Head Injuries and Hormones: The Overlooked Link After a Concussion or TBI
The pituitary gland helps direct several hormone systems, and a traumatic brain injury can affect it. Research describes a portion of people developing pituitary hormone changes after a head injury, sometimes months or years later, which can look like low testosterone, thyroid changes, fatigue, mood changes, or trouble recovering. It does not happen to everyone, and a screen is not a diagnosis. But because the connection is easy to miss, it can be worth considering an evaluation if symptoms followed a head injury.
Key Takeaways
A car accident in your twenties. A hard hit on the field. A fall, a blast, a fight you would rather forget. Years later, the energy is not there, recovery takes longer, mood and focus are off, and it is easy to chalk it up to age or stress. One possibility that often goes unexamined is whether an old head injury left a mark on the hormone system.
This is an area where the research is genuinely interesting, and also one where it is important not to overstate things. Here is a measured look at what is known, why the link is easy to miss, and when it may be worth a closer look.
How a Head Injury Can Touch the Hormone System
The pituitary gland sits at the base of the brain and acts as a kind of relay for several hormone systems, including those involving testosterone, thyroid, growth hormone, and the stress hormone cortisol. Its location and blood supply appear to make it vulnerable to the forces involved in a head injury. When that signaling is disrupted, the downstream hormones can drift, which is why a brain injury can have effects that show up well beyond the brain.
How Common Is It?
Estimates vary quite a bit depending on how and when people are studied. A 2024 systematic review and meta-analysis pooling dozens of studies put the prevalence of some pituitary hormone dysfunction after TBI at roughly a third of people, while individual studies have reported figures across a wide range. A detailed review in Endocrine Reviews by Tanriverdi and colleagues describes the same overall pattern. The honest takeaway is that it is common enough to take seriously, but it does not happen to everyone, and the numbers should be read as a reason to consider evaluation rather than to assume a problem.
Why the Link Is So Easy to Miss
A few things make this connection slip through the cracks:
- The symptoms are gradual and non-specific. Fatigue, low mood, weight changes, low libido, and slow recovery rarely announce their cause.
- Time has passed. When symptoms show up years after an injury, few people, or clinicians, think to connect the two.
- The injury may never have been diagnosed. Sports hits, minor accidents, and unreported events often go unevaluated at the time.
- Symptoms get treated separately. Low energy, mood, and weight are often addressed one by one, without anyone asking what they might share.
What an Evaluation Looks Like
Looking into this generally means reviewing your history and symptoms alongside lab work that checks the relevant hormone systems. The Millennium TBI Protocol, developed by Dr. Mark Gordon, is one structured framework for that kind of assessment, and it is the approach we use at Asymmetric Health.
Whether anything comes of an evaluation, and what that might be, depends entirely on what the testing shows and is worked out with a clinician on an individual basis. The goal of looking is simply to find out whether an old injury is part of the current picture, so it can be considered properly rather than guessed at.
Wondering if a past injury is worth a closer look?
The HELPS screening tool is a short, free questionnaire designed to flag head injuries that may have been overlooked. It is a starting point for a conversation, not a diagnosis.
Take the HELPS