Sunscreen Works, If You Use it Right
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- Опубликовано: 19 июл 2014
- Thanks to Audible.com for supporting this episode of Healthcare Triage. You can download a free audio book of your choice at Audible.com: www.audible.com/triage
When I was a kid, I remember people talking about putting on suntan lotion to help them absorb the sun's rays. Those days are over. Too much sun can be terrible for you. Besides the fact that it significantly increases the risk of skin cancer, the sun will age your skin and make you look older, too. Who wants that? Today, we use sunscreen to protect us from the sun. But most of us are doing it wrong. How so? Watch and learn.
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Just dig a hole, fill it with water, dirt, and clay to make mud. Jump in and cover yourself head to toe.
Then go to any sunny open place and lay down. Let the mud bake around your skin until it's fully hardened. You have now created an indestructible mud armor. Go forth and vanquish your enemies.
But as you said...people just AREN'T going to use it as recommended. That means that the first priority should be figuring out a way to make effective sun screen that only needs ONE application for an entire day and/or that works in smaller quantities. Yes, people can do better, but science needs to rise to this challenge.
I protect myself from sun damage by being ugly and never going outside.
If you have sensitive skin or bad acne, sunscreen is something you totally should wear, especially if you're taking any sort of medicine. Skin often gets irritated by UVA and adding extra stuff makes it easier to irritate, so sunscreen is basically a must. Also, important note, UVA is not affected by the weather. Like, ever. UVB is, but UVA is going to occur even when it's cloudy outside, even when it's raining. Sunscreen => do it.
Excellent advice! A broad-spectrum sunscreen should be worn on a daily basis. If you don't need a flashlight to see outside you need to be wearing sunscreen! SPF 20+ should be the minimum. Also, people should keep in mind that UVA rays shoot straight through glass so sunscreen should be worn indoors as well.
Friends think I'm crazy for wearing it in a long car ride or on cloudy but non-radiant days
I have family history with melanoma, thank you for clearing up so many misconceptions and potentially saving me from getting skin cancer.
Your show is amazing. I recommend it to others regularly and I have used it to improve my health care decisions. This is the kind of show we need on television.
As someone with both fair skin and fair hair (who sunburns *very* easily), I can say that my one biggest tip to people (especially swimmers) isn't the SPF, it's buy Bullfrog. I don't know why, but Bullfrog (when applied regularly, of course) does wonders for preventing sunburn while at water parks. I have no idea why it works so well (certainly better than any other sunscreen I've tried), but yeah, buy Bullfrog for your day at the beach. :)
This is a topic that's near and dear to my heart as I have a chronic photosensitive disorder. A good alternative to sunscreen is UV protective clothing. Companies such as Solumbra, and Coolibar make a wide variety of clothing that WORKS! Even companies such as Columbia are getting in on the action. There's some pretty strong misconceptions about sun protection too. Such as you get more sun protection from sun screen than you do from standing in the shade. (False.) Or that you get 80% of the damage you'll ever receive in your life by the time you're 18. (Also false.) Or that high noon is the very apex of the strongest sun off the day. (It's around two.) I will say though, one great side affect of having a photosensitive disease is I always look ten years younger than my peers.
I am a nurse from germany and just got home from late shift. As always. It's been a pleasure. I often share your videos, unfortunatly most germans don't watch english videos that often, since most of us do speak and understand english but maybe not always enough to understand a full video with important details. Luckely I do (besides some bad puncation and misspelling :) and I always look forward to your Topics. Keep up and Auf Wiedersehen!
YES! This is a fantastic channel - thank you vlogbrothers for helping education expand
Thanks! Keep up the great work spreading scholarly information to the public
I was waiting for a demonstration!
I would like to start by thanking Healthcare Triage for this video because I believe that this is a common issue. I firmly believe that most people myself include, do not know how to correctly apply sunscreen. I also believe that this goes for other remedies such as skin care products, antibiotic ointments, and many other body surface commodities. So why do we not know the proper way to utilize these substances? Is it because we weren’t properly informed? I believe that the problem starts with how the product is advertised and it continues to how the labeling on these products works. In both of these instances, companies love to use fine print. Often times in advertisements they will have distractions all over the screen and then on the very bottom in tiny, faint writing it will say “Must apply liberally every 20 minutes” or something along those lines; just like they do on the products themselves. On the products they will have the company names printed in size 72 fonts and then on the back they’ll have the vital information for proper use printed in size 6 fonts. So my thought is that companies should feel ethically responsible to convey the more important information to the consumers. Instead of fine print warnings or a speed talker stating the proper way to apply and the risk they should have an additional section of the advertisement informing consumers of the more important details. But then again, that would cost them more money.
