What is CosDNA and how do I use it?

December 11, 2017

You may have seen a lot of beauty bloggers mention CosDNA in their reviews/posts, but what exactly is CosDNA?

Short for Cosmetics DNA, CosDNA is a website (which I think is based in China) where you can check the comodogenic-ness (whether it will cause acne), irritation level and safety level of cosmetic products, both skincare and makeup. Its useful for people and bloggers who want to know what's inside their products before they use it. 

For example, here's the CosDNA sheet for Pyunkang Yul's Essence Toner:

You can see the ingredients included and the function of each ingredient. The sheet will also show you if how comedogenic it is, how irritating it is and how safe it is.

The first two columns show how acne-causing & irritatable the ingredients is, so the lower the value, the better. I'm not sure what the standard for these 2 columns are, but for the Safety column it's more comprehensive. 

The Safety column focuses on safety of long term usage of a certain ingredient. The range is from 1-9, 0-2 being low, 3-6 being moderate and 7-9 being high.

There's different rating sources from international organizations like CIR, RTECS, FDA, etc. and I suppose CosDNA takes their info from those organizations. Another group, the EWG (Environmental Working Group) has a similar rating system from 1-10 (0-2 means low hazard, 3-6 means moderate and 7-10 means high hazard). I'm not sure if CosDNA averages out different sources' ratings, but TL:DR, low numbers mean low risk, high numbers mean high risk.

In the long run, these ratings are there to show how the ingredient will effect your skin after long time use. I read online that ingredients with moderate ratings don't necessarily mean that they're bad. Sometimes products need to include cenrtain ingredients to work, and those products just have those ratings. Since the skin condition of each person is different and each person's own skin condition constantly changes, CosDNA acts more of a ingredient reference than a checklist on whether or not you should get a product.

The products listed on CosDNA aren't just Korean. Anyone can submit a product, so products from all over the world can be checked. You can check 1 ingredients rating:

If you add 1 more ingredient, you'll have the option to submit a product:

So that was a brief intro to how CosDNA works! I've seen fellow bloggers like Moikobeauty and YourGirlBoss frequently check ingredients on CosDNA, and maybe I should too 😅 It's certainly better to know what's inside your products, but aside from screening for harmful ingredients, I don't think I'll do much individual research per ingredients haha.

And that's it for this post! I hope you guys found it interesting and informative. As always, thanks for reading and see y'all in the next post!


  1. so if its a 1 on acne will it cause acne or not?

    1. Hi! If it has a acne/safety rating of 1, the likeliness of it causing acne is low. But do keep in mind that acne can be caused by a lot of reasons + everyone's skin is different :)


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