Paula's Choice Calm Barrier Protect Mineral Sunscreen SPF 30 Versus Paula's Choice Defense Essential Glow Moisturizer SPF 30

Caprylic Triglyceride is made by combining glycerin with coconut oil, forming a clear liquid. Though it behaves like an oil, it is not technically one due to its chemical composition. It is very stable, resistant to oxidation, and unlikely to go rancid. In practice, that translates to a long shelf life and a consistently elegant skin feel.

While there is an assumption Caprylic Triglyceride can clog pores due to it being derived from coconut oil, there is no research supporting this. Be sure to patch test if you have concerns.

Fractionated coconut oil and MCT Oil are both listed as Caprylic/Capric Triglyceride according to INCI. This is because INCI names are based on the ingredient’s final chemical composition and not its marketing name or source.

However, this exfoliating effect only happens at high concentrations (20%) which can be hard to find in cosmetic products.

Due to this, citric acid is usually included in small amounts as a pH adjuster. This helps keep products slightly more acidic and compatible with skin's natural pH.

In skincare formulas, citric acid can:

While it can provide some skin benefits, research shows lactic acid and glycolic acid are generally more effective and less irritating exfoliants.

Most citric acid used in skincare today is made by fermenting sugars (usually from molasses). This synthetic version is identical to the natural citrus form but easier to stabilize and use in formulations.

Read more about some other popular AHA's here:

Your skin makes glycerin on its own (mostly from sebaceous oil breakdown) and shuttles it to your outermost layer of skin, or your epidermis, via aquaporin-3.

Aquaporin-3 is a transporter that is essential for normal skin hydration, elasticity, and repair. Interestingly, mice lacking in AQP3 have dry and less elastic skin that can be fully corrected with glycerin.

This ingredient is non-irritating, plays well with almost every ingredient, and works across all skin types. Typical use is anywhere between 3-10% but can go up to 79% in some leave-on products.

Just know very high concentrations (>40%) can feel tacky in low humidity.

Glycerin is the name for this ingredient in American English. British English uses Glycerol/Glycerine.

This ingredient is typically used in concentrations between 1-10%. Studies have found it to be non-sensitizing, non-phototoxic, and non-photoallergenic.

A close cousin of this ingredient is Glyceryl Stearate SE ("self-emulsifying"). This just has a small amount of sodium or potassium stearate added so it can emulsify without a co-emulsifier.

Since this ingredient is an ester of a C18 fatty acid, it may not be fungal acne safe. The Malassezia yeast can potentially metabolize within the C11-C24 range.

Fun fact: The human body also creates Glyceryl Stearate naturally.

It plays well with most ingredients and is typically used at 0.1-1%. However, concentrations up to 50% have been reported in moisturizers.

Depending on the source of this ingredient, lecithin may not be fungal acne safe. This is because some sources of lecithin come from soybean oil, which may feed the malassezia yeast that causes fungal acne.

We recommend reaching out to the brand you are purchasing from to inquire about the source of their lecithin.

Depending on the concentration, it can drastically change the texture of a product from pasty solid (like lipstick) to sprayable liquid.

The CIR Expert Panel for Cosmetic Ingredient Safety has concluded this ingredient to be safe in cosmetics. The highest reported use concentration is 14.2% in lipsticks.

Titanium dioxide provides broad-spectrum protection mostly in the UVB and UVAII range, with some protection in the UVAI range.

While its UVA protection isn’t as strong as zinc oxide’s, the difference is minor.

A common myth is that mineral UV filters reflect UV light. However, modern research shows titanium dioxide absorbs UV radiation like chemical filters (~95% absorption & 5% reflection).

Thanks to its non-irritating nature, titanium dioxide is suitable for sensitive, acne-prone, or redness-prone skin. It is unlikely to cause "eye sting" like other sunscreen ingredients.

A major drawback of this ingredient is its white cast and thick texture. This is why mineral sunscreens often leave a white cast and are less cosmetically elegant than chemical/hybrid sunscreens.

To improve white cast and spreadability, micronized or nano-sized titanium dioxide is often used.

There are ongoing concerns surrounding nano-titanium oxide's impact on marine ecosystems.