My wife researched this a while back, and I was definitely surprised by the answers. It's changed our practice significantly. Great video, and very valuable! :)
Question though: Are some of the ingredients safer than others? I've read a lot about recommendations for sunscreens that contain chemicals less likely to be harmful over the long term (many of them were also lower SPF ratings). But I just went with the recommendation rather than checking the research on that one. (Because, well... why not? They weren't more expensive or anything.) But I'm curious all the same.
I don't sunburn easily and I don't sunbathe, so I've never thought I needed to apply sunscreen unless I was going to be out in the sun ALL day (which is rare). This video changed my mind (admittedly by scaring the crap out of me, but hey, it worked). Healthcare Triage saves lives!
i don't understand why this channel doesn't have a lot more subscribers
Thank you so much for making this an episode.
im an md and this guy is 100% on the dot. If you've ever been to the tropics you've learned the hard way that only frequent applications can save you from the burn, no matter what the FPS.
why was i not subbed to this channel i love coming here.
This is a great episode. So I wonder, Dr. Carroll, is there a difference in ingredients of sunscreen and their efficacy? I did a science project in middle school (back in the late 90's) and my study showed that of all the samples, only two did better than the control, and those two had one common ingredient that the others didn't. Granted, this is middle school science that involved photo paper and light meters, but still my findings surprised me.
Also, the way you described inorganic and organic sunscreens, I wonder if there is a major difference in them in one being more effective and better.
Great video! I wear sunscreen every day, but will be applying it much more often now. Thanks!
Thanks for the information. I had no idea the SPF was so unimportant.
This video was awesome! Though I did laugh at the "...that would mean you'd use up most of your bottle of sunscreen. Who does that?" part. I'm married to a VERY fair skinned redhead. Every time we go to the beach or water park, we literally use up just about an entire can per each of us. (We use the aerosol spray sunscreens.) We re-apply the sunscreen every 35 minutes in copious quantities, most especially my husband, because his skin would practically cook if he didn't.
I once bought a thing of "SPF 100+" sunscreen before heading to the beach. I applied it in the usual, human, less-than-recommended manner, and I got badly burned. Anecdotal evidence, sure, but it goes to show that, as mentioned here, SPF is much less important than application technique.
Very true! You are markedly better off with a liberally applied SPF 30 than a haphazardly applied SPF 100+.
Very insightful. Thanks for sharing with us.
I wish the information had been around when I was in my 20's and 30's. My dermatologist called me with "it's malignant" when I was in my young 40's. That was on the Ides of March in 1988. I'm still around. But I don't use as much screen as I should. I'll have to do better and I appreciate the advice.
If only I could be so grossly incandescent!
Would you like to join me in some jolly cooperation?
Seriously, I need help getting some of that sunscreen on my back.
***** Dont worry, we sunbros got your back.
As others have mentioned, you do also need to wear sunscreen in the winter, and I'm surprised you didn't mention that. It's actually more important in the winter, I would argue, depending in part where you live, because snow and ice could actually amplify your exposure by reflecting all of those UV rays onto you.
Super helpful! I put sunscreen on before I went to the beach a couple weekends ago, but still got horribly sunburned. Turns out I wasn't applying the sunscreen properly! I'll keep this advice in mind for next time :D
The video is very factual, but just using of sunscreen and not using it enough is something that shocked me and is something I didn't know. The amount needed which is the amount compared to a shot glass is not even close to what many people use. Many people just barely put some on and call it good, many don't know the true amount and get burnt to where they hurt their skin and bodies. I believe if everyone knew the correct amounts it would cause a little more safety conditions and wouldn't have people just doing the amount they want.
If you did another Q&A episode, I would find it very useful if you could address the following two questions:
1. I know this question's answer may have a lot of conditions, but in a general sense, when is it better to A) make an appointment to see your GP, B) Go to an Urgent Care Clinic or C) Go to the ER? Are there certain symptoms that are better treated at an Urgent Care clinic vs. an ER (or vice versa)? I know there are times when I feel sicker than usual, or have an unusual symptom(s), I'm never sure which choice is best.
