Some By Mi Retinol Intense Reactivating Serum Versus Cosmedix Define Age-Defying Treatment
Updated on August 07, 2024
Overview
What they are
These products are both reef safe . They have a total of 13 ingredients in common
Cool Features
They both contain retinoid and Vitamin E
Suited For
They're both likely to be good for fighting acne, anti aging, dry skin, brightening skin, sensitive skin, oily skin, reducing pores, scar healing, dark spots and better texture
Free From
They both do not contain any parabens or sulfates
What's Inside
They both contain fragrances and oils
We independently verify ingredients, and our claims are backed by peer-reviewed research. Spot a product that needs an update? Let us know.
Ingredient Info
Some By Mi Retinol Intense Reactivating Serum 65 ingredients
Cosmedix Define Age-Defying Treatment 49 ingredients
What's inside (and what isn't)
What's inside (and what isn't)
At a glance
Click on any of the items below to learn more
Some By Mi Retinol Intense Reactivating Serum 65 ingredients
Cosmedix Define Age-Defying Treatment 49 ingredients
Key Ingredients
Benefits
Concerns
Key Ingredients
Benefits
Concerns
Ingredients Side-by-side
Ingredients Explained
These ingredients are found in both products.
Ingredients higher up in an ingredient list are typically present in a larger amount.
Water. It's the most common cosmetic ingredient of all. You'll usually see it at the top of ingredient lists, meaning that it makes up the largest part of the product.
So why is it so popular? Water most often acts as a solvent - this means that it helps dissolve other ingredients into the formulation.
You'll also recognize water as that liquid we all need to stay alive. If you see this, drink a glass of water. Stay hydrated!
Learn more about WaterGlycerin is already naturally found in your skin. It helps moisturize and protect your skin.
A study from 2016 found glycerin to be more effective as a humectant than AHAs and hyaluronic acid.
As a humectant, it helps the skin stay hydrated by pulling moisture to your skin. The low molecular weight of glycerin allows it to pull moisture into the deeper layers of your skin.
Hydrated skin improves your skin barrier; Your skin barrier helps protect against irritants and bacteria.
Glycerin has also been found to have antimicrobial and antiviral properties. Due to these properties, glycerin is often used in wound and burn treatments.
In cosmetics, glycerin is usually derived from plants such as soybean or palm. However, it can also be sourced from animals, such as tallow or animal fat.
This ingredient is organic, colorless, odorless, and non-toxic.
Glycerin is the name for this ingredient in American English. British English uses Glycerol/Glycerine.
Learn more about GlycerinTocopheryl Acetate is AKA Vitamin E. It is an antioxidant and protects your skin from free radicals. Free radicals damage the skin by breaking down collagen.
One study found using Tocopheryl Acetate with Vitamin C decreased the number of sunburned cells.
Tocopheryl Acetate is commonly found in both skincare and dietary supplements.
Learn more about Tocopheryl AcetateGlyceryl Stearate is a mix of glycerin and stearic acid.
It is used to stabilize the mixing of water and oil ingredients. By preventing these ingredients from separating, it can help elongate shelf life. It can also help thicken the product's texture.
As an emollient, it helps soften skin and supports barrier-replenishing ingredients.
In cosmetics, Glyceryl Stearate is often made from vegetable oils or synthetically produced.
This ingredient may not be fungal-acne safe
Fun fact: The human body also creates Glyceryl Stearate naturally.
Learn more about Glyceryl StearateStearic Acid is a fatty acid. It is an emollient, emulsifier, and texture enhancer.
As an emollient, stearic acid helps soften skin. It aids the skin's protective barrier by preventing water loss. It also provides a gentle cleansing effect without stripping away natural oils.
Stearic acid may also be used to enhance the texture of products. It can add volume and stabilize ingredients such as water and oil. This can help water and oil ingredients from separating.
Sources of stearic acid include animal or vegetable fats/oils such as coconut or shea. It can be naturally found in butter, cocoa butter, shea butter, vegetable fats, and animal tallow.
This ingredient may not be Malassezia folliculitis, or fungal-acne safe.
