Namaskarams,

I have 3 questions regarding mantras and slokas:

1) I know that not everyone should chant Vedic mantras and that it requires initiation. Is this true also for puranas and itihasas and upanishads? The reason why I ask is because while one terms components of Vedas as “mantras” one calls them “slokas” in puranas, itihasas and upanishads (like for example Gita). Can everyone read puranas, upanishads and itihasas and recite their slokas? Is there any restriction or criterion like initiation?

2) Another question, how does one distinguish a mantra from a sloka if one does not know the source. For example, I have heard many people recite/post a narasimha sloka starting “ugram viram maha vishnum…”.

Is this a sloka or mantra? How do we know? By mantra I mean something which requires initiation or some sort of qualification to be recited.

People say that if it starts with ‘om’ and ends with ‘namah’, it is a mantra but how about ashotaras where one says “om” and “namah” with every name. Does that mean it becomes a mantra?

3) I heard that naamam can be chanted by anyone at anytime. Does this limit its potency? The reason why I ask is because I heard that mantras are like a heavy dose pill and naamam is like over-the-counter pill. Heavy dose pill works immediately but we need prescription just like mantras which are very effective but need initiation. Over-the-counter pills take more time to work but we can just drop by a medical store and buy it like naamam which can be chanted by anyone without restriction but takes more time than a mantra to do good. Is this true?

Thank you. Namaskarams