If you live in an area with hard water or you’ve travelled to somewhere that has it, you might have noticed your hair feeling drier, rougher, or more brittle than usual. But why is this? To understand what’s really going on, we looked at the research to see whether hard water can cause hair loss or damage, and what practical steps you can take to manage it.
What You’ll Learn
Ø What hard water is
Ø The effects of hard water on hair
Ø Whether hard water causes hair loss
Ø How to minimize damage from hard water
What is hard water?
Hard water contains high concentrations of minerals magnesium and calcium. The area you live in, and where your water comes from, will determine how hard or soft your water is. You’ll usually know if you live in a hard water area because your kettle will fill up with limescale, and you might notice a white, chalky film over your shower screen. Hard water can also make it more difficult for soaps, washing up liquid and laundry detergents to lather up.
But what effect does hard water have on your hair?
The studies investigating the effect of hard water on hair are both limited and find conflicting results. Some conclude that hard water damages and weakens hair, while others say it has no effect.
We’ve summarised the results briefly below so you can have a look for yourself:
· In a 2013 study, hair from 15 volunteers was cut in two to get two samples from each person, then placed in either distilled water or hard water for 10 minutes every second day, to replicate washing hair with hard or soft water. They measured the strength and elasticity before the experiment started, and again after 30 days of treatment. They found that hard water didn’t affect hair strength or elasticity.
· This 2016 study used very similar methods on the hair of 15 participants, but this time they used an electron microscope to examine the surface of the hair. In this study, researchers found that hair treated with hard water had a ‘ruffled appearance’ and was thinner compared to hair treated with distilled water.
· A 2018 study collected hair samples from 70 male volunteers, split them into three, and tested on control, ‘deionized’ water (aka soft water) and hard water. They found that hard water made hair weaker and increased breakage.
· Another 2016 study, using the hair of 76 men, tested the strands with deionized water and hard water for 3 months. They found that the strength of hair in the group treated with hard water was decreased.
As you can see from the summary of the studies above, the picture is somewhat mixed. One study says that hard water has no effect on the strength of hair, while others say it weakens the hair. To help explain the discrepancy, it may be worth taking the conditions of the studies into account. The study which found no effect used a smaller sample size (15 people) and a shorter duration (30 days), compared to longer studies with more participants, which generally found that hard water does cause hair damage.
Can hard water cause hair loss?
Based on the research available so far, hard water is unlikely to directly cause hair loss. However, it can affect the hair’s quality, strength, and overall appearance.
One proposed explanation is that the calcium and magnesium in hard water leave mineral deposits on the hair. These deposits can make it harder for moisture to enter the hair shaft, resulting in dryness and brittleness. Hard water also makes it more difficult for shampoo to lather, which may lead to more vigorous scrubbing and increased friction during washing, both of which can contribute to breakage. Anecdotally, many people on forums such as Reddit report that their hair feels weaker, frizzier, and drier when they regularly wash it in hard water.
What can you do about it?
Shower filter
You can buy filters which remove chlorine, heavy metals and impurities from water, which may be better for your hair and skin. An added bonus is that it may also have benefits for your water bill by improving water pressure while using less water.
Clarifying hair products
These shampoos are stronger than everyday shampoo, containing heavy surfactants which can help remove buildup and impurities from hair. They are only designed to be used every once in a while, e.g once every two weeks.
All of our blog articles are reviewed by our Medical Director before publication.
