in your body to cause oxidative stress, which eventually ends up damaging your DNA just as well. A very similar story to the one about manmade non-ionising radiation in this recent article. Sunscreen can therefore lull you into a false sense of security making you soak up far more UVA than you otherwise would.

Look for sunscreens with a broad-spectrum label, they will protect you from both UVA and UVB. SPF system doesn’t apply to UVA protection, since UVAs don’t produce redness in the same way and therefore aren’t measured.

If you remember our last week’s article, we talked about the importance of UVB radiation to enable vitamin D synthesis in our bodies. Keep that in mind when using sunscreen as it will block most of the much-needed radiation.

The two broad types of sunscreen

What your sunscreen is made of will heavily influence not only how it protects you but in what way it can harm you. There are two broad categories: organic and inorganic, or maybe a more clear distinction would be chemical vs mineral. The former group uses chemicals as active ingredients while the latter uses metals like titanium and zinc.

Chemical sunscreens

The way these sunscreens work is that they absorb the UV light and convert them into heat which disperses locally in your skin. Despite the fact that it sounds scary, the chemical process is safe because the UV rays never actually penetrate your body.

The problem is that the chemicals used in these sunscreens are potential endocrine disruptors and they have the ability to cross the blood-brain barrier where they can damage your neurons. They are usually not recommended for children, but I don’t see a good reason why an adult would use them either.

There is a good reason we have a blood-brain barrier, blood-ovary barrier, and blood-testis barrier in the body - to prevent harmful toxins from entering and damaging your brain and reproductive abilities, because that’s where genetic material resides and neurons don’t really turn over. The ones you’ve got, you’ve got for the rest of your life, warns neuroscientist Dr Andrew Huberman. You want to do everything you can to protect them.

One of many randomized controlled trials showed that four common chemicals used in sunscreens (avobenzone, oxybenzone, octocrylene, and ecamsule) were absorbed into the bloodstream at concentrations above the FDA's potential toxicological threshold.

Here is the list of commonly used chemicals you should try to avoid:

Triclosan
Avobenzone
Oxybenzone
Octinoxate
Octisalate
Octocrylene
Padimate O
Octocrylene
Ecamsule
Homosalate

Chemical sunscreens are much friendlier to use since they are much easier to spread than mineral-containing ones. They also usually smell better because they are often produced with perfumes which are additional hormone disruptors on their own. Although there are new products on the market that reportedly use safer chemicals, in my opinion, it is best to steer clear of these sunscreens unless unavoidable for short-term use.

Mineral sunscreens

Well, I guess that solves it, then. You should opt for the mineral sunscreens that use the minerals to physically reflect light and are not absorbed into the skin?

Well, first of all, contrary to the popular belief, these physical sunscreens actually provide UV protection primarily via absorption of UV radiation and not through significant reflection or scattering. Just like chemical sunscreens, mineral ones primarily protect the skin by absorbing UV rays into the skin and then turning them into heat. The only difference is that chemical products absorb 100 per cent of UV rays, while mineral sunscreen absorbs about 95 per cent of rays and reflects back around 5 per cent of UV rays

Titanium dioxide and zinc dioxide are two key ingredients in mineral sun protection products.

Titanium dioxide (TiO2) is the naturally occurring oxide of titanium. It’s a white powder that’s widely used as a whitening agent, UV filter, and thickener in many consumer products, even food. Because it protects skin from both UVA and UVB radiation, titanium dioxide has been used in sunscreens for decades and is even considered safe for babies.

Surprisingly, TiO2 has been classified as a Group 2B carcinogen meaning “possibly carcinogenic to humans” in 2006. The problem is with its nano-form. TiO2 leaves white streaks when applied to the skin, so the manufacturers came up with a solution to break it down into nanoparticles.

Studies have shown that these particles could penetrate the deeper layers of skin and end up in the bloodstream, potentially interfering with your immune system and brain and causing some cancers. Inhalation is especially a concern, so avoid using spray sunscreens. A paper published in 2006 concluded that long-term exposure to nanoparticles of titanium dioxide causes oxidative damage to DNA.

There are sunscreen companies that make non-nano zinc oxide or titanium dioxide particles, which seem to be much safer. Look for those labels when purchasing.

It’s important to note that you shouldn’t skip sunscreen if you are planning a prolonged exposure to sunlight. Many people don’t apply enough sunscreen. You shouldn't forget to re-apply every two hours if you are continually exposed to the sun. Skin cancer can definitely kill, nanoparticles we’re still not so sure about especially in moderate amounts.

Vitamin A for young skin

If your aim is to rejuvenate your skin and protect it from aging effects, dermatologists suggest using over-the-counter retinol (vitamin A), which is a weaker version of the prescription-based retinoid. The treatment does not remove dead skin cells, as many other products for mature skin do. It rather penetrates beneath the epidermis (outer layer of skin) to your dermis and helps neutralise free radicals. Retinol eventually turns into retinoic acid.

Retinoic acid (RA) is derived from retinol and plays important role in cell growth. It acts like a hormone and acts on an intracellular and DNA levels. It affects the transcription of many genes, promotes collagen synthesis and increases the turnover of skin cells. It is known to be one of the best-known skin care ingredients mainly used to treat mature-looking skin and acne.

How long it takes to turn to RA depends on the individual, anywhere from 2 to 6 months. However, that doesn’t mean there are no improvements before that. It just takes time for the skin to turnover.

Retinol has many potential skincare benefits, but there are side effects to consider, too. Please do additional research and consult your dermatologist before committing.

Conclusion

Essentially, many sunscreens can be the very cause of the disease you are trying to protect yourself from in the first place. A more natural approach would be to reduce the inflammation in the body with a healthy balanced diet and gently coax your body into producing more of the skin pigment melanin, all while carefully managing your exposure to sunlight. Timing, duration and protective clothing are much safer and more natural ways than applying any product and hoping it will do wonders.

If there is no way to manage your UV radiation exposure and you are stuck out in the sun for long periods of time don’t avoid putting on sunscreen. Even an occasional chemical cocktail might do less damage than a severe sunburn. The amount of hormone disruption is highly dependent on the dose of toxins you apply to your body, inhale or ingest.

Look for sunscreens with mineral ingredients as their active agent, if possible without nanoparticles. Additional ingredients in the product should also resemble a guided tour through a botanical garden rather than a twenty-syllable unpronounceable chemical shopping list.

Think of the sun as your feisty friend. Enjoy its company, and thrive on its endless energy, but don’t let it hurt you.

Resources:

https://pubmed.ncbi.nlm.nih.gov/26785166/

https://www.hellonaturalliving.com/titanium-dioxide-is-it-safe-or-should-you-avoid-it/

https://pubmed.ncbi.nlm.nih.gov/26431814/

https://peterattiamd.com/brettkotlus/ (from 46:30)

https://labmuffin.com/how-long-do-retinoids-take-to-work/

https://www.mustelausa.com/blogs/mustela-mag/mineral-vs-chemical-sunscreen-know-the-difference