What makes something science is not so much the subject matter as the process. Scientific information is obtained by clear methods that others should be able to repeat. It is above all based on evidence. There are lots of different kinds of evidence and different ways of analyzing and interpreting it. Show what your evidence is. Tell how you analyzed your raw data. Explain how you interpret these data in light of theory. This is the scientific approach. It is not magic. It is not vague. It is not private.
It is susceptible to disagreement if others disagree with your methods, your analyses, or your interpretations. Part of that disagreement should not be because you had access to something secret, or your critic had access to something secret.
This is why you need to resist the temptation to refer to data you are not sharing at this time, or to communications that are not public. Science does not work by deferring to authority. It advances with data, analysis, and interpretation. These three things reveal theories that are supported. These three things are the way in which we reject theories, no matter how eminent the person advancing them is. This is a wonderful thing about science. It is the source of all its power.
But life is complicated and you may have a piece of a puzzle that impacts a publishable study that itself is not quite ready for publication, or that belongs to a different set of co-authors. You may want to say personal communication to acknowledge an idea that was not yours. But you should not do either of these things. Restrict your story to the facts that are revealed. Save the rest for later.
I really like it that the US Proceedings of the National Academy of Sciences, PNAS, explicitly disallows these practices: “Data not shown and personal communications cannot be used to support claims in the work,” from PNAS editorial policies.