Fact-check Friday: Do Stridex products have the right pH to work?

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How to cite: Wong M. Fact-check Friday: Do Stridex products have the right pH to work?. Lab Muffin Beauty Science. April 25, 2014. Accessed May 28, 2024. https://labmuffin.com/fact-check-friday-do-stridex-products-have-the-right-ph-to-work/

Note: This information is not quite correct. There’s some evidence to show that the pH of salicylic acid products isn’t that important to how well they work – for a longer explanation check out this post on pH and AHAs and BHAs.


Stridex “in the red box”, manufactured by Blistex, is a cult product that’s worthy of the hype – it’s cheap ($4.28 for a box of 55 wipes on iHerb, with plenty of juice so you can use it for far longer), and contains a tried-and-true product with multiple benefits: salicylic acid (aka BHA), which is exfoliating, turnover-improving, anti-acne and anti-irritant to boot. But salicylic acid is only really effective at certain pHs concentrations (more on why this is next week) – so will this actually be as effective as more expensive products?


I have Stridex in both the red and blue packaging.

The red version excitingly labels itself as Maximum, referring to the 2% salicylic acid it contains (2% is the highest allowed for an over the counter skincare product in the US).

The blue version brands itself as Essential with Vitamins. It contains 1% salicylic acid, along with vitamin E (antioxidant) and C (antioxidant, but notoriously unstable so the unsealed jar packaging isn’t doing it any favours).

Both tick the box for the recommended concentration (1-2%), but don’t have any information on their pH (lower than pH 4 is needed for an effective product at these concentrations).

pH test:


Red box is at a comfortable pH 3-4
Blue box is at a higher pH of 4-5

(I actually repeated the test with some strips that have a more distinguishable difference between pH 4 and 5, and confirmed the same results.)

Red box: Good concentration? Check! Good pH? Check! Stridex in the red box is ideal if you want maximum salicylic acid action at a bargain price – just look out for irritation and allergic reactions, and if you have sensitive skin, start off slowly (once every three days at first or less).

Blue box: While having a pH slightly out of the recommended range isn’t an automatic death knell for HA products (more on this in a later post), combined with the low 1% concentration, we have a product that’s unlikely to deliver enough salicylic acid for you to notice any exfoliant or turnover improving benefits. It will still work as a toner that’s pH appropriate for skin and will remove any makeup you didn’t manage to wash off, but it doesn’t really have any other noteworthy skincare benefits. (This tub is Lot 041306, Exp 04/15, in case they ever change the formulation.)

There’s also Stridex in green packaging which has 0.5% salicylic acid – I’m not sure about the pH, but since it’s branded as “sensitive” I would guess that it’s above the recommended pH, and it’s on the dilute side, so I doubt the salicylic acid would have much effect. Another option, Natural Control, has 1% salicylic acid, unknown pH.

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18 thoughts on “Fact-check Friday: Do Stridex products have the right pH to work?”

    • No problems – I really wanted to find out for myself! I’ve seen the pH of the red box reported before, but afaik the blue one was a mystery, and unfortunately it was the only one left on iHerb for one of my previous orders.

  1. Firstly, Ive mad respect for all your doing with this site. I’m new but busy reading – thank you for making the complicated comprehendible!!

    I was happily stunned to see the combo 2% salicylic acid and crazy low price but am concerned since this is not in a lotion, serumn or cream will the BHA remain on skin long enough to be a significant exfoliant.

    I realize this is not a cleanser but when SA is put in cleansers, Beautypedia says its ineffective because its not in contact with the skin for long enough. Realize this is alcohol free but I imagine the liquid is still like alcohol or like water, so wondering if this “stays”‘ on skin for the BHA to make a difference.

      • That was an interesting listen, thank you, and I see why you conclude as you do.

        What do you think of Beautypedia low rating based on assertion “contain menthol and detergent cleansing agents that should not be left on skin”. Ive respect for what Paula’s team does and not saying Stridex is as great as their own $30 BHA. YET seems a conflict of interest for them to endorse another BHA that for same $30 could pay for a year’s supply.

        I don’t have sensitive skin but I do have dry 50yr skin with mild crows feet, significant horizontal forehead wrinkles so I face a dilemma. I began using a hydrating cleanser, alcohol-free toner, Vit C E Ferulic serum, Olay Microsculpt serum and retinol lotion. I will be adding an SPF moisturizer, an AHA and yesterday purchased the max Stridex as BHA.

        Do you think any Stridex ingredients left on skin would dry my skin or do you think it wouldnt be a concern either at all or due to other moisturizing products.
        Stridex cost/ value is nice trade off of other skincare expense but possibly not if its working against the anti-aging, moisturizing products.

  2. Is the menthol in this product so damaging to the skin that I should stop use?? Like is it going to do anything drastic like break my skin’s lipid barrier or lead to more broken capillaries, etc.?

    • I doubt it! It’s impossible to break the skin’s lipid barrier… but I’d recommend using a humectant moisturiser afterwards.


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