There is no conclusive evidence that any form of titanium oxide (or any other sunscreen ingredients) will cause harm to marine ecosystems or coral reefs. The science is still developing but many consumers are keeping a close eye on this issue.

Please note, many destinations have reef-safety sunscreen rules. For instance, the U.S. Virgin Islands advises all visitors to use non-nano mineral sunscreens.

Nano mineral sunscreens once raised safety concerns about absorption into skin.

Extensive research has shown that they do not penetrate healthy or damaged skin; they remain safely on the surface and the top layer of dead skin (stratum corneum).

You'll likely find titanium dioxide bundled with alumina, silica, or dimethicone. These ingredients help make titanium dioxide highly photostable; this prevents it from interacting with other formula components under UV light.

Topically applied tocopherol has been shown to protect against UV damage by ramping up the skin's own natural defense enzymes.

It also acts as a skin conditioning agent; some studies show that regular topical use can improve the skin's water-binding capacity over 2-4 weeks.

This ingredient is especially loved for being a team player. When combined with Vitamin C, the photoprotective effect of both ingredients roughly doubles and the combo also helps reduce UV-induced DNA damage.

This ingredient has some brightening potential but it's more of a prevention ingredient than spot-fader. Cell studies show it can slow down melanin production but it's worth noting that it's not the most powerful brightener out there.

In formulations, it also serves as a stabilizer that helps protect other oxidation-prone ingredients from degrading.

Concentrations usually range from 0.1-1% in most leave-on products.

This ingredient is typically used at low levels (up to 2.5% in eyeshadow and 1% in lipstick).

You'll also recognize water as that liquid we all need to stay alive. If you see this, drink a glass of water. Remember to stay hydrated!

Xanthan gum is a pretty common and great ingredient. It is a natural, non-toxic, non-irritating ingredient that is also commonly used in food products.

Another great benefit? This ingredient is highly photostable so it won't degrade easily under sunlight.

A common myth is that mineral UV filters are widely believed to primarily reflect UV light.

However, modern research shows titanium dioxide absorbs UV radiation like chemical filters (~95% absorption & 5% reflection).

Zinc oxide has great skin soothing properties so you'll likely find this in sunscreens formulated for sensitive skin or babies/children. It is unlikely to cause "eye sting" like other sunscreen ingredients.
Regulatory agencies consider zinc oxide to be non-toxic and safe. It has also been shown to not penetrate the skin.

Unfortunately, this ingredient does leave a visible white cast. This is why mineral sunscreens are often less cosmetically elegant than chemical or hybrid ones.

In cosmetics, zinc oxide can be found in both non-nano and nano-sized forms. The nano version is used to reduce white cast and improve the texture of sunscreen formulas.

There are ongoing concerns surrounding nano-zinc oxide's impact on marine ecosystems and whether it can be absorbed into skin.

Regarding marine ecosystems and coral reefs, there is no conclusive evidence that any form of zinc oxide (or any other sunscreen ingredients) will cause harm. The science is still developing but many consumers are keeping a close eye on this issue.

Please note, many destinations have reef-safety sunscreen rules. For instance, the U.S. Virgin Islands advises all visitors to use non-nano mineral sunscreens.

There has also been some stir about whether micronized or nano zinc oxide has potential photoxicity and absorption through the skin/lungs.

An in-vitro (done in a test tube or petri dish) study demonstrated micronized zinc oxide to have potential phototoxicity. There's no need to fret; the EU Commission's Scientific Committee on Consumer Safety has stated, "The relevance of these findings needs to be clarified by appropriate investigations in vivo." Or in other words, further studies done on living organisms are needed to prove this.

Current research shows zinc oxide nanoparticles do not penetrate intact or sunburned skin. They either remain on the surface or in the outermost layer of dead skin (stratum corneum).

Zinc oxide is one of only two classified mineral UV filters with titanium dioxide being the other one.

Fun fact: Zinc has been used throughout history as an ingredient in paint and medicine. An Indian text from 500BC is believed to list zinc oxide as a salve for open wound. The Ancient Greek physician Dioscorides has also mentioned the use of zinc as an ointment in 1AD.