Current as of 2026-11-06. This is general information, not medical advice. Guidelines and VA regulations get revised, so verify anything here with your own clinician or a VA-accredited representative before you act on it.
Short answer: Published research and a Department of Defense clinical recommendation both say that hormone problems from the pituitary gland can follow a traumatic brain injury (TBI), including blast-related mild TBI, and that the symptoms look a lot like PTSD, depression, and poor sleep. How common this is after mild TBI is not settled. The best-known blast study in veterans had 26 men in the exposed group. The practical takeaway is narrow: if symptoms persist, low testosterone is one of several treatable possibilities worth testing for properly, and a result should never be read as proof that a blast caused it.
What the research actually shows
The study people cite most often was published in 2012 in Frontiers in Neurology by Wilkinson and colleagues, who worked with male Iraq and Afghanistan veterans. There were 26 men with blast-related mild TBI, 7 deployed controls with no blast exposure, and a reference group of 59 used only to set normal ranges.
Eleven of the 26 men with blast-related mild TBI (42 percent) had an abnormal value on at least one pituitary or target-organ axis. None of the 7 controls did. Only 3 of the 26 had the pattern that fits low testosterone from a pituitary cause: total testosterone below the 5th percentile along with a low LH or FSH. Five had low IGF-I, a growth hormone marker.
The authors call it a preliminary study. The injured group was a convenience sample, only basal hormone levels were measured, and the authors describe those results as screening values and not diagnoses. The testosterone subgroup is three people. That makes it a signal worth following. It is too small to give you a rate for any veteran you have not examined.
A later conference presentation from the same research group, given at the Endocrine Society meeting in 2016, reported 41 male veterans. Twelve of 27 with blast concussion (44 percent) had abnormal hormone levels, compared with 1 of 14 (7 percent) of the deployed veterans without blast exposure. Those with abnormal hormones reported poorer sleep, more depressive symptoms, and more fatigue than those with a blast concussion and normal hormones. The Endocrine Society press release does not say whether this was peer reviewed or published, and the design looks cross-sectional, which shows association and cannot show cause.
The broader literature gives a rough frame. A 2007 systematic review in JAMA (Schneider and colleagues) pooled 19 studies with 1,137 patients and estimated that about 27.5 percent of people with TBI had hypopituitarism in the chronic phase. Prevalence was higher after severe TBI than after mild or moderate TBI. Those studies used different methods and populations, and some early abnormalities in the literature were transient.
What DoD and VA guidance say
The Defense Department's TBI Center of Excellence has a clinical recommendation on neuroendocrine dysfunction after mild TBI, released August 2012 and reviewed April 2021. A few points from it:
- The anterior pituitary is the structure most often affected, and growth hormone and gonadotropin (LH, FSH, testosterone) deficiencies are the most common.
- Consider it when symptoms persist beyond three months after a confirmed mild TBI, or when new symptoms appear up to 36 months later.
- Screening should not be routinely ordered in the early post-injury period.
- Screening results are one part of a full clinical evaluation and should not be used alone for decisions.
- Referral to endocrinology is advised when labs suggest a problem, or when suspicion stays strong despite negative screening and other causes have been excluded.
The VA/DoD clinical practice guideline for post-acute mild TBI (version 3.0, June 2021) is more cautious. It says symptoms attributed to mild TBI are nonspecific, that the exact cause is often hard to determine when symptoms span psychological, neurological, and neuroendocrine domains, and that assuming every symptom comes from the TBI can lead to repeated, unhelpful workups. It also lists the assessment of neuroendocrine disorders in adults with mild TBI as an area needing further research. The official position, in plain terms, is to keep the possibility open and avoid assuming it.
Why it gets missed
The DoD recommendation says the symptoms of neuroendocrine dysfunction overlap with post-concussion syndrome, sleep disorders, PTSD, and depression. That overlap is the core of the problem. Fatigue, low mood, poor concentration, disrupted sleep, and low libido can come from any of those, from medications, from alcohol, from sleep apnea, or from low testosterone. Each is a reasonable explanation, so the search often stops at the first one found.
The Wilkinson authors raise the same point in their discussion: hypopituitarism symptoms overlap with PTSD symptoms, which could matter for diagnosis and treatment. The paper did not measure PTSD itself, so it cannot tell you how often one is mistaken for the other.
What testing a clinician typically orders
For testosterone specifically, the 2018 Endocrine Society guideline is the usual standard. It says to diagnose hypogonadism only in men who have symptoms and signs of testosterone deficiency and consistently low testosterone. That means a fasting morning total testosterone, confirmed by a repeat morning fasting measurement. Free testosterone is added when the total is borderline or when sex hormone-binding globulin may be altered. LH and FSH are measured to separate a testicular cause (primary) from a pituitary or hypothalamic cause (secondary). The guideline also calls for pituitary imaging when secondary hypogonadism is severe, with serum testosterone under 150 ng/dL given as an example, or when there are other pituitary warning signs.
The DoD post-TBI screening panel is broader than testosterone. It lists:
- 8 a.m. cortisol
- IGF-1
- TSH and free T4
- LH and FSH
- Testosterone in men
It also says local lab reference ranges should be used to decide what counts as low. A single abnormal draw is not a diagnosis. Sleep, illness, and time of day all move these numbers, which is why a repeat is built into the guideline.
