Why You Should Never Use a Lemon on Your Hair

Why You Should Never Use a Lemon on Your Hair

As natural and organic products continue to become more mainstream, home remedies keep on popping up as well. Yet, as I have pointed out in my articles about the dangers of the apple cider vinegar and baking soda hair cleansing method and natural products in general, some of these methods from the kitchen can be breeding grounds for irritation, inefficacy, and even bacterial and fungal infections.


One of these methods that is super popular in the summer is applying lemon to your hair for all-over lightening or highlighted streaks. While lemon does effectively lighten the hair, there are some little-known concerns you should keep in mind:

1.) Lemon will affect hair dye’s ability to penetrate the hair.

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Boxed hair dye essentially works in three simple steps: First, the hair cuticle is opened using an alkaline (high pH) solution. Next, hair color is applied. Because the cuticle has already been opened, the hair color can penetrate to the hair’s inner cortex, where it can react with the hair’s pigment molecules to produce a color change.  Lastly, acidic solutions are applied to help reseal the cuticle.

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However, if lemon is applied, its acidity will affect hair dye’s ability to penetrate the hair. Lemon has a very low, highly acidic pH – 2 – acidifying subsequent solutions applied, making it harder to open the cuticle. If youmust use lemon, take care to wash your hair thoroughly before applying any hair dyes.

2.) Lemon makes the hair thinner.

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Almost everyone I speak to wants thicker hair.  Thickening agents typically work in one of three ways (also shown above):

  • Penetrate the hair shaft, filling it. This is the way that many hair thickening agents work. For instance, cosmetic giant L’Oréal has the Fiberceutic line ($20.99, Amazon.com), which fills the hair with Intra-Cylane™, a flexible soft fiber.  Intra-Cylane™ deposits in the hair as water evaporation takes place.  It is designed to help reinforce the protective keratin layer of hair. 
  • Penetrate the hair shaft, causing it to swell. Many hair care products with alcohol will partially penetrate the hair shaft and cause a temporary “swelling.”
  • Create increased spaces between each hair. This is the way that the Living Proof Full Thickening products work; they use substances called fluoroesters that create small spaces in-between each hair. The fluoroesters stick to one another loosely, like Post-It notes. To the naked eye, this makes hair appear fuller and thicker.

However, lemon is the opposite. Lemon’s acidity causes the hair shaft to shrink, resulting in a decreased diameter to the microscope and flat, limp hair to the naked eye. Not cool.

3.) Lemon makes the hair drier.

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Lemon lightens the hair primarily because it increases hair’s sensitivity to the sun (JMCPP, 2010). As UV light hits the hair, it destroys melanin within your hair. Lemon accelerates the rate of this reaction, acting as what is known as a catalyst.

Because lemon enhances the sun’s ability to degrade melanin, it also affects other interactions of the sun with your hair as well. For instance, the sun is capable of drying the hair by stripping it of essential oils. Lemon only enhances this interaction, resulting in drier hair.

Why You Should Never Use a Lemon on Your Hair

When UV light hits your skin, it also destroys the melanin within your skin. Unlike hair that is made of dead cells, the skin is able to react. In response to destroyed melanin, the skin reflexively produces more melanin, resulting in a tan (if you’re lucky) or sunspots (if you’re not). Hair just remains with its destroyed melanin.

Bottom Line

Why You Should Never Use a Lemon on Your Hair

Food you ingest should be kept natural and organic, but what you apply to your skin is a different story. Some natural and organic compounds, like lemon, can do far more harm than synthetic hair treatments. With a pH of 2, lemon is a chemical that acts as a catalyst in the reaction between your hair and the sun, resulting in thinner, drier strands. And unlike many new synthetic dyes, where hairstylists can “turn off” the pigment-degrading reactions with a specially-formulated rinse, you can’t do that with lemons. So your hair keeps getting fried, time and time again. Do yourself a favor and find a new hair lightener!

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