I Tested The Sunday Riley Retinol Serum Daily For 6 Weeks — These Are My Honest Thoughts

If you were to say, “Quick: grab the only skincare products you can’t live without!” I would run to my bathroom and, with zero hesitation, hand you an SPF, a vitamin C serum, and a retinol product. This is my holy trifecta. Together, these ingredients have the power to tick off every box on my anti-aging must-have list: sun damage prevention, brightening skin, and reducing the appearance of wrinkles.

EDITOR’S NOTE: Retinol shouldn’t be used by women who are pregnant, considering getting pregnant, or nursing. Please consult with your doctor before use.

I’m so passionate about these three categories that I’ve always insisted that I use the best products my face — and budget — can handle. For retinol, that means I’ve typically bypassed over-the-counter products for the more heavy-hitting prescription-strength retinoid (called tretinoin). In fact, earlier this year, I graduated myself from the 0.05 percent formulation to the 0.1 percent one. I was oddly proud of this accomplishment, but my skin, on the other hand, was not pleased.

EDITOR’S NOTE: As always, talk to your doctor before starting any prescription-strength products.

About two weeks in, I noticed dry, patchy areas, particularly on my forehead and around my chin. According to Cincinnati-based cosmetic chemist Kelly Dobos, this is a common reaction to the potent ingredient, though I hadn’t experienced it until now. “Prescription treatments containing retinoic acids offer the highest level of efficacy but greater risk for irritation,” she says. So, I reluctantly dialed back my tretinoin use to every other night, and when that didn’t help, I benched my Rx cream and decided it was time to introduce a much gentler version instead. 

In particular, Sunday Riley® A+ High-Dose Retinoid SerumTM ($85) stood out to me because of the brand’s claims that it has all of the benefits of a traditional retinol without all of the drawbacks (and, let’s face it, the term “high dose” was pretty persuasive). This product is Sunday Riley’s second foray into retinol (the first was the cult classic Luna Sleeping Night Oil, $105). A+ is described as a more “advanced-strength retinoid serum” that can tackle multiple concerns, including reducing the appearance of fine wrinkles and improving skin clarity. 

Putting The Plus In A+

Retinoids are often considered the ultimate anti-aging ingredient in skincare, but there are so many products boasting the inclusion of them nowadays that it can make your head spin trying to figure out what they are and how this ingredient category actually works. 

The word “retinoid” is a generic term used to classify the family of chemical compounds that are derived from vitamin A. Some of the most popular forms of retinoids that you’ll find in skincare include retinol, tretinoin, and retinaldehyde. The main difference between all of them is how fast they convert into the active ingredient “retinoic acid” in order to be properly absorbed by the skin. 

On one side of the spectrum, you’ll find prescription products that contain tretinoin, a “first generation” retinoid that is considered the most intense of the bunch. According to Kim Nichols, MD, a board-certified cosmetic dermatologist in Greenwich, CT, it can work relatively quickly at improving skin tone and texture. “Tretinoin causes the cell turnover process to occur a lot quicker, and therefore, the results are seen sooner,” she says. 

To understand what cell turnover actually looks like, imagine a snake shedding its skin to reveal its shiny new scales underneath. When applied topically, retinoids increase cell turnover on the topmost layer of our skin which, in turn, has some very beneficial effects. “This shedding process reveals fresh new skin, which can help to improve the appearance of pore size, uneven skin tone, and even fine lines and wrinkles,” explains Dr. Nichols. 

OTC products like the Sunday Riley A+ serum are considered to be topical retinoids, and still offer excellent, skin-smoothing results. However, if you select an option in this category rather than a prescription formula, you will be waiting a bit longer to see the benefits. “Technically, you can get the same results from using an over-the-counter retinol versus a prescription-strength retinoid, but the results will come at different paces,” explains Dr. Nichols.

Dobos agrees, adding that gentle doesn’t necessarily mean ineffective: “While ingredients used at low levels [in skincare] are often questionable in terms of real efficacy, retinol and retinoids are an exception,” she says. “Levels of 0.1 percent or less of retinol have been shown to visibly improve the signs of aging.” 

The A+ serum contains a whopping 6.5 percent solution of retinoid blends, but don’t let that number sway you into thinking it’s that much more impactful. It’s ultimately still a “solution,” and contains different (albeit unique) concentrations and blends of the active form of vitamin A than a prescription formula. 

Leading the pack in Sunday’s concoction is a five percent retinoid ester called hydryoxypinacolone retinoate (HPR). HPR is sometimes referred to as “granactive retinoid” and, according to Dobos, is one of the newest forms of vitamin A to boast efficacy without irritation. “Unlike many retinoids, which lose potency as they are converted to retinoic acid in the skin, HPR is effective because it can bind directly to retinoid receptors,” she explains. 

Other off-shoots of vitamin A in the bottle include 1.0 percent encapsulated retinol and 0.5 percent blue-green algae, which the brand maintains is a “natural, retinoid alternative.” Dobos says she is, however, skeptical of that claim. “Algae extract may help hydrate the skin, but I have not seen any definitive data that shows it is as efficacious as retinol.” Michele Green, MD, a board-certified dermatologist in New York City, has a similar point of view. “While these ‘green’ alternatives may have some antioxidant benefits, they do not offer the anti-aging effect retinol does,” Dr. Green says. “They are unable to reverse the signs of aging and soften [the appearance of] existing wrinkles, while preventing the formation of new ones.”

