How To Make Mineral Sunscreen With Zinc Oxide

Sun Protection 101

I’ll admit it - I’m a sun-worshiper! I LOVE basking in the sunlight and having a golden tan.

I also know now that I’ve probably done some damage from "extreme" sun-tanning as a teen and tanning beds during my University years.

As I get older (and slightly wiser), I realize I don’t want to look like a leather face in 20 years. I need to start being more conscious of my exposure to the sun and protect my skin, my freckly husband’s skin, and my fair and delicate-skinned daughter—so that’s my mission.

Over the past few years, I’ve been actively experimenting with and researching sunscreens.  From all the research I’ve done, I’ve found that there is a lot to learn about the sun and sunscreen.

Some articles state that certain sunscreens are bad for you (and by bad, I mean cancer-causing), while others say they’re completely safe and necessary for preventing skin cancer. The whole thing makes my head spin a bit, and it seems everyone has an opinion.

I wanted to feel informed on the subject before choosing the sunscreen brand that was right for me and the ingredients that I wanted to put into my own, so I’ve looked at various sides of this “sunscreen-story” and have come to a conclusion that I feel comfortable with.

As usual, I’d like to share some of what I’ve learned. Below are some questions of my own that I wanted to be answered in my search to find the perfect sunscreen.

Sun Protection 101

Sunscreen vs Sunblock

Sunscreen uses organic and inorganic chemical filters to prevent the sun’s rays from penetrating the deeper layers of the skin. Common sun-filtering ingredients in chemical sunscreens are oxybenzone, avobenzone, octisalate, octocrylene, homosalate and octinoxate.

Sunblockuses mineral filters, usually zinc oxide or titanium dioxide, which reflect or scatter the rays to prevent them from reaching the skin.

What is SPF, and how does it work?

SPF stands for Sun Protection Factor and refers to the ability of a sunscreen to block ultraviolet B (UVB) rays, which are responsible for burning the skin's surface. However, SPF does not block ultraviolet A (UVA) rays, which penetrate deep into the layers of the skin, causing skin damage, aging, and skin cancer, specifically squamous cell carcinoma.

When thinking about SPF, most people would probably assume SPF 30 is twice as effective as SPF 15, but that’s not the case.

  • SPF 15 blocks about 93% of UVB rays,

  • SPF 30 blocks 97%,

  • SPF 50 block 98%, and

  • SPF 100+ blocks about 99.1%.

So you can see that anything higher than SPF 50 can get pretty unnecessary—it’s usually just more expensive (but potentially more toxic, which I’ll talk more about in a minute.)

Theoretically, the SPF number can also help you determine how long you can stay in the sun. If you can generally stay in the sun for 10 minutes before burning, then applying sunscreen with an SPF of 10 will allow you to stay in the sun 10x longer without burning (100 min).

Do we need sunscreen?

There are a couple of ways to look at this question: while sunscreen can protect us from cancer-causing UV rays, it may also change our behaviour and, therefore, increase our exposure to the sun.

First, it’s no secret that melanoma is on the rise, and according to the National Cancer Institute, the rate of melanoma cases has tripled in the past 35 years. Although there is speculation as to whether or not the sun is the primary cause of this increase, melanoma can be caused by overexposure to UVB and, more specifically, UVA rays.

The problem with most sunscreens is that they don’t provide adequate UVA protection. Even those that do are just not enough because avobenzone, the primary UVA filter added to almost all chemical sunscreen, breaks down in sunlight.So yes, we need sunscreen to protect us from the potentially damaging effects of the sun, but sunscreen alone is not sufficient.

On the other hand, “problems lie in individuals who use sunscreens to stay out longer in the sun than they otherwise would.” Staying in the sun for more extended periods increases our exposure to harmful UVA rays.

Is sunscreen toxic?

The BIG question! While many continue to recommend sunscreen “whole heatedly,” the Environmental Working Group (EWG) has a different opinion.

Sunscreen’s active ingredient comes in the form of chemical and mineral filters. It’s the chemical sunscreens that are causing the need for concern.

According to the EWG,

[chemical sunscreens] combine three to six of these active ingredients: oxybenzone, avobenzone, octisalate, octocrylene, homosalate and octinoxate. The most problematic sunscreen chemical used in the U.S. is oxybenzone, found in 80 percent of chemical sunscreens. EWG recommends that consumers avoid oxybenzone because it can penetrate the skin, cause allergic skin reactions and may disrupt hormones.

In one study, based on a sample of more than 2500 adults and children, 96% of them were detected to have oxybenzone in their systems.

As I mentioned earlier, higher SPF doesn’t necessarily mean better protection from the sun, and the EWG advises avoiding sunscreens with high SPF because they require higher concentrations of sun-filtering chemicals than low-SPF sunscreens. 

This study from Harvard states, “The sun protection factor (SPF) you see on the label of sunscreens is misleading. It’s not a measure of total sun protection but protection against sunburn from UVB light.” They advise consumers to look at the ingredients instead of the SPF and suggest that “the lotions containing zinc oxide and titanium dioxide may be the best bet.”

