Sunday, August 2, 2020

How Old Is That Sunscreen? ©




 
Sunscreen bottles, photograph by the author.

Have you ever wondered just how old your bottle of sunscreen is?  How old is too old?  These are both good questions, and so I thought I would find the answers.


 
Close-up of sunscreen bottles, and their code numbers.  Both bottles were manufactured in 2015, the one on the left is from April 1st and the one on the right is from April 15th, and both are now expired1 and should be discarded.  Photograph by the author.
  
The U.S. Food and Drug Administration (FDA) requires sunscreen to have a three-year shelf life, during which the sunscreen must remain at its original strength.  When the sunscreen has a shelf life of three years, the FDA doesn’t require the manufacturer to print an expiration date on their sunscreen bottles.  So, if there isn’t an expiration date on your bottle of sunscreen, it should be good for three years2.  However, if the sunscreen expires in less than three years, the manufacturer must print an expiration date on the bottle. 

If there isn’t an expiration date printed on your sunscreen bottle of sunscreen, and you want to know if it is expired or not, you can call the customer service number that's printed on the label.  By calling this number and giving them the code number printed on the label, or on the bottle or on the cap, they can tell you whether your bottle of sunscreen has expired or not3.  



So, if you know your bottle is older than three years or is past the expiration date printed on the bottle, throw it out!  But time isn’t the only factor, how and where it has been stored also is a factor on whether your sunscreen is still good or not.

To stay in good condition sunscreen must be kept out of the sun and away of excessive heat and humidity.  When you are out, at the beach or in the wilderness, put your sunscreen bottle in the shade, wrap it up in your towel or put it back into your pack, when you are done with it.

If your sunscreen has a foul smell, if the color doesn’t look quite right, if it is runny or if it has crystalized, it probably expired, so throw it out!
 
A quote from a lecture I gave, graphic by the author.

Below are some talking points from a lecture, that I gave a year ago, on how to protect yourself from the sun while out in the wilderness.



·       Everyone, especially people with fair skin tones.

·       Remember, people with dark skin tones who rarely become sunburnt, can still develop skin cancer, and will benefit from sunscreen.

·       People taking medications, since sun sensitivity is increased by acne treatments, antihistamines, antibiotics, some anti-inflammatories, and herbal supplements, always double check all your medications for cautions about the Sun.

·       And children, who have thinner more sensitive skin.

·       Additionally, people need sunscreen when…
Ø They are in high elevations, because the higher in elevation you are, the thinner the atmosphere and the more intense the UV rays.

Ø They are in equatorial or polar region because the Sun is more directly overhead in the Tropics and there is less atmosphere to reduce harmful UV rays at the Poles: UV rays are less intense in the mid-latitudes.

Ø They are on or near snow or water because you can be burned by reflected UV rays, even if you are in the shade if you are near snow or water.

Ø It is a cloudy day, because unless the cloud color is very thick, enough UV rays can penetrate the cloud cover to burn you.

Ø They are outside during peak daylight hours, which are between 9:00 am to 3:00 pm, because solar rays are more intense at midday.  So, get up early, and then take a siesta at midday, to avoid the sun.



·       SPF is a rating that indicates a sunscreens effectiveness against ultraviolet B, or UVB rays, which are the most damaging type of light and cause sunburns and skin-cancer. 

·       Sunscreen Labeled as Broad Spectrum will shield skin from both UVB and UVA rays.  And according to the FDA a Broad-Spectrum sunscreen’s UVA protection is roughly proportional to its UVB SPF rating protection level.

Ø SPF 15 blocks 93% of UVB rays, and is the minimum rating recommended by Skin Cancer Foundation.
Ø SPF 30 blocks 97% of UVB rays and the Skin Cancer Foundation recommends SPF 30 or higher for extended outdoor activities.
Ø SPF 50 blocks 98% of UVB rays, and according to “How to Choose and Use Sunscreen”, SPF ratings above 50 aren’t useful, as nothing blocks 100% of UVB rays and a SPF100 sunscreen, which blocks 99% of UVB rays, blocks only 1% more UVB rays than a SPF 50 sunscreen4.

·       The SPF rating is also a gauge of how much time a person can be exposed to the Sun before being burned.  So, if you would normally begin to burn in 10 minutes, and you use a liberal dose of SPF15 sunscreen, you would be protected from sunburn for 150 minutes.

·       Water Resistant means that the sunscreen works well despite the presence of water or sweat.  The FDA testing determines one of two ratings, water resistant for 40 minutes and water resistant for 80 minutes.

·       Applying sunscreen on top of a DEET based insect repellent, can reduce the effectiveness of the sunscreen.  A study of persons who applied a 33% DEET repellent followed by a SPF 15 sunscreen, found an average 33% decrease in SPF, although the insect repellent maintained its potency5.  If you are going to apply DEET after putting on sunscreen, wait 15 minutes after applying the sunscreen to apply the insect repellent6.

·       Some products contain a combination of sunscreen and DEET and will deliver the SPF stated on the label, however these products are generally not the best choice, because it is rare that the need to reapply sunscreen and repellent occur at the same time.



