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Can you use diaper rash cream as sunscreen? Episode 162

Can you use diaper rash cream as sunscreen?

Mari asks…Today a customer came into the retail pharmacy where I work and demanded that we sell him zinc oxide diaper rash paste so he could use it as sunscreen. I tried to steer him in the direction of actual sunscreens with listed SPFs, but he was not to be dissuaded and ended up leaving with a tube of generic diaper rash cream (with no listed SPF) in hand. His rationale was that diaper rash paste has a higher percentage of zinc oxide than zinc oxide sunscreens. Although this is sometimes true, depending on the brand, my concern is that (a) the formulation of a diaper rash paste might not make it an effective sunscreen and (b) without a listed SPF, there’s no way to really know. What are your thoughts on this?

We’ve talked quite a bit about sunscreens on the showgram but believe this is the first time that diaper rash products have come up. So a little quick background discussion is in order.

We used to think that urine was the primary cause of diaper rash which makes sense since a baby (especially under 2 months) can urinate up to 20 times per day. But the hypothesis was that urine releases ammonia which raises the pH of skin which opens it up to damage. But it turns out urine is NOT the primary cause…it’s feces.

The pH of feces is acidic due to bile and studies have shown that diaper rash is more prominent where the feces contact the skin. This contact can lead to yeast and bacterial infection. So mark your calendars that today was the day that the whole urine-diaper rash myth was busted.

And that brings us back to diaper rash creams. In case you didn’t know, both sunscreens and diaper creams are Over the Counter drugs and are controlled by the FDA.

Sunscreens are 1 type of drug…they are sunscreens. But diaper rash creams are actually not 1…not 2…not 3 but actually 4 different types of drug products: External Analgesic, Topical Antifungal, Topical Antimicrobial, and Skin Protectant.

In addition to Zinc Oxide other approved diaper rash ingredients include mineral oil, petrolatum, cornstarch, allantoin, calamine, dimethicone, kaolin clay, and cod liver oil.

How does ZnO help with diaper rash? It works 3 ways: It helps water proof (or feces proof) skin, it’s a mild astringent which means it can cause the contraction of body tissues, and it has some antimicrobial properties. That’s what makes it suitable for use in the 4 drug product categories we just mentioned.

So Zinc Oxide is an approved drug ingredient that is used in both products. But does that mean you could use them interchangeably? Can you use diaper cream as a sunscreen as the demanding gentleman in Mari’s pharmacy intended to do.

And conversely, can you use sunscreen on diaper rash?

Let’s begin by answering a fundamental question: is the zinc oxide used in diaper creams the same as the zinc oxide used in sunscreens?

In classic Beauty Brains fashion, the answer is yes and no. Chemically, they’re identical. Both have to use USP grade [what does USP stand for] which means they have to meet certain purity requirements.

BTW did you know that, being a natural product, zinc oxide contains somewhere between 1 and 10 ppm of lead?

Physically, there are differences. Zinc oxide powders are sold with different particle sizes and the size of the particle impacts how well the zinc screens out UV rays. It’s even more complicated than that because it’s not just the size of the particles but these particles tend to stick together to form clumps or aggregates which affect how well the zinc scatters UV rays.

In addition to different particle sizes zinc oxide is commercially available in different varieties such as surface coated varieties as well as dispersions in different materials like natural oils and silicone fluids.

So sunscreens HAVE TO use a version of zinc oxide that’s designed to scatter UV rays…and sunscreens are tested to ensure that they do indeed do that. But diaper rash creams do NOT have to use one of those forms. They may or may not and there’s no way to know since diaper rash products are not tested for UV protection. So that’s issue #1.

Here’s issue #2: Even if a diaper rash cream uses the exact same grade as a sunscreen, the way the diaper rash cream is formulated can impact level of UV protection it provides.

Yeah, the medium in which the zinc is dispersed can determine the final opacity of the product. In other words, the oils, waxes, and other ingredients used in diaper creams can make the final formula more transparent in which case it won’t filter out as much UV radiation.

And then there’s issue #3: The way the product is processed makes a difference as well. For sunscreens, specific dispersion technology can be used to one way to make sure these particle agglomerates are broken up.

Diaper rash products wouldn’t necessarily require the same kind of dispersion technology.

What does all this mean? IF a diaper rash cream contains the right kind of ZnO, and IF it’s used at the correct concentration and IF it’s properly processed, and IF the final formula doesn’t contain any ingredients that can compromise the UV scattering properties of the ZnO, THEN you certainly could use a diaper cream as a sunscreen.

But the only way to know for sure is to conduct SPF testing and it’s doubtful any company will do that because even if it works they can’t use that data to promote the product? Why not? Because the drug monographs and don’t allow for any combined claims.

Even if I knew all those IFs where true I’m not sure I’d want to use diaper rash cream instead of sunscreen. Aesthetically it could be a trainwreck: a diaper cream’s PRIMARY purpose is to create a hydrophobic barrier so they use high amounts of things like petrolatum. A high ZnO/petrolatum cream is great for babies but not very pleasant when smearing all over your face or body.

