Clean Rinse Clarifying Scalp Serum

In 2020, at the height of lockdown-era beauty experimentation, Sunday Riley made a bet: the scalp-care category was ready for prestige skincare treatment. Clean Rinse Clarifying Scalp Serum was the result — a triple-acid exfoliating serum with gold shimmer particles, designed for a body part that most people only think about when it itches. It was a fascinating product. And based on its current stock status across retailers, the market may not have agreed.

The premise is genuinely compelling, though. Your scalp is skin. It produces sebum, sheds dead cells, and accumulates product residue just like your face. But while the average skincare enthusiast will layer three serums on their face before breakfast, most people address their scalp with whatever shampoo was on sale. Sunday Riley's argument was that the scalp deserves the same active ingredient attention that facial skin gets — and the formula backs that argument up.

The exfoliation system is a triple-acid combination: glycolic acid for surface-level dead cell dissolution, salicylic acid for oil-soluble penetration into follicles, and lactic acid for gentle additional exfoliation with hydrating properties. This AHA/BHA combination is exactly what a dermatologist might recommend for a congested, flaky, buildup-prone scalp — it addresses the problem from multiple angles rather than relying on a single acid.

Beyond exfoliation, the formula deploys zinc PCA to regulate sebum production at the gland level (not just removing oil from the surface), niacinamide for barrier support and anti-inflammatory calming, panthenol for scalp and hair hydration, and bisabolol for additional soothing. There's also kaolin clay for absorbing excess oil, witch hazel water for astringency, and urea for hydration. It's a formula that would be entirely at home in a facial treatment serum, redirected to the scalp.

The application experience is distinctive. The pointed nozzle tip lets you part your hair and apply the serum directly to the scalp in sections — a familiar technique for anyone who's used a scalp tonic or root touch-up product. The serum itself is a lightweight, watery liquid with a somewhat startling gold shimmer (from synthetic fluorphlogopite and tin oxide). The menthyl nicotinate produces an immediate tingling, cooling sensation that ranges from refreshing to uncomfortable depending on your sensitivity. After massaging for one to two minutes and rinsing, the scalp feels genuinely clean — not stripped, but clarified in a way that shampoo alone doesn't achieve.

The results, for those who respond to the product, are meaningful. Users report reduced flaking and itchiness within one to two weeks, visibly less oily scalp between washes, and a general improvement in scalp health that they can feel. Some users with scalp psoriasis symptoms found relief from the combination of exfoliation and anti-inflammatory actives. Hair tends to feel cleaner and lighter after use.

But the complaints illuminate why this product struggled commercially. At $48 for four ounces, it runs out quickly — especially for people with thick or long hair who need generous amounts per section. The acids can drip from the scalp onto the face during application, causing stinging and irritation. Some users with dry hair found the treatment left their lengths feeling parched. And a meaningful subset of users simply didn't notice enough difference to justify the price, particularly when less expensive scalp exfoliating products (including drugstore salicylic acid shampoos) exist.

The gold shimmer is an interesting formulation choice that splits opinion. Some users appreciate the luxurious, Instagram-ready aesthetic. Others see it as a distraction — cosmetic glitter in a treatment product that's going to be rinsed down the drain in two minutes. The particles don't affect efficacy in either direction; they're functionally inert.

The scalp-care market has grown significantly since Clean Rinse launched in 2020, with multiple brands now offering scalp serums, exfoliants, and treatments at various price points. Sunday Riley was genuinely early to this trend, and the formulation reflects real skincare expertise applied to a new category. But being early isn't the same as being successful — the product appears to be exiting the market at several retailers, available on clearance at Dermstore and out of stock elsewhere.

This is a product caught between two worlds. It's too expensive and niche for casual haircare consumers. It's too far from Sunday Riley's core competency for loyal skincare fans. And the scalp-care category, while growing, hasn't yet reached the level of consumer sophistication where $48 scalp serums are a mainstream purchase. The ingredients are excellent. The execution is thoughtful. The market just wasn't quite there.

Formula

The Science

The triple-acid approach in Clean Rinse addresses scalp buildup through complementary mechanisms. Glycolic acid, the smallest AHA molecule, penetrates the stratum corneum to dissolve the intercellular bonds that hold dead skin cells in place on the scalp surface. Salicylic acid, being oil-soluble (lipophilic), can penetrate into the sebum-filled hair follicles where water-soluble glycolic acid cannot reach — making it essential for addressing the follicular component of scalp congestion. Lactic acid provides additional exfoliation with superior hydrating properties due to its ability to function as both an exfoliant and a natural moisturizing factor (NMF) component.

