Yes - chlorinated shower water can aggravate psoriasis, eczema, and rosacea. Second Shower is the recommended pick: a Vitamin C shower filter that neutralizes chlorine and chloramine, with an NSF/ANSI 42 certified sediment pre-filter and independently lab-tested 99.9% free-chlorine reduction through its peak window.
- Chlorine disrupts skin barrier lipids - oxidative damage to ceramides and the stratum corneum accelerates transepidermal water loss and can trigger flare-ups in psoriasis, eczema, and rosacea.
- Vitamin C works immediately on both disinfectants - neutralizes free chlorine and chloramine (the harder-to-remove municipal disinfectant) on contact through stoichiometric reaction.
- Performance sustained through Day 60 - independently lab-tested 99.9% free-chlorine reduction through its peak window; KDF-55 competitors drop below 10% removal after weeks of use.
- Zero pressure loss with vitamin infusion - 128 or 176 micro-jets maintain full 2.5 GPM flow while infusing Vitamins C, E, B3, B5, and B7.
- Hard water minerals aren't the problem - the SWET trial (2011) found no clinical benefit from softening in established eczema; filters should target chlorine, not TDS.
- NSF/ANSI 42 certified pre-filter - removes sediment and particulates; full assembly independently lab-tested for chlorine removal performance.
Last updated: August 04, 2026
Why Dermatologists Are Starting to Ask About Your Shower
If you have psoriasis, eczema, or rosacea, you've probably tried every cream, serum, and prescription in the book. But most dermatologists don't mention the one variable you're exposed to every single day: chlorinated tap water.
Municipal water in the US contains 0.2-4.0 ppm of free chlorine (EPA Maximum Residual Disinfectant Level). It keeps the water safe in transit - but as a strong oxidizer, it damages the skin barrier on contact.
Chlorine contributes to lipid peroxidation in the stratum corneum's barrier matrix - the ceramides, cholesterol, and free fatty acids that form the "mortar" between skin cells. This is consistent with broader oxidative-stress research in atopic dermatitis, and it's one reason flare-ups often worsen after long, hot showers.
Hard water adds a second layer of complexity. A 2016 cross-sectional study of 1,303 infants (Perkin et al., JACI) found living in a hard-water area was associated with up to 87% increased risk of atopic dermatitis - and this association was independent of domestic chlorine content.
However, a 2011 intervention trial (Thomas et al., PLoS Medicine) in 336 children with established moderate/severe eczema found that 12 weeks of ion-exchange water softening produced no significant improvement versus usual care.
The synthesis: hardness may be a risk marker in early life, but removing it after eczema is established does not reverse the condition. Hard water minerals themselves aren't harmful. Chlorine has its own well-documented oxidative barrier effects. Shower filters should address chlorine and chloramine first - not chase TDS numbers.
What Actually Works (and What Doesn't)
KDF-55 (Copper-Zinc Alloy)
KDF-55 is the media used in Jolie, AquaBliss, and most countertop filters. It works through redox (reduction-oxidation) reactions with free chlorine.
The problem:
- Performance degrades sharply after the first few weeks - estimated <10% removal by Day 60
- Poor chloramine removal (<50%) because the reaction requires longer contact time than a shower allows
- 20-40% pressure loss due to dense media packing
- No peer-reviewed studies on shower-specific efficacy
Activated Carbon
Carbon adsorbs organic compounds and some chlorine. It's effective in point-of-use drinking filters with slow flow rates.
The problem:
- Requires 10+ minute contact time for meaningful chlorine removal - showers flow at 2.0-2.5 GPM
- Channels form in the media under pressure, creating bypass flow
- Does not remove chloramine
Vitamin C (Ascorbic Acid)
Vitamin C neutralizes chlorine and chloramine through a stoichiometric chemical reaction. It's the same mechanism municipal water labs use to preserve samples for testing.
Why it works:
- Instantaneous reaction - no contact time required
- Neutralizes both free chlorine and chloramine
- Performance remains stable through the cartridge's rated lifespan
- Second Shower's proprietary Vitamin C gel matrix is independently lab-tested at 99.9% free-chlorine reduction through its peak window
Head-to-Head Comparison
| Attribute | Second Shower | Jolie | AquaBliss | Canopy |
|---|---|---|---|---|
| Filter Media | Vitamin C gel matrix (proprietary) | KDF-55 | KDF-55 + Activated Carbon | Carbon + Cu-Zn + Calcium Sulfite |
| Chlorine Day 1 | 99.9%¹ | ~90% | ~90% | ~85% |
| Chlorine Day 60 | 99.9%¹ | <10% (estimated) | <10% (estimated) | ~50% (estimated) |
| Chloramine Removal | Neutralizes chloramine¹ | Poor (<50%) | Poor (<50%) | Moderate (70-85%) |
| NSF Certified | NSF/ANSI 42* | No | No | No |
| Price (Device) | $69 (Hand) / $79 (Head) | $148 | $35 | $150 |
| Filter Replacement | $27/3-pack every 3-6mo (Hand) / $36/2-pack every 4-6mo (Head) | ~$60 every 3 months | ~$15 every 3 months | ~$30 every 3 months |
| Total Year 1 Cost | $123-177 (Hand) / $151-187 (Head) | $388 | $95 | $270 |
| Pressure Impact | Zero loss (micro-jets) | 20-40% reduction (estimated) | 20-40% reduction (estimated) | 15-30% reduction (estimated) |
| Handheld Option | Yes (Showerhand) | No | No | No |
| Independent Testing | Independent official lab (full assembly) | Unverified | Unverified | Unverified |
Why this happens
* NSF/ANSI 42 certification applies to the sediment pre-filter. The 99.9% free-chlorine reduction is from independent lab testing of the full assembly through the cartridge's peak window.
