Dandruff Is a Scalp Microbiome Imbalance, Not a Hygiene Failure, Here's What Indian Scalps Actually Need

Malassezia is a yeast-like fungus present on virtually every human scalp. Under normal conditions, it feeds on sebum, the natural oil your scalp produces, and causes no visible problem. When it overgrows, it breaks down that sebum into oleic acid, a fatty acid that irritates the skin barrier, accelerates cell turnover, and produces the white or yellowish flakes recognised as dandruff. A 2007 study published in the Journal of Investigative Dermatology confirmed Malassezia globosa as the primary species responsible for dandruff globally, and identified oleic acid sensitivity as the mechanism, not bacterial infection and not dirt.
The hygiene explanation for dandruff persists partly because flaking looks like something that should wash off. It doesn't, because the flakes are dead skin cells shed faster than usual, a response to fungal irritation happening below the surface. Washing removes the flakes temporarily. It does nothing to the Malassezia population driving their production.
Heat and humidity accelerate sebum production. The scalp of someone living in Chennai or Mumbai in peak summer produces more oil than the same scalp would in a drier, cooler environment. Malassezia thrives on sebum. More sebum means a richer food source, which means faster fungal proliferation. This is why dandruff tends to worsen through monsoon and summer months for many Indian adults, the climate creates ideal conditions for Malassezia overgrowth regardless of how often the person shampoos.
Hard water, common across much of urban India, adds a separate layer of disruption. Calcium and magnesium deposits from hard water alter the scalp's pH, weakening the acid mantle that normally keeps microbial populations in check. A study in the International Journal of Trichology found that hard water exposure increased scalp irritation markers and disrupted the skin barrier, both conditions that allow Malassezia to gain ground.

Daily shampooing strips the scalp of sebum. The scalp responds by producing more oil to compensate. More oil feeds more Malassezia. The cycle tightens. Many people with chronic dandruff have been washing their hair daily for years, convinced that more frequent cleaning is the solution, when the washing frequency is part of what sustains the imbalance.
Harsh sulphate-based shampoos compound the problem. They clean efficiently but disrupt the scalp microbiome, the broader community of bacteria and fungi that, in a balanced state, keep any single species from dominating. When that community is repeatedly stripped, Malassezia faces less competition. The scalp's microbial diversity drops, and the conditions for overgrowth stabilise rather than resolve.

Antifungal actives are the only category that addresses the root cause. Zinc pyrithione, ketoconazole, selenium sulphide, and piroctone olamine all reduce Malassezia populations directly. Ketoconazole shampoos, available in India as prescription and over-the-counter formulations, have the strongest clinical evidence, a controlled trial in the British Journal of Dermatology showed significant reduction in Malassezia counts and flaking after four weeks of twice-weekly use.
Salicylic acid helps by clearing the build-up of dead skin cells, but it is a descaling agent, not an antifungal. Used alone, it removes the visible symptom without addressing fungal load. The combination of an antifungal active with a gentle, pH-balanced base gives the scalp the best chance of restoring balance without stripping the microbiome further.

Neem oil and tea tree oil have genuine antifungal properties, studies on both show inhibition of Malassezia in vitro, but concentration matters. The dilutions in most commercial shampoos are often too low to be clinically meaningful. Using neem oil directly on the scalp before washing, a practice common in many South Indian households, delivers a higher concentration. The evidence for this as a standalone treatment is limited, but as an adjunct to an antifungal shampoo it is reasonable.
Dandruff treated as a hygiene problem leads to more washing, stronger cleansers, and a cycle that never resolves. Dandruff treated as a microbiome imbalance leads to different choices: reducing wash frequency to stop stripping the scalp's natural defences, switching to an antifungal active during flare periods, and recognising that the goal is not a surgically clean scalp but a balanced one.
The scalp microbiome recovers. Given the right conditions, less disruption, targeted antifungal treatment during active overgrowth, and a shampoo that cleans without destroying microbial diversity, Malassezia returns to its normal, non-irritating role. The flaking stops because the trigger for accelerated cell turnover is gone, not because the scalp has been scrubbed into submission.
Dandruff is persistent in India partly because the climate genuinely favours Malassezia, and partly because the standard advice runs in the wrong direction. Every bottle promising a cleaner scalp is solving for the wrong variable. The scalp does not need to be cleaner. It needs to be balanced.