US Defense Secretary Pete Hegseth revealed plans on Wednesday for mandatory annual testosterone screenings targeting troops aged 30 and above. The program seeks to counter testosterone shortfalls that may harm overall health and performance.

"It is well-established science that as we age, testosterone levels naturally drop," Hegseth stated in his video message shared on X.

The checks will form part of the yearly health review for all personnel. Those 30 and older will receive automatic inclusion while younger members may choose to participate voluntarily.

Individuals whose levels fall short of the standard will receive offers of testosterone replacement therapy. "It is entirely your choice," Hegseth added.

Hegseth clarified that the effort "is not about artificial enhancement." Instead it aims to restore and safeguard service members natural abilities along with their long-term health.

The defense secretary further asserted that tackling testosterone shortfalls would boost both mental readiness and physical endurance among the forces.

"By addressing these health markers early, we are keeping you on the leading edge of lethality and giving the same level of support that you give this nation," Hegseth said.

When contacted by NBC News the Defense Department declined to address whether estrogen checks would apply to female personnel or what consequences might follow if members turned down the suggested treatment. Officials instead directed inquiries to Hegseth video.

Testosterone levels are declining worldwide, new study reveals

A recent study found that average testosterone levels among men worldwide have dropped by 54 percent over fewer than five decades.

Low testosterone can appear as fatigue, lowered sex drive, erectile issues, reduced muscle mass, higher body fat, and weaker bones. Some men also report mood changes, trouble focusing, and lower sperm output.

US Health Department eases some restrictions on HRT

The announcement follows moves by the US Department of Health and Human Services to loosen certain limits on testosterone replacement therapies. Last month the department said it would pursue removal of restrictions on use in men with age-related low testosterone.

Hegseth plan drew criticism from opposition Democrats who highlighted his earlier ban on transgender service members who often relied on hormone treatments.

"So now y'all support gender-affirming care?" Democratic Congresswoman Summer Lee said.

"Sounds like gender-affirming care to me," Senator Tammy Duckworth added.

Reuters and Itay Gal contributed to this report.