What to actually check on a supplement label
Ingredients list first, front-of-pack claims second. A short, recognisable ingredients list is generally easier to make sense of than a long one full of unfamiliar names.
Check the serving size against the total container size, so you know how long a tin or bottle actually lasts at the recommended dose — it changes the real cost per week.
Look for a batch or lot number and an expiry date; both should be printed somewhere on the packaging, not just on a sticker.
If a product is meant to be cycled — used for a set number of days, then paused — that instruction should be on the label itself, not something you have to look up separately.