The Pentagon is reinstituting a mandatory testing program for testosterone deficiency among US service members age 30 and older, a spokesperson said on Thursday, bringing back a programme that many medical experts have described as unnecessary and potentially harmful.

US Defence Secretary Pete Hegseth, who has promoted the use of ​testosterone to improve military readiness, first announced the screening mandate in July.

Under the announced guidance, women were also set to be screened through a questionnaire and could then move to treatment for conditions related to hormonal imbalances.

In early September, however, the Pentagon temporarily rescinded the published medical guidance for the testosterone screening “to allow for updates”.

The latest move lifts that pause, allowing testing to go forward. It was not immediately clear what, if any, updates had been made to the original policy.

“Effective immediately, this guidance addresses male testosterone deficiency, establishing uniform screening and treatment pathways,” Pentagon spokesperson Sean Parnell said in a statement.

Medical ​professionals have warned that testosterone, if prescribed inappropriately, could increase service members’ risk of infertility or lead to other health consequences.