Is it safe to wash your hair with dishwashing liquid?
Every so often a questionable beauty trend goes viral, spreading its way through social media and ruining hair and skin everywhere. Every so often, these dangerous haircare trends get recycled and now it's washing your hair with dishwashing liquid. . .again.
That's right, a few social media 'beauty gurus' are once again pushing dishwashing liquid as an alternative to shampoo - and plenty of people are lapping it right up.
According to their claims, shampoo and dishwashing liquid are basically the same thing; both of them have the same ingredients and both of them will get your hair clean. Only difference is, one is cheaper and gets your hair way cleaner - so the story goes.
If you feel your eyebrow rising, then that's just your good instincts. Since including this craze in our list of dangerous trends, we've gotten a few questions so decided to break it down to the nitty gritty. Here's exactly why ever letting dishwashing liquid touch your hair is (mostly) a pretty bad idea.
Is dishwashing liquid the same as shampoo?
Dishwashing liquids aren't the same as shampoos. The consistencies are different, so is the foamability, plus the fact that dermatologists advise that you wear gloves when using one of them in case it dries out your skin.
Unlike the bad science being pushed on social suggests, the ingredients in these two products are not the same. Here's are some shampoo formulation examples from a cosmetics ingredient manufacturer. Now here's one for dishwashing liquid.
As you can see, different ingredients. For one, most dish detergents are formulated with sodium lauryl sulfate. This ingredient is their primary surfactant, the one that does the heavy duty cleaning work.
Sodium lauryl sulfate shampoos are now extremely rare thanks to the anti-sulfate campaign, which rightly got formulators to swap them for the gentler sodium laureth sulfate.
Dishwashing liquid almost always contains another potentially drying ingredient: sodium chloride (salt). Other common ingredients include SD alcohol and cocamide DEA - which isn't compatible with certain haircare ingredients.
The concentrations of the main surfactants are also different. Dishwashing liquids have more heavy duty cleaning to do, so they contain a higher amount of surfactant than shampoo.
Then there's the fact that there's A LOT of variability in the shampoo category. Unlike dish detergents, which tend to have more or less straightforward formulas, shampoo formulations vary widely.
Shampoo ingredients vary based on their purpose. Clockwise from top left: Halka Baba De Caracol Sulphate-Free Shampoo is for mild to moderate cleansing; atrActiva Anti-Stress Shampoo is a deep cleanser; Silicon Mix Shampoo is a moisturising cleanser; Capilo La Aplanadora Shampoo is deep-cleansing.
Shampoos are formulated to clean different hair types, to different degrees, under different conditions and often impart other unique benefits - which means a ton of different ingredients and concentration levels. Given the extent of this variation alone, it's impossible for dishwashing liquid to be "just like" shampoo.
Is one type of dishwashing liquid safer than the others?
When it comes to dish detergent, you'll find that many formulas are pretty much the same across brands. Cheaper ones will contain more water, but there's far less variability overall.
This isn't a huge surprise. After all, dish detergents are built to wash dishes, which are way less complicated and variable than hair. Most dishwashing liquids follow the same simple formula: primary surfactant, secondary surfactant, thickener, pH adjuster, hydrotrope, preservatives and water.
Certain Instagrammers urging people to try dishwashing liquid have declared one brand superior to the others. They claim it's gentle because it's been used on rescued ducklings to remove crude oil after oil spills. But that doesn't make it gentle enough to use as shampoo - and there's no indication of the manufacturers ever advising people to use their product in this way.
While some innovative formulas do contain conditioning ingredients to make them softer on your hands, or different surfactants to make them more environmentally friendly, there's a limit to how gentle dishwashing liquid can be and still be good at its job. If it wasn't harsh enough to lift the grime off greasy pots and pans nobody would buy it.
This is why even dishwashing liquids that are marketed as safer - milder and more ecofriendly - are still much more concentrated than even a clarifying shampoo.
"But I just used dishwashing liquid to wash and my hair was fine."
The effects of using such a strong cleanser on your hair happen at a microscopic level so don't expect to see most changes right away, unless your hair is very damaged or sensitive. The effects are cumulative though, so you will begin to see the impact on your hair after using it a few times.
Just so you can make your own informed decision on whether to use it or not, here's exactly what happens when you use a typical dishwashing liquid to wash your hair:
1. Dishwashing liquid dries out your scalp and hair
This is the most obvious ill effect. Sodium lauryl sulfate is an extremely powerful cleanser. It's great at dissolving all kinds of oils - including the ones that keep your skin and hair moisturised. Once it rips away these natural moisturising lipids, your skin loses hydration rapidly.
Because it usually contains sodium lauryl sulfate, dishwashing liquid can exacerbate dry scalp, leaving it flaky and irritated. And if you have an oily scalp, your sebaceous glands may start to overcompensate for the huge loss of sebum - and give you even more oiliness to deal with.
The salt in dish soap (used as a cheap way to thicken the formula) will also seriously dry out your hair. Anyone who's ever been to the beach knows salt air alone is enough to leave your hair looking like tumbleweed - and a dip in the sea without preparing your hair adequately can leave it dehydrated for weeks after.
Then there's the SD alcohol in some dish detergents: it's highly astringent so dissolves your natural oils with ease. If there's enough in the formula, it could also swell your strands till they fracture.
2. Dish soap removes the outer coating from your hair
Your cuticle's job is to protect the inner layers of your hair. But did you know that there's a layer on top of the cuticle that protects the cuticle itself? That's your epicuticle, and it's made up mostly of lipids, which provide a chemical surface barrier for your hair.
Since it's so good at breaking down oils, using sodium lauryl sulfate regularly will eventually completely remove this protective layer. Once it dissolves the epicuticle, it gets to work dissolving the entire cuticle, including the cell membrane complex - the 'glue' that holds your hair together.
3. Dishwashing liquid can trigger dermatitis in your scalp
The main ingredient in most dish detergents is so irritating that scientists regularly use it to trigger contact dermatitis for experimental purposes.
When used to wash hair, sodium lauryl sulfate has been shown to set off another skin condition: atopic dermatitis. It turns out the salt in dish detergent isn't just drying: mixed with the sodium lauryl sulfate in the formula it becomes a serious irritant. The problem is rinseability: these formulas rinse pretty easily off of dishes. Rinsing it off a human being is another story.
As soon as the sodium lauryl sulfate-salt combination gets in contact with keratin - the stuff your hair and the outer layers of your skin are made of - it sticks to it.
That's creepy, but also pretty ironic, considering that the social media users who push dishwashing liquid think they're getting their hair cleaner. In reality, they're actually creating more buildup.
This is bad for your hair, but it's the consequences for your skin and body that are most worrying. The fact that you can't rinse dishwashing liquid off fully means it has more time to stay on your skin and potentially cause irritation.
The safe level for sodium lauryl sulfate in leave on products is very low; 1%. The level in dishwashing liquid is several times that. If the residue it leaves behind exceeds that 1% concentration, or you use this stuff repeatedly and it starts to accumulate on your skin, it could potentially be toxic.
4. Washing up liquid creates buildup when you use it in hard water
Sodium lauryl sulfate loves to form complexes with the metal ions that hang out in hard water. This creates more buildup, aka surfactant residue, which sits on your hair, slowly dissolving your strands, even when you're not shampooing.
The damage this causes leads to chronic breakage, which could get in the way of your hair growth goals, as well as worsening other problems with manageability and shine. The residue sits on your scalp too, causing dryness and potential irritation.
DHA Hair Care Experts