Chlorine in Shower Water: What It Actually Does to Your Skin and Hair

Chlorine is in your shower water on purpose, and that is a good thing: it is the reason water reaches your bathroom free of the microbes that once made tap water dangerous. But the chemistry that protects the water is not especially kind to skin and hair — and in the UAE you meet it in a hot shower every single day.

Here is what the evidence actually supports, what it does not, and what is worth changing tonight.

• Chlorine is an oxidising agent. At tap-water levels it can lower how much water your skin's outer layer holds, and it roughens the outer scales of the hair shaft.
• The effect is small on any one day. Daily exposure, at shower temperature, is what adds up.
• Chlorine damages the hair you already have — the strand, the cuticle, the colour. It does not attack the follicle that grows it, and the swimmer research is clear on this point.
• A shower filter reduces chlorine at the point it reaches you. It does not soften water: nothing in a filter cartridge reduces calcium or magnesium.
• Chlorinated tap water is safe. This is a comfort-and-condition question, not a safety one.

The short answer

Chlorine dries skin and roughens hair, gradually. It is an oxidising agent, so at the levels found in treated tap water it can strip some of the lipids that keep your skin barrier sealed, and it can lift the cuticle — the overlapping outer scales that make hair lie flat and look glossy. What you experience is tightness, itch, dullness, tangling and faster colour fade.

What it does not do is cause hair loss, cause eczema, or make tap water unsafe. Reducing chlorine at the shower head is the most direct way to take it out of the equation, and it is one variable among several.

Why there is chlorine in your shower water

Chlorine is left in the water deliberately, as a preservative for the journey. Disinfection does not stop at the treatment plant: a small residual travels with the water so it stays protected across kilometres of pipework to your tap. The World Health Organization notes chlorine is present in most disinfected drinking water at 0.2–1 mg/L, and sets a guideline value of 5 mg/L — far above anything a municipal supply carries. That is why UAE tap water is genuinely safe to drink.

Two forms matter. Free chlorine is what the plant adds, present in water as hypochlorous acid and hypochlorite ions. Chloramines form when chlorine meets ammonia; the US Environmental Protection Agency notes utilities also add them deliberately, because they last longer through the distribution network. They are also what produces the sharp "swimming pool" smell — an odour that comes from chlorine which has already reacted with sweat and cosmetics, not from an excess of chlorine.

What chlorine does to your skin

Chlorine reduces how much water your skin's outer layer can hold, and sensitive skin feels it at lower concentrations. Your stratum corneum works like a brick wall: cells held together by lipids that keep water in and irritants out. Strip those lipids and the wall gets leakier — which feels tight, dry and itchy, often within minutes of towelling off.

The most directly relevant research was done in bath water, not a pool. In 2003, researchers at Toyama Medical and Pharmaceutical University measured skin hydration in 20 people with atopic dermatitis and 10 healthy controls after a ten-minute forearm immersion in 40 °C water at residual-chlorine levels of 0, 0.5, 1.0 and 2.0 mg/L. In the atopic group, hydration after bathing at 1.0 and 2.0 mg/L was significantly lower than in essentially chlorine-free water, and water-holding capacity dropped significantly from 0.5 mg/L upward. Healthy skin proved more resilient: only the 2.0 mg/L bath produced a significant difference.

Two honest caveats. That was a ten-minute immersion, harsher than a shower. And chlorine is not the only mechanism at work: when a larger study at Sheffield and King's College London washed 80 participants in water of varying hardness and chlorine levels, it was hard water that significantly increased irritating surfactant deposits — the same paper states "a clear effect of chlorine was not observed" in that protocol. Both arrive out of the same shower head, which is why the effect is so hard to out-moisturise.

What chlorine does to your hair

Chlorine attacks the strand, not the follicle. Hair is keratin, and keratin holds its shape partly through sulphur-containing bonds that oxidising agents are very good at breaking. Once the cuticle lifts, hair loses moisture faster, tangles more and feels coarse.

The clearest real-world evidence comes from competitive swimmers. A study published in the Journal of Dermatology in 2000 compared 67 elite Japanese swimmers with 54 non-swimmers and found hair discolouration in 61% of the swimmers and none of the controls. Electron microscopy showed the cuticle had disappeared entirely in the discoloured hair, melanosomes in the cortex were fewer and smaller, and chlorine was detectable inside the fibre.

That study is worth citing for what it did not find. The swimmers' hair was coarse and visibly damaged, but they were not losing more hair than the controls. Brittle hair breaks more, and breakage looks exactly like shedding in the shower drain — which is where most of the confusion about chlorine and hair loss comes from.

And the green hair? That is copper

Blonde hair turning green after a summer of swimming gets blamed on chlorine constantly, and that is the wrong culprit. The green comes from copper — dissolved from pipes and from copper-based algaecides — which chlorine oxidises into compounds that bind to keratin in the cuticle. Chlorine is the accomplice, not the pigment.