2. If you live near a major urban center that has "world renown" hospital(s) (Like Mass Gen/The Brigam's or Johns Hopkins or the Mayo Clinic), when is it better to make the extra effort to go to the fancy hospital vs. your hometown ER?
What do you think of the aerosol sunscreens that are becomming more popular? How does that change how much you should be applying?
Healthcare Triage SPF (sun protection factor) actually refers to the amount of time that the sunscreen remains effective. You multiply the SPF by the amount of time it takes for the particular person to get a sunburn. For example, if it takes me 10 minutes to get a sunburn when exposed to a certain level of sunlight and I use SPF 15, it would take 150 minutes for me to get a sunburn in that same level of sunlight. SPF is less about how effective the sunscreen is and more about how long it is effective for.
As a side note, any skiers/boarders out there, remember you need sunscreen when on the slopes. The sun reflects of the snow and you can get really bad burns (and those every so beautiful goggle tans)
I would like a Vit D conversation about the topic of sun, healthy sun, the the benefits of supplementing with Vit. D3
are you serious, I just came back from a weekend beach trip today, and now this video comes out
I love this show!
I've always found that the best way to not get burnt is to cover up. Apply loads of sun cream to the areas that are exposed, but wear something that covers your skin and is also light. Anything made of light cotton or linen is ideal, because that way you wont be too hot. Saying this as someone who generally burns within 3 seconds of stepping out the door without the whole bottle of sun cream on my skin.
I generally use the Neutrogena spf 50 mist stuff on my body (arms, legs, neck, back/stomach if swimming, etc) but only a relatively thin layer compared to the cream sunscreen that I use on my face. Does the mist work as well as the cream since it is so much thinner? Does it work as well? Or is it just like applying a heck of a lot less protection?
I just become more sedentary during the summer, and more active during fall and winter. Works pretty well for me.
Thanks for the video! Important info. :)
Quick question about the procedure, though: 20 minutes later than what? Later than the initial application (which was 30 minutes before going out in the sun), or later than going out in the sun (50 minutes after the initial application)?
As always, great data. I guess I won't waste as much money on SPF 50 unless I think I'll REALLY be outside baking in the sun for a long time.
While we're on the topic of being safe in the sun, could an episode be done on checking your own moles and freckles? There's a lot of conflicting information on what to check for, might be good do have some more definitive info.
I'm a ginger and I work outside in the sun 8-9 hours a day.
My usual application schedule goes like this:
Arrive at work, spray vulnerable areas thoroughly with SPF 30 Spray lotion
Reapply after first break (2 hours)
Reapply after lunch (3 hours, but only 2 hours in the sun)
Reapply after last break (2 hours)
I never get sunburned, though I have tanned a bit. Is this an acceptable schedule or am I still getting skin damage?
I prefer sun protective clothing to sunscreen for my body and avoiding the sun between 10 and 2 (tends to be too hot being out in the sun during that time anyway)
I wish I had this video yesterday. I'm so sunburned
NO-AD sunscreen is usually decently priced and has a range of SPF options. Living in Florida, I always bank on a higher SPF.
I feel that the video lacked some definition on SPF. I was told a while ago (by researchers) that the SPF is related to the time of sun protection by the time it takes for the skin to burn without sunscreen. Is that right?
Also, after a quick check on the video references I see that the SPF is a value achieved on application, so the bottle value is achieved in lab, while the actual consumer application might achieve a significant lower value. This statement feels a bit lacking without a clear SPF definition, but still something to keep in mind.
Any big difference between the spray on and cream sunscreen? The spray on kind is much faster to apply but is it as effective as the cream?
If you use the inorganic physical-blocking sunscreen, would you still need to apply it 30 minutes before sun exposure? Thanks for another great episode!
The "Yes to Carrots" brand now sells mineral sunscreen containing zinc oxide and titanium dioxide. The website claims that those two minerals don't break down in the sun like other sunscreens do. Does that mean you don't have to reapply it? Because while not having to reapply sunscreen sounds fabulous, the concept seems a little suspect.
I protect myself from the sun by staying indoors all the time.
I'll have to do a much better job on the sunblock. No wonder I've been getting burned even while applying it - I'm not applying nearly enough.
Congrats on getting a sponsor.
Does sunscreen affect vitamin D absorption? What about use of sunscreen on cloudy days, or in the winter (especially in Canada where we get really slow sun-angles but lots of snow reflection but have vitamine D deficiency issues in winter)?
