What’s the hype?

Baking soda and lemon juice have been praised for whitening teeth, curing acne, and erasing scars. Still, others insist that combining the two is dangerous for both your teeth and skin. While there haven’t been many studies done on using both ingredients together, there are several studies that look at the cosmetic benefits of baking soda and lemon juice individually.

These studies, combined with information about the pH of both baking soda and lemon juice, suggest that each of these ingredients may have benefits on its own. However, you might want to think twice before combining them. Keep reading to learn why.

Before diving into the effects of baking soda and lemon juice, it’s important to understand the basics of the pH scale. This scale, which ranges from 1 to 14, refers to how acidic or basic (the opposite of acidic) something is. The lower the number on the pH scale, the more acidic something is. The higher the number, the more basic it is.

Baking soda has a pH of about 9, meaning it’s basic. Lemon juice has a pH of about 2, meaning it’s very acidic.

The claim

Baking soda can remove stains, including those caused by coffee, wine, and smoking, from your teeth. Adding lemon into the mix makes the baking soda even more effective.

The research

A report in the Journal of Clinical Dentistry reviewed five studies that looked at baking soda’s ability to remove plaque from teeth. All five studies found that baking soda alone effectively removed plaque.

However, a 2015 study found that lemon juice eats away at tooth enamel, which protects your teeth from decay. Unlike other protective shields, such as your nails, tooth enamel doesn’t regrow.

Many proponents of using baking soda and lemon juice for whiter teeth insist that the harmful acid in lemon juice is balanced out by the high pH of baking soda. However, there’s no evidence that baking soda completely neutralizes the acidity of lemon juice. It’s also very hard to know whether you have the right ratio of acid to base when making your own paste at home.

Given the risk of permanently damaging your tooth enamel, it’s best to leave the lemons in the kitchen.

Try this instead

If you’re interested in whitening your teeth, talk to your dentist first. They can recommend safe over-the-counter options or discuss more intensive treatments with you.

To reap the dental benefits of baking soda, try brushing your teeth with a mixture containing 1 teaspoon of baking soda and 2 teaspoons of water. You can also look for a toothpaste that contains baking soda and hydrogen peroxide. A six-week clinical trial found that toothpaste with these ingredients whitened teeth more than regular toothpaste did.

Learn about other ways you can whiten your teeth at home. »

The claims

When applied to the skin, lemon juice can reduce wrinkles, fade scars, and brighten your skin. The gritty texture of baking soda works as an exfoliator to clean out your pores. When you mix these two together, you get an easy, homemade scrub that does the work of several products.

The research

Baking soda

There’s no evidence that baking soda provides any benefits for your skin, even when combined with lemon juice. In fact, baking soda can actually harm your skin.

The average pH of skin is between 4 and 6, meaning it’s slightly acidic. When you introduce something with a higher pH, such as baking soda, it changes the pH of your skin. Slight disturbances in your skin’s pH level, especially those that raise it, can lead to many skin problems, such as peeling, acne, and dermatitis. Using a scrubbing motion to distribute baking soda on your face just makes it more irritating for your skin.

It may seem like lemon juice would be a good way to counteract the high pH of baking soda, but similarly to making your own toothpaste, it’s hard to get the proportions right outside of a laboratory. Adding even slightly too much baking soda or lemon juice could wreak havoc on your skin.

Learn more about the effects of washing your face with baking soda. »

Lemon juice

On its own, lemon juice seems like it would be good for your skin. It’s full of vitamin C, which can help reduce inflammation and skin damage from UV rays. It also contains citric acid, which has been shown to dry out pimples.

However, research indicates that vitamin C and citric acid only provide skin benefits when they’re highly concentrated. The concentrations of both vitamin C and citric acid in lemon juice are too low to effectively penetrate your skin.

Try this instead

Ditch baking soda and get the benefits of vitamin C and citric acid by using an acid designed for your skin. If you’re prone to acne, try salicylic acid. For antiaging benefits, try an alpha-hydroxy acid, such as glycolic acid.

Always test out an acid on a small part of your skin before putting it on your face.

Learn more about choosing the right face acid for your skin. »

Baking soda and lemon juice might seem like harmless ingredients, but they can actually damage your teeth and skin when used incorrectly.

There’s some evidence that baking soda effectively removes plaque from your teeth, but adding lemon into the equation can eat away your enamel.

When it comes to your skin, lemon juice seems like a logical solution since it contains both vitamin C and citric acid. However, lemon juice won’t provide either of these in concentrations high enough to make a difference.