This or That? Drunk Elephant C-Firma Serum vs. Sunday Riley CEO Serum

I’ve been avid user of Vitamin C serums for a few years now. Throughout the process I’ve tried various brands. But my favorite has been the Drunk Elephant C-Firma Day Serum and I’ve been using it for a little over a year now. Over the summer I was gifted (via Instagram giveaway by the brand) the Sunday Riley CEO Serum. I thought this would be the perfect opportunity to test it out and see how the two compare and differ from one another.

Disclosure: Some of the links below are affiliate links, meaning, at no additional cost to you, I will earn a commission if you click through and make a purchase.

What is Vitamin C and why is it used?

Vitamin C is often used for its brightening effects and it’s anti-aging properties. Some studies have even noted Vitamin C being able to help and prevent UV photo damage. I’ve been using various vitamin C serums for the past couple of years within my morning skincare routine.

I’ll mostly be discussing the following types of Vitamin C:

L-Ascorbic acid (found in the Drunk Elephant C-Firma)- known to penetrate the skin tissue and is more active in collagen production. It comes from natural sources like oranges. L-Ascorbic acid is the most active, but known to be the most unstable and to oxidize quickly. It usually comes in concentrations between 5-15%. It’s been said that people with both dry and oily skin textures can benefit from the usage, but not great for those with sensitive skin types.

THD ascorbate (vitamin C) (found in the Sunday Riley CEO Serum)- also known as Tetrahexyldecyl ascorbate is a form of vitamin C which been modified to better penetrate the skin. Known to be one of the more stable types of Vitamin C. It’s said to be great for those who have sensitive skin types as it’s a more gentle formula of Vitamin C.

Other forms of Vitamin C- sodium ascorbyl phosphate, ascorbyl palmitate, retinyl ascorbate, tetrahexyldecyl ascorbate, magnesium ascorbyl phosphate, and ascorbyl glucoside. 


C-Firma vs. CEO

Size: 1 ounce Price: $80

Scent: Citrus

What is it? 15 percent L-Ascorbic acid, one-half percent ferulic acid (an antioxidant found in the cell walls of plants that enhances the stability and the efficacy of vitamins C) and one percent vitamin E.

Skin types suitable for: All Skin Types

C-Firma™ has a reservoir effect, which means it will stay active on skin for up to 72 hours and cannot be washed or rubbed off. Its pH level is 3.3, which Drunk Elephant believes is the key to a non-irritating formula.

Texture: Serum

Suggested Usage:
-In the morning, apply evenly to clean, dry face, neck, chest, and backs of hands.
-Tip: C-Firma™ contains pure l-ascorbic acid and yields best results when used fresh, so use immediately and don't stock up.
-After first use, this product may be stored in the refrigerator to help maintain its potent antioxidant activity and effectiveness.

Ingredients: Water, Dimethyl Isosorbide, Ascorbic Acid, Laureth-23, Glycerin, Lactobacillus/Pumpkin Ferment Extract, Sclerocarya Birrea Seed Oil, Dipotassium Glycyrrhizate, Glycyrrhiza Glabra (Licorice) Root Extract, Vitis Vinifera (Grape) Juice Extract, Phyllanthus Emblica Fruit Extract, Camellia Sinensis Leaf Extract, Tocopherol, Lactobacillus/Punica Granatum Fruit Ferment Extract, Sodium Hyaluronate Crosspolymer, Hydrolyzed Quinoa, Phytosterols, Glutamylamidoethyl Imidazole, Hydrolyzed Wheat Protein, Ferulic Acid, Acetyl Glucosamine, Sodium Hyaluronate, Tetrahydrobisdemethoxydiferuloylmethane, Tetrahydrodemethoxydiferuloylmethane, Tetrahydrodiferuloylmethane, Glycine, Leuconostoc/Radish Root Ferment Filtrate, Sucrose, Maltodextrin, Chondrus Crispus Extract, Hydroxyethyl Acrylate/Sodium Acryloyldimethyl Taurate Copolymer, Isohexadecane, Phenoxyethanol, Caprylhydroxamic Acid, Caprylyl Glycol, Sorbitan Isostearate, Propanediol, Pentylene Glycol, Xanthan Gum, Butylene Glycol, Sodium Hydroxide, Chlorphenesin, Polysorbate 60, Sodium Dehydroacetate, Potassium Sorbate, Sorbic Acid, Ethylhexylglycerin.