Hi there, enjoyed your video as always. Would you please comment on the chemical Oxybenzone and whether there is any data supporting the notion that it is harmful or cancer causing? It is an active ingredient in almost all sunscreens that I can find and I am having trouble sifting fact from conspiracy with this one. Much appreciated.
In New Zealand we are recommended to use a high SPF due to the lack of ozone. In such a situation would you still hold the same recommendation?
I'm allergic to an active ingredient in most sunscreens I find, and the only ones I've seen that don't have it are sunscreens for infants, which is always more expensive. So I don't wear sunscreen for anything other than the beach; I just can't afford it. Most of the time I simply wear long sleeve shirts (that holds true whether I'm outside for a long time or not), so the only part of me that really gets a fair amount of exposure is my face, hands, and feet
I went inside at 16 because I get red and freckle and tended to avoid the sun for the next 30 years. I have MS but my skin looks fantastic. I look 15 years younger than some of my peers. I now take anti-flare meds and vitamin D supplements and do get outside to exercise a couple days a week. I have gone from a whiter shade of pale to a paler shade of pale and though I have some tingling in my left toes and fingers, I am not disabled. Scary diagnosis, though. My sister and dad have each had some skin cancers removed a couple of years ago, so we can't win for loosing as far as the sun goes.
Duly noted. Next time I go outdoors I will apply the appropriate amount of sunsceen.
That time should come in 10-20 years.
This comment is unrelated to sunscreen usage, but I was wondering if you had read the review, recently published in the British Journal of Nutrition, which offers some evidence that organic produce may have slight health benefits as compared to conventional produce. I'd love to hear your take on this and whether or not it alters or reaffirms your position on conventional vs organic produce. Thanks!
Does your statement at 4:32 (higher SPF is not that much better) impact your statement about "theoretical" and "actual" applications of wearers habits at 3:47? Can I assume longer protection above that 94% mark if I'm using an SPF above 15?
People also have to be cognizant of the expire by date on sunscreen. I have a cousin, whom, a few years ago wore SPF 90 sunscreen at her college graduation that was 3 years expired; she got a nearly purple sunburn on her neck and shoulders.
I use SPF 60 only because, in general, it smells better (to me).
I just avoid going outside, then apply sunscreen somewhat haphazardly whenever I do.
My pool gets too hot during the summer to be useful during the day (it's basically body temperature or higher, so 92F+), so I only go swimming in it after dark. The beach is an hour+ away through LA traffic, so I don't tend to do that all that often.
My area has crap options for hikes, most of which boil down to desert hills with live tumbleweeds and slightly more entertaining rock formations. I'd have to drive over a hundred miles to get to anything resembling greenery.
Dirt biking is an option, but I don't own one, and only know one friend who does. Paintballing is also an option, but most of the fields near me rip you off like you're the last apple in the world and they're a starving man.
Basically, going outside is something I can only really do on select occasions.
I just fill up a bathtub with this stuff, dive in, and spin really quickly. Give it a moment and once it doesn't feel cold anymore I step out and I'm ready for a walk in LA!
Although once it starts drying the stuff becomes clear and I realize that I missed the step of putting on clothing which then calls into question just how safe I am from the sun...
and law enforcement...
Oh dear.
How are you supposee to apply more sunscreen if you wear makeup? I can buy makeup with spf but I can't keep applying more throughout the day.
Even after applying regular sun screen, I was getting sunburns on my face. Then I switched to zinc oxide (inorganic) and that helped a lot. Why would the organic one not be as effective?
OK I'm confused.
If I put on say SPF 30 suncream as much as I would normally, i.e. step into the Sun and put it on and then not apply any more for several hours, am I getting benefits that are worthwhile, or should I make a large conscious effort to change this?
Use an umbrella. Also, stay out of the sun between 9 A.M. and 6 P.M.
I'm a vitamin D deficient ginger lady who goes out in the sun bathed in sunscreen. Thanks for the new information. I knew they lied on the bottle! Also I was wondering... I do go out in the sun a lot. I have a toddler son and a garden. My vitamin D is 5. My doctor thinks I lie about being out in the sun. Anyone know what's wrong with me? I've had this all my life and every doctor says I don't go out in the sun because I'm pale.
So doc, solar cream and melanoma.
