How effective are post-wash scalp serums?

As scalp serums gain more traction on social media, we speak to experts to find out how far a post-wash, leave-in scalp serum can go

If there’s something common that haircare brands across the world are doing at the moment—besides launching hair oils, of course—it is coming up with scalp serums. With scalp care taking top billing in the recent past, there are newer scalp-first products making their way into the haircare market, creating a whole new category—scalp care. Very recently, we also spoke about how scalp care is poised to be the new haircare. While hair oils, as a means of fortifying and nourishing the scalp, have been a significant part of beauty regimens in India for centuries, scalp serums have emerged as their present-day counterpart. With scalp serums, especially those meant for leave-in wear, the tried-and-tested succour of traditional ingredients come together with the potency of modern-day actives sans the greasiness of oil, boosting the effectiveness and convenience of scalp care products. 

However, scalp serums also strongly claim to mimic the benefits of hair oil—from thickening and densifying the hair to growth-boosting and conditioning. We ask experts to weigh in their opinion on the product and whether it actually has the merit to stand tall to its claims.

What does a leave-in scalp serum do?

According to Mumbai-based celebrity dermatologist Dr Madhuri Agarwal, the basic job of a post-wash scalp serum is to hydrate the scalp. “It is equivalent to a moisturiser for the face; it relieves a dry, itchy scalp by hydrating and calming it.” Today, a bunch of brands specialising in haircare such as Fable & Mane, Kérastase, Virtue, Schwarzkopf Professional, JVN Hair, and Bread Beauty have come up with their versions of post-wash scalp serums. A healthy scalp supports healthy hair growth and is the first step to achieving beautiful hair, believes Bony Sasidharan, creative head, Schwarzkopf Professional India. “For us, leave-in scalp serums have always been an important part when it comes to scalp care routine as we believe that a scalp care routine is incomplete without it.”

Pre-wash versus post-wash scalp serums

It’s key to know that scalp serums are of two types—pre-wash or pre-shampoo serums and leave-in, post-wash serums. While pre-wash scalp serums are mostly treatment-specific and usually oil-based or heavy on chemical active ingredients, post-wash serums are more soothing and nourishing, with ingredients that enrich the scalp’s health through formulations and textures that are easier to stay [on the scalp] for a longer period of time and won’t require a hair wash soon after. “Wash-away serums are mostly additives and are highly concentrated compared to post-wash serums, hence they need to be rinsed off. Wash-away serums act like a catalyst, whereas post-wash serums are for maintenance and scalp care,” explains Sasidharan.

“Typically haircare products have multiple ingredients that are subsequently washed off during a wash,” informs Prudvi Mohan Kaka, chief scientific officer, The Ordinary. “A scalp treatment is then applied and left on the scalp; it is the treatment step where you will see results through the delivery of ingredients.” Post-wash, leave-in scalp serums also help achieve long-term goals like a healthier scalp or boosted hair growth versus a pre-wash one that targets concerns like dandruff and dryness.  

The play of active ingredients

The proliferation of the scalp care industry means that several ingredients conventionally found in skincare products are now being introduced to haircare formulations–in scalp serums too–such as peptides, lactic acid, vitamins and taurine (an amino acid). Scalp serums can offer a multitude of benefits, depending on the active ingredients found within their formulas, believes Kaka. 

“The Ordinary Natural Moisturizing Factors + HA for Scalp is a milky serum that contains a combination of ingredients that mimic the function of natural moisturising factors (NMF) as well as hyaluronic acid (HA) and squalane that are naturally produced within the skin. The combination of these ingredients help provide skin hydration and scalp barrier function support,” adds Kaka. The brand also has a Multi-Peptide Serum for Hair Density which provides fuller-looking hair through a mix of peptides and plant-based extracts. Talking about the BC Scalp Genesis from Schwarzkopf Professional, Sasidharan says, “It contains carnitine tartrate (an antioxidant), taurine (an amino acid) and echinacea (a perennial herb), that activate the hair roots and increase the ratio of active hair follicles to reduce non-pathological hair loss. 

While the Genesis Anti-Hair Fall Serum from Kérastase is enriched with a combination of Aminexil, Edelweiss native cells and ginger root, the Initialiste Advanced Scalp & Hair Serum contains anti-oxidants and ceramides. By scrutinising the ingredient labels of these products, one can estimate the scale at which active ingredients are implemented into hair care products today.

Do scalp serums really work?

Agarwal isn’t very sure about post-wash serums as the product passes as more of a feel-good concept for her. “In humid weather, like in India, post-wash scalp serums do not make much sense as they can clog the scalp and lead to more problems,” warns the dermatologist. However, you can rule that out by choosing the right product. “You should look for serums that are silicone-free,” Dr Margarita Lolis, MD, board-certified dermatologist at Schweiger Dermatology Group in Hackensack, New Jersey, had told Allure. “While silicones such as dimethicone are great for creating lustrous locks, the residue left by silicone-based serums on the scalp is what clogs pores, blocks hair follicles and increases sebum production, hair shedding, and flakiness.”

“We recommend that the product is used on clean and dry hair. Start by separating the hair into sections and dispense a small amount directly onto the scalp in the desired area and massage it into the scalp. Ideally, apply at bedtime onto a clean and dry scalp,” advises Kaka.

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