Beyond retinoids, the A+ Serum includes a number of antioxidants and other skin-balancing ingredients. Encapsulated CoQ10 helps “protect the skin from free radicals generated by oxidative stress from things like [sun] exposure and pollutants,” says Dobos. Ginger, bisabolol (a botanical extract), and rare Hawaiian white honey help soothe the skin. Honey, in particular, adds Dobos, is “known to have antibacterial and anti-inflammatory properties.”

Finally, it’s worth noting that the potion is free of sulfates, parabens, gluten, soy, phthalates, and fragrance.  

Application And Wear

I was really impressed with the packaging of this serum — much like the Sunday Riley Good Genes Treatment® ($105), it comes in a chic glass bottle with a pump. Dobos notes that gives extra assurance the ingredients inside are sealed tight. “Retinol’s stability can be impacted by heat, light, and exposure to air,” she warns. “Cosmetic chemists can employ techniques to aid in stability or use more stable derivatives, but opaque, airtight packaging is an added layer of security.”

I also like that the pump makes it easy to measure exactly the amount you need. The metal tube my tretinoin comes in often makes it messy to dispense and the cap never seems to fit right. 

Sunday Riley recommends applying one to two pumps of the A+ Serum at night to clean, dry skin — however, a little goes a long way. You can definitely get away with using just one or one and a half pumps to cover your entire face and neck. It comes out in a pale yellow fluid that’s easy to spread (I suspect that is due partially to the inclusion of the emollient dimethicone) and more reminiscent of a light lotion than a tacky serum.

I found that it absorbs quickly, doesn’t feel greasy or heavy, and leaves no tingling sensation behind. While the brand claims there is no added fragrance, I did detect a chemical-ish scent that lingered for a few minutes after I spread it over my face. It wasn’t offputting to me at all (if you’ve ever used Good Genes, you may recognize the smell), but I’ve noticed a small number of reviewers describe it as rancid or like a damp dishcloth. Those who have a sensitive nose may want to consider getting a sample size to see if it’s tolerable for them. 

I consider myself an advanced retinoid user, so per Sunday Riley’s instructions, I used the serum daily, but only in the evening. I am a firm believer in using retinoids only at night because you want to give it time to work its magic, but also because the ingredient is known to make you more susceptible to sunburn. (Read more about precautions when using retinol during the day.) Regardless of what type of retinoid you use, you should also wear sunscreen every single day.

Sunday suggests following the A+ Serum up with an oil or moisturizer. Interestingly enough, I often didn’t even feel the need to do this because my skin already felt appropriately hydrated with just that one product. I imagine if I were writing this review in the dry winter months instead of early fall, though, I would’ve chosen to layer something lightweight but still nourishing — like the Wander Beauty® Glow AheadTM Face Oil ($48) — on top.

Those with sensitive skin are instructed to do the reverse: Use oil or moisturizer before the A+ serum in order to provide an extra buffer. (This is also known as the retinoid sandwich technique.) They may also want to follow the brand’s instructions for new retinoid users, which is to start small with one application every two nights until they can work their way to every other night, then to daily, nighttime use. 


I used the A+ Serum nightly for six weeks (to coincide with the timeline of the brand’s own clinical study), however, I question whether this was truly enough time to produce major results. After all, according to Dr. Nichols, “Three to six months is the standard timeline where consumers can expect to notice changes in the skin.”  

So while I can’t really speak to the anti-aging benefits (my lines and wrinkles look unchanged), I can report back that my skin has continued to look brighter and much more even with each passing day (especially first thing in the morning). The clusters of hormonal acne I’ve been battling on my chin (finally!) started to calm down, and there’s noticeably less oiliness in my T-zone. 

I’m really pleased with my progress with this potion in general, but there is one caveat. I noticed some angry, red patches popping up around my lips about three weeks in. I’ve had what’s known as perioral dermatitis many times before, so I know what it looks and feels like when it’s provoked (and can distinguish it from that aforementioned retinoid-induced flakiness). I was hoping that the A+ Serum wasn’t the culprit, but it’s the only new product I’ve introduced into my routine as of late. Upon further inspection of the ingredient list, low and behold, there are some hanging out near the bottom (like benzoic acid and phenoxyethanol) that I know — thanks to cosmetic allergy testing — that I’m allergic to. Major bummer!

Ultimately, the “high dose” serum still gets some high praise from a seasoned tretinoin user like me. The combination of hydration and exfoliation makes it a very capable retinoid, but even more so for those with oily, acne-prone skin. Those with sensitive skin may also find success with this product, just be sure to heed my warning: read the label first.

Dr. Kim Nichols is a paid Allergan® consultant.

Complimentary product was provided to the author for the purpose of writing this article.

Product prices may vary from the time this article was written.

Allergan® may receive commissions for purchases made through links in this article.