A couple of months ago, I found myself wondering if sunscreens really work. No, not in general, but rather whether the particular sunscreen you use work. With recent reports from the Environmental Working Group disproving the high SPF claims from established household names like Neutrogena and Coppertone, it is no longer a given to trust that our sunscreens protect as much as it says on the bottle. So I went looking for an easy, non-chemist/pro way that I could use to quickly check if the sunscreen I’m currently using really does block out UV rays the way it was supposed to.

I then stumbled upon this Science Buddies experiment that used a UV meter to test individual sunscreens. There are other ways to do it, like this Steve Spangler project that conducts testing with photosensitive beads or paper, but that seemed a little too middle school to me. I need to adult, y’know? And while I was Amazon-ing for UV meters to do this, a better option came up. SKIN ANALYSERS.

In this post:

  • Function 1: Analysing skin condition
  • Function 2: Measuring UV index
  • A disclaimer (and how I’d be using this)

1. Beauty Sign Plus Skin Analyzer Front With Cover

Other than providing a UV index, skin analysers are able to read the moisture, oil, and softness levels of your skin. I chose the Beauty Signature+, a device produced by the Japan Weather Association to help lovely Japanese know when to slather on the extra powerful SPF100 PA++++ sporty sunscreen by checking the daily UV index. You can get it for USD36 on Amazon. It also comes with a case for easy carrying.


1. Beauty Sign Plus Skin Analyzer UV spectrum

From top to bottom: moisture, oil, and softness (or suppleness) bars.

1. Beauty Sign Plus Skin Analyzer Button

The two functions of this egg-shaped cutie are activated in different ways. This switch on the side of the device prompts the skin-reading to start.

1. Beauty Sign Plus Skin Analyzer Full Reading

Both moisture and oil levels run from -7 to +4 (yeah i know it’s weird), while softness can be anywhere from -6 to +5.

1. Beauty Sign Plus Skin Analyzer On Thigh

Wait, but how does this little egg determine your skin bits? If you’ve ever had your body mass/fat thingy measured in gyms and gotten a piece of paper with embarrassing numbers on it, you’d be somewhat familiar with this experience. It uses the same BIA (Bio Impedance Analysis) technology, which works by sending a light electrical current (you can’t feel it) that is able to detect water and oil levels separately in your skin by measuring your body’s resistance to it. The current flows easily through fluid (water) but not oil as it’s not able to conduct it.

I’m probably doing a hideously rubbish job at explaining this measurement method employed by the healthcare/beauty industries so if you’re inclined, you can read more about it from the pros here.

So to analyse your skin, all you have to do is press the button and press the retractable prongs lightly on your skin. In 5 seconds, a reading is done.

1. Beauty Sign Plus UV reader skin reading

Don’t judge, these are done impromptu after a day out. The first is a reading taken off my thigh…

1. Beauty Sign Plus UV reader face reading

… and my grimy face. I expect the moisture and softness levels to be low, but it’s intriguing that the oil reading is in the negative range too because I have oil rig class skin. This may be due to a new moisturiser prescribed by my dermatologist (I had an emergency allergy reaction two weeks back) but that’s for another post.


1. Beauty Sign Plus UV reader reading under sunlight

The UV meter is activated upon pressing the silver button on the front, and it works by measuring the rays with the little pinhole above the logo. The five bulbs below the button means (from L to R): Low, Moderate, High, Very High, Extreme, and this is based on the Japan UV index, which is the same as the one prescribed globally by the World Health Organisation. The full explanation can be found here. I’ve stolen referenced a table below from the full guide to quickly illustrate the index range:

Global UV index summary

To translate this to the device, Low = <2, Moderate = 3 to 5, High = 6 to 7, Very High = 8 to 10, and Extreme = >11. As you can see above, the UV index on the day I measured was a 4.4, a moderate. I measured this without the cling wrap before and had the same reading, this picture is to act as the control (i.e. the cling wrap does not interfere with the analysis).

1. Beauty Sign Plus UV reader reading with sunscreen

To check if my sunscreen works – in this case the Biore UV Aqua Rich Watery Mousse SPF50 PA++++, which I’ve been testing for close to a month, I smeared product on cling wrap – you’re supposed to put on the same amount you use for your face, which is two milligrams per square centimetre of skin (or a nickel dollop) – but obviously I can’t measure to that precision, so I put on roughly the same amount that would have covered my skin over the size of the UV lens. I left the sunscreen sitting on the clingwrap for five minutes before testing.

And voilà, the miracles of modern sun protection. The UV reading now stands at a much more desirable 0.8, and upon multiple tries with the sun sometimes hiding behind rolling clouds, the reading remained in the same index ranging from 0.7 to 1.3.


I’m not a chemist. Or a beautician. Or scientist. I’m just a regular girl (albeit very vain) who’s doing everything I can to get radiant, clear skin, and explaining technology or science stuff isn’t something I’m particularly good at or am comfortable with. I got this partly for the novelty. Do I know how the pinhole lens thingy captures and measures UV rays? No. However, it is sanctioned by a Japanese government entity and manufactured by a Japanese company, so personally I do have a fair amount of trust in the quality of the product.

To be completely transparent, I’m not so much bothered by the measurement technology behind this. Sure, it’ll be cool to know fancy shit, but I’ve never been the type to comb through heavy academic papers. That said, I do believe the method that I plan on using this device is fairly objective and likely to garner accurate results.

What is the reason for this device? To check if my products are working and if my skin’s condition is improving.

How am I going to use it? By comparison testing. This eliminates all other variables and puts trial factors on even ground. It doesn’t matter what measurement is being used, because if I control every other factor, I will be able to isolate the efficiency of a product easily.

Say, if I’m testing a moisturiser (like this Cremorlab flop), I apply it on half my face. Both sides would have gone through the same exfoliation, cleansing, acids, and essences etc prior. By comparing the two results, or by analysing my skin levels before applying the test product, I can immediately see if the product works like it should. Of course, I can’t determined the exact amount of moisture a product pumps into your skin or anything to that degree, but for an easy, compact device that costs less than $40, this skin analyser does everything I need it to do.

To illustrate how hesitant I was about this post – one, the manual was in full Japanese, Google Translate did not work and two, I wasn’t confident about explaining the exact technicality of how the device works – I received this slightly more than a month ago and am only writing about it now. I kept trying to research more because I was so afraid of posting up anything misleading or inaccurate due to my own negligence or ignorance.

With all that boo boo said and done, I’m really *quite* excited about this because reviews up till recently have been based off how my skin feels. With this device, I get to at least have a reading that either backs up my skin’s emotions or flag a need for extra testing (why does my skin feel tight and parched when moisture levels have increased?)

As with the UV guide, the skin readings act as a guide, are not intended as a medical analysis of your skin’s condition. When in doubt, always consult the experts. Everything listed here is 100% paid out of my own pocket, and the layman observations are mine alone. Links are non-affiliated. 


  1. I can’t believe how affordable this device is! If this was a US manufacturer the price would double, at least. Very telling of how different Western and Asian industries are as well. How do you think the quality is when it comes to durability? Likely purchasing one for myself, even as a licensed professional I’m quite intrigued. And when I post about it I will be linking to your post…your explanation is clear and to be honest I’m way too lazy for that shit! haha

    • i think there’s this assumption with high prices and quality that Western industries market to, whereas Asian industries like to target everyone with a reasonable price point (before slowly introducing more expensive stuff haha). For this meter, I can’t speak for its durability. It was manufactured by the Japan weather board for home use.

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