I bought the Anua azelaic acid first, wrote it up, and then ordered the SKIN1004 one straight after because I was curious. Apparently I can't stop buying things. So here's the SKIN1004 one on its own.
Is SKIN1004 azelaic acid good?
For my skin, yes, and it's the one I'd call the safer bet. I've got type 1 rosacea, ocular rosacea, seb derm and Malassezia to think about, and I'm on the drier side. It's gentle, the formula is clean, and it does the one job I need from it, which is keeping redness down and my skin calm, without extra actives my face might complain about. It's also £12.99, nearly half the price of the Anua.
The texture
It's watery. Properly watery. It absorbs straight away and there's almost nothing to it on the skin, which is a relief if you layer a lot or you've ever had an azelaic acid pill under SPF (the cyclodextrin in it is what lets it stay that thin instead of turning gritty).
Is it fungal acne safe?
This is where it surprised me. There are no fatty oils, no shea, no problem esters and no ferments in it, and Skincarisma shows zero fungal acne triggers in the list. Tocopherol sits very low down, which some people will flag. I'd give it 9.5 out of 10 for fungal acne safety.
Who it's not for
If you've got acne, pigmentation or oily skin alongside your redness, the Anua is doing more work, and that's the one I'd point you at instead.
The full ingredient lists, side by side, are in my Anua vs SKIN1004 azelaic acid comparison.