Do UVA Rays Cause Tanning?



The UV emission of the sun. Pretty; scary. Get it?


CPD generation.

It is a well-established fact that UVB rays cause direct DNA damage in the form of cyclobutane pyrimidine dimers (CPDs), which are when the molecular bases incorrectly link together with bases from the same strand of DNA, rather than those of the opposite strand. This in turn, leads to melanogenesis and the consequent darkening of the skin.

It is also a well-established notion that UVB rays are solely responsible for tanning, while UVA rays are responsible for “aging.” Hundreds of health and beauty blog authors oversimplify the idea to: UVB means “Burning” and UVA means “Aging.” I’m sure all of you have seen that phrase. This notion however, is not accurate.

Both UVA and UVB Cause Tanning

While UVA irradiation may not induce melanogenesis, it will still increase the darkening of the skin. Therefore, it has a similar cosmetic effect as UVB-induced tanning, albeit a less dramatic one. There are two main avenues through which UVA achieves this effect. Firstly, UVA rays will oxidize and/or polymerize already existing melanin and transform it to become even darker and more apparent. This occurs immediately upon exposure to UVA rays.

Secondly, UVA stimulates initially colorless melanogenic precursors such as DHICA and 6H5MICA and changes them into a dark-colored pigment. This phenomenon occurs outside of melanocytes, which are the cells responsible for melanin production.

What Does This Mean?

UVA irradiation actually DOES cause immediate darkening or “tanning” of the skin. So ironically, while many people think that their “tans from yesterday at the beach” are because of UVB irradiation and therefore, additional melanin, these tans may actually be from UVA irradiation. And because the melanogenic precursors mentioned above don’t provide an additional level of UV protection (unlike actual melanin), it’s rather dangerous to think that, “Oh, this tan is going to provide extra protection against the sun.”

***Keep in mind that the darkening from UVA irradiation does tend to not be as pronounced as that induced by UVB irradiation.

What Can You Do to Protect Yourself?

Here’s what the sun does to polypropylene rope. This isn’t pretty; just scary.

You absolutely have to use sunscreens that provide good to excellent protection against UVA rays. I really hate that many experts claim that, “If your sunscreen provides broad-spectrum protection, you can rest assured that you’re getting adequate protection from UVA rays.” For example, I recently read a review on Beautypedia ran by Paula Begoun, that generally speaking, 2% titanium dioxide is sufficient to provide adequate broad-spectrum protection. WHAT?! And then in a video by Dr. Neal Schultz, he stated that it doesn’t matter what concentration of UV filters is present because, “All chem.-free sunscreens have UVA protection.” The relevant question begins at 6:25.

Now, if you’ve been one of my longtime readers, you’ll know that I’m a big fan of both of these pioneers. However, that doesn’t mean I agree with everything they say. Yes, all chem.-free or inorganic sunscreens provide SOME form of UVA protection, but that doesn’t tell me how much. There seems to be this incorrect perception that your sunscreen provides “broad-spectrum” protection, or it doesn’t. As if, you get either 100% UVA protection or none at all.

Let me tell you, that rationalization is WRONG! UVA rays are just like UVB rays in the sense that UV filters provide a percentage of protection against them. And while UVA rays are less potent (due to having less energy as a photon with a longer wavelength) than UVB rays, there is so much more of the former present in natural sunlight than the latter: the UV component of the sun is made up of approximately 94% UVA rays and 6% UVB rays. That’s almost a twenty-fold difference!

Be Diligent and Vigilant

So if you want to trust these recommendations, then by all means, no one can stop you. But my personal recommendations are as follows:

If you’re using an organic sunscreen, look for ones that contain at least 3% avobenzone that’s been stabilized by good amounts of octocrylene and/or oxybenzone, assuming that you don’t have access to Tinosorb S or M. Of course, look for high amounts of UVB-absorbing UV filters as well. Avoid sunscreens that contain both avobenzone and octinoxate.

If you’re using an inorganic sunscreen, look for ones that contain “high” amounts of UV filters. I can’t make a blanket recommendation as to which number is sufficient because “high” depends on a variety of factors such as which UV filters are present, how much of each is present, and whether or not organic sunscreens are present as well. But ideally, use the highest concentrations of inorganic UV filters that you can accept aesthetically.

I hope this was an informative post and make sure to enter my giveaway! It’s way to help me, help you!  

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  • @France

    Welcome, welcome.

  • France

    Thanks again John. I’ll try that eyes-closed-deep-breaths trick. It will surely come in handy 😉

  • @France

    You’re welcome! Congrats on the precious additions to the family. 🙂 Try to find just a few minutes a day for yourself. I tend to just stop doing everything, close my eyes and take deep breaths. Oh and don’t forget to smile.

    If someone witnessed these little sessions, I’d probably appear high or something haha. But they do help a bit.

