Neutrogena Rapid Wrinkle Repair Serum

This ingredient is considered a modified starch. Starch can also be found naturally in plants.

One study from 1991 found that 5% of this ingredient enhanced titanium dioxide SPF by as much as 40%. The study found 1% titanium dioxide had a 5.6 SPF and adding 5% of aluminum starch octenylsuccinate boosted it to an SPF of 8.1

Although “aluminum” in an ingredient name can raise red flags for some consumers, the form and usage context matter significantly. For typical topical applications, there is no substantial evidence of health risks - such as cancer, neurotoxicity, or systemic “aluminum overload.”

The Cosmetic Ingredient Review (CIR) Expert Panel evaluated it (along with 22 other acryloyldimethyltaurate polymers) and concluded it's:

Due to its large molecular size, it sits on the surface of skin rather than penetrating it.

This ingredient may not be reef-safe.

As an emollient, C12-15 Alkyl Benzoate helps soften and hydrate your skin. Emollients create a film on your skin that traps moisture within.

This ingredient has been reported to cause eye irritation.

Ascorbyl Glucoside is an antioxidant. Antioxidants help fight free-radicals, or molecules that may damage skin cells.

It can help to reduce redness, improve skin texture, reduce the effects of aging, reduce the visibility of dark spots, and brighten skin.

Read more about other types of Vitamin C:

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.

Because it is not a free-fatty acid or alcohol, this ingredient is fungal acne safe (there's nothing for Malassezia to feed on).

It should be noted the precursor to Polyacrylamide is acrylamide. Acrylamide is a carcinogen. Most reputable sources of Polyacrylamide will screen for residual acrylamide to make sure the count is in a safe range. Acrylamide is not able to be absorbed through the skin.

We recommend speaking with a professional if you have concerns.

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.

For instance, Habanolide is a proprietary trade name for a specific aroma chemical. When used as a fragrance ingredient in cosmetics, most aroma chemicals fall under the broad labeling category of “FRAGRANCE” or “PARFUM” according to EU and US regulations.

The term 'parfum' or 'fragrance' is not regulated in many countries. In many cases, it is up to the brand to define this term.

For instance, many brands choose to label themselves as "fragrance-free" because they are not using synthetic fragrances. However, their products may still contain ingredients such as essential oils that are considered a fragrance by INCI standards.

One example is Calendula flower extract. Calendula is an essential oil that still imparts a scent or 'fragrance'.

Depending on the blend, the ingredients in the mixture can cause allergies and sensitivities on the skin. Some ingredients that are known EU allergens include linalool and citronellol.

Parfum can also be used to mask or cover an unpleasant scent.

The bottom line is: not all fragrances/parfum/ingredients are created equally. If you are worried about fragrances, we recommend taking a closer look at an ingredient. And of course, we always recommend speaking with a professional.

As an emollient, it helps keep the skin soft and smooth by creating a barrier on top. This barrier traps moisture in, keeping the skin hydrated.

C13-14 Isoparaffin may not be fungal-acne safe.

Interestingly, the size of the molecule affects its behavior:

Some clinical evidence links low molecular weight versions to improved wrinkle depth, elasticity, anti-inflammatory effects, and barrier repair.

Many serums use a blend of both weights so you can get surface hydration plus longer-lasting and deeper effects.

You'll typically see concentrations between 0.1-2% for this ingredient.

High percentages of Sodium Lactate can have an exfoliating effect.

Fun fact: Sodium Lactate is produced from fermented sugar.

Your skin has a natural pH and acid mantle. This acid mantle helps prevent harmful bacteria from breaking through. The acid mantle also helps keep your skin hydrated.

"Alkaline" refers to a high pH level. A low pH level would be considered acidic.

As a preservative, it is used to stabilize products and prevent them from degrading. Specifically, BHT prevents degradation from oxidation.

The concerns related to BHT come from oral studies; this ingredient is currently allowed for use by both the FDA and EU.

However, it was recently restricted for use in the UK as of April 2024.

On top of that, this ingredient can counteract the effects of hard water by binding to the minerals in it.

One thing worth knowing is that Disodium EDTA has been shown to be a mild penetration enhancer. It can help other ingredients absorb into skin more effectively which can be a double-edged sword (great for actives, but can also make the active too strong if you have sensitive skin).

Clinical patch testing showed no significant skin irritation at typical use concentrations and minimal dermal absorption.

You'll most likely see this ingredient near the end of an ingredient list. It's typically found in concentrations less than 1%.

The common safety discussion around this ingredient involves a manufacturing byproduct called 1,4-dioxane.

Trace amounts can form during production but the EU's Scientific Committee on Consumer Safety has concluded that levels at/below 10 ppm in finished products are safe (commercial products consistently fall within acceptable margins).

True allergic reactions are uncommon and the CIR Expert Panel has confirmed this ingredient to be safe as used in cosmetics.

Because it is derived from lauric acid, it may not be fungal acne safe.

It has the most scientific studies backing up its skin benefits out of all the non-prescription ingredients.

Retinol is proven to:

This is why retinol is effective at removing wrinkles, fading dark spots, treating acne, and reducing the appearance of pores.

Studies show retinol is less effective when exposed to UV. Be sure to look for appropriate packaging to keep your retinol potent (similar to Vitamin C).

Using retinol or any retinoids will increase sun-sensitivity in the first few months. Though studies show retinoids increase your skin's natural SPF with continuous use, it is best to always wear sunscreen and sun-protection.

We recommend speaking with a medical professional about using this ingredient during pregnancy.

Retinol may cause irritation in some people, so be sure to patch test. Experts recommend 'ramping up' retinol use: start using this ingredient once a week and work up to using it daily.

Read about Tretinoin

This ingredient has skin conditioning, anti-inflammatory, and humectant properties. Humectants help hydrate your skin by drawing moisture from the air. This helps keep your skin moisturized.

As a humectant, Sorbitol helps draw water to the skin. This helps keep the skin hydrated. Sorbitol also helps create a thicker texture in products. You might find sorbitol in your toothpaste and other gels.

It is a non-irritating ingredient that is great for those with dry skin.

Sorbitol is a prebiotic. It helps promote the growth of healthy bacteria on your skin. The bacteria on your skin form a microbiome. This microbiome helps protect your skin from infection and harmful bacteria.

Reviews of this ingredient have found it to be neither a dermal irritant nor a sensitizer.

Fun fact: Proline can be found in protein-rich foods like meat, fish, eggs, and dairy.

This ingredient is often coated with metal oxides like titanium dioxide. Trace amounts of heavy metals may be found in mica, but these metals are not harmful in our personal products.

Mica has been used since prehistoric times throughout the world. Ancient Egyptian, Indian, Greek, Roman, Aztec, and Chinese civilizations have used mica.

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.