Learn more about Stearic AcidXanthan gum is used as a stabilizer and thickener within cosmetic products. It helps give products a sticky, thick feeling - preventing them from being too runny.
On the technical side of things, xanthan gum is a polysaccharide - a combination consisting of multiple sugar molecules bonded together.
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.
Learn more about Xanthan GumRetinol is a gold-standard ingredient for anti-aging. It is a form of Vitamin A and belongs to the class of retinoids that also includes tretinoin.
Why is retinol famous?
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
Learn more about RetinolCetyl Alcohol is a fatty alcohol. Fatty Alcohols are most often used as an emollient or to thicken a product.
Its main roles are:
Though it has "alcohol" in the name, it is not related to denatured alcohol or ethyl alcohol. The FDA allows products labeled "alcohol-free" to have fatty alcohols.
Learn more about Cetyl AlcoholBHT is a synthetic antioxidant and preservative.
As an antioxidant, it helps your body fight off free-radicals. Free-radicals are molecules that may damage your skin cells.
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.
Learn more about BHTThis BHA stands for butylated hydroxyanisole. If you are looking for the beta-hydroxy acid, aka as Salicylic Acid, click here.
In cosmetics, butylated hydroxyanisole is used as a perservative. It also has antioxidant properties. The concentrations usually used in skincare are low and do not penetrate through skin.
It is only considered a carcinogen when ingested.
Butylated Hydroxyanisole is a synthetic and waxy petrochemical. It is used as a preservative in foods and cosmetics.
Learn more about BHALeuconostoc/Radish Root Ferment Filtrate is a natural preservative. It comes from fermenting radish roots with a bacteria called leuconostoc.
Leuconostoc comes from lactic acid.
This ingredient has antimicrobial properties and helps prevent the growth of bacteria in a product.
Leuconostoc is used to make the traditional Korean side-dish, kimchi. It is also used to make sourdough bread (both incredibly yummy foods).
Learn more about Leuconostoc/Radish Root Ferment FiltrateTocopherol (also known as Vitamin E) is a common antioxidant used to help protect the skin from free-radicals and strengthen the skin barrier. It's also fat soluble - this means our skin is great at absorbing it.
Vitamin E also helps keep your natural skin lipids healthy. Your lipid skin barrier naturally consists of lipids, ceramides, and fatty acids. Vitamin E offers extra protection for your skin’s lipid barrier, keeping your skin healthy and nourished.
Another benefit is a bit of UV protection. Vitamin E helps reduce the damage caused by UVB rays. (It should not replace your sunscreen). Combining it with Vitamin C can decrease sunburned cells and hyperpigmentation after UV exposure.
You might have noticed Vitamin E + C often paired together. This is because it is great at stabilizing Vitamin C. Using the two together helps increase the effectiveness of both ingredients.
There are often claims that Vitamin E can reduce/prevent scarring, but these claims haven't been confirmed by scientific research.
Learn more about TocopherolPolysorbate 20 is made by combining ethoxylation of sorbitan, ethylene oxide, and lauric acid. It is a mild cleansing agent, surfactant, and emulsifier.
As a surfactant, it helps collect dirt and oils for washing. Emulsifiers prevent oils and water from separating.
Polysorbate 20 also adds scent to a product. Since it is made using sorbitol, it has a sweet scent. Sorbitol can also be found in fruits such as apples and peaches.
The lauric acid used to create Polysorbate 20 is often derived from coconuts.
Polysorbate 20 may not be fungal acne safe.
Learn more about Polysorbate 20Ingredient Ratings
Here's what our community thinks of the ingredients in these products.
When to use
Some By Mi Retinol Intense Reactivating Serum 65 ingredients
Cosmedix Define Age-Defying Treatment 49 ingredients

Reviews
Here's what our community thinks
Some By Mi Retinol Intense Reactivating Serum 65 ingredients
Good intro to retinol. Pretty gentle in a serum form with a lot of my favorite ingredients included. It has a scent to it, but I find it enjoyable. It’s left my skin feeling smooth, less irritated, and hydrated. It also helps in reducing redness, which is one of my biggest concerns!