5 Skincare Myths: Debunked

5 skincare myths debunked

I know I'm not the only one who loved watching Mythbusters as a kid, or just, generally likes to see misinformation suffer the fiery death it deserves.

There's something very satisfying about uncovering the truth, even if the journey to it means having to wade through a sea of ignorance and lies. The world of skincare, much like most things, has no shortage of both.

So, let's have a nice session of myth bashing and shoot down five skincare myths I would love to see die. Permanently.

Myth 1 - "I can use vitamin E, essential oils, or grapeseed extract as a natural preservative in homemade products."

essential oil bottle with herb plant

(source: pexels)

No. No you absolutely cannot.

This one stems from some understandable confusion between antioxidants and preservatives. If you've read my post on ingredients, you'll know I've mentioned this before. It bears repeating here however, as well as a more detailed look at how both of these substances work.

Much like the relationship between solvents and emulsifiers, antioxidants and preservatives may appear similar at a glance, but their modes of action are very different. Antioxidants protect against oxidative damage, whereas preservatives inhibit microbial growth and prevent spoilage. 

Let's take a closer look at some key differences between spoilage and oxidative damage, and how to inhibit both.

Spoilage and Microbial Growth

When something spoils it usually turns rotten or sour, and gets moldy. This happens in part due to the presence of microbes like bacteria, fungus, and mold spores. We prevent this in food via freezing, refrigeration, canning, curing, drying, and preservatives. All preservation methods rely on creating a hostile environment where microbes can't flourish. 

Microbes flourish the most where water is present. A general rule is that if something contains water, or will come in regular contact with water, it needs a preservative.

So, why do vitamin E and grapeseed extract not count as preservatives?


Because they are antioxidants and don't inhibit microbial growth. We'll see in a moment what they actually do.

What about essential oils?


Some essential oils (namely tea tree and lavender) have shown promising antimicrobial properties. But, it is important to note that they are not broad spectrum. They are very effective against certain types of microbes, but less so on others, making it not enough to rely on them solely as preservatives. There are also limitations to use of essential oils, as they can be irritating at certain concentrations, even low ones. They work best in small amounts in combination with actual preservatives to ensure the safety and stability of cosmetics.

Sure, you could probably get away with selling a water-based toner with tea tree oil without adding a preservative, and it might not grow something gross after the customer opens it, but why risk it?


When something oxidizes, things are very different. Apples and avocados turn brown after cutting because of oxidation. In order to understand this process, we'll have to get a little bit technical, but bear with me.

First, the term 'oxidation' is a bit of a misnomer. Normal molecules have their electrons tied up in pairs. When something breaks up one of those pairs and an electron is lost, the molecule becomes oxidized. This process is called oxidation because it was first discovered to occur when oxygen was added to a molecule. However, there are other agents besides oxygen that can cause this. Bromine is one such substance.

You may have heard the term oxidation in junction with the term "free radicals". Free radicals are the aforementioned molecules with unpaired electrons. They float around looking to steal electrons from other molecules in order to stabilize themselves. The molecules they steal from become unstable in turn, and undergo oxidative stress.

antioxidant donating an electron to a free radical

This is where antioxidants come in. Antioxidants are special molecules that can donate electrons to neighboring molecules without becoming unstable*. Certain vitamins like A, C, E, and K are antioxidants. Ever wonder why putting lemon juice on a cut avocado or apple keeps it from turning brown as quickly? It's because lemon juice contains vitamin C. Some plant pigments like carotenoids (found in yellow, orange, and red fruits & veggies) and anthocyanins (found in deep red, purple, blue, and black fruits & veggies) are also antioxidants.

*Vitamin C in the form of L-Ascorbic acid is actually a very unstable antioxidant, quick to break down in the presence of air, heat, and light. In vitamin C serums, cosmetic chemists get around this by adding other antioxidants to stabilize it, usually vitamin E and/or ferulic acid. Meccanisms Green-C Vitamin C Oil uses a non-acidic, oil based type of vitamin C, which is much gentler on sensitive skin and more shelf stable than L-Ascorbic acid.

To summarize, oxidation and microbial growth/spoilage are very different processes. A cut apple that's turned a little brown is still perfectly safe to eat. A rotten or moldy apple, not so much. Antioxidants and preservatives should not be used in place of each other when making skincare products for sale.

Myth 2 - "Carrot oil and coconut oil have SPF"

Carrot in the sun(source: pexels)


They don't.

Well, not enough to matter.

Some sites claim that the carrot oil myth stems from this study that looked at the efficacy of herb containing sunscreens. However, this study does not reference carrot oil anywhere in the text (and yes that is the full text), so there's no telling where that myth came from. But it needs to die.

More recent studies have come out which show that carrier oils like carrot and coconut do not have substantial SPF.

Which brings us to the next myth...

Myth 3 - "I can make my own DIY sunscreen"

black woman making skincare products(source: pexels)


You really shouldn't.

Unless you have access to lab equipment that can homogenize your sunscreen effectively, testing materials that can determine if your sunscreen protects against a significant UV range, and the money and resources required for all of this, homemade sunscreen is not a good idea. Let's break down why a little bit more.

