Instagram's messaging rules are short and absolute: a business cannot open a conversation with someone who has not messaged it first. Meta requires the correspondent to initiate. There is no API scope, no partner tier, and no growth hack that changes this. Only automation that violates the platform's terms and burns the account running it.
That constraint is why Instagram is not a GTM channel at all. We looked at shipping it as inbound and engagement only, decided a channel that cannot start a conversation is not an outbound channel, and dropped it rather than list it and explain the asterisk on every call.
What actually works there
The one compliant route to a cold audience is comment-keyword automation: someone comments a keyword on your post, and that comment, because they initiated it. Opens the door to a private reply. It is a real mechanic with real reach. The audience selects itself by acting, which is better targeting than any list, and the reply arrives while the interest is minutes old.
Everything else on Instagram is conversation you answer, not conversation you start. If you are already running comment automation, keep running it. It just is not a thing a go-to-market agent can drive on your behalf, so GTM sends on email and LinkedIn and says nothing about the rest.
How to read a tool that promises otherwise
A vendor marketing cold Instagram DMs at volume is describing one of two things. Either automation driving a real account against Meta's terms until it is banned, or a definition of cold that quietly requires the recipient to have messaged first. The gap between the pitch and the platform is where the product actually lives. The constraint is Meta's. Printing it is ours.