It concludes: “Ladies, For the purpose of transparency I have included you in this email.
“Likewise if you want to discuss my door is always open.”
Scottish Justice Secretary Humza Yousaf said the language used in the email was “utterly intolerable”.
“That is not the kind of language I would expect any police officer, junior or senior, to be using but it will be for the chief constable, undoubtedly, to investigate and we will leave that in his hands,” he told BBC Scotland.
Police Scotland has 572 Authorised Firearms Officers – 539 male and 33 female.
Two former female firearms officers are taking legal action against the chief constable on the grounds of discrimination.
Chief Superintendent Matt Richards, divisional commander for specialist services, said: “The email was dealt with immediately and the matter was investigated fully.
“The officer fully accepts the wording was unacceptable and does not meet our values of fairness, integrity and respect.
“He was spoken to by senior management and issued with corrective advice. The officer has apologised and the matter was dealt with internally.”