How To Test Your Shampoo pH Level

If the PH of your shampoo is too high, it can make your hair frizzy, tangled and rough, even break it off.

But a shampoo's pH doesn't have to be listed on the label and rarely ever is.
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So how do you know what pH your shampoo has? You test it, like this...

Why You Should Definitely Test Your Shampoo's pH

Most shampoos won't tell you what their pH is on the label.

​And it's little wonder that they don't: studies on shampoo pHs have revealed how most shampoos have a pH that is too alkaline for hair. When a shampoo's pH is too high, it sets off the Static-Frizz-Tangle Cycle in your hair, which ultimately leads to breakage. And when the pH is too high for your scalp, irritation and the risk of infection go way up.

​A lot of your worst experiences with shampoos could come down, not to the usual suspects like sulfates but to using a shampoo with the wrong pH for your hair. The role shampoo pH plays in breakage alone gives you every reason to play detective with your shampoo - if only to keep your length retention on course.

​2 Ways To Test Shampoo pH

Luckily, you don't have to be a real chemist to find out. pH meters sell for very cheaply online (like under a tenner) and you can also pick up pH strips for even less from a lot of brick and mortar pharmacies.

​Here's how to test the pH either way. It's easy...

How To Test Shampoo pH: The Materials You'll Need

Most of the steps to testing pH are the same whether you use strips or a pH meter. Follow these steps then choose your test tool of choice at the end. First, here's what you'll need:

​Materials:

Digital scale
2 glass beakers or jars, 1 with a lid
Butter knife, poon or small spatula
Shampoo
Water (preferably distilled)
​pH strips OR pH meter

Step-By-Step Shampoo pH Test Method

1. Start with clean, dry hands.
2. Turn on the scale, place a beaker on it and reset it to zero.
3. Make sure the scale is set to grams.
4. Carefully pour 10g of shampoo into the beaker.
5. Remove the beaker with the shampoo from the scale.
6. Place the second beaker on the scale and reset to zero.
7. Pour 100g of water into the beaker, adjusting level as needed.
8. Empty the beaker containing the water into the shampoo beaker.
9. Mix gently but thoroughly with butter knife - don't make too much lather.
10. Cover and leave undisturbed for 30 minutes.
11. Check the pH using a meter or pH strips in line with the instructions below.​
    

​Here's an infographic that breaks down the whole process:

​How to test shampoo pH with pH strips

pH strips aren't usually as accurate as pH meters, but you can still use these to give you an idea of the pH of your shampoo.

If you use strips, make sure you get the type that give accurate enough results from 0-14. You don't want something ultra basic that only gives 'acid' , 'base' and 'neutral' readings.

​Your pH strips should come with a colour chart that you can compare your tester with after you've dipped it in the shampoo.

pH strips should come with a colour chart to compare after dipping in your shampoo.

Step-by-step: How to use pH strips to test shampoo

Here are the steps for getting a reliable pH reading with pH strips:

1. Prepare the solution according to steps above.
2. Remove the strip from its packaging.
3. Dip the pH strip in the soap mixture and wait for the colour to change in line with the instructions.
4. Compare the colour of the pH strips with the colour chart to determine the pH.

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How to test shampoo pH with a pH meter

This is how to use a pH meter to test your shampoo pH:

1. Prepare the solution according to steps above.
2. Turn the meter on, calibrate it if needed, and dip it into the solution.
3. With the meter, the results will appear after a second or two, either on a dial or a digital interface if you decide to go for the pricier option.​

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How to test the pH of shampoo bars and soaps

Despite their marketing, shampoo bars are soap. You can test their pH in the same way that you test soap. Here's what you'll need:

Materials:
Digital scale
Knife for scraping soap
Butter knife, spoon or small spatula
Saucer
2 glass beakers or jars
Soap
Water (preferably distilled)
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​Step-by-step method for pH testing soaps & shampoo bars

1. Start with clean, dry hands.
2. Place the soap in the saucer.
3. Cut a small section of the soap with the sharp knife.
4. Turn on the scale and place the beaker on it.
5. Press  'zero' to reset.
6. Place the cut section of soap in the beaker.
7. Add or remove soap until you have a 5 gram sample in the beaker.
8. Remove the beaker with the soap from the scale.
9. Place the second beaker on the scale and reset to zero.
10. Pour 50g of water into the beaker, adjusting the level as needed.
11. Empty the beaker containing the water into the soap beaker.
12. Mix gently with butter knife - don't create too much lather.
13. Cover and leave undisturbed for 24 hours to allow the soap to dissolve fully.
14. Follow the instructions above on how to check shampoo pH with a pH meter or how to check shampoo pH with pH strips.

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What's the right pH for a shampoo?

The pH of hair is pretty acidic: 3.67. The ideal pH for your scalp is a little higher, but still slightly acidic - around 5.5.

​Since there is no established ideal shampoo pH, researchers from a recent study which looked at the pH of over 100 shampoos decided to categorise safe pH shampoos as 5.5 and under.

​Unfortunately, most shampoos are a lot higher than this - that same study found a shampoo with a pH of 9, while soaps and shampoo bars tend to be in the 9-10 range. Since the pH scale runs from 1-14, with 1 being highly acidic and 14 being highly alkaline, scores as high as these take your hair and scalp way out of their comfort zone.

Like we mentioned above: a pH that's too high for your hair can set off the Static-Frizz-Tangle Cycle for your hair, while if it's too high for your scalp, you risk irritation and even infection. There's more on the effects of extreme shampoo pH on your hair here.

​Wondering what you should do if your shampoo pH is too high - and you've already used it on your hair?