Wanna naturally lighten your hair? Grab a lemon (but there’s a catch)

In high school, the name of the game was to use Sun-in, AKA that hair spray that somehow magically lightens your strands a shade or two as the summer months pass by. These days, as a grown-up, I’ve been looking for tips on how to naturally lighten hair that are more, well, modern.

The method I’m seeing everywhere? Squeezing some lemon juice onto your strands, which has some backing by pros in the beauty biz…to an extent. “Lemons have citric acid and this can lighten hair,” says Shiva Rose, a DIY beauty expert, founder of Shiva Rose Beauty, and author of Whole Beauty. The way it works is that the sun opens your hair cuticles. “If you place a lemon on your hair and then go into the sun, the heat of the sun will work to open the cuticle,” says Gina Rivera, hair artist, creator of By Gina, and owner of Phenix Salon Suites. And once the lemon juice enters the cuticle, it acts to break down the color in hair, which ultimately lightens it. A-ha.

On a more scientific level, Dominic Burg, PhD, a chief scientist, hair biologist, and trichologist at Evolis Professional says that the chemical and structural changes from lemon juice in your hair speeds up the destruction of melanin pigments in the hair by UV radiation in sunlight. “UV radiation breaks apart the bonds in the melanin in your hair, causing them to lose their color,” he explains.

But for it to really work, you need a number of factors: to have light hair to begin with, and a clean scalp. “If the hair is a darker color, it may not be as effective as it is on a lighter shade of hair,” says Rivera. “Also, it’s important to detox the scalp first in order to get rid of the deposits on the hair.” Then the sun can get right to the lemon juice and lift the color out.

It’ll also work better on finer hair. “Finer and thinner hair is going to lighten faster, while courser and thicker hair tends to take longer,” she says. “The denser the strand of hair, the longer it takes for it to be penetrated.” To be honest, it’s kind of a wild card in terms of what color you’re actually going to wind up with. “Unlike a professional color where the results are predictable, the results with lemon juice can be very unpredictable, and it’s easy to wind up with unwanted tones such as golds, oranges, and yellows.”

If you’re thinking of going for it, know that the lemon juice trick can come with its own setbacks (besides not giving you a specific hair shade). Since the ingredient is so acidic, it can be problematic on your hair—especially if it’s already damaged. “I recommend caution in individuals who have psoriasis or damaged hair because the acidic nature of the lemon juice can further damage it,” says Francesca Fusco, MD, a dermatologist with Wexler Dermatology. “It’s okay once in a while to do on healthy hair but it’s better to seek a professional colorist for highlights.”

Also, since lemon juice doesn’t work that well on lightening darker hair shades, you might be tempted to keep trying—AKA stay out in the sun, head covered in lemon juice, longer. “The hair lightening effect of lemon juice and sunlight is still very weak and the effects will only really be seen in lighter colored hair or already chemically treated hair,” says Dr. Burg. “Those of us with dark hair may not see any effect at all.” While you’re attempting this all-natural hack, you may be saving money, but you’re getting more UV exposure than you probably should. “While the UV rays are damaging your melanin pigments in your hair, they are also damaging the molecules and DNA in your skin—which can lead to burning and damage that can lead to skin aging and cancers such as melanoma,” he says, stressing the importance of a high SPF (as we always preach).

If you’re still going to go for it, keep your strands as healthy as possible when using lemon juice, and don’t squeeze it over your entire head. “The components of lemon juice will cause damage to your hair structure, so if you are going to give it a try, make sure you only treat the mid lengths and ends and ensure you follow up with a good deep hydrating and repairing mask,” says Dr. Berg, who recommends the évolis Professional Promote Mask ($40).

Or, ya know, you can always leave the hair lightening task to the professionals. “I’m a firm advocate of always using a salon professional when coloring the hair,” says Rivera. “Science plays a strong role when it comes to achieving the right color, and hairstylists are professionally trained to know how to work with a vast array of shades as well as the chemicals required to achieve them.” They also know how to keep your hair healthy… and you can’t say the same for lemons. So maybe keep them for your lemonade.

To keep your hair as healthy as possible, the key is to invest in one of these scalp serums. And here are 11 hair-care products that’ll protect your hair from the sun (and revive it after a day at the beach or the pool).