Why the UAE makes it add up faster

Nothing about chlorine chemistry is unique to Dubai. What differs is the dose and the company it keeps.

• It is daily, not occasional. A swimmer meets chlorinated water a few times a week. You meet it every time you shower, often twice a day in summer.
• It is hot. Heat opens the hair cuticle and lifts more oil from the skin, so warm water amplifies whatever it carries.
• It does not arrive alone. UAE tap water is desalinated and then re-mineralised, so it is hard — chlorine strips oils while dissolved minerals and soap residue sit on top of skin and hair.
• The journey adds to it. Water crosses long, hot distribution lines and often a rooftop tank, picking up rust, sediment and metal traces from ageing pipework.

What actually helps

Change the habits first, because they are free, and only then change the water. Here is what each lever actually addresses.

What you change	Chlorine	Hardness	Cost	Best for
Shorter, cooler showers; gentle cleanser; moisturise while damp	Less contact time	Less residue	Free	Everyone, first
Shower filter at the head	Reduced	Unchanged	Low; no plumbing	Renters; daily exposure
Plumbed-in ion-exchange softener	Unchanged	Removed	Thousands of dirhams	Owners with limescale problems
Richer moisturiser alone	Unchanged	Unchanged	Ongoing	Treating the symptom only

Habits worth changing tonight

The American Academy of Dermatology's advice for dry skin is specific and free: limit showers to five to ten minutes using warm — not hot — water, wash with a gentle, fragrance-free cleanser, pat rather than rub yourself dry, and moisturise while skin is still damp. If your hair is coloured, finish with a cool rinse to help the cuticle lie flat.

What does not work is piling on more product. A rich cream on a barrier stripped every morning is working uphill.

Filter the water where it touches you

The direct fix is to reduce chlorine at the shower head. The word that matters is certified, because "tested to" is marketing language and certification is not — and, as NSF notes, there are no federal regulations governing residential shower filters in the US. NSF/ANSI 177 is the shower-specific standard, and its scope is verified reduction of aesthetic free available chlorine plus materials safety and durability. NSF/ANSI 42 is the broader drinking-water aesthetic-effects standard, covering chlorine, chloramine, taste, odour and particulate.

blu's Ionic Shower Head & Filter is built on an NSF/ANSI 42 certified filtration medium — a certification of the Nano Molecular Cluster medium itself, not of the finished product or the company. The cartridge reduces chlorine, heavy metal ions, dirt and odours rather than eliminating them. blu's cartridge was tested by Eurofins, which measured free chlorine reduced from 17.09 mg/L to 0.09 mg/L (a 99.5% reduction), and the filter was named Best Overall in Gulf News' March 2024 UAE shower-filter roundup; the medium is explained on The Science page.

One caveat we would rather state ourselves: a shower filter is not a water softener. It does not reduce calcium or magnesium — that requires ion-exchange resin, which is what the separate NXT LVL Shower Softener & Filter uses. Filtered water tends to feel gentler from the first shower, which is not the same thing. Cartridges wear out: blu rates one at roughly 70 to 100 showers, about two months.

Frequently asked questions

Sources

• World Health Organization, Chlorine in Drinking-water chemical fact sheet (residual 0.2–1 mg/L; guideline value 5 mg/L) — who.int
• US Environmental Protection Agency, "Chloramines in Drinking Water" — epa.gov
• American Chemistry Council, "Chloramines: Understanding Pool Smell" — chemicalsafetyfacts.org
• Seki T, Morimatsu S, Nagahori H, Morohashi M. "Free residual chlorine in bathing water reduces the water-holding capacity of the stratum corneum in atopic skin." Journal of Dermatology 2003;30(3):196–202 — PubMed 12692355
• Danby SG, Brown K, Wigley AM, et al. "The Effect of Water Hardness on Surfactant Deposition after Washing and Subsequent Skin Irritation in Atopic Dermatitis Patients and Healthy Control Subjects." Journal of Investigative Dermatology 2018;138(1):68–77 — PubMed 28927888
• Nanko H, Mutoh Y, Atsumi R, et al. "Hair-discoloration of Japanese elite swimmers." Journal of Dermatology 2000;27(10):625–34 — PubMed 11092265
• The Conversation, "Why does my hair turn green from the swimming pool?" — theconversation.com
• American Academy of Dermatology, "Dermatologists' top tips for relieving dry skin" — aad.org
• NSF, "NSF/ANSI 177 – Shower Filter Certification" — nsf.org
• NSF knowledge library, "Filtration Systems Standards" (scope of NSF/ANSI 42) — nsf.org
• Eurofins, test report EFSN24031276 (free chlorine reduction, blu handheld NMC cartridge, 3 April 2024) — Eurofins report (PDF)
• blu, The Science and Results — medium, certification and laboratory characterisation, retrieved 1 September 2026.

This article is general information, not medical advice. If your skin is painful, cracked, infected or not settling, or if your hair fall is heavy or persistent, see a doctor or dermatologist.