Sunday Riley CEO Rapid Flash Brightening Serum Review

I finally finished the Sunday Riley CEO Rapid Flash Brightening Serum that I got as part of my Allure beauty box subscription last year. It took me about ~8 months of on and off use, though I will admit that I got bored of it midway and switched to the Dermadoctor Kakadu C Serum. After finishing that Ferulic-acid based serum, I returned to finish up the Sunday Riley.

Sunday Riley CEO Rapid Flash Brightening Serum

Key Ingredients

The headlining ingredient is the 15% vitamin C. This serum uses THD ascorbate, a stable and more lipid-soluble variant that is supposed to penetrate skin better - though it has to be converted back into active L-ascorbic acid first. (Read more about the different formulations of vitamin C here.) Other standout ingredients include squalane, an excellent moisturizing ingredient with plenty of fatty acids, and glycolic acid, an AHA that is commonly used for skin renewal and a brighter complexion.

What initially drew me to this serum was the high concentration of vitamin C, which is more potent as the percentage increases up to 20%. The flipside is that this formulation confused me a bit by adding the glycolic acid for exfoliation. I like to use my vitamin C serums in the morning under sunscreen, as studies show that layering vitamin C and sunscreen has a greater than additive effect against phototoxicity (PubMed ID: 8869680). However, it’s recommended that AHAs like glycolic acid be used at night because they increase photosensitivty…so these two ingredients seem to complicate where this serum fits in.


I decided to use this serum as part of my AM routine anyway, layering it over a gel moisturizer and under an SPF 50 sunscreen. The texture is more like a cream lotion than a serum. It is light and spreadable with a mild orange fragrance. While it does leave a slight stickiness if you use too much (more than two pumps), it’s generally OK under makeup if you matte down your face with powder.


The bottle retails for $85 at Anthropologie and Sephora. It’s in-line with how other prestige brands price their vitamin C serums - especially ones with newer formulations like THD ascorbate. However, there are definitely more inexpensive options out there that still have concentrations >=15%, such as the Japanese Rohto Melano CC.


I liked it, but would not repurchase. While I did see an increase in overall radiance (that vitamin C glow!), I would have liked to see more progress on my dark spots. When I say more” progress, I really mean any” progress - I could not notice any lightening of my hyperpigmentation when I used this serum vs. a more traditional, Ferulic-acid stabilized vitamin C compound. A part of me is less confident because there’s less research on the efficacy of THC ascorbate as it is newer.

The benefit of Sunday Riley’s formulation is that the non-acidity (as it is oil-based) is great for people with sensitive skin. However, my skin is pretty non-reactive, so this was not the best formulation for me.

· vitamin C · sunday riley · sephora

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