Is Double Shampooing Necessary? Experts Break It Down

Feeling like your shampoo isn't, well, shampooing as it should? Before you toss the bottle and start shopping for a new one, consider that the problem might be the cleansing technique rather than the cleanser itself. And adding a double shampoo to your shower routine could be the answer. The double shampoo method—or just shampooing twice—is like double-cleansing your face: If the first wash removes the dirt and product buildup, the second wash is able to penetrate deeper to clean.

So how often should you lather, rinse, and repeat, and is there such a thing as over-washing your hair? We talked to trichologist, Anabel Kingsley, and hairstylists, Sal Salcedo and Devin Toth, to discover how double shampooing can benefit your hair. Keep reading to see how this extra step in your wash routine makes a difference.

What Is Double Shampooing?

Simply put, the double shampoo method is shampooing twice in the same shower session. You've likely already read the tenets on every shampoo bottle: Lather once, rinse it out, and then repeat the process. It’s not needed every time you wash your hair, but shampooing twice gives you a deeper cleanse that could be beneficial if you have a buildup of product (like dry shampoo), you’ve been swimming in the ocean, or if you have dandruff and need the extra wash to lift away flakes. The idea is to give adequate attention to both your hair and your scalp: The first wash should break down any product or mineral buildup on your strands, paving the way for the second wash to scrub your scalp clean and fully clear out the buildup, excess oil, or flakes that the first wash rustled up.

The Benefits of Double Shampooing

• Removes excess product: A double shampoo will feel especially good if your hair is coated in extra hairspray or other styling products from a fussy updo. The first shampoo will loosen the film of the product, and the second will lift it away and clean your scalp.  
• Lifts and rinses flakes away: "If you have a scaly scalp condition, like dandruff or seborrhoeic dermatitis, and are unable to shampoo daily, double cleansing on the days you do wash your hair with a targeted shampoo will help to lift and rinse flakes away most effectively," says Kingsley. 
• Thoroughly cleans hair after exposure to chlorine, ocean water, or hard water mineral deposits: Kingsley recommends the double shampoo method after swimming in salt or chlorinated water because it's filled with minerals that tend to cling to your strands, making them feel brittle, tangled, and dry. A double shampoo should thoroughly clear away any buildup. 
• Preps the hair for scalp masks or other treatments: Along with giving your scalp a deep clean, the double shampoo method also "helps to create a good canvas for the penetration of active ingredients," says Kingsley. "If your scalp is very scaly, active ingredients tend to sit on top of [it] rather than penetrate the skin." Once your scalp and hair are thoroughly cleansed, they will absorb all the good, nutritious ingredients that follow in a mask or conditioning treatment. 

Who Should Double Shampoo?

All hair types can benefit from a double shampoo every once in a while (or as needed). However, Kingsley and Toth agree that the double shampoo method is best for those who do not wash their hair daily. “Anyone who washes their hair once every week or so would benefit from the double shampoo method,” says Toth. “Anyone who washes their hair daily or every other day does not need to use this method. It comes down to how often you wash your hair and not what type of hair you have.”

How to Double Shampoo

The process is pretty straightforward, but proper washing technique is helpful. "Wet your hair thoroughly, pour a small amount of shampoo into the palms of your hands, and smooth [the shampoo] over your hair, focusing on your roots," says Kingsley. "Using the tips of your fingers, gently but firmly massage your scalp for approximately 60 seconds and squeeze any suds through the lengths of your hair, but do not rub or pull at your strands—wet hair is weaker and easily damaged." Then, rinse well and repeat.

Unlike double cleansing your skin, you shouldn't double shampoo daily. Over-cleansing your hair will eventually strip it of its natural oils and could lead to damage over time or cause your scalp to over-produce sebum (which then leads to dandruff and oily hair). 

"Shampooing your hair twice is beneficial because it allows for proper cleansing, giving you longer periods with a clean scalp and helps control oily hair. It also keeps you away from over-shampooing your hair," says Salcedo, who adds that excessive shampooing can over-dry your hair and that most of the styling problems and difficulties people encounter come from having overly-dried hair.

The right products also play an important role in a good double cleanse. You can use the same shampoo twice, but if you're double shampooing in the first place, chances are your hair needs a little extra TLC and could use multiple products to get it back into tip-top shape. "Anyone with a flaky, itchy, or irritated scalp should use a soothing anti-fungal product for their first shampoo," says Kingsley; we like Briogeo's Scalp Revival MegaStrength+ Shampoo. Then, follow with a shampoo that suits your hair type. If you're set on keeping it down to one product or aren't targeting anything particular, Toth recommends something super gentle or oil-based. Try Shu Uemura's Gentle Radiance Cleansing Oil Shampoo.

Double Shampooing vs. Clarifying Shampoo

Much like double shampooing, clarifying shampoos remove product residue and chemical buildup in the hair. While both options claim to achieve the same outcome of deep cleaning the hair, double shampooing does so through frequency of use while clarifying shampoos do so through the ingredients in their formulations. (Chelating shampoos are also similar but tend to have more potent formulations geared to breaking up mineral deposits from hard water, chlorine, or salt water exposure.) The two, however, needn't be exclusive as clarifying shampoos can (and some experts say, should) be a part of your double cleanse routine if your hair type and needs call for it. If you have hard water damage, for example, start with a clarifying or chelating shampoo, like Ouai's Detox Shampoo, and then follow with something super hydrating and nourishing, such as Maui Moisture's Heal and Hydrate Shea Butter Shampoo.

Potential Side Effects of Double Shampooing

Double shampooing typically won't produce adverse side effects, but the frequency of donig so can. Toth notes that over-cleansing with a strong shampoo could "strip your scalp of its natural oils, which may, in turn, cause your scalp to overcompensate and produce more oil." As we mentioned earlier, double shampooing shouldn't be part of a daily cleansing routine but is best shelved for weekly consistency.

The Final Takeaway

Like double cleansing your face, the double shampoo method is a great way to ensure your hair is clean and clear of any product, buildup, or flaky skin. Not only will your hair and scalp feel better, but you'll also be prepping your hair to receive the benefits of any following masks or conditioning treatments. If you're gentle and only adopt the double shampoo method when needed, it's a great and easy way to get a clean slate for your hair.