Why do I need industry grade equipment to make sunscreen when a hand mixer works just fine for homemade lotions and creams? Why can't I just buy some zinc oxide off Amazon and mix it in a lotion to make sunscreen?


Good questions. This is because while all cosmetics are FDA regulated, sunscreens must also be FDA approved. In the US, sunscreens are classified as over the counter drugs and require much more rigorous testing than other cosmetics before they are allowed to be sold.

For starters, UV wavelengths are measured in nanometers. To put that in perspective, a sheet of paper is about 100,000 nanometers thick, whereas UV light is measured at a scale of between 10 and 400 nanometers. There is no way the human eye can detect if a product is evenly dispersed at the nano scale, and a hand mixer just won't cut it. Without proper dispersion in your products, the UV filters will leave gaps and can cause sunburns in those areas.

hand mixer blades

This is the working head on a hand mixer. It uses blades spinning really fast to mix and whip things. They usually cost between $10 and $50.

homogenizer emulsifier sonicator

This is the working head on an industry grade homogenizer. No blades or whisks to be found. Depending on the type, homogenizers use high power vibrations or sonic waves to homogenize liquids and break apart cell walls. This particular one costs about $400 on Amazon, and it uses a combination of suction and vibration to, and I quote from the product description, "make the cell membrane rupture to nuclear separation, and can be used at different speeds to break the DNA chain, or make large molecules to break into small molecules."

So yeah. "Blades spinning really fast" isn't going to be able to compete with that.

Crunchy DIYer: "It doesn't matter if it's dispersed at the nano scale. Non-nano zinc sunscreens exist."

Non-nano zinc and titanium sunscreens are still formulated with industry grade equipment and rigorously tested. Sunscreens with "chemical" filters like avobenzone, homosalate, etc still need to be properly homogenized and evenly dispersed, even though they don't contain the same type of particles as zinc or titanium.


Regarding testing, it requires a lot more than just applying the sunscreen, going outside, and seeing if you get sunburned. A solar simulator is needed to accurately determine a sunscreen's effectiveness. The FDA has certain specifications for these machines along with the testing guidelines. Read them here.  

Solar simulator prices


Solar simulator prices ebay


These machines are crazy expensive for DIYers and small businesses, whether you buy one yourself or pay a laboratory to use their services. These labs often require you to request a quote, and I was too lazy to do that after writing this post, but the lowest estimate I could find for SPF testing was $3000-$4000 per test. Other estimates I found were in the $5000-$10,000 range per test (and if you're into skincare science you should be reading LabMuffin's stuff anyway -cough-). As you can imagine, rarely do these things nail it on the first try, so multiple rounds of testing gets very expensive very quickly.

Oh, and even if you do manage to snag some kind of deal on the machine itself, you'll still need to shell out to have a professional run tests on your product with it.

And, the other ingredients matter just as much, even if they aren't UV filters. Some can influence how evenly the UV filters stay dispersed, changing the final SPF of your product. Some ingredients affect viscosity, which affect spreadability on the skin, which can effect the final SPF. Even adding fragrance can shift that value. Not to mention that some essential oils are phototoxic, meaning they turn volatile in sunlight and can cause skin reactions, so it's vital that there are none of these in your sunscreen. Given the propensity of some DIYers to put essential oils in everything, homemade sunscreen often turns from something inadvisable, to outright dangerous.

In short, this is why I don't make sunscreen.


Myth 4 - "I need to use toner after washing my face."

toner(source: pexels)



According to Dr. Davin Lim, toner was initially invented back in the days where people were removing their makeup with cold cream and washing their faces with soaps. These toners were usually alcohol based and intended to remove any residual film leftover from the cleansers or grease from the cold cream.

Nowadays cleansers don't leave that film anymore, soap formulations have improved, and most people use a dedicated makeup remover instead of cold cream. Meaning toners are optional. Toners also come in many different varieties now, including alcohol free versions, toners designed to pH balance the skin, toners that hydrate, toners that soothe inflammation, toners that fight acne, etc. 

This is great if you like customizing and personalizing your routine, or need a balancing toner after using certain products, but it isn't a requirement to having healthy skin. Only use toners if you feel your skin benefits in some way from it, or you really like including them in your routine.

Myth 5 - "Oils are bad for your skin."

Olive oil(source: pexels)


Couldn't be further from the truth.

Many moons ago, it was thought that clogged pores caused acne, and that the presence of oil caused clogged pores.

Now we know that there are many different kinds of acne, each with a somewhat different set of causes. We also know now that the skin has a lipid-rich barrier that keeps it healthy. Our skin actually needs oils in order to function properly, as disruption of this barrier has been shown to cause skin issues. This is true even in people with very oily skin such as myself. 

Don't fall into the trap of thinking all oils are bad just because certain ones have been shown to clog pores in some people, like coconut oil. I had to try several oils before I found ones that didn't break me out. Olive oil was a no-go for me, despite it working great as a moisturizer for many people. There are plenty of others that might work for your skin type, and they each have different properties that benefit the skin in different ways. 

And that's it! 

Here's to healthy skin!

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1 comment

Today I learned that I can’t make my own sunscreen, oils aren’t bad for my skin, and toner is completely optional

Tiffany Carlton November 02, 2021

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