Skin Protection

Because of the effect of light on the skin, Marshall Protocol (MP) patients who exhibit photosensitivityAbnormal sensitivity to sunlight and bright lights. Also referred to as "sun flare" or "light flare." must protect their skin from exposure to natural light.


MP patients should wear dark clothing outdoors, because dark, dense fabric blocks all types of light better than white fabric, which lets some light through. Darker, thicker clothing stops all light energy from falling on the skin. That is the goal. The thin, light-colored fabrics that are supposed to stop UV should not be used. Outdoor attire should include shirt with a high collar and long sleeves, trousers or a long skirt, socks and shoes, a wide-brimmed hat and gloves.


Sunscreen use should not be seen as a replacement for sun avoidance measures, but only as a tool that sometimes helps when used in conjunction with sun avoidance measures.

The only sunscreen ingredients which appear to offer a significant level of protection from vitamin D production and sun flare symptoms in Th1 patients are zinc oxide, Helioplex, and titanium dioxide.

Joyce Waterhouse, PhD has produced a review of the various types of sunscreen. A summary of that review is reproduced below.

Zinc oxide

Sunscreens containing zinc oxide appear to work as well or better than ketoconazole cream for blocking sun sensitivity symptoms. Zinc oxide containing sunscreens appear to be more effective when they contain a higher percentage of zinc oxide: 16-25% vs. 3-10%. It should be remembered, though, that even a high percent of zinc oxide sunscreen only blocks a percentage of light radiation, so the longer the skin is exposed, the less effective it is. If one is exposed to light for more than a few hours, it becomes completely ineffective.

Zinc oxide is recommended for MP patients over ketoconazole cream because it inhibits both 25-DThe vitamin D metabolite widely (and erroneously) considered best indicator of vitamin D "deficiency." Inactivates the Vitamin D Nuclear Receptor. Produced by hydroxylation of vitamin D3 in the liver. and 1,25-DPrimary biologically active vitamin D hormone. Activates the vitamin D nuclear receptor. Produced by hydroxylation of 25-D. Also known as 1,25-dihydroxycholecalciferol, 1,25-hydroxyvitamin D and calcitirol. production, whereas ketoconazole cream only affects the conversion of 25-D to 1,25-D. Ketoconazole also is likely to interfere with the VDRThe Vitamin D Receptor. A nuclear receptor located throughout the body that plays a key role in the innate immune response. and becomes ineffective in dealing with Stage 5 reactions to light.

Neutrogena products with Helioplex offer some protection, but it only lasts for about 90 minutes after each application, whereas zinc oxide products work until the sunscreen is washed off.

Ketoconazole cream

Main article: Antifungal agents

Related article: Skin protection

Ketoconazole cream, sometimes referred to as “K-cream,” is a topical cream or shampoo that may reduce sun flare or light-driven immunopathology. Although ketoconazole cream was once recommended to MP patients, the recommendation that patients routinely use K-cream has been withdrawn. Like the other antifungals, ketoconazole cream may inhibit bacteria die-off, especially in the skin areas where it has the highest concentration.

Patients for whom light sensitivity is a problem should consider zinc oxide as an alternative for preventing moderate symptoms associated with sun exposure that cannot be avoided. For some of the most severely sun sensitive, ketoconazole cream or shampoo seems to work better for preventing or reducing sun flare symptoms, but for others, zinc oxide (not an anti-fungal) seems to work better. Both may have inhibitory effects on the immune response.

Effect of sunscreen on vitamin D production

Several researchers have concluded that even when throughly applied and regularly used, sunscreen has a limited effect in slowing vitamin D production:

Several large prospective studies have shown that vitamin D deficiency does not result from regular sunscreen use.

W.L. Scarlett 1)

Vitamin D levels are not significantly affected by regular use of a sunscreen.

F.J. Moloney, et al. 2)

Clinically prescribed sunscreen creams (sun protection factor 15) caused a minor decrease in 25-hydroxyvitamin D levels, which did not induce secondary hyperparathyroidism or an increment in bone biological markers.

J. Farrerons, et al. 3)

One research team, studying patients with xeroderma pigmentosum (XP), a genetic disorder in which patients are unable to repair damage caused by ultraviolet light, found that vitamin D levels are maintained even when patients practice at least six years of rigorous photoprotection and not supplementing with vitamin D. More importantly, the researchers also concluded that the clinical manifestations of vitamin D “deficiency” were absent.

