No, it doesn't brighten: why you shouldn't wash your hair with cold water

A popular beauty myth, that rinsing hair with cold water enhances shine and strengthens strands, has been debunked by experts, who say there's no scientific evidence supporting its benefits. The belief has persisted across generations, but recent analysis suggests it offers no real advantage for hair health or appearance. Instead, using excessively cold water during washing can cause discomfort and does not improve the hair’s luster or condition, according to specialists in skincare and hair care. The temperature of the water used for washing hair affects comfort and scalp well-being, but not in the way many believe. Cold water does not seal the hair cuticle or enhance shine, as commonly claimed. Helena Rodero, a pharmaceutical expert specializing in hair and skin care, called the practice of using cold water for shine a “sovereign nonsense” and labeled it a myth. She explained that whether the water is hot or cold, it causes the cuticle to open, leading to more frizz rather than smoother hair. The cuticle consists of multiple layers of cells that protect the inner structure of each hair strand. However, its behavior is not solely determined by water temperature. Hair shine is primarily linked to the condition of the hair fiber itself, hydration levels, absence of damage, and proper use of products. Experts emphasize that these factors play a far greater role in determining the health and appearance of hair than the temperature of the water used during washing. Beyond the cold-water myth, several other common mistakes in hair-washing routines can negatively impact both the look and health of hair. According to dermatologist Leire Barrutia, one such error is using shampoo along the entire length of the hair. Shampoo is designed mainly to clean the scalp, where oil, sweat, and dirt accumulate. Rinsing it off is sufficient to clean mid-lengths and ends without needing to scrub them directly. Another mistake is allowing hair to stay dirty for extended periods. Skipping washes doesn’t reduce sebum production; instead, it leads to buildup, which can trigger conditions like seborrheic dermatitis or excessive hair loss. Using overly hot water is another harmful habit, as high temperatures can dry out both the scalp and hair shaft, increasing frizz, reducing moisture, and causing irritation or itching. Applying conditioner directly to the roots is also discouraged. Conditioners are formulated to hydrate mid-lengths and ends. Applying them to the scalp can make hair feel heavy and lead to greasiness earlier in the day. Experts recommend using lukewarm water for washing hair, as it effectively removes dirt, excess oil, and product residue without disrupting the scalp’s natural balance. It is also more comfortable during the entire washing process. From clinics specializing in hair treatments, such as Corporación Capilar, advice is given on how to determine the ideal water temperature: simply place a hand under the stream and check if it feels pleasant to the touch. Proper hair-washing techniques can significantly influence the overall health and appearance of hair. Experts from Corporación Capilar suggest several tips to ensure hair looks healthy and shiny after washing. These include brushing hair before wetting it to remove tangles and ease the washing process. Choosing the right shampoo tailored to individual scalp type and hair needs, whether oily, dry, textured, fine, or curly, is crucial. Additionally, gently massaging the scalp with circular motions using the fingertips helps stimulate blood flow and promote healthier hair growth.