Almost everyone uses too little sunscreen and almost no one puts it on correctly, so use the guidelines below.  The way you use a sunscreen is more important than its SPF, as SPF 30 sunscreen used well is better than a SPF 50 used poorly.

·       Apply sunscreen 15 minutes before Sun exposure

·       Apply sunscreen first to your most vulnerable areas, such as the nose, ears and back of hands and neck since these areas tend to receive more sun exposure than other areas.

·       Use massively more sunscreen than you think you should: a rule-of-thumb is, for a person wearing shorts and a tee-shirt, use 1 ounce of sunscreen (a full shot glass) and cover ALL exposed skin.

·       Pack enough sunscreen for the entire trip, and since according to dermatologists, two people on a four-hour hike on a sunny day should use an entire 4 fl. oz. tube of sunscreen, which is only two applications of two ounces, one ounce per person.  So, for long trips, instead of multiple tubes of sunscreen, plan on staying out of the sun or wear long pants, long-sleeved shirts, and a wide-brimmed hat.

·       Reapply at least every two hours, even though time is a factor in SPF Testing, the Federal Food and Drug Administration (FDA), which regulates sunscreens, recommends that you reapply any sunscreen every two hours, regardless of its SPF.

·       Toweling off your skin after swimming removes sunscreen, so reapply after toweling.

So, go out and enjoy all that warm weather and all that sunshine, just be smart and use your sunscreen, because nobody wants to get pre-cancerous lesions frozen off their face!
 
After cryo-therapy to have a pre-cancerous lesion frozen off my face, probably caused by too much Sun, photograph by the author.

I hope that you continue to enjoy The Woodsman’s Journal Online and look for me on YouTube at Bandanaman Productions for other related videos, HERE.  Don’t forget to follow me on both The Woodsman’s Journal Online, HERE, and subscribe to BandanaMan Productions on YouTube.  If you have questions, as always, feel free to leave a comment on either site.  I announce new articles on Facebook at Eric Reynolds, on Instagram at bandanamanaproductions, and on VK at Eric Reynolds, so watch for me.

That is all for now, and as always, until next time, Happy Trails!


Notes

1 I called the customer service number at Banana Boat®, 1-800-SAFESUN, and they explained that the first two numbers are the year in which was the product was manufactured and that the next three numbers are Julian date on which it was manufactured, so the 91st day of the year is April 1st and the 105th date of the year is April 15th.

2 With new bottles of sunscreen, if there isn’t an expiration date printed on the bottle, you should write the purchase date on the bottle with a permanent marker.

3 This code number records the date, batch, and location of where and when your bottle of sunscreen was manufactured.

4 Andy Chien, MD, PhD., David Kulow, “How to Choose and Use Sunscreen”

5 Paul S. Auerbach, Benjamin B. Constance, Luanne Freer; Field Guide To Wilderness Medicine, 4th Edition,

6 “How to Use Insect Repellents”


Sources

American Academy of Dermatology, “Can I use the sunscreen I bought last summer”, [© 2020 American Academy of Dermatology Association.], https://www.aad.org/public/everyday-care/sun-protection/sunscreen-patients/sunscreen-faqs, accessed July 14, 2020

Andre, Tifani; Bolitho, Carley; Smith, Scott F.; “How to Choose Sun Protection (UPF) Clothing”, [© 2020 Recreational Equipment, Inc.], https://www.rei.com/learn/expert-advice/sun-protection.html, accessed January 15, 2018

Auerbach, Paul S., Constance, Benjamin B., Freer; Luanne; Field Guide To Wilderness Medicine, 4th Edition, [Elsevier Mosby, Philadelphia, Pennsylvania; 2013], page 480

Chien, Andy, MD, PhD., Kulow, David; “How to Choose and Use Sunscreen”, [© 2020 Recreational Equipment, Inc.], https://www.rei.com/learn/expert-advice/sunscreen.html, accessed January 15, 2018

Fayed, Lisa; medically reviewed by Gallagher, Casey MD; “Does Sunscreen Expire?”, updated on January 27, 2020
[© 2020 About, Inc. (Dotdash)], https://www.verywellhealth.com/how-do-you-know-if-sunscreen-has-expired-514400, accessed July 21, 2020

Gibson, Lawrence E., M.D.; “Is sunscreen from last year still good? When does sunscreen expire?”, May 23, 2019, [© 1998-2020 Mayo Foundation for Medical Education and Research (MFMER)], https://www.mayoclinic.org/healthy-lifestyle/adult-health/expert-answers/sunscreen-expire/faq-20057957, accessed July 14, 2020

“How to Use Insect Repellents”, [© 2020 Recreational Equipment, Inc.],

“SPF vs. UPF- What is the difference?”, February 10, 2017, [© 2020 Sungrubbies], https://www.sungrubbies.com/blogs/news-articles/spf-upf-rating-differences, accessed January 27, 2018

U.S. Food & Drug Administration, “Sunscreen: How to Help Protect Your Skin from the Sun”

Weisberger, Mindy; “Is Expired Sunscreen Better Than No Sunscreen?”, June 11, 2018, [© Future US, Inc. 11 West 42nd Street, 15th Floor, New York, NY 10036], https://www.livescience.com/62783-does-expired-sunscreen-work.html, accessed July 14, 2020


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