Is there ANY reason why you’d want to do this? I’m guessing it’s motivated by cost: depending on the brand, diaper rash creams can be cheaper than sunscreens. For example, Desitin costs about $1.75/oz while a ZnO-only sunscreen like Badger costs about $4.70/oz.

So the Beauty Brains bottom line is amount of money you save is not worth the risk of compromised UV protection or the sacrifice of aesthetics.


Is facial massage good for winkles?

Mark asks…is facial massage good for wrinkles?

We’ve touched on this before. Way back in Episode 14 we answered a question about facial yoga being good for wrinkles. So go listen to that for a full recap. But the basic idea is that “plumping up” muscles by exercising them gets rid of wrinkles. Massage is essentially another way to stimulate facial muscles.

But as we pointed out at the time, muscle laxity is not the cause of wrinkles – rather it’s the collapse of structural elements like collagen and elastin. So if we’ve covered this before why are we answering it again? Because it gives us an excuse to discuss another aspect of this which is using electrical stimulation to get rid of wrinkles.

CNN recently reported electro-stim for skin and they quoted Jennifer Aniston who said that “”It’s like a little workout for your face.” And an aesthetician they interviewed said that the more times you have the procedure the more results you’ll see.

Sure, get a bunch of treatments – depending on where you have it done it costs between $200 and $600!

However, the consensus of the medical experts they talked to is that “there is no data demonstrating its effectiveness.” I did find a couple of papers on the subject. One study tested 6 women. Another evaluated 108 women and did show that the procedure resulted in SOME difference in facial muscle thickness.

But it required treatment for 20 min/day, 5 days/week for 12 weeks. That would cost you between $12000 and $36000. Who’s going to spend that kind of money for such a small benefit?

As always the important takeaway is that you think critically when you hear about treatments like this. Not everyone thinks like that. 

RS: When I posted this on Facebook, one commenter said “Clearly Mr. Knott needs to experience micro current himself because regardless of “data” it most certainly does produce results and it is so much more than a “feel good” skincare modality. It seems like he is trying to discredit skincare therapists.”

I replied: DM: It may be nice for Mr. Knott to experience the treatment but that doesn’t prove or disprove that it really works. That’s what “data” is for and in this case there doesn’t seem to be sufficient data to prove that this treatment really works. If you’re familiar with any evidence we’d love to see it and share it with our readers.

Does this plant extract boost collagen?

Ana asks…We love the beautybrains podcast here in Portugal and I finally have a question to ask. I read recently about a plant called bulbine frutescens that is kind of similar to aloe. In some studies it says the juice of the plant stimulates collagen production. Have you heard about it? Do you think it would be a good think to use on the skin for the anti aging properties?

Bulbine frutescens is similar to aloe in that their both used in the treatment of skin wounds and burns. We found a study showing that leaf gel extracts can increase collagen deposition in wounds on pig skin.

I won’t go into details on how the testing was done but unfortunately I CAN’T say that “no pigs were harmed during the course of this study.”

But even if there is some data, before you get too excited, consider 2 of the Kligman questions. Remember what those are?

Mechanism, penetration, and data it works on real people.

In this case they’re applying the BF leaf extract directly to a wound. So the extract doesn’t need to penetrate and the mechanism of wound healing is NOT the same as the production of normal collagen that keeps your skin looking smooth and healthy.

In fact, we couldn’t find anything to suggest this material has anti-aging properties when applied to healthy skin.

If it is similar to aloe it may have some moisturizing properties and it may be good for sunburn but don’t expect it to fix the kind of collagen loss we all experience as we age.


https://www.researchgate.net/publication/232319403_Bulbine_Natalensis_and_Bulbine_Frutescens_promote_cutaneous_wound_healing [accessed Jun 21, 2017].

Beauty Science News

J&J vs natural products


I want to give a quick mention of an article I saw on Global Cosmetic News about Johnson & Johnson speaking out on natural products. First of all I love the title: J&J calls parents bluff over natural baby products. Let me quote the article:
“While many parents want all-natural products for their baby, natural or organic isn’t always what’s safest for baby,” said David Mays, Senior Director of Global Scientific Engagement at Johnson & Johnson in an email sent to Forbes. “The debate over naturals and chemicals has been oversimplified where many consumers now believe that the more natural something is, the better and safer it is. It’s just not that simple and in fact that oversimplification is doing a great disservice to consumers.” I think important take away is this quote: ‘being natural is never more important than being safe.’

Artificial sun tan


iTunes reviews

  • Ouija says…Your “showgrams” are fun, educational, and a much needed public service. Put me down for a yes on the banter.
  • Tornadogirl1981 from Germany says…So useful! Should be on a list for everyone who spends money on skincare. In addition to substance, the form of delivery makes you laugh out loud so beware when listening to the Beauty Brains in public places.
  • Tavelbella says…Just when I thought I knew it all! Love sharing your factoids with my clueless friends.
  • Rose from Australia…Great to learn more about beauty products and how they work 🙂
  • Sashawhyismynamenotavailable says…Great podcast for the closeted cosmetics junkie (or junkie to be) — 5 stars
  • Togahairgurl…I absolutely love listening to these Cos-chesmonauts! I would love to be in your industry, so listening to your podcast is fascinating.

