Vitamin C in my product?

[novembersnow]

How do you know if your skincare product has ingredients that has or is Vitamin C but doesn't necessarily advertise it as it may not contain as high of a ratio?

I've bought The Ordinary's Niacinamide 10% + Zinc 1% serum, and I know vitamin C can interfere with niacinamide. I've heard that the serum can be quite drying, so I've bought a moisturizer (not from Sephora- but if you're curious, Dr. Belmeur's Clarifying Moisturizer), and I'm just a bit worried that it might contain ingredients that might interfere with the serum working to its maximum capacity!
Any help to shed some light on it would be much appreciated!

Thanks in advance!

[RGbrown]

@novembersnow 

Not being able to mix niacinamide and vitamin C is a myth; you can use both without loss of efficacy or any harmful effects.

To answer the direct question though, vitamin c variants include the following (basically, you are looking for "ascorb-" in the ingredient list):

magnesium ascorbyl phosphate, L-ascorbic acid, tetrahexyldecyl ascorbate, ascorbyl palmitate, ascorbyl glucosamine, ascorbyl tetraisopalmitate, ascorbic acid polypeptide, ascorbyl glucoside, sodium ascorbyl palmitate, sodium ascorbyl phosphate

(The myth also states that only the L-ascorbic acid version of vitamin C is a problem, but again, it's a myth...you can mix the two)