Are High SPF Sunscreens Safe?
May 3rd, 2012
Neutrogena is just one brand that makes SPF 100.
Dear Nicki,
I’ve been reading a lot of reports lately that high SPF sunscreens contain too many chemicals and are unsafe. Is this true?
-Robin
Dear Robin,
It is well-known that over 80 percent of the visible signs of aging are attributable to sun damage. So it’s no wonder that the U.S. sunscreen market has been growing at a rate of 30% a year, to $650 million in 2011 (Mintel Sun Care Report, 2011).
Unfortunately, the sometimes overly alarmist Environmental Working Group said high SPF sunscreens can “penetrate through the skin, where they have been linked to tissue damage and potential hormone disruption.”
Analyzing the Negative Claims
Let's take a look closer!
When such claims are made, we must always consider the following:
- Were the studies done on humans? While the medical and scientific communities must start with animal studies, these models are much smaller than humans, resulting in them being subjected to very high doses of the matter being tested. What’s more, sometimes these animal models lack the advanced protective mechanisms of humans, resulting in false alarming conclusions. It’s always best to go with the human studies when they are available!
- Were the studies done in vitro (on cells) or in vivo (in living systems)? Organisms have evolved to have a number of protective mechanisms that can combat issues like oxidative stress and metabolic issues when these dysfunctions are minor, i.e., on the small scale. Sometimes applying an agent to a cell can seem negative, but can actually be beneficial to the system at large once other mechanisms are taken into account. Take, for instance, many antioxidant fruit oils, which have been found in many studies to be toxic to cells, or cytotoxic, but which have been found to have protective effects to the system at large in vivo (Cancer Research).
- Are the concentrations key ingredients used in the experiments typical of the amount of exposure from application of the product? For instance, even vitamin C can be toxic at doses above 2000 mg/day for the average 150 lb. person. Some studies test large doses of ingredients on very small animals, and the media often runs rampant with these terrible conclusions, which are largely unfounded, as has occurred with many of the studies on parabens.
- Does the person or group making the statement or conclusion have underlying motivations? While the Environmental Working Group is a “non-profit” that comprises some scientists, it also has a number of political activists behind it who are working to get a large following. Hence many of their claims are bold and audacious, go “viral” online, and are refuted by other scientists later – but the media rarely picks the rebuttals up because they’re considered “boring”. Take, for instance, what happened with retinyl palmitate in 2010: The Environmental Working Group released information that the retinyl palmitate in sunscreens could potentially cause skin tumors, and the report went viral, with over 2000 reports written and millions of shares within the first week. Yet the report was based upon a single study in which a high concentration of retinyl palmitate was used as the only ingredient, applied to mouse skin, and irradiated with light. The experimental design was clearly flawed, as Dr. Steven Q. Wang, M.D. Ph.D., director of dermatologic surgery at Memorial-Sloan Kettering Cancer Center later explained, “Despite the concerns raised by these non-human studies, retinyl palmitate operates within the skin as only one component of a complex antioxidant network. In these non-human studies, retinyl palmitate was the only compound studied, making the biological relevance of these findings to humans unclear.” So be careful – the Environmental Working Group essentially wants your “share” on Facebook as much as cosmetics companies want a sale! This is not to say that some of their work is not good. However, it is meant to make you more skeptical of sensationalist headlines in general. Remember: if it sounds too good or bad to be true, it probably is!
- Is the ingredient studied actually the same? Be careful – ingredients that sound the same can sometimes be drastically different. For instance, it has been found that retinol is 100 times as potent as retinyl palmitate!
Breaking down the science of the sun care issue
High SPF sunscreens typically use non-oxide chemical sunscreens, like avobenzone, oxybenzone, and Parsol 1789, which work by transforming UV light into non-harmful forms of energy, like heat or non-UV light.
The two major issues with high SPF sunscreens are irritation (called contact dermatitis) and systemic absorption.
Contact dermatitis will result in red, sore, and inflamed after contact with the sunscreen. If this occurs, you should switch to another sunscreen, perhaps one with micronized zinc or titanium oxide, which have lower risks of irritation.
As for systemic absorption, it is not to be a concern for anyone who is not nursing, pregnant, or a small child. At this time, avobenzone and oxybenzone are not considered to be toxic agents (Journal of Cosmetic Dermatology, 2010). Yet many dermatologists, including Dr. Leslie Baumann, M.D., still do not recommended that sunscreens with avobenzone or oxybenzone be used on children or by pregnant or nursing women, because they are absorbed into the body.