What's the NNT to prevent one melanoma? How many thousands of gallons of suncream to prevent a single melanoma, and how expansive is that? That's what I really want to know.
I wish you would have talked about if you need to apply even under clothing, I haven't seen a good consensus on that issue.
At 3:12, is the second application to be applied 20 minutes after the first application or 20 minutes after you go outside?
Watching this with a sunburn - I wish I had seen it earlier /:
What about SPF in facial moisturisers? They're not designed to be re-applied because they're worn under make up. Do they still work all day?
Probably not. I have a sunhat stashed in my bag if I'm gonna be out more than a few minutes.
OK Jodie, excellent question! First of all, the only difference between a daily moisturizer with SPF and regular sunscreen is that the former usually contains beneficial skin care ingredients and is more elegant. You should still think of both as regular sunscreens and apply them as you would a regular sunscreen.
Now in terms of reapplication: if the only exposure you get is incidental i.e. walking to your car, driving to and from work, going to lunch and you have less than 4 hours of total exposure a day chances are your sunscreen is still going strong at the end of the day and you do not need to reapply ( assuming you've applied enough in the first place). Sunscreen breaks down with exposure to the sun not with the passage of time.
What if you're spending a long day out doors, or you sit near a window at work and the sun shines in all day? Then yes, you do need to touch up your SPF at least every two hours and there are ways to do this elegantly. You can consider makeup with added SPF such as foundations, pressed or loose powders since layering is an excellent way to strengthen and/or refresh SPF. Hope this helps!
How does using the spray kind affect how we should use sunscreen?
Informative! Ignore SPF values, and apply religiously.
Great video, but it seems to me that you have misunderstood UV percentage blocking part. Let me explain :D
SPF factor shows what part of sunburn-producing UV rays reach the skin.
For example SPF 15 means that at recommended usage 1/15th of "bad" sun rays reach your skin. That is around 7%. That means, as you said, that it blocks 93% of rays.
But the important part what percentage of rays it DOESN'T block. Sun effects on skin are proportionate to the amount of rays that "pass through" the sunscreen and NOT the amount that sunscreen blocks. That means that 60SPF IS actually twice as good as 30SPF.
He never denied that SPF60 offers twice the protection than SPF30, but did say the doubled potency does not mean you can put on half the sunscreen. He is correct about that part. "Twice" doesn't guarantee a large absolute difference in protection; that is a relative relationship, not an absolute difference.
Here's a fabricated example: if I'm 0.000001% at risk of developing stomach cancer and eating my favorite cereal every day doubles my risk over my lifetime. Still, I care so little that I continue to eat the cereal every day. Doubling the risk for stomach cancer sounds frightening but two times 0.000001% is just 0.000002%. The absolute increase in risk is extremely small. The same goes for SPF protection. Double the protection may sound awesome, but there's very little absolute increase in protection.
Random Guy's point was that if you're already only receiving 6% of the suns energy by using SPF 15 effectively, then 1.5-3% reduction is a major difference. It's true that effectively using SPF 15 over nothing makes a bigger difference than using SPF 60 over 15, but it's still true that effectively using SPF 60 over effectively using SPF 15 is much much better.
Aaron's argument is to effectively using ANY sunscreen while Random Guy's is a mathematical argument about relative effectiveness between SPF values.
Here's a fabricated example: Let's say being exposed to the sun gave you a 100% chance of developing skin cancer. Using SPF 15 sunscreen effectively might reduce that to 6%. That's a pretty big difference. If using SPF 60 dropped that to 3%, you're still HALF as likely to get skin cancer.
Let me stress, relative vs absolute risk is definitely important, especially when comparing cost, but you can get SPF 60 in the states for less than 50 cents per ounce. SPF 60 doesn't cost you twice as much, but might reduce your risk by half vs 15.
That being said, I think we all agree that any sunscreen is better than no sunscreen which was the major take away from the video.
Do a podcast!!
i usually go to the beach in the earlier hours and don't end up staying for long at all, and since i only ever tan slightly and evenly i've been fairly negligent in applying sunscreen.
(besides, having to constantly lather up and get sticky doesn't sound appealing at all.)
nevertheless, i do recommend applying it whenever one's going on an extensive mountain hike bc the sun _burns_ up there like woah
help ,I used spf50 in the past now I move on to spf 70 but I'm actually sunburn in a higher percentage ,when it should be the opposite since 70 has more protection then 50,any recomendations???