Sunday Riley CEO Rapid Brightening Serum

Size: 1 ounce Price: $85

Scent: Citrus

What is it? 15 percent THD ascorbate which delivers stable advanced vitamin C and is oil oil-soluble.

Skin types suitable for: All Skin Types

Texture: Consistency of a lotion

Suggested Usage:
-Apply one to two pumps to clean skin, morning and night.
-For enhanced visible brightening, follow with Good Genes, CEO Protect + Repair Cream, or Tidal Brightening Enzyme Water Cream.
-Vitamin C pairs excellently with retinol, so this product works very well when applied on top of Luna Sleeping Night Oil.

Ingredients: Water, Tetrahexyldecyl Ascorbate, Squalane, PEG-8 Beeswax, Hydrogenated Polydecene, Polyglyceryl-6 Distearate, PPG-12/SMDI Copolymer, Phenoxyethanol, Acetamidoethoxyethanol, Jojoba Esters, Sodium Acrylate/Sodium Acryloyldimethyl Taurate Copolymer, Glycine Soja Sterols, Tocopherol, Glycolic Acid, Caprylyl Glycol, Sodium Phytate, Citrus Aurantium Dulcis (Sweet Orange) Oil, Chlorphenesin, Cera Alba, Glycerin, Isosqualane, C30 Hydrocarbons, Saccharide Isomerate.


This or THat? Sunday Riley Ceo Serum or

Drunk Elephant C-Firma Serum?

I’ve been using the Drunk Elephant C-Firma Serum for little over a year now. When the opportunity presented itself to try out the Sunday Riley CEO Serum I thought it would be a good idea to see how similar or different the two are from one another. Both serums contain 15% of vitamin C. But as previously mentioned, the vitamin C are two different types.

It said that that THD, the main vitamin C ingredient in the Sunday Riley CEO Serum, to be more gentle than L-Ascorbic acid (found in C-Firma). I did my due diligence and checked out multiple reviews on the CEO serum. Many of the reviews contained complaints of people breaking out in acne or bumps when using the CEO Serum. I can’t say that one formula is gentler than the other because that truly depends on the skin texture of the individual using it.

The major complaint that I noticed for the C-Firma were of people complaining of the shelf life. Many mentioned that that the serum oxidized on them from a light orange color to dark orange color after 3 months of usage. When vitamin C serum oxidizes it usually an indicator that your vitamin C serum no longer just contains L-ascorbic acid. This makes me wonder how often is the serum being stocked and date checked while on store shelves. After reading about those claims months ago, I actually opened my serum. I didn’t know what it looked like when I initially purchased it, so I took a picture of it and wrote down the serial number on the bottle and reached out to a rep at Drunk Elephant. I was asked when I opened the bottle and was informed that my serum was just fine. I was also informed when to discontinue usage of it as well.

The one major con for me regarding the Sunday Riley CEO Serum is that the full size, 1 ounce, only lasted about 3 months. According to the packaging of the CEO serum, it states that the product has a shelf life of 12 months. Whereas the full size of the Drunk Elephant C-Firma Serum 1 ounce lasted about 6-7 months and it’s shelf life is marketed as 6 months.


Drum Roll…The Final Decision

Both serums were used in the morning along with my other skincare items (cleanser, toner, essence and moisturizer). I did not experience any type of purging, acne or sensitivity to the ingredients in either serum. Both gave me the same results of glowy skin and help to fade minor dark spots on face. I honestly really enjoyed using the CEO Serum, but the fact that it depleted so quickly was a major deal breaker for me.

Both product retails in the $80 range. Drunk Elephant also makes a midi size of the C-Firma mid-size (15 ml) for $44 and a travel size due for $23. These additional size options are great for those that are afraid of taking the plunge right away into the full price. Also the smaller size gives you a better opportunity to finish the entire serum. In my opinion, this makes the Drunk Elephant a better buy for me.


Just a few Things to remember when using Vitamin C….

  1. Keep away from sunlight

  2. Should be stored in an airtight package

  3. Should also be stored in a cool temperature.

  4. Don’t forget to wear sunscreen. You wouldn’t want to cause harm to your skin when you’re trying to improve it or protect it, Right?!


Have you tried either the Sunday Riley CEO Serum or the Drunk elephant c-firma serum? if so, please comment your favorite below.

Beauty Blogger with a love for fashion and lifestyle.