The patients all wore protective clothing and sunscreens when outdoors. Estimated mean vitamin D intake was normal. The mean values of serum 25-OHD were low normal, but 1,25-(OH)2D, calcium, ionized calcium and parathyroid hormone levels were normal…. Despite rigorous sun protection normal vitamin D levels can be maintained in ambulatory patients with XP.

R.B. Sallitto, et al. 4)

Window coverings

Rooms inhabited most will need dark curtain material or some other covering that will block virtually all visible, infrared and ultraviolet light. Miniblinds or vertical blinds on windows are typically not enough protection.

Redi-Shades - We found a great product at Lowes (or Home Depot) to put under shades or curtains. It is inexpensive, easy to install and does the trick. It comes in two sizes: 36“ wide or 48” wide, both are 72“ long. It can be cut down to a smaller width easily. We taped it to the bedroom window top and bottom and it blocks quite a bit of light. Since I rarely go thru the rest of my house we just keep the rest at a minimum amount of light.

Delray, MarshallProtocol.com

I found I needed to get the room darker than I could with mini-blinds. My solution was to get some blackout curtain backing fabric to use to make temporary curtains. I found the fabric at the Jo-Ann Fabrics store. My husband cut the fabric to size to fit over 4 large picture windows we have in our living room. We also put it up over the bedroom windows. My mother-in-law helped out by sewing small curtain rings onto the upper corners of the fabric. We put some small nails up at the upper corners of the windows. This way we can hang the curtains up but still easily take them down, for instance in the evening after it is dark. I like to look out at the city lights then and it helps ease the sense of claustrophobia from having the blinds closed all day long. This has been a great solution for me.

Catlady, MarshallProtocol.com

My daughter bought these really cool brown leather curtains for her livingroom at Penny's. Really total blackout and a rather modern look for her, so we are both happy. So when I visit, no more sun issue.

Melinda, MarshallProtocol.com

I purchased 15 packages of black vinyl opaque shower curtains from Walmart and will be nailing them to the windows today! My husband, Tom and the plants will have the guest room as a retreat. Heavy Duty Commercial Grade Black Vinyl Shower Curtain or Liner. We did a few of the windows today and they worked out beautifully. Hopefully, they will also help with some of the heating costs as well.

DianeC, MarshallProtocol.com

Read more

===== Notes and comments =====

Paul, I was thinking you should probably add a stronger statement to the KB https://mpkb.org/home/lifestyle/light/skin_protection#zinc_oxide based on what Trevor said.

– basically that we now strongly discourage the use of ketonconazole due to its effects on the P450 enzyme system as well as other effects.


* Hi Trevor, I realized due to being too busy I had not finished with this issue. I hadn't been thinking about it until Joyful brought the recent sunscreen discussion to my attention. Were discussing the sunscreen threads that I posted in the moderators forum and was about to put in a section where people could see them back in mid November. Your comments are below and in response to them: I added a statement about ketoconazole cream and the P450 system. I replaced the statement about 400 IU D that you objected to with this: The symptoms I experienced were identical to what I got from increased IP due to antibiotics. So, if that is alright, I will move these several posts to a forum where everyone can see them, since now, the sunscreen overview is mentioned in the kb but the link doesn't work due to it being in an archived forum. Joyful, which thread did you think these should go into? I thought that it should be one everyone could see? Joyce *

Well, if you put my disclaimer about ketoconazole right at the beginning of where you start talking about it then I think people are more likely to see it. And add the interference with the key P450 enzymes too. Remember that ketoconazole was banned from internal use after it was found to be toxic. Incidentally, I also have reservations about zinc, you may recall.

I am not trying to 'buy an argument' but just making sure we document things exactly correctly.

DeLuca did not find quantities of 25-D being expressed. He most certainly would have quoted Holick if he had found production. Do you want to hang our science on a 1980 Holick paper? To be honest, I haven't had time to re-read either paper - working on abstracts for two conferences at the moment. Tomorrow may be a better time for me.


