Vitamin C is not stable. It will discolor as it oxidizes and may give you that warning. Of all the vitamins, it is less stable than many others.
The calcium is an inert mineral. It may still be good.
The CoQ-10...? not sure.
signs of decay are:
an odd odor (which differs from fresh)
strange discolorations
tablets falling apart (moisture)
Capsules getting really hard --powder solidifying. (take one apart).
Some minerals like magnesium attract moisture and sweat.
oil based supplements may become rancid--react with oxygen and be harmful when consumed.. they usually darken when this happens.
supplements packed in glass can stay fresher longer than plastic.
The enemies of drugs or supplements are
Heat
light
moisture
Unless packed under nitrogen, a sealed bottle can still degrade.
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All truths are easy to understand once they are discovered; the point is to discover them.-- Galileo Galilei
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Weezie looking at petunias 8.25.2017
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