How VA and TRICARE handle evaluation
The VA/DoD guideline says most patients with mild TBI symptoms should be managed in primary care. The DoD recommendation was written specifically to support the primary care provider and points to endocrinology when results are abnormal. For a veteran or service member, that makes the first step a conversation with a primary care clinician about persistent symptoms, including whether an endocrine workup fits.
The VA/DoD guideline states that it does not represent VA or TRICARE policy and that a recommendation in it does not guarantee coverage of civilian care. We could not open an official TRICARE policy page on testosterone, so we are not going to describe what TRICARE covers or how it handles prior authorization. Ask your TRICARE contractor or your military treatment facility directly. If you serve in a community with special medical standards, such as aviation, diving, or submarine duty, read our special duty article before starting any hormone therapy.
How a disability claim relates, if at all
This part is narrow and specific, and a VA-accredited representative is the right person to apply it to your case.
Under VA regulation 38 CFR 3.310(d), for a veteran who has a service-connected TBI, certain conditions are held to be the proximate result of that TBI in the absence of clear evidence to the contrary. One of them is, in the regulation's words, diseases of hormone deficiency that result from hypothalamo-pituitary changes, if manifest within 12 months of moderate or severe TBI. VA's 2013 rulemaking cited an Institute of Medicine finding of sufficient evidence of an association between moderate or severe TBI and endocrine dysfunction, particularly hypopituitarism.
Two limits matter. First, that rule is written for moderate or severe TBI. Mild TBI is named in it only for depression, within 12 months. Second, the regulation says those severity levels and time limits do not preclude a finding of service connection for conditions shown by evidence to be proximately due to the TBI. So a hormone deficiency after mild TBI, or one that appears later than 12 months, is not excluded automatically. It is decided under the general rules, which means medical evidence and a medical opinion carry the weight.
We are a private practice. We cannot tell you whether you have a claim, and a low testosterone result does not establish one.
What this means for treatment
Testosterone therapy is a treatment for confirmed testosterone deficiency. It is not a treatment for TBI, concussion symptoms, or PTSD, and nothing cited here shows that it is. If a workup confirms low testosterone from a pituitary cause, treating that deficiency is a separate question from treating the injury. Other pituitary axes may also be affected, which is why a broader workup and an endocrinologist's input matter more here than in a routine low-T visit.
Questions people actually ask
Does blast exposure cause low testosterone? Some studies find more abnormal hormone results in blast-exposed veterans than in controls. Those studies are small, and association is all they show. The VA/DoD guideline lists the assessment of neuroendocrine disorders in mild TBI as a research need.
How long after the injury can it show up? The DoD recommendation says onset can occur anytime from the event up to 36 months after injury, and suggests considering it when symptoms last more than three months.
I have PTSD. Could my fatigue and low libido still be hormonal? They could be. They could also be PTSD, sleep apnea, medication effects, or depression, and more than one can be true at once. Only testing sorts these apart.
Is one low testosterone number enough? No. The Endocrine Society guideline calls for symptoms plus consistently low morning fasting levels, confirmed on repeat.
Should I be screened right after a head injury? The DoD recommendation advises against routinely ordering neuroendocrine screening in the early post-injury period.
Will a low result help my VA claim? It is one piece of evidence. Its weight depends on your records and on how VA applies its rules to your case, so talk to an accredited representative.
Where we fit
Hew Health is a private, cash-pay practice with locations in Destin and Orlando, Florida, and telemedicine in 47 states. We do not replace the VA or your military treatment facility, and you do not have to choose between them and us.
If you want a second look, we run the workup the guidelines describe: repeat fasting morning testosterone before any prescription, plus LH and FSH. If the pattern points to a pituitary problem beyond testosterone, we will tell you to see an endocrinologist, because treating one number while other axes are off helps no one. If you are in a special duty community, talk to your flight surgeon or medical officer first.
To talk it through, request a consultation at hewhealth.com or call (850) 820-8850.
Related dispatches
- TRT and Special Duty: Flight Status, Dive, Submarine, and Nuclear
- The Military's New Testosterone Screening, Explained
- Getting Out on TRT: The Gap Between TRICARE and the VA
Hew Health is a private medical practice and is not affiliated with, endorsed by, or connected to the Department of Veterans Affairs, the Department of Defense, or TRICARE. This article summarizes published research and public guidance as of 2026-11-06. It is general information, not medical advice, and does not diagnose or promise any result. Testosterone is a Schedule III controlled substance. FDA-approved testosterone products are indicated for men with low testosterone caused by an associated medical condition.
Sources: Wilkinson CW et al., Frontiers in Neurology 2012;3:11. Endocrine Society press release, April 2016 (conference presentation). Schneider HJ et al., JAMA 2007. DoD/TBICoE Clinical Recommendation, Indications and Conditions for Neuroendocrine Dysfunction Screening Post Mild TBI (Aug 2012, reviewed Apr 2021). VA/DoD Clinical Practice Guideline for Post-Acute Mild TBI, version 3.0, 2021. Bhasin S et al., Endocrine Society guideline, J Clin Endocrinol Metab 2018;103:1715. 38 CFR 3.310 and VA final rule, 78 Fed. Reg. 242 (Dec. 17, 2013).