What about someone like me who has a fairly severe vitamin D deficiency? My doctor told me I shouldn't wear sunscreen until my levels improve because they block the kind of rays that make you produce the vitamin. Is that not true? D:
To be honest, I've worn no sunscreen this summer and my skin is a lot healthier (less blemishes, healing faster, etc) than it's been in years. I've been deficient for a long, long time and I'm finally getting back to a normal level. I'm supposed to go back to wearing it as directed after I get back to normal. Not saying you should never wear it, just wondering if it really does block those specific rays, too.
if only this video came out before i went to barcelona...
What about avoiding the sun mostly throughout the day? I still use sunscreen, but I'll wait until at least 6 of clock to go out longer than fifteen minutes. Sunscreen is expensive and I think that factor should also be considered.
Wait what about if you use a liquid, spray-on sunscreen? How do you know how much to use.
What about rash guards? They are better protection than sunscreen, right?
1) I'm allergic to sunscreen. I break out in itchy bumps that feel like im covered in bug bites.
2) I dont seem to need sunscreen. A couple years ago, I attended my summer band camp, where we stayed out in the sun from 8am-6pm every weekday for two weeks. I never used sun screen, and I never got burned. Am I superhuman or something?
Is there a difference between the lotion and the spray?
So my friend is pasty white because he rarely goes outside. However, when he does go outside he doesn't burn or tan, while I do when I have a darker complexion (still Caucasian). Anyone have an explanation for this?
What about zinc oxide and titanium oxide versus the more common compounds?
XShrike +
I'm going to a concert with a very, very pale friend this summer - pale enough that the extra 1% she would get from 60 or 70 SPF might be worth it. I'll try to make sure she applies often enough.
We need a uniform UVA block rating system!!! I go for all out application on the face and have accumulated outdoor clothing with known UPF ratings for most of the rest of me.
Surprise! Sunscreen and reapplication is a MUST but it still needs support. That means UV protective sunglasses, wide brimmed hats, sun protective clothing (long sleeves, sun gaiters,etc), and monitoring the UV index everyday (3 and over is considered mid-high to high). Seems like a lot but trust me you get the hang of it easily.
i use sunscreen correctly! whoo! but I learned to do that the hard way. i'm very pale. i blister. it's really terrible. mostly i just stay indoors.
When reapplying sun screen after 2 hours. If I am out at the beach and under the sun is it ok to reapply it while under the sun?
The instructions are confusing
Thanks
This summer, I'm working outside 8 hours a day. I've never before had nearly this much sun in my life.
I only have time to put on sunscreen twice a day (before work, and during my lunch break). I'm a little overwhelmed by all this. Am I roasting myself alive?
I understand you can't take breaks all day to reapply sunscreen, but as Aron mentioned in the video it is best to apply 30 minutes before sun exposure and then reapply 20 minutes later. I think the 2 applications in the morning will be worth it. I would also look into a water resistant formulation so that sweating won't be as much of a problem.
What is the NNT and NNH for sunscreen? Yea sunscreen prevents skin cancer and wrinkles, but by how much? With no one following the required application of sunscreen, not sure it's really giving us all that much protection.
Can you do a video about melanotan injectons?
Now how do I make my body produce SPF and distribute it to my skin where exposed to sunlight?
What if you are tan or get tan?
Maybe I'm going to die of melanoma, but I usually incrementally tan until my skin resists sun burn as much as possible. I'll go out for about 30% of the time it takes to burn two times a day separated by a few hours without sunscreen for a few days. Each time I go out, it takes longer for me to burn, so eventually I reach my body's maximum melanin production.
I'll still use sunscreen when I stay out a long time, but if I get my body to produce more melanin without developing a burn, shouldn't that protect me?
a suntan is not just your body producing more melanin. It produces more melanin because the radiation has already begun to damage the DNA in your skin cells and it's trying to protect itself from further damage. It doesn't matter if you tan or burn, sun exposure does damage to your skin and will cause aging and potentially skin cancer. Tanning is bad for you.
In Australia, we have one of the highest rates of skin cancer in the world. People with tanned skin have cancer in higher rates here than any other group. As our public health announcements on tv state "there is nothing healthy about a tan"
Your body's response to sun damaging your skin is to produce melanin. If your skin was not being damaged, your body wouldn't think anything is wrong and you wouldn't get a tan. That's why sunscreens stop/slow tanning.