Serious Question: Why Does My Hair Look Greasy Right After I Wash It?

Few things get under my skin like psyching myself up to wash my hair and blow-drying it with painstaking precision, only for it to look — and feel — just as greasy as before. You know the frustration and it seems countless others do, too.

On TikTok the queries “Why is my hair greasy all of a sudden after a wash?” and “Why is my hair greasy underneath after washing?” serve up hundreds of videos with thousands of views, likes and comments. It’s quite the common conundrum. Suppose you’re doing everything right, like double cleansing your scalp, being sparing with hair oil and not touching your hair as much throughout the day. Why, then, does your hair never feel clean? 

I put the question to Anabel Kingsley, a consultant trichologist and brand president at Philip Kingsley, and Alicia Dobson, a celebrity hairstylist and Bellissima ambassador. What I learnt totally transformed both my shower- and hairstyling routines for the better.

Interestingly, Kingsley points out that your hair texture can impact how oily your scalp is. “Those with finer hair tend to have more hairs per centimetre on their head [compared to] those with thicker, coarser or coiled hair textures, and therefore, they have more oil glands producing more sebum,” she explains. This, adds Kingsley, is why fine hair often becomes greasy faster.

With genetics out of the way, there are a handful of other reasons why your hair might look and feel oily even after you’ve washed it: “Firstly, not washing your hair thoroughly to properly cleanse away oils, product build-up and pollution can leave your scalp feeling dirtier,” says Kingsley. 

She believes that there’s only one correct way to wash your hair: “Wet the hair fully, [apply] shampoo and clean the scalp thoroughly for one minute. Then [repeat the step], rinse with water and apply a conditioner to the ends before rinsing again.” As a rule of thumb, Kingsley says that massaging shampoo into your scalp should take a full 60 seconds — no less. 

Contrary to popular belief, you can’t “train” your hair to become less oily by reducing the amount you wash it. “There are no pros to not washing your hair regularly,” says Kingsley. “You wouldn’t leave more than three days between washing your face, and you likely wouldn’t wear the same outfit more than a few times before washing it. Apply the same thinking to your hair and scalp,” she says. 

Infrequent shampooing can also contribute to scalp problems, says Kingsley. “It leaves excess oils sitting on your scalp and certain yeasts called malassezia thrive in an oily environment. When these yeasts overgrow, your scalp can become flaky and irritated.”

The type of shampoo you use matters, though. Kingsley says it’s imperative to choose a product suited to your hair texture so that it provides the right level of cleansing and moisturising ingredients — and doesn’t weigh your hair down. Those with fine hair might like to opt for a 'volumising' or 'thickening' shampoo which will clean your hair and scalp without leaving behind a heavy feeling, suggests Kingsley. She uses the Body Building Shampoo, £27.

If your hair is thick, curly or coily, consider something packed with hydrating and moisturising agents like OUAI Thick Hair Shampoo, £28, with panthenol and shea butter, Maui Moisture Nourish & Moisture Coconut Milk Shampoo, £8.99, with mango butter and guava oil, or Fenty Beauty The Rich One Moisture Repair Shampoo, £29, with plant oils and strengthening amino acids.

As long as you’re washing your hair thoroughly as per Kingsley’s advice, you shouldn’t need to enlist a clarifying shampoo every time. But Dobson says that using one every one to two weeks is helpful to remove product build-up, which she says is one of the biggest culprits for making hair appear unclean: “If you’re using styling creams and oils too often, they can leave behind a residue that weighs your hair down and causes it to look greasy,” she says.

Kingsley suggests shampooing twice using something with the ingredient lauryl betaine, which cleanses deeply without causing irritation. She recommends the Philip Kingsley Flaky/Itchy Anti-Dandruff Shampoo, £14. Also try Aveda Scalp Solutions Balancing Shampoo, £30, or Noughty Detox Dynamo Clarifying Shampoo, £8.99, if you’d rather spend less. 

Assuming you’ve switched up your shampoo routine, your next port of call is rethinking your conditioner, says Dobson: “A conditioner can also be an element of your routine that’s making your hair look greasy,” she says. Conditioners that boast ingredients like moisturising shea butter, nourishing coconut oil or shine-enhancing silicones are beneficial for thicker, drier hair, but Dobson says that they can be too heavy for other hair types. “If you have finer hair, a lightweight conditioner — free from silicones — or even just using a leave-in spray post-shower, could be a better option,” says Dobson.

Exactly where you apply your conditioner matters, too: “Do so from the mid-lengths [downwards] rather than directly on your scalp, as it can lead to product build-up,” says Dobson. Kingsley agrees: “To avoid heaviness at the roots, keep conditioner away from the scalp,” she says. “Use it on the lengths and ends of your hair only.” Just be sure you’re rinsing it out properly: “Sometimes people rush this step which leaves behind traces of product that makes your hair look dull and greasy,” says Dobson. Like massaging in your shampoo, aim for a full minute when rinsing away the conditioner. 

Dobson believes that allowing your hair to air-dry naturally is not only potentially damaging (this is because hair is at its most fragile and prone to breakage when wet), but it could be a reason why it appears oilier than usual: “When you blow-dry your hair, it disperses the natural oils through the root to tip — and closes the hair cuticle,” she explains. 

Kingsley agrees that a gentle blowdry can help smooth down the hair cuticle, making hair more sleek and minimising tangles. In fact, she prefers not leaving the scalp damp for long periods — and certainly not overnight. “[An oil-rich], humid environment can encourage the overgrowth of the yeasts that live naturally on our scalps, potentially triggering dandruff,” says Kingsley. 

In other words, there are benefits to blow-drying — even rough-drying — your hair. Just be aware of the temperature: “Excessive heat styling can cause the hair to become brittle and more prone to breakage,” says Kingsley, “so remember to keep the heat setting on medium or low.” She also advises heat protection, whether that’s a lightweight spray for those with fine hair, or a moisturising leave-in product for thicker lengths. 

Try Philip Kingsley Protecting Primer, £25, ghd Bodyguard Heat Protect Spray, £23.90, or Redken One United Multi-Benefit Treatment Spray, £23.60.

Besides washing your hair regularly (with the right shampoo for your hair type), and using conditioner sparingly, Kingsley says that topical toners and serums can help to balance the scalp and minimise oil production. She suggests Philip Kingsley’s Flaky/Itchy Anti-Dandruff Scalp Toner, £12, with the star ingredient piroctone olamine, which soothes scalp irritation and targets the yeast that causes dandruff. If you use lots of styling products including dry shampoo, hair oils or a particularly thick conditioner or hair mask, consider The Inkey List Salicylic Acid Exfoliating Scalp Treatment, £15, with exfoliating salicylic acid to gently chip away at dead skin, oil and product build-up, or Alpha-H Healthy Hair Exfoliating Treatment, £25, with salicylic and lactic acid to reduce oil and flakes. 

On the topic of styling products, it’s easy to go overboard. Start with a small amount and gradually add more if you think your hair needs it.

Lastly, while there is little scientific research to suggest that shower filters are beneficial to prevent greasy hair, Dobson believes that your water quality is an important factor in how hair looks after it has been washed: “Hard water contains a high amount of minerals, which often build up on your scalp and make hair feel heavy or look greasy, and a shower filter can help with this,” she says.

If you’re intrigued, try the Hello Klean Shower Filter 2.0, £45, which reduces chlorine and heavy metals, or if you have a little more to spend, the Act+Acre Showerhead Filter, £116, which makes hard water softer.