Does lemon juice lighten dark hair?

Remember back in the 90s when one of the most beloved beauty products was Sun-In? Maybe you had your own bottle or maybe you snuck spritzes out of your sister's. Whatever the case may be, there was nothing quite as satisfying as spritzing your strands with a seemingly-magical solution only to look noticeably blonder (and, okay, often brassier) after just a few hours in the sun. 

While Sun-In still exists today, in the age of DIY beauty, we can’t help but wonder: Do you know how the product works in the first place? The lightning effect achieved by Sun-In actually occurs because of one of its key ingredients: lemon juice. In fact, next to water, hydrogen peroxide, and aloe lead juice, it’s the fourth most abundant ingredient in the nostalgic beauty buy. Which begs the question: Can you lighten your hair with a simple spritz of lemon?

To find out just that, we chatted with a couple of celebrity colorists for the 4-1-1 on all things citric acid and hair. Keep reading to learn everything there is to know about using lemon juice for hair.

Lemon Juice For Hair Lightening: How Does It Work?

According to colorist and #mydentity brand founder, Guy Tang, the primary reason why lemon juice changes the color of hair isn’t so much about the ingredient as it is about the reaction that occurs when it’s exposed to UV light. “The sun will always affect the tone of the hair, but it is magnified with lemon juice due to the high acidity level,” he explains, noting that lemons have a pH of 2 and your natural hair’s pH is between 3 and 4. Since it’s so close to your hair’s natural pH, it’s better able to alter its color. 

Master colorist and founder of Grettacole salons and spas, Gretta Monahan, tacks on to this, noting that the lemon’s acidity deteriorates the cuticle layer of the hair, which ultimately reduces your hair’s color pigment. “When combined with exposure to sunlight, the citric acid accelerates the bleaching process and basically this reaction breaks up hair pigment to expose the underlying lighter color(s),” she explains.

 In terms of timing, Monahan says that it typically takes three to four applications for noticeable lightening from lemon juice. While that may not seem like much, keep in mind that the more you expose your hair to citric acid, the more you’re deteriorating it over time. More on that below. 

Can You Use Lemon Juice to Lighten Dark Hair?

As is the case with skincare and different skin types, citric acid will affect different hair types—think both texture and color—differently.

“Anyone can put lemon on their hair safely but the results will vary greatly,” Monahan says. “As an example, someone who has very dark hair naturally has a lot of pigment and isn’t likely to see a noticeable result or can actually experience a red-orange/brassy result.” She goes on to explain that most people with extremely dark hair will likely need more than a few applications paired with exposure to notice even the slightest change. “Redheads will notice more brightness and vibrancy with a lemon juice treatment, and if they do it multiple times, they will see bold gold,” she adds. 

At the end of the day, however, Monahan says that the lighter your hair is naturally, the more effective lemon juice will be as a lightener. “Even with naturally blonde hair, it will still be much more subtle than a salon bleach,” she points out. And, for what it's worth, you don't have to have fully-blonde locks. Even if you have light highlights, spritzing in some lemon can brighten them up.

How to Effectively Use Lemon Juice to Lighten Hair

Still intrigued? If you really want to test your hand at lemon lightening, here’s the safest way to do so, according to Monahan. Just be sure to read our "risks" section below before you get started so you can weigh the pros and cons of this process.

You’ll need:

• One lemon
• Chamomile tea bag
• Spray bottle

Instructions:

1. Squeeze your juice. "Roll and squeeze all the juice from one natural lemon and measure the liquid," Monahan instructs.

2. Make a cup of chamomile. "Steep a chamomile tea bag until strong and let it cool off," Monahan says.

3. Combine both liquids. Mix two-parts cold tea water to one-part lemon juice and put it in a spritz bottle.

4. Spritz hair. Saturate hair generously so it’s damp to the touch, then sit in the sun for a minimum of one hour. (You can also use a blow dryer for 30 minutes, concentrating the heat on the areas you want to lighten but it’s not as effective as the sun.)

5. Repeat until you notice results. “Spritzing daily, say, while on vacation, is fine,” Monahan says.

“My suggestion is to spritz around the face and ends for a beachy look, and always deep condition after,” Monahan says. “If you have fragile hair, you can add a teaspoon of conditioner to the spritz bottle to protect strands from drying out.”

How Long Do the Lightened Effects Last?

If you reach the point where your hair actually looks lighter and brighter, you might think that, like a faux tan, the result is fleeting. On the contrary, Monahan says that, since lemon juice breaks up your hair’s natural pigment, applying it to your strands can permanently alter the way they look. 

While it, like all color-treated hair, will dull over time, Tang says that since it was created with a reaction to UV light, it will also get brassier and brassier as time goes on. “The only way to counteract this result is to tone the hair with a color that is the opposite of your underlying pigment on the color wheel,” he says. “For example, yellow needs purple applied on top to make the hair white; red/orange hair needs green to achieve a caramel tone.”

The Risks

Remember how we mentioned that lightning occurs due to the deterioration of pigment? In addition to breaking down your hair’s cuticle, both Tang and Monahan say that applying lemon juice to your strands can cause them to feel extremely dry and brittle. As a result, lemon juice can cause breakage and make hair look duller than it really is. 

Because of this, Tang recommends rinsing the lemon juice out of your hair as soon as it’s dry. “Your hair cuticle is highly contracted and becomes dry and brittle with it in,” he explains. “It is as if the hair cuticle is being suffocated by the combination of lemon juice and the sun.”

Fortunately, if you rinse the lemon juice out as soon as it’s dry, Tang says that you can avoid much of the damage. The trick is to re-wet the hair post-rinse and douse it with your favorite leave-in conditioner—team Byrdie loves Drunk Elephant’s Wild Marula™ Tangle Spray ($25). “This way, you reduce the amount of breakage and stress you are putting on an already stressed hair cuticle, and you counteract and stabilize the pH of your hair back to its natural healthy state,” he says.

The Takeaway

While lemon juice paired with sun exposure can absolutely change the color of your hair, Tang reminds us that the very process required to do so causes damage too. But, then again, so does any other color processing treatment. Nevertheless, he recommends leaving your hair—and your desired color—in a professional colorist’s hands, as they’re equipped with knowledge of color theory and safe formulations to ensure your hair looks beautiful and bright, not dehydrated and brassy. 

“Your hair is fragile,” he says. “People often forget because it grows back. What people don’t realize is that the ends of your hair—if longer than your shoulders—are probably eight-year-old hair strands. You have to take care of them to keep them hanging on for that long. Leave it up to the stylists to create that perfect sun-kissed hair color of your dreams.”

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