How to Make Your Sunscreen Safe – And Reduce Your Cancer Risk at the Same Time

Dr. Frank Shallenberger, MD

May 27, 2019



It’s Memorial Day. A great day to remember our fallen service members. And it’s the unofficial kickoff to summer. While summer doesn’t officially start until June 21, some parts of the country are already experiencing 90-100 degree temps. That means it’s time to get outside and enjoy the sun. Oh, wait, the sun is supposed to be bad for us, isn’t it?

Well, I have news for you. Everything you’ve been taught about the sun by the mainstream media and the medical establishment is flat wrong!

For years, medical experts told us to stay out of the sun because it causes cancer. Turns out, the sun is actually good for you. And now the evidence is showing that if you listen to their advice, you will significantly increase your risk of breast cancer.

Two revealing studies, presented at the annual meeting of the American Association for Cancer Research, have seriously undermined conventional wisdom about the sun. In the first study, out of the University of California at San Diego, researchers tested the blood levels of vitamin D in more than 1,750 women. They compared the levels between women who developed breast cancer and those who didn’t. Turns out that the women with the highest levels of vitamin D (greater than 52 nanograms per milliliter) had less than half the chance of getting cancer than the women with lower levels.

The important thing that the researchers noted was that in order to reach these higher levels of vitamin D, regular sunlight exposure is required. As you may know, sunlight exposure increases vitamin D production, and when exposure is low, the result is low vitamin D. This study (and others like it) conclusively proves that lack of adequate sunlight exposure increases your risk of breast cancer.

Sunlight Reduces Breast Cancer Risk by 40%

The second study also demonstrated the link between sunlight and breast cancer risk. Researchers at Mount Sinai Hospital in Toronto interviewed 1,700 women. Approximately one-third of the women were breast cancer patients. They found that the women who had the highest levels of sunlight exposure between the ages of 10 and 29 had a 40% reduced risk of breast cancer compared to women with the lowest exposure. The researchers believe that sunlight exposure during these years when breast tissue is in rapid development helps protect the breasts from cancer later in life.

Robert Bazell, a health correspondent on NBC, commented on the minimum amount of sunlight that’s required to prevent breast cancer. He said that exposing your arms and face to direct sunlight at mid-day for 10 minutes is probably all that is needed. But that’s an oversimplification. It’s true if you live in sunny southern California. But you need much more time in the sun if you live in more northern latitudes.

What’s astounding is that many Americans don’t even get that much. But mainstream medicine along with the media has urged people to avoid sunlight at all costs. The amazing thing is that people go outside at all, with that dreadful sun shining all over the place. As with most things, the truth lies somewhere in the middle.

It’s true that too much sunlight, especially in lighter skinned people, causes a benign skin cancer called basal cell cancer. But too little sunlight can cause many more serious cancers. I recommend that everyone get at least two hours of sun exposure per week during the summer. By the way, even cloudy days are good sources of sunlight. Those in the northern latitudes should get outside as much as possible during the winter months.

How to Keep Your Sunscreen From Poisoning You

Now that I’ve told you to get outside and play in the sun, don’t spend too much time in direct sunlight. Doing so might require you to use sunscreen. You may have heard that sunscreen blocks the amount of vitamin D your body gets from the sun. But now there’s an even bigger concern. Sunscreen can poison your thyroid!

Some might say that’s preposterous. After all, the thyroid is inside your body and you apply sunscreen to the outside of your body. You don’t eat it. The problem is that the chemicals in sunscreen pass through your skin and go right into your bloodstream. And one of the chemicals is very toxic to your thyroid.

The chemical is 4-methylbenzylidene-camphor. That’s a mouthful, so we’ll call it 4MBC. 4MBC is a hormonally active compound used in sunscreens and other cosmetics, such as anti-aging lotions and day care products. It absorbs ultraviolet light. This is what makes it effective as a sunscreen. It prevents the skin from sunburn and the skin aging effects of UV rays.

But scientists in Germany recently studied the effects of 4MBC on thyroid function. They exposed rats to it for five days. They found that the compound caused an increase in the hormone TSH (thyroid stimulating hormone) along with a decrease in the hormone thyroxine (T4). This pattern is typical in the early stages of hypothyroidism. The chemical also increased the weight of their thyroid gland. This is another indicator of thyroid suppression.

Some might argue that the FDA hasn’t approved 4MBC for use in the United States. That’s true. It’s used mostly in Europe. But the researchers also found that the FDA-approved sunscreen BP2 (benzophenone 2, also known as oxybenzone) has the exact same effect.

