Why Blonde Hair Turns Green by the Pool and How to Prevent It
With beach season upon us, the three horsemen of the summer apocalypse have also arrived- sunburn, upper lip sweat, and blondes saying hello to green hair.
Blonde hair can turn green after swimming in a pool due to the presence of dissolved copper and other metals in the water. Contrary to popular belief, chlorine itself is not the direct cause. When copper is present in pool water—often introduced through pool pipes, algaecides, or the water source—it can undergo a chemical reaction, particularly when the water is chlorinated. Chlorine acts as an oxidizing agent, causing the copper to oxidize into copper oxide. This copper oxide is then attracted to the proteins in the hair shaft, especially keratin, which is the primary structural protein in hair. When these copper particles bind to the keratin in the hair, they impart a greenish tint, which is more noticeable in lighter hair colors like blonde.
Several factors can make this green tint more pronounced. The concentration of copper in the pool water is one key factor—the higher the copper content, the more metal is available to bind with the hair, resulting in a more intense green hue. The condition of the hair also plays a significant role; hair that is damaged, overly porous, or weakened by frequent bleaching, coloring, or heat styling is more susceptible to absorbing copper. Porous hair allows more water—and thus more copper ions—to penetrate the hair shaft, increasing the likelihood of a green tint developing. The frequency of exposure to pool water can lead to a cumulative effect; the more often the hair is exposed, the more copper can accumulate, leading to a deeper green coloration over time.
The pH levels of the pool water further influence this process. If the pool's pH is not properly balanced, the copper ions can become more reactive and more likely to bind with the hair. Pools with lower pH (more acidic) are particularly prone to increasing the reactivity of copper ions, which heightens the chance of hair turning green.
So how can you prevent blonde hair turning green in the summer? “If your hair is recently dyed, you’re more likely to experience a green tint from chlorine, as hair dye can sometimes alter your hair’s structure, making it react more strongly with chlorine” comments Jason Collier, Key Opinion Leader at Jerome Russell Bblonde, and stylist to the likes of Victoria Beckham, Sienna Miller and Eva Longoria.
“To avoid your hair turning green from chlorine, rinse your locks thoroughly with clean water before swimming to reduce chlorine absorption, and use a clarifying shampoo after swimming to remove any residual chlorine and metals. I also recommend applying a leave-in conditioner or protective hair oil before swimming to create a barrier against chlorine, and if your hair is recently dyed, try to minimise exposure to chlorinated water as much as possible.
If your hair has already turned green from chlorine, use a clarifying shampoo to help remove the discoloration, you can also apply a mixture of baking soda and water to gently scrub the affected areas. Rinsing your hair with a mixture of equal parts vinegar and water can also help neutralise the green tint.
After treatment, make sure to condition your hair well to restore moisture and prevent further damage.”
Embracing the joys of summer shouldn't come with the unintended side effect of a new, unplanned hair color. By understanding the science behind pool-induced green hair and taking proactive steps, blondes—and anyone else prone to this issue—can keep their locks luminous and vibrant all season long. So, as you dive into the refreshing waters and bask under the sun, remember that a little pre-swim preparation can go a long way in ensuring that your hair reflects only the golden hues of summer, not the green of the deep end.