There is also speculation about whether or not the sun or the overuse of sunscreen is causing this spike in skin cancer. This question points to a particular sunscreen ingredient, vitamin A, and the EWG advises avoiding sunscreens that contain Vitamin A (labelled retinyl palmitate).

The sunscreen industry adds a form of vitamin A to nearly one-quarter of all sunscreens. Retinyl palmitate is an anti-oxidant that slows skin aging. However, federal studies indicate that it may speed the development of skin tumours and lesions when applied to the skin in sunlight.

Although no sunscreen seems to be without its risks, sunblocks that use these mineral filters are considered safe, “non-toxic” options. 

Mineral sunblocks use zinc oxide and titanium dioxide to reflect or scatter UV rays. They do not permeate the skin and are stable in the presence of sunlight. Zinc oxide is the optimal ingredient in sunblock because it provides strong sun protection with few health concerns; it doesn’t break down in the sunlight and offers good protection against UVA rays!

Nano-zinc vs Non-nano zinc. Are they safe?

A nanometer is about one hundred thousand times smaller than a human hair. There is concern that zinc nanoparticles can be absorbed into the skin and bloodstream. There are no studies out there proving that nano-particles of zinc oxide can penetrate the human skin. Instead, much research proves quite the opposite (1)(2).

Cosmetically, nano-zinc is a better option because, when applied, it doesn’t leave behind the white film (you know, that lifeguard look?) Based on my research, I feel comfortable using nano-zinc and have used it in the sunscreen that I’ve made for our trip. If you don’t feel comfortable using nano-zinc, use non-nanozinc with larger particles.

Remember that zinc oxide doesn’t go without its dangers, either. When inhaled, it can damage the lungs and enter the bloodstream.

Personal Conclusion

My conclusion about sunscreen is probably pretty apparent by now. After some research and reading what the EWG had to say about chemical sunscreens, I’ve decided to play it safe and opt for sunscreens/sunblocks that:

  • Have zinc oxide or titanium dioxide as the primary sun-filtering ingredient.

  • Don’t contain oxybenzone.

  • Don’t contain Vitamin A (labelled retinyl palmitate).

  • Have an SPF of less than 50.

But more importantly than what type of sunscreen to use, be cautious about the time spent in the sun, and do not solely rely on sunscreen for UV protection — wear a hat, cover-up, and spend time in the shade.

Check out "What Not To Bring On Vacation," and this list, put out by the EWG, to see if your sunscreen passed the test!

How do I make sunscreen?

Easy! And Affordable!

First, you need about 1 Cup of lotion or body butter—I’ve made my own base lotion, using oils that are naturally high in SPF (recipe below). Then, add zinc oxide to the lotion/butter using the chart below to determine your preferred SPF level.

How much zinc oxide do I use?

For a higher level of protection, you’ll want to add 20% of the weight of the lotions in zinc oxide. For a low to moderate level of protection, you’ll want to add 5-15% of the lotion's weight in zinc oxide.

For example, the lotion I use as the base for this sunblock is about 8-10 oz (let’s say 9 for this example). If I want a sunscreen that’s about SPF 15, then I’ll add about 1.08oz of zinc oxide.

*** Please note, I have NOT scientifically tested these SPF levels in a lab***

Zinc to Lotion Ratio

If you don't have a kitchen scale Use this ounce to Tablespoon Converter to help you determine how many tablespoons of zinc added.

What oils naturally contain SPF?

Many oils are already naturally high in SPF! So even before adding the zinc oxide to your lotion/butter, it will already have an SPF of at least 2. In my sunblock, I usually use avocado oil because it has an SPF as high as 15!

Oils with SPF

I hope I've provided you with enough information to make your own homemade, moisturizing sunblock with zinc oxide!

You'll be lookin' as cool as I do showing up to the beach...with a mason jar full of homemade sunblock ;)

Homemade Sunblock with Zinc Oxide

Ingredients

  • 1/4 cup Coconut Oil

  • 1/4 cup Shea Butter

  • 1/2 Cup of one of the oils listed in the "Oils with SPF" chart above; I used avocado oil because that's what I had

  • 2-3 tbsp Beeswax

  • 10-15 Drops Essential Oils (optional)

  • Zinc Oxide amount is determined in the "Zinc Oxide to Lotion Ratio" chart above. I used a little over 2 tbsp to give it an SPF of around 15.

Instructions

  1. Melt coconut oil, shea butter and beeswax in a double boiler. To do this, I put the ingredients in a jar and then put the jar in a simmering pan of water. Remove from heat as soon as they have melted.

  2. Stir in the ½ cup of oil (e.g. Avocado oil)

  3. Wearing a mask, stir in the zinc oxide. To prevent it from clumping up in the lotion, try sifting it first.

  4. Thoroughly incorporate the zinc, stirring every few minutes until it cools.

  5. Once it reaches room temperature, stir in the essential oils if using.

  6. Store in an airtight container in a cool place or in the fridge.

  7. Use within six months.

*Notes:

  • The SPF levels are not exact, as I haven't tested them in a lab.

  • Remember to re-apply after swimming!

  • For babies and young children, the main form of UV protection should be to keep them covered up and in the shade.

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