Hot Vs Cold Water: Shampooing 101


We've all heard recommendations for the best water temperature for our showers. Hot water steams our pores and opens them, but it can dry out our scalp. Cold water is invigorating and can leave our hair shiny, but it can be hard to handle frigid showers. If we ask 10 people, we can get 10 different answers. 

But what does science say about it? Should we be using cold water on our hair, or is hot water better for hair washes?

We sat down with Dr. Debra Lin, Chief Scientific Officer at Better Not Younger, to give us the scientific intel on why water temperature matters when we wash our hair and which temperature is best. 

How Does Water Temperature Affect the Hair Structure?

In simplest terms, our proteins that form and define our hair structure generally will not change under normal shower temperatures. But the act of wetting our hair does have an impact, according to Dr. Lin.

“Regardless of the temperature of your shower, water can enter the hair shaft, which

can swell hair strands and slightly lift cuticles,” says Dr. Lin. “Wetting hair can also disrupt the weak hydrogen and salt bonds that occur naturally in our hair.” This disruption causes hair to be stretchier and more susceptible to damage. (This is why you should never brush fragile hair while it's wet—gentle combing only!) 

Does Hot Water Cause Hair Loss?

No, there are not any definitive studies that have shown that shower-level hot water causes hair loss. However, using excessively hot water on hair can cause other issues that can harm the scalp, which can interfere with healthy hair growth, notes Dr. Lin. It can damage and dry out the scalp where follicles reside, disrupting hair growth. 

So while hot water doesn't cause hair loss, or alter the hair structure, on its own, it can harm our scalp. And a healthy scalp is vital for preventing excess hair fall and supporting new, healthy hair growth. To protect your scalp, skip the scalding water. 

After your cooler shower, try giving your scalp even more love with a nourishing scalp serum (applied to towel-dried or fully dried hair) and gentle massage. Our Superpower Hair & Scalp Duo combines our Superpower serum and a gentle, round-tipped scalp massager to evenly dispense the serum to help rejuvenate hair follicles and support a healthy scalp. 

Does Cold Water Help Hair Growth?

There have not been any definitive studies that have shown that cold water itself stimulates hair growth. But cold water can help prevent over-cleansing hair.

“Because shampoos don't lather as well in cold water as they do in warmer water, using cold water on dry hair and scalp may help retain more natural moisture,” says Dr. Lin. To pack even more moisture into your wash sessions, try our hydrating Second Chance Repairing Shampoo and Conditioner to restore shine and body to dry, damaged tresses!

So Should I Wash My Hair with Hot or Cold Water?

For most of us, lukewarm water around 100F (just above body temperature) provides enough warmth for shampoos to cleanse hair well without damaging the scalp.

There are two instances when we might want to deviate from a lukewarm hair wash:

  • Warmer water temperatures offer a deeper cleanse because the heat helps make sebum buildup less waxy. So slightly hotter water temperature would benefit those of us with especially oily scalps. Be careful not to go too hot because scalding water can overly strip the hair's natural oils while irritating and drying out the scalp.
  • Cold water can help decrease the stripping of our hair's natural oils, and the presence of less steam can potentially reduce frizz for porous, fragile hair. Don't go too chilly with your shower, though. Using freezing cold water on your hair can constrict the scalp's capillaries, and your scalp needs good blood flow to be its healthiest and support hair growth.

How Do My Hair-Care Products Factor In?

Shampoo works with water to wet the hair surface and disrupt oily build-up. The cleansing surfactants disrupt the surface tension between water and your scalp's natural oils and allow build-up to be washed away.

 Conditioners nourish hair and smooth down cuticles to seal moisture into our hair. After-wash products like butter masques, hair serums and leave-in conditioners pick up where your in-shower conditioner left off to maximize hydration and protection. 

How Often Should I Wash My Hair?

This answer really depends on many factors: your hair length and texture, scalp health, daily activities, environmental factors and more. Unfortunately, there's no one-size-fits-all solution, but for mature, delicate hair, 2 to 3 times a week is a good place to begin. You likely don't need to be washing your hair every day, unless you have an especially oily scalp—but keep in mind, sometimes, daily washings can be the culprit behind an oilier scalp! Plus, daily long showers expose hair to more cycles of swelling and potential over-cleansing, which can lead to damage. Reducing the frequency and length of showers can help keep your hair and scalp healthy.

 Pro-tip: If you can't bear to skimp on showers, keep your daily shower routine and invest in a quality reusable shower cap to extend the time between hair washes without sacrificing shower time.


What Is the Best Way to Dry My Hair?

Wet hair is more fragile and stretchy than dry hair. This is why it's important that our hair is completely dry before brushing. Use a wide-tooth comb to gently detangle wet hair. Instead of using standard cotton towels, try a soft T-shirt or microfiber towel to dry hair, especially if you have fine, fragile locks.

Applying excessive heat can damage hair strands, especially when they're wet. “As water vaporizes in the hair strand, it causes breakage and can even leave bubbles in the strand of hair itself,” warns Dr. Lin. So be sure to let hair dry a bit prior to using your blow-dryer. And before using a flat iron or curling iron, remember, your hair should be completely dry!

Along with any heat styling, adding a heat protectant ups the level of protection for your tresses, as high temperatures from heat tools can impact hair structure. We love our No Remorse Heat Protection & Taming Spray for a smoothing option that protects hair from heat treatments while also taming frizz. 

We've all heard so many myths regarding water temperature and how to protect our hair structure that separating fact from fiction has been tough! The truth is that both cold water and hot water for hair washing have their place, but only in certain instances. Using lukewarm water is best because it activates the cleansers in your shampoo while protecting your hair and scalp for your healthiest hair growth.

At Better Not Younger, we developed our entire line of shampoos and conditioners to promote healthy, vibrant hair at any age and protect tresses against excessive hair fall. Healthy hair starts in the shower, and our entire lineup of shampoos and conditioners is formulated to help give all women the gorgeous hair they want!

Tell Us: What is your water temperature routine when washing your hair? Share in the comments below!

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