When I signed up for triathlon training, I had to buy a pair of swim goggles so I didn't crash into things like the lane markers, the other people swimming around me, and the wall at the end of the pool. (Ouch.) While buying that little necessity, the sales staff talked me into buying some special chlorine-removing shampoo. Naturally I was curious about whether it was actually significantly different from my normal shampoo or if it was just marketing, which is the majority of the difference between most normal shampoos, so I bought the little sample size bottle to test it out.
Using it in place of my normal shampoo after the swim didn't seem to make a difference that I could notice, but then I did make sure to pre-soak myself in the pool showers before jumping in. Hair absorbs a remarkable amount of water, so getting it to absorb low-chlorine tap water before it hits the high-chlorine pool water will provide some partial protection right there.
I remember my grandfather's white hair turning green when I was a kid and we'd go to the public pool (which I found out as an adult is due to copper from the pipes, not the chlorination). I also remember how the pool smell would cling even after that post-swim rinse.
So, looking at the ingredients printed on the bottle of the particular shampoo I bought (tri-swim) I see:
- aloe vera leaf juice
- sodium laureth sulfate
- disodium cocoamphodiacetate
- cocamidopropyl betaine
- sodium chloride
- vitamin E acetate
- vitamin A palmitate
- provitamin B5
- nasturtium officinale extract (watercress)
- chamomilla recutita extract (chamomile)
- magnesium sulfate
- sodium thiosulfate
- DMDM hydantoin
- citric acid
- iodopropynyl butylcarbamate
- sodium borate
- trisodium EDTA
- tetrasodium EDTA
- disodium EDTA
- yellow 5
- red 33
- blue 1
This has a lot of ingredients in common with normal shampoos. Sodium laureth sulfate, disodium cocoamphodiacetate, and cocamidopropyl betaine are all types of soaps. DMDM hydantoin, iodopropynyl butylcarbamate, sodium borate, and urea are all types of preservatives. Vitamins, fragrances, plant extracts, and colours are added for (usually) marketing reasons. Citric acid is probably there to keep the pH where it belongs. Water, of course, is the solvent that everything is mixed into.
That leaves sodium thiosulfate, the three EDTA compounds, urea, magnesium sulfate, and sodium chloride.
Urea and magnesium sulfate are often used as skin softeners, along with aloe vera juice. Since public swimming pools do tend to dry your skin, these are good things to have, although not unique to a swimmer's shampoo.
EDTA is a chemical widely used to grab hold of metals so they can't react with anything else. It's in quite a few soaps where it is mostly used to grab the calcium and magnesium that make water "hard", to prevent those dissolved metals from reacting with the soap and making that nasty hard-water soap scum. It will also grab onto any copper from the pool water. Not unique to a swimmer's shampoo, though they may put a bit more than normal in.
Sodium chloride is table salt. It's there to adjust how thick the mixture feels. Not unique to a swimmer's shampoo.
And of course the ingredient I left for last is sodium thiosulfate. This reacts very well with chlorine, converting it to a largely non-reactive form. It's used in a lot of places, such as dechlorinating water to avoid killing fish, and chlorine-removing shampoos.
So, the claim is definitely plausible. The next question is, is a special chlorine-removing shampoo worth buying?
Well, for me, with my 1hr swims three times a week in an indoor pool, with pre-soaking and immediate post-rinsing, and without drying off in the sun—no, not really.
For somebody in the pool a lot more often or a lot longer, or somebody who doesn't pre-soak and post-rinse, which you don't have time to do in a triathlon race situation—it could be.