What do leave-in conditioners do?

According to Mathilde Heather, Kérastase ambassador and founder of The Suite, “a leave in conditioner hydrates and moisturises the hair continuously. It also provides much needed protection for styling.”

They’re particularly great for those of us perpetually in a rush — for when we may not have 15 minutes to wait for a hair mask to work its magic, but we still want to give our hair a little extra love.

“A well-chosen leave-in conditioner can be beneficial for many hair types – the key is choosing the one best suited to your hair type or concerns. Their primary aim is to detangle and condition hair, but they can be incredibly versatile depending on the formulation, whether it’s to reduce dryness and frizz or to add a shine-boosting finishing touch,” says Catherine Leray, Head of Research and Development at THG LABS.

As far as consistencies go, Mathilde shares that “creams are ideal for coarse and thick hair,” while “serums and lightweight sprays are a great option for all hair types.”

What ingredients should I look for in leave-in conditioners?

What’s shopping for a new hair-care product without considering chemistry? Cosmetic chemist Ginger King suggests ingredients like oils, fatty alcohols, and triglycerides that will “smooth the cuticles and keep the hair in place.” For detangling in particular, King notes that compounds like quaternium 4, 7, and 11 work well (and to look out for ingredient names that start with quaternium or polyquaternium).

Mona Gohara, MD, a board-certified dermatologist based in Connecticut, notes that humectants like hyaluronic acid in hair care can be key. “[Hyaluronic acid] revives dry strands and restores softness in just one minute,” she says. “Just like your skin, your hair loses moisture daily—from heat styling, environmental stressors, and even washing. Without proper hydration, it becomes dry, brittle, and prone to breakage.”

Can I use a leave-in conditioner every day?

Leave-in conditioners are designed to be lightweight and provide ongoing hydration and nourishment to the hair without weighing it down. However, it’s essential to consider your hair type, texture, and specific needs when determining the frequency of use.

“Using a leave-in conditioner every day is safe and can be good for your hair if you are looking for added moisture, protection, or nourishment in between washes. You need to consider your hair type and concerns as some leave-in conditioners might be heavier than others, weighing your hair down or showing signs of build-up on your hair,” adds Catherine.

It’s also worth noting that using too much product or applying it too close to the roots can lead to build-up, so be mindful of the amount and placement of the leave-in conditioner to maintain a balanced and healthy hair environment.

How to use a leave-in conditioner correctly

“Putting on soaking wet hair will force the product to slide right off. You want to apply to damp or towel dried hair for best absorption,” shares Mathilde. Ideally, she recommends using it “after your cleansing (shampooing) routine.”

First, she advises to “gently towel dry your hair and apply a small amount of the leave in conditioner.”

Next, “proceed to comb through your hair from root to tip (starting at your mid lengths) then apply another small amount,” she adds.