Comments on this entry are closed.

  • Jamie July 20, 2017, 7:51 pm

    Using diaper cream as sunscreen is actually fairly common in surfing circles! Some people swear by it, insisting it’s the only thing that prevents sunburn after long surf sessions although I suspect that has more to do with water resistance (90% of “ultra water resistant” sunscreens completely rinse off after a few waves whereas diaper cream manages to stay on much better) than UV filtering capabilities.

    On that topic, do you guys have any guidance of what ingredients to look for in identifying sunscreens with reliable water resistance?

  • Margaret July 21, 2017, 12:03 pm

    Web MD states that feces is normal pH of 7 to 7.5, NOT acidic. Could it be something ELSE in ca-ca causing diaper rash instead of the pH, since it’s pretty well neutral in pH?

    • Randy Schueller July 24, 2017, 8:38 am

      Hmmm. It looks the original reference we found stating that feces are (is?) acidic is not completely accurate. Maybe WebMD isn’t either. I checked with Quest Diagnostics (a major medical test lab) and their pH range for feces if 5.82 – 8.0. http://www.questdiagnostics.com/testcenter/BUOrderInfo.action?tc=1304&labCode=AMD So it looks like feces can be acidic but not always. Also, I’m not sure if the pH of infant feces is any different. Thanks for catching this!

  • Katt Philipps July 29, 2017, 2:25 pm

    Nice episode, however, I believe the way you answered the question on facial massage may have been misleading. The question was if it were good for wrinkles, and I agree, there is no specific data to support that, however, that isn’t to say that there is NO benefit. Facial massage stimulates the lymphatic system similar to the way that exercise works on the rest of the body. Studies done at the University of Illinois, showed massage to benefit vascular function and the increased circulatory response lasted several days (full disclosure: studies were done on sedentary patients). https://www.sciencedaily.com/releases/2014/04/140416125434.htm
    Massage increases blood flow and nutrients to the skin, there is significant evidence of that. I agree that doesn’t mean it erases wrinkles, but it doesn’t make it worthless as your statements implied.
    I believe you did not actually answer the proposed question, “Is facial massage good for wrinkles?” the answer you provided was “Does electro-stim work for removing wrinkles?” Which that modality works on the muscle, not by massage. Also, Jennifer Aniston uses micro current, and not micro-stim (micro-stim is the technology that was called the TENS unit which was using milliamps which is a higher voltage, micro current uses micro amps). I have no knowledge or assumptions on either modalities effectiveness.
    I apologize for being nit-picky, but as an avid listener, I was surprised to see you answer a question with the data from what seemed to be entirely different type of question.

    • Randy Schueller July 30, 2017, 8:10 am

      Excellent comments, Katt, thank you. I agree we did sort of switch topics while answering this question. We tried to point that out during the show but apparently that didn’t come through very well. Nit pickers like you keep us on our toes!

  • Anna August 23, 2017, 12:37 pm

    Hi, I hope this is ok to to ask here. Could you talk about the importance of film formers in sunscreen and what if any are the best ones to look out for? Is there also anything we should not be doing that would affect the integrity of these film formers?

    Thank you so much!

    • Randy Schueller August 24, 2017, 7:35 am

      Hi Anna. I don’t really know how to answer this. Just looking for film formers won’t really tell you much about how the formula works. Sunscreen formulas are complicated and how they work is a function of many factors.

  • Laura May 2, 2018, 4:30 pm

    I was out with my son today, searching for the sunscreen and realizing I forgot to bring it. Given the zinc oxide content (13%; Walgreens brand) I thought I’d try some of the diaper rash cream. We were out in the park, mostly staying in the shade from 10am to noon, plus some biking in the sun. I definitely feel like I got a bit of sun, and my son, who ran off to play in the sun and refused to wear his sunhat had bright red cheeks after 20 min (which is when I realized it was time to get home). Overall I’d say the diaper rash cream was better than nothing, but was a terrible substitute for sunscreen.

    • Perry Romanowski June 15, 2019, 12:12 pm

      I’d agree. Better than nothing but not a good sunscreen.

  • Hallie Harris January 15, 2019, 9:55 pm

    My company is Pinxav (pink salve) a diaper rash cream invented by my grandfather in 1927. Can you help me by reviewing by product? I feel your site has been so informative for my diaper rash formula.
    I want to connect in any way possible.
    Thank you

    • admin January 16, 2019, 7:54 am

      Thanks for your comments. We do not currently do product reviews.

  • Ron May 21, 2020, 12:22 am

    I know this is an old post, but anyway: In the 1980s, sailors, skiers and surfers used opaque sunscreens. Usually white, but sometimes other colours. I want a product like that so I can see that it is there. I am a long distance cyclist, and I don’t have time to stop every hour to apply sunscreen. I already look awful on the bike. A bit of war paint won’t make it worse.

    • Perry Romanowski May 22, 2020, 8:41 am

      Look for products that contain a high level of Zinc Oxide

  • Leslie June 10, 2020, 3:58 am

    These are some of the basic uses of diaper rash cream listed. I am amazed to read these uses of rash cream.