Why does my obverse cream contain on the ingredients document: "citric tart and/or sodium hydroxide"?

It's on a tube of benzoyl peroxide that I'm using at the moment. Doesn't it seem strange, considering the two ingredients are so amazingly different but can still be substituted for one another?Why does my obverse cream contain on the ingredients document: "citric tart and/or sodium hydroxide"?
Actually they aren't being substituted one for the other at adjectives. When they produce a product for facial use, they have to adjust the final pH to clash that of human skin. One or the other will be used depending on if the batch is alkaline or sharp, to counter balance the entire shipment. So either one or the other would enjoy been used, but not both. If the shipment was alkaline, they would imagined have used the citric acerbic, and if it were bitter they would use the sodium hydroxide. It's not like you didn't own garlic powder so you used a clove of garlic. It's so you don't chemically burn your skin with a product that's too tart or too base.
Believe they both qualify as astringents or "pore reducers."