welcome to hcm
thanks for he query
Normal levels of creatinine
in the blood are approximately 0.6 to 1.2 milligrams (mg) per deciliter.Muscular young or middle-aged adults may have little high value than normal people
i will suggest you to repeat the test again. if again the level found increased its advisable to go for detail clinical check up and evaluation. you may need some other investigations
are you on some medications?
as such there is no harm in taking vit c supplements.