I bought some creatine, put it in the cupboard and forgot about it. It’s now passed the expiry date. Is it still safe to use?
Creatine Monohydrate is quite stable and as long as it is kept dry and not exposed to high temperatures, won’t quickly degrade and will be good well past its BBE or sell-by date.
Putting it into solution, getting it wet, on the other hand, will cause conversion to creatinine, degradation, loss of potency and possibly fungal growth.
So, although time eventually will affect your product, moisture and heat are your real enemies here.