* At 04:39 PM 11/15/2010, Jcwat101@aol.com wrote: Trevor, I am shortly planning to post what I have just posted in the moderator thread in the General Discussion thread. Joyful and Paul and I agreed this was probably the best way to handle the situation with that thread I had started and linking to it in the KB. Then, we will link to these posts in the KB. One of the posts has a link to the discussion thread that I started where people share experiences. I had to repost since we were linking to the sunscreen overview in the KB but it had become inaccessible due to the archiving. If you don't object, I'll start posting it in the public area this evening and work out with Paul what articles in the KB will link to which posts. Let me know if you have any comments or suggestions. Joyce </blockquote> *Legacy content * https://www.marshallprotocol.com/view_topic.php?id=33&forum_id=2&jump_to=74930#p74930 * https://www.marshallprotocol.com/view_topic.php?id=33&forum_id=2&jump_to=84637#p84637 * https://www.marshallprotocol.com/forum37/2613.html * https://www.marshallprotocol.com/forum32/2957.html#p26171 * https://www.marshallprotocol.com/view_topic.php?id=2957&forum_id=32&jump_to=140087#p140087 Clothing issues in warm weather**
From: neldawhite
Date: 2010-07-01 20:06:11
Reply: https://mp-lifestyles.org/reply.php?topic_id=5

Here are my experiences and success in trying to cool down while exposed to hot weather and sun. I still hot flash and do not properly perspire so I overheat very easily and become very sick if I do not cool my body down quickly once the overheating process starts. Yesterday in Sacramento it was about 108 so even indoors I used my cooling vest and the wet wrist bands to keep my wrists cool especially while on my lap top.

First off I have found that if I must be in the hot sun I must protect most of my body from the sun rays that pierces clothing and causes heat directly from contact. I prefer to wear a large lined black hooded loose fitting trench coat with hood that completely blocks the sun rays from getting near my skin. Thin black clothing just attracts the sun and makes the skin feel hot so the coat or cover must be thick enough to block all rays while fitting loose allowing skin to breath. While the coat seems hot it actually keeps you much cooler as it blocks out all sun. And an umbrella is a must for face and head.


I get a larger size so it fits loose

I wear a thin t-shirt underneath the coat with a Polar wet cooling vest, very wet so that it wets the t-shirt and wets the upper areas of my pant waist line a bit as well. I then wear a thin swimming jacket from Coolibar to protect the Trench Coat a bit from the wet vest. Also if I need to remove the trench coat then I have a long sleeved thin 50spf jacket on, for shade or indoor settings.

If it’s really hot I will wear my black swim tights and put them on slightly damp, with either a long dark skirt or thin pants over them. This keeps the sun off my skin while keeping me very cool. It seems binding but it is quiet cooling on the body.

I also wear the wet wrist bands on wrist and ankles. I keep a portable handheld fan nearby. I also keep a personal mister (see below) to spray and fan my face should I continue to overheat. Fans work so much better on damp skin. I also wear a wet neck bandana which I turn over continually as it gets warm. I keep a large baggie or mini cooler with extra water for dipping garments in as they dry.

If I don’t wear the trench coat in the car I at least drape it over my lap to keep the sun rays off. Makes a world of difference in personal comfort.

When we travel to our time share in Cabo each year I love this outfit as I can easily slip in and out of the cool (hot) tub/ pool fully dressed in my fully swimmable outfit. Then wear it down to walk the beach or eat in the restaurant there.

I’ve never used the skull wet caps or wet baseball caps but I’ve included the links here also. My hair is so thick it would not penetrate but for the men it could be refreshing. Also these links show women’s styles but they have everything for men as well

https://www.coolibarimages.com/Section-pages-icons/customers/c256/03209/generated/03209_298A_205x240.jpg https://www.coolibar.com/03209.html
Swim jacket Sunteck Fabric

https://www.coolibarimages.com/Section-pages-icons/customers/c256/03210/generated/03210_580A_205x240.jpg https://www.coolibar.com/03210.html
swim tights.


I personally like the styles that do not require ice as it melts fast and it’s hard to replace the ice when you’re out, and ice is often uncomfortably cold. However these styles only require quickly soaking in water. I can use a public rest room or pack a small carry thermal case with cold/icy water and rewet there if necessary. I bought two sets of wristlets and wear the 2nd on my ankles, or place one wet under bra or under panty line. Sorry to be so graphic but hey whatever cools us down.

This vest fits perfectly under a nice v lined sleeveless top so I wear it under evening wear as well.



Chill out and relax with the Evaporative Cooling Vest by Polar Products. Don't let the summer heat get you down! This stylish personal cooling vest breaks through the heat like a fresh breeze with its polymer fabric, enabling you to enjoy being outside in the sweltering sun. This cooling vest is designed to help individuals with multiple sclerosis or other neurological or physical disabilities which cause intolerance to heat.

How to use

Submerse in water for 1-3 minutes
Wring out excess water
Provides hours of cooling relief
https://www.painreliever.com/polarproducts_EvaBallCap.htm l



I have about 4 of these misters and everyone steals them from me. I don’t sweat so it really helps to apply a thin layer of mist to my face or chest and use a small personal fan to cool down for those moments when you are really overheating and just need some relief. It is small and works on a pump action. I found mine at Wal-Mart.