  • France

    Thank you for your response John, and for your wise advice. You are absolutely right. I did have two children in the past five years, which would probably explain a lot, lol! A change in hormones, an increase in stress and a lack of sleep just comes with becoming a mom I guess, and it doesn’t help your skin, but the joy you get from it is absolutely worth it. Thanks again! 🙂

  • @France

    Oops sorry about the confusion. When I say to avoid octinoxate, because it was part of the discussion of avobenzone, I meant that you shouldn’t use sunscreens that include BOTH ingredients. I apologize for the confusion. Octinoxate is great when used to boost the UVB attenuating aspects of ZnO, and in conjunction with other non-avobenzone organic UV filters!

    And your SkinActives sunscreen looks fine!

    Finally, as to how “old” you look, I really can’t give you a good answer. One, I can’t seem to find the ingredient lists for the Coppertone products and the Olay product is decent too. As long as you applied sunscreen regularly and in proper amounts, they should have fufilled their purpose. And over the course of five years, a lot of other aspects can affect your skin including diet, hormones, levels of stress, behavioral habits, etc… But I’m sure you don’t look very old at all!

    So from a sunscreen point of view, I THINK you did a pretty good job at preventing the signs of aging. But yeah, I’m not really sure what to tell you. I think the most important thing is to not dwell on the past; you can’t go back in time. Just do the absolute best that you can starting from today!

  • @Lucas

    Yeah, I can’t fathom how low %s of inorganic UV filters can provide good UVA protection.

    Thanks for reading!

  • France

    Hi John! Great, interesting article, as always! I have three related questions for you: Above, you say to avoid sunscreens with octinoxate, but the article you link to says to avoid sunscreens that have BOTH octinoxate and avobenzone. So, if a sunscreen does have octinoxate, but no avobenzone, would you still advise to avoid it? (This is the case of my current sunscreen, the Olay Complete SPF 30, and I was planning on replacing it with the SkinActives sunscreen (to avoid niacinamide in the morning, with the use of vitamin C), whose active ingredients are Octinoxate 7.5%, Zinc Oxide 7% and Octisalate 5%. Do you think the SkinActives sunscreen looks efficient?
    I have been using sunscreen on my face every day since I was fifteen. Well, I am now 33, and I cannot say that I look any younger than my friends who are the same age as me, and who have never worn sunscreen on an everyday basis, or have only started to do so in the last few years. I used the Coppertone Oil Free (SPF 15 for the first few years, and then SPF 30) from the age of 15 until I was about 27, at which time I switched to the Olay Complete SPF 30. I know the Coppertone (and maybe the Olay) might not have provided the best UVA/UVB protection, but it is still discouraging to think of all the money I have spent on these sunblocks for almost 20 years, with no real benefit, wrinkle-wise, at least as far as I can tell. (I think I even look about five years older than I actually am. I now have quite a few wrinkles around my eyes and on my forehead, and my skin has started to sag, which is very obvious in pictures.) Which brings me to my third question: John, why do you think these sunblocks have not worked in my case, to prevent the signs of aging?
    By the way, my profile picture that appears on the left is from 2007 (I totally have to update this picture, lol!) and I definitely look much older now. I would say ten years older, even if it’s only been five years.
    As always, thanks John for all of this very useful information!

  • Lucas

    I always found it weird how Beautypedia grants UVA protection to sunscreen which aren’t that great. I mean, 2-5% inorganic filters will provide some protection, but is that the best out there? I don’t think so. The same goes for sunscreens containing only 2% avobenzone.

    “There seems to be this incorrect perception that your sunscreen provides “broad-spectrum” protection, or it doesn’t. As if, you get either 100% UVA protection or none at all.”
    I totally agree this seems to be a problem. And with the new FDA regulation regarding UVA, although it is quite good, they might have promoted that idea further on, since a sunscreen either DOES or DOESN’T provide “Broad Spectrum” protection.

    Another great post, John!

  • @Mae

    Well, I believe that sunscreens are the first line of defense because it’s right on the surface of the skin. When it comes to sun protective clothing, unless you’re completely covered up, it just isn’t as effective as a good sunscreen. Remember, sunlight reflects off of virtually everything: the floor, glass, sand, water, you name it. So yeah, if you’re wearing a big hat, an umbrella, sunglasses, gloves, etc… if you can see light, that means it can “see” you too, meaning that UV light is hitting at least the skin on your face. So without sunscreen, that just won’t do.

    Plus, protective clothing just isn’t very desirable or practical sometimes. Granted, they should definitely be used in conjunction with a good sunscreen.

    And of course, I’d want everyone to just avoid the sun. But again, that’s just not possible. So we work with what we have. And sunscreen remains the absolute #1 option! Sun protective clothing is supplementary.

  • Mae

    I would also recommend covering up as an alternative or complement to sunscreens. People see sunscreen as the only form of sunprotection, but I would argue it is a very expensive one and probably less effective than sun protective clothing, wide brimmed hats, umbrellas, protective gloves, and embracing shade during peak UV hours – due to the issues described above, and due to the fact that most people use sunscreens incorrectly by applying too little and applying too infrequently.

    I’m not just trying to plug my company because we make sun protection hats, but because covering up is as effective (if not more) as sunscreen and often more cost effective.

    Thank you for all this information!

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