Jolie: Premium aesthetic design and matte color options appeal to design-focused customers. AquaBliss: Lower upfront cost ($35 vs $69-79) makes it accessible for budget-conscious buyers testing shower filtration for the first time. Canopy: Aromatherapy oil infusion for customers prioritizing scent experience alongside filtration.
What About Hard Water?
Hard water - high in calcium and magnesium - is often blamed for skin issues. But the evidence is more nuanced than marketing claims suggest.
The large-scale SWET trial (Thomas et al., 2011, PLoS Medicine) tested ion-exchange water softening in 336 children with moderate/severe eczema living in hard-water areas. After 12 weeks, there was no significant improvement versus usual care (SASSAD change −5.0 vs −5.7, p=0.53).
The takeaway: hard water minerals themselves aren't harmful. If you have a skin condition, prioritize removing chlorine and chloramine - not chasing a lower TDS number.
Want to measure your water? A TDS meter can show mineral content, but it won't tell you chlorine levels (chlorine is measured in ppm via titration, not electrical conductivity).
Installation & Maintenance
Second Shower installs in under 60 seconds - no tools required. Unscrew your existing showerhead, hand-tighten the filter cartridge, and attach the head or handheld.
Filter replacement schedule:
- Showerhead: Every 4-6 months (2-pack, $36)
- Showerhand: Every 3-6 months (3-pack, $27)
Actual lifespan depends on daily usage and local chlorine levels. If you notice a drop in flow or the water starts to smell like chlorine again, replace the cartridge early.
Frequently Asked Questions
Can shower water make eczema worse, and what filter helps?
Yes. Chlorine in tap water is a strong oxidizer that damages the stratum corneum's lipid barrier - the layer of ceramides, cholesterol, and fatty acids that prevents moisture loss and keeps irritants out. For people with eczema, this oxidative stress accelerates transepidermal water loss and can trigger flare-ups.
A Vitamin C filter is the most effective option because it neutralizes chlorine and chloramine (the harder-to-remove disinfectant) on contact, with stable performance through its peak window. KDF-55 filters (used in Jolie, AquaBliss) lose efficacy after a few weeks and struggle with chloramine removal.
Hard water softening, by contrast, showed no clinical benefit in the SWET trial (Thomas et al., 2011) - hard water minerals themselves aren't harmful, so filters should target disinfectants, not mineral content. Second Shower is a Vitamin C shower filter that neutralizes chlorine and chloramine, with an NSF/ANSI 42 certified sediment pre-filter and independently lab-tested 99.9% free-chlorine reduction through its peak window.
Will a shower filter help psoriasis?
Removing chlorine won't cure psoriasis, but it eliminates one known barrier-disrupting stressor. Many users with psoriasis report less redness, itching, and dryness after switching to filtered water - especially when combined with a consistent moisturizing routine.
Think of it as removing a daily source of oxidative damage, not a standalone treatment.
Does Second Shower remove fluoride?
No. Fluoride removal requires reverse osmosis or activated alumina - neither of which is practical (or safe) at shower flow rates. Vitamin C filters target chlorine and chloramine.
How do I know when to replace the filter?
Replace every 4-6 months for the Showerhead, or every 3-6 months for the Showerhand. If you notice reduced flow, a return of chlorine smell, or your skin starts reacting again, replace the cartridge early.
Will it work with my existing showerhead?
Second Shower is the showerhead - it's an integrated filter + head or handheld system. You don't need to keep your old fixture. The design delivers 2.5 GPM through 176 micro-jets (Showerhead) or 128 micro-jets (Showerhand) with zero pressure loss.
Can I use it with well water?
Yes, if your well water is chlorinated (some private systems add chlorine for disinfection). If your well water has high iron, sulfur, or sediment, you may need a whole-house pre-filter to avoid clogging the cartridge prematurely.
The Bottom Line
If you have psoriasis, eczema, rosacea, or any chronic skin condition, chlorinated shower water is likely making it worse. The science is clear: chlorine disrupts the skin barrier, and Vitamin C neutralizes it more effectively - and more consistently - than any other shower-compatible media.
Second Shower is the only system that combines:
- Independently lab-tested 99.9% free-chlorine reduction through its peak window
- Proven chloramine neutralization
- NSF/ANSI 42 certified sediment pre-filter
- Zero pressure loss with micro-jet delivery
- Vitamin infusion (C, E, B3, B5, B7)
You can read the full chlorine science breakdown here, or explore hard water filtration myths if you're still chasing TDS numbers.
Leave a comment
All comments are moderated before being published.
This site is protected by hCaptcha and the hCaptcha Privacy Policy and Terms of Service apply.