Yes, avobenzone and oxybenzone are secreted in the urine.
In a study from The Lancet, patients applied avobenzone and oxybenzone sunscreens. In the hours after, traces of avobenzone and oxybenzone were found within their urine, indicating the substances are in fact systemically absorbed.
It is thereby best to use a formula with a physical block, like micronized zinc oxide or titanium oxide, on children, or if you are pregnant or nursing. We like the following:
- Neutrogena Pure Free Baby Block SPF 60 ($11.99, Amazon.com) – All of the high SPF Neutrogena is known for, combined with the safety of a zinc or titanium oxide with a silicone base, so there is little or no systemic absorption.
- Elemental Herbs Sunscreen Sport ($15.99, Elementalherbs.com) – A new line, this company specializes in using organic herbs I know my “green” readers will love!
- MyChelle Sun Screen SPF 28 ($35.69, Amazon.com) – An old favorite of mine, this sunscreen does the job, dries clear, and provides serious protection despite the SPF 28 rating.
- NIA 24 Sunscreen SPF 30 ($38.25, Amazon.com) – With skin-brightening and ultra-refining nicotinic acid, a derivative of vitamin B3, this sunscreen acts as a 2-in-1 treatment program and sun protection method. My only qualm about it is that it is not for the weak: Your skin will likely get a little red and raw from it in the first few days, only to be highly refined in the weeks afterwards. I love it!
The True Difference Between High and Low SPF
Let’s say you are in love with a chemical sunscreen with a high SPF and don’t want to switch to zinc or titanium oxide.
Truth be told, there is very little difference in the systemic absorption of high and low SPF chemical sunscreens for the average user.
As an example, let’s look at the active ingredients in Neutrogena Ultra Sheer Dry Touch SPF 100:
- Avobenzone (3%)
- Homosalate (15%)
- Octisalate (5%)
- Octocrylene (10%)
- Oxybenzone (6%)
And in Neutrogena Ultra Sheer Dry Touch SPF 30:
- Avobenzone (2%)
- Homosalate (7%)
- Octinoxate (7.5%)
- Octisalate (5%)
- Oxybenzone (3%)
That “giant SPF 70 difference” comes down to the following difference in percentages:
- Avobenzone 1%
- Homosalate 8%
- Octocrylene 10%
- Octinoxate (-7.5%)
- Octisalate 0%
- Oxybenzone 3%
Not very much, is it? Of those ingredients associated with systemic absorption, you are getting just 1% more avobenzone and 3% more oxybenzone from SPF 100 than SPF 30. Yet let’s take this a step further. Studies have shown most users apply only 25%-33% of the sunscreen they need to get the protection listed on the bottle! [Read More: The Ugly Truth about Makeup and Moisturizers with SPF!]
With Neutrogena Ultra Sheer products as the example, this means you are only getting about 0.3% more avobenzone and about 1% more oxybenzone from SPF 100 than SPF 30 from typical applications of both. Even less than this is absorbed systemically.
Put another way, the difference over your entire body is minor, but the difference in UV protection this makes to your skin is substantial! Unless you are pregnant, nursing, or applying sunscreen on a small child, I would not worry about the increase in chemical exposure when increasing from SPF 30 to 100. (And if I was pregnant, nursing, or applying sunscreen on a small child, I would simply switch to a high SPF micronized zinc or titanium oxide, which have not been associated with systemic absorption at all).
Bottom Line
The true risk of switching from a low SPF to a high SPF may simply be the false sense of security you get from the higher number. In fact, Philippe Autier, a scientist at the International Agency for Research on Cancer, conducted a study and affirmed high-SPF products do in fact spur “profound changes in sun behavior” that may account for the increased melanoma risk found in some studies. So it is crucial, even with SPF 100 products on your back, to always reapply sunscreen every 4 hours and after immediate water exposure, and to avoid the sun as much as possible between the hours of 10 AM and 4 PM.
Regardless, if you are not pregnant, nursing, or applying sunscreen to a small child, I would not worry about using products with avobenzone and oxybenzone. However, if you are the cautious type, take solace in the fact that sunscreens with zinc and titanium oxide have not been associated with systemic absorption as of yet.
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