Hope this gives you some ideas.


The section in the KB that addresses this to some degree is here:


We could add your paragraph: “A short amount of time outside without sunscreen (20-30 min.) will produce all the vitamin D for the day in most cases. If you reacted less than 12 hours after the sun exposure, then that part of the reaction was unlikely to be IP (but instead, some other sort of photosensitivity). The IP part takes longer, from what I have observed and read – beginning about 20 hours later and peaking 2-3 days later. But the CGA cuts that increased IP part off very quickly – within an hour.”

As a quotation at the end of that section if you think that is sufficient?

Or perhaps a new section to differentiate between IP from D production v.s. other photosensitivity could be added below this section?



I previously computed that Ketoconazole was a high-affinity VDR antagonistA substance such as 25-D or certain bacterial ligands which inactivates the Vitamin D Receptor the receptor which transcribes the genes necessary for a proper innate immune response., but it seems it also has direct affinity for key enzymes in the D metabolism.

DeLuca's group wrote the paper linked above, so it is focused on the past, with the first sentences of the introduction being boiler-plate peer-reviewer-aggrandizement, but there is a lot of interesting stuff in the paper, especially in the Discussion.

Bottom line is that we want to cohort to understand why Ketoconozole is (generally) palliative, and why it was banned from internal use some years ago. In short, it is dangerous to life.

Enjoy (and thanks for the link, Ragnar)


From: jcwat101Date: 2011-02-21 11:06:19 Reply: https://marshallprotocol.com/reply.php?topic_id=13718

The two studies Trevor cited regarding sunscreen did not use zinc oxide but the synthetic chemical sunscreens.

I find that zinc oxide at high concentrations (18-25 %) does work for me if I'm not outside a long time.

But it only blocks 90% or so of the sun's effects.

If you are outside more than two or three hours, it becomes less effective. If you are out 5 or 6 it is almost like you didn't wear it because of the % of the light that gets past the sunscreen.

I also have evidence from my own experience that the zinc oxide is not absorbed significantly, since if I don't wash it off, it continues to work for days. Yet briefly washing one's hands for instance means the effect is gone.

This is unlike the synthetic chemical sunscreens that break down and/or are absorbed within a couple hours of putting them on.

This supports various studies various laboratory studies of zinc oxide. I know Trevor is skeptical about the absorption, but since my experience agrees with the studies, I tend to think they are correct.

Joyce Waterhouse

See https://marshallprotocol.com/forum11/13724 for discussion of sun exposure and sunscreens etc…

From: Dr Trevor Marshall Date: 2011-02-21 11:40:42 Reply: https://marshallprotocol.com/reply.php?topic_id=13718

Joyce is correct, sunscreens are still a grey area where there is a paucity of real data :)

===== References =====

Scarlett WL. Ultraviolet radiation: sun exposure, tanning beds, and vitamin D levels. What you need to know and how to decrease the risk of skin cancer. J Am Osteopath Assoc. 2003 Aug;103(8):371-5.
[PMID: 12956250]
Moloney FJ, Collins S, Murphy GM. Sunscreens: safety, efficacy and appropriate use. Am J Clin Dermatol. 2002;3(3):185-91. doi: 10.2165/00128071-200203030-00005.
[PMID: 11978139] [DOI: 10.2165/00128071-200203030-00005]
Farrerons J, Barnadas M, Rodríguez J, Renau A, Yoldi B, López-Navidad A, Moragas J. Clinically prescribed sunscreen (sun protection factor 15) does not decrease serum vitamin D concentration sufficiently either to induce changes in parathyroid function or in metabolic markers. Br J Dermatol. 1998 Sep;139(3):422-7. doi: 10.1046/j.1365-2133.1998.02405.x.
[PMID: 9767286] [DOI: 10.1046/j.1365-2133.1998.02405.x]
Sollitto RB, Kraemer KH, DiGiovanna JJ. Normal vitamin D levels can be maintained despite rigorous photoprotection: six years' experience with xeroderma pigmentosum. J Am Acad Dermatol. 1997 Dec;37(6):942-7. doi: 10.1016/s0190-9622(97)70069-0.
[PMID: 9418761] [DOI: 10.1016/s0190-9622(97)70069-0]
home/lifestyle/light/skin_protection.txt · Last modified: 09.14.2022 by
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