All the questions you’ve ever had about hair conditioner, answered by trichologists

When I was younger I lived for those little L’Oreal Kids 2-in-1 shampoos with the little eyes and scales on them. I didn’t care about what kind of hair it was actually for, I just cared about the colors and smell. Someone please take me back to when my biggest problem was that they didn’t have the watermelon scent in stock at Target. But like everything, my hair-care routine only became more complicated as I got older. When did there become so many rules about conditioner? Like, I can barely manage to sometimes make dinner for myself, and now you want me to remember that conditioner can’t touch my scalp unless it’s on the third Thursday of the month and also a full moon? What are the real tips, and what are the conditioner myths?

I don’t have the answers. But the two trichologists (specialist for the hair and scalp) that I asked to lend their expertise. Here’s what they had to say.

Is conditioner necessary every time you shampoo?

Dr. Dominic Burg, trichologist and chief scientist at Evolis Professional, says that there are a lot of variables to consider, particularly around the type of shampoo you use. “What kind of shampoo have you used? Is it a harsh detergent or a more gentle one, have you shampooed the entire shaft or only the scalp and first few inches of hair? Was the shampoo alkaline, or more balanced, or acidic?” he says. It depends on if your scalp hair type is on the oily or dry side.

“Shampoos, particularly stronger ones, strip away the hairs natural waxes and oils which add natural condition—a conditioner is required to help replace those or add polymers that can replicate their effect of shine and smoothness,” he says. With drier hair, he recommends using a high-quality conditioner with silicones or polymers to “create a synthetic barrier that adds shine and smoothness to the hair.”

“Conditioners are valuable for all hair types but it is the frequency of conditioning that can vary based on different types/textures,” says Michelle Blaisure, certified trichologist and product and technical specialist for Bosley Professional Strength.

If your hair is damaged or color-treated, you should use a conditioner every time you shampoo. “A small proportion of women with short hair and men can find that their natural oils keep their hair in check and don’t require conditioner, but this will depend on the type of shampoo used, how oily or dry the person’s hair type is and whether the hair has been treated or colored,” he says.

Is conditioner the be-all, end-all when it comes to detangling?

Dr. Burg says you should actually do your detangling before hopping in the shower, because when your hair is wet it is more prone to breakage. He recommends using a wide-tooth comb and using a bit of conditioner or hair oil if you have a really bad tangle to provide some lubrication.

Do you really need to avoid putting conditioner on your scalp?

I don’t think conditioner has come near my scalp in like 15 years, because I have fine hair and this was one of the tips that was repeated in basically every hair story for people with fine hair. “If you have an oily scalp then conditioning near the scalp is going to create the effect of more oils, that is if those are the backbones of your conditioner,” says Dr. Burg. If your conditioner is mostly silicones and synthetics, he says to avoid your scalp because these ingredients can cause build up over time. But if you have a dry scalp, get thee a conditioner based with “natural nourishing oils such as baobab or jojoba, or natural waxes,” and get it all up in there—Dr. Burg says it should be no problem at all.

Can conditioner cause bacne?

Blaisure says that many heavy conditioners contain oils that can clog pores if they aren’t properly rinsed from the skin. “It’s important to rinse not only your hair but the body as well after conditioning to ensure there isn’t any product residue on the back,” she says. It’s likely your bacne is caused by something like hormones, changes in medication or diet, or synthetic clothing. “If you are worried about the conditioner then swap it out for one with a different formulation, while keeping everything else the same, and see if it causes an improvement,” he advises.

Does it matter how long you leave your conditioner on?

To answer this, let’s take a look at how conditioners actually work. Conditioners work on several levels, pH, electrostatic or chemical interaction, and penetration of oils/waxes and proteins such as keratin or hydrolysed wheat or soy,” says Dr. Burg. He explains that the penetration of the oils and protein is the thing that takes time—for a regular conditioner, that’s a couple of minutes. (Aside: talking about hair products is the only acceptable way to use the word penetrate.) If you think you’re leaving your conditioner on for a full one-to-two minutes, you’re probably wrong. “Most people think they are leaving it on that long but in reality, they are rinsing too soon,” she says.

If you’re using a deep treatment mask, “the longer you leave them in the better and deeper the penetration of the oils, proteins and waxes on your hair,” he says.

Does rinsing your hair with cold water really make your hair shinier?

It’s a real catch 22: I want shiny hair, but I also hate being cold. Must I really endure 30 seconds of non-scalding water in order to make my hair looks its best? Short answer: yeah, there is truth to this. “There are a couple of things going on here. One, cold water will help close down your cuticles. A good conditioner will do this itself to a large extent, but you may see an improvement in smoothness and shine with a cold-water rinse,” says Dr. Burg. “The other reason why you should rinse in cold or cool water is that you don’t want to mobilize and wash away any of the nice oils and waxes you’ve just waited those long minutes to penetrate and nourish your strands. Hot water can make those oils and waxes more likely to rinse off.”

What’s up with these foam conditioners?

It may seem like foam conditioners are inherently better for fine hair because, well, they’re less weighty than a regular conditioner. But really, they’re about the same. “Foam conditioners are a fun way to deliver some of the same beneficial ingredients as liquid conditioners,” says Blaisure. “They are simply a different vehicle and experience than liquid and not necessarily better,” says Dr. Burg, adding that basically all these are doing is adding small air bubbles to the conditioner. As long as you are dispersing your conditioner through your hair effectively, like using a wide tooth comb or your fingers, then you should be fine,” he says.

Now find out how to care for the hair down there:

If you want healthier hair, you should start thinking about your scalp—here’s why. And these are the best drugstore shampoos for every hair type.