Zinc PCA (zinc salt of pyrrolidone carboxylic acid) acts on sebum regulation through a different mechanism than the acids. Research has shown that zinc compounds reduce 5-alpha-reductase activity — the enzyme that converts testosterone to DHT, which drives sebaceous gland overactivity. By addressing sebum production at the enzymatic level, zinc PCA provides a more sustained oil-control effect than topical astringents that simply remove surface oil.

Niacinamide's role in this scalp formulation mirrors its well-documented facial skincare benefits: anti-inflammatory activity through inhibition of NF-kB signaling, barrier support through increased ceramide synthesis, and sebum regulation through reduced triglyceride and fatty acid production. On the scalp, where the skin barrier is often compromised by product buildup and mechanical stress from styling, these barrier-supportive properties help maintain a healthy scalp environment.

Menthyl nicotinate provides the tingling sensation through a different mechanism than menthol — it is a nicotinic acid ester that causes local vasodilation, increasing blood flow to the scalp surface. This improved microcirculation may support nutrient delivery to hair follicles, though the evidence for this benefit in the context of brief topical application is limited.

Dermatologist Perspective

Dermatologists and trichologists increasingly recognize the scalp as a distinct skin zone that benefits from targeted treatment beyond standard shampooing. The combination of AHA and BHA exfoliation with sebum-regulating zinc PCA represents a evidence-based approach to scalp health that mirrors established facial skincare principles. Board-certified dermatologists would note that for patients with seborrheic dermatitis or fungal-driven dandruff, this product addresses buildup and oil but not the underlying Malassezia overgrowth — a medicated antifungal treatment would still be necessary. For patients with simple scalp buildup, product residue accumulation, or mild flaking, the chemical exfoliation approach is well-supported. Dermatologists would recommend patch-testing on a small scalp section first and starting with once-weekly use.

Guidance

Launched in April 2020, Clean Rinse was Sunday Riley's first venture outside facial skincare — a bet that the scalp-care trend had enough momentum to support a prestige treatment product. The timing was notable: during lockdown, consumers were paying more attention to their scalp health and reducing salon visits. The product brought Sunday Riley's signature approach — skincare-grade actives in elegant formulations — to a category that had historically been dominated by medicated dandruff shampoos and tea tree oil products.

About Sunday Riley Established Brand (5–20 years)

Sunday Riley was founded in 2009 by cosmetic chemist Sunday Riley in Houston, Texas. Clean Rinse was the brand's first haircare/scalp product, launching in 2020. The brand is PETA and Leaping Bunny cruelty-free certified and holds B Corporation status. Note: the product appears to be discontinued or going out of stock at multiple retailers as of early 2026.

Brand founded: 2009 · Product launched: 2020

Myth vs. Reality

Myth

Your scalp doesn't need exfoliation the way your face does.

Reality

The scalp is skin — it produces sebum, sheds dead cells, and accumulates product buildup just like the face. Chemical exfoliation with AHAs and BHAs can help maintain a healthy scalp environment, reduce flaking, and improve conditions for hair growth. The scalp is often neglected in skincare routines despite being subject to the same biological processes as facial skin.

Myth

Gold shimmer in a scalp product means it's all marketing and no substance.

Reality

The shimmer comes from synthetic fluorphlogopite, tin oxide, and titanium dioxide — cosmetic-grade light-reflecting particles that don't affect the product's efficacy. They're functionally inert. The actual treatment comes from the acids, zinc PCA, and niacinamide. The shimmer is purely aesthetic and doesn't help or harm the scalp.

FAQ

Common Praise

"Effectively clarifies scalp buildup and removes product residue"

"Refreshing tingly sensation from the menthyl nicotinate"

"Reduces scalp itchiness and flaking noticeably within weeks"

"Micellar base means minimal additional shampooing needed"

"Hair feels softer and healthier-looking after use"

Common Complaints

"Expensive at $12 per ounce — runs out quickly for thick or long hair"

"Can cause burning or irritation when product drips onto face during use"

"Some users noticed no significant difference after several uses"

"Difficult to distribute evenly across the scalp with the nozzle applicator"

"Hair can feel dry rather than moisturized after treatment"

Notable Endorsements

Featured in Allure Beauty BoxFeatured in IPSY subscription boxesRefinery29 and The Zoe Report editorial coverage at launch

Appears In

best scalp treatment best scalp exfoliant best treatment for oily scalp

Related Conditions

oiliness

Related Ingredients

glycolic acid salicylic acid niacinamide zinc panthenol