Say what you will, but many an ITG editor has accepted the “rinse your hair in cold water to make it shinier' gospel and come away disappointed. Maybe it's shinier...? Who can tell? And if you're that unsure about results, chances are there are some pretty unsubstantiated rumors flying around.

Then, a quick email got us back on track (as it always does). We shot off a note to Dr. Eric Pressly, one of the University of California, Santa Barbara-based inventors of hair-color savior Olaplex. “I think it's BS,” he quickly retorted to whether or not cold water can affect shine.

To elaborate: “Water, itself, can open or close the cuticle through absorption and swelling of the hair. This is a very fast process, and the difference between hot and cold water is negligible. To increase the opening of the cuticle cells, you can increase the pH of the solution above 10, which adds negative repulsion between the cells,” Pressly said. But we're going to go ahead and guess you don't want to be thinking about pH balance when you're in the shower.

Anyway, that had us all about convinced, but a second opinion is always a responsible course of action. Over we went to the Philip Kingsley Trichological Clinic, where Anabel Kingsley fielded the question. Not only did she emphasize that “once the hair has grown past the scalp, it is technically dead tissue—it neither contains blood vessels nor nerves. Rinsing with cold water therefore has the same effect on hair as rinsing with warm water does,” but there's also a potential side effect of the cold-water myth. Namely, “rinsing with cold water can constrict the blood capillaries in your scalp. As these capillaries carry vital nutrients to the hair follicles, in theory, it may actually be harmful to hair growth,” Kingsley added.

But there's good news, too! Mainly that you should just be investing your time in finding the best shine-boosting products instead of gritting your teeth through an uncomfortably cold end to what was a comfortably hot shower just seconds before. Staying in the family, Philip Kingsley's Elasticizer is a good pre-shampoo treatment once a week that helps address any damage that might be plaguing your hair cuticle. Follow that up with your favorite deep conditioner (we like the Davines Nourishing Vegetarian Miracle Conditioner) and, once dry, a dollop of Frederic Fekkai Brilliant Glossing Styling Crème. All of a sudden, cold showers are a thing of the past.

Illustration by Lucy Han.

Amp up the shine with three hair dryers that are worth the investment. Read more from Water Week here.