Navy SEAL PED Use Under Scrutiny Amid a Death During Hell Week

Navy SEALs are apparently using performance-enhancing drugs en masse -- a phenomenon under the microscope after a recent death -- and now ... the branch is cracking down.

This all came under increased scrutiny after 24-year-old SEAL trainee Kyle Mullen died suddenly earlier this year while he was participating in the training program ... specifically, during Hell Week, where would-be SEALs are put through extreme conditions.

While Mullen's mother denies her son was on any type of steroid/PED that could've adversely affected his health -- paraphernalia found in his car shortly after his death has caused concern among Navy brass, spurring them to request more testing to detect this stuff.

There's a list of banned substances -- including PEDs -- that the Navy doesn't want its recruits using ... even though, in reality, it seems many of them are. Mullen's mother told CNN that her son relayed this to her while he was alive ... that more often than not, prospective SEALs were juicing up for competitive advantages in the elite program.

Officials believe this problem goes beyond just human growth hormone, BTW -- the PED problem is said to be rampant and wide-ranging ... which is obviously worrying, seeing how much this stuff has been found to be bad for the average person's health, increasing heart rate and blood pressure levels beyond normal -- and that can lead to death.

After Mullen's death, other cadets were ordered to undergo urinalysis to test for PEDs, but the Navy wants blood testing approved (and funded) because they believe this issue needs to be weeded out and strictly forbidden.

A Naval senior officer told CNN ... there is "beyond a reasonable doubt that a significant portion of the candidate population is utilizing a wide range of performance-enhancing drugs."