And another FDA-approved sunscreen chemical, OMC (octyl-methoxycinnamate, also known as octinoxate) also suppresses thyroid function.

Right after I finished writing this article, I looked at the sunscreens we have in the house. There were three different brands, and sure enough, each one featured both octinoxate (OMC) and oxybenzone (BP2).

Fortunately, there’s an easy way to prevent the damage of BP2. All you have to do is take iodine supplements. The iodine prevents the thyroid-suppressing effect of BP2. So if you must use sunscreen, find a brand that has just BP2 and take plenty of iodine.

How to Prevent Skin Cancer

Amazingly, the same little nutrient that prevents breast cancer also prevents skin cancer. Here’s the evidence.

Not too long ago, I saw a patient that has a serious history of skin cancer. When I asked her how her day was going, she said, “I just came from my monthly visit to my dermatologist to have my skin cancers removed. I get them all the time.” Sure enough, she had a two-inch incision on her neck to prove it. Then she went on to say that this was something that happened almost every month.

She had that good old type-1 skin that is so sensitive to sunlight-induced skin cancers. Her doctor had been telling her that the only way to prevent them was to use sunscreen every day, but that didn’t seem to be working at all. Fortunately, all you need to do to prevent skin cancers is to take a rather large dose of vitamin D. This study proves it.

Researchers at the University of Sydney in Australia were looking at the effects of damaging doses of ultraviolet radiation on the skin. This is the same kind of UV radiation that you would get from an excessive exposure of sunlight. They found out that one of the effects of too much UV is the creation of damaged DNA molecules called CPDs. According to these scientists, CPDs are “highly” inducive of cancer. At the same time, they suppress the immune system in the skin. But that’s not all they found.

They also noted that the same UV rays that produce CPDs also produce vitamin D. And then they discovered that the vitamin D that they produce was able to protect the skin from the cancer-causing effects of CPDs.

To do this they used mice that were similar to my patient. They had genetically bred them to have skin that is especially susceptible to sunlight-induced cancers. Then they gave the mice vitamin D supplements. They found that the vitamin D supplements were “effective inhibitors of UV damage” in these mice, and that they “significantly reduced UV-induced CPDs and immunosuppression.” The supplements also “inhibited skin-tumor development,” including “squamous cell carcinomas, in these mice.”

The researchers concluded that, “The observed reduction of these UV-induced effects by vitamin D3 suggests a role for these compounds in prevention against skin carcinogenesis.”

Now here are a few thoughts on this study. First of all, my patient’s vitamin D blood level was low – 37 ng/ml. In order to have maximum anti-cancer protection from vitamin D, you must have blood levels up around 70 ng/ml.

Next, why were her blood levels so low? Maybe it was from the sunscreen that she was continually using. Ironically, since sunscreen blocks out the UV rays that stimulate skin cells to produce vitamin D, it’s one of the major causes of low vitamin D levels. Is it possible that her use of sunscreen was actually contributing to her tendency to develop skin cancers by lowering her vitamin D levels? I think it’s possible.

Ever since sunscreens came on the market, the incidence of skin cancers has skyrocketed. And there’s an almost one-to-one relationship between the rising use of sunscreens and the increasing rate of skin cancers. This statistical relationship doesn’t really prove anything. But given the results of this study, it certainly makes you wonder.

I’m like my patient and these mice. I have type-1 skin. So I use a completely natural zinc oxide-based sunscreen when I am on my boat or my bike. But I also take enough vitamin D to bring my level up to 70 ng/ml. In my case, and in the case of many people, this often means taking 10,000-15,000 units of vitamin D3 per day. If your skin isn’t this sensitive, then 5,000 IU daily might be enough.


Hamann, I.H., C. Schmutzler, P. Kirschmeyer, et al. “4-methylbenzylidene-camphor (4MBC) causes pituitary effects comparable to hypothyroidism,” Endocrine Abstracts, (2006) 11 OC60.

Ready To Upgrade?

Upgrade now to a Second Opinion Newsletter Subscription so you don't miss out on the healthy, active life you deserve.

Plus, Get Up To 18 Free Reports When You Click Here To Upgrade Today!

Get A Free Copy Of This Powerful Report

Inside You'll Discover

► A little secret that not only relieves stress but can actually banish stress from your life!

► If you are exercising too hard to be healthy.

► And, an optimal exercise regimen to excerise smarter, not harder!

Enter your name and email to claim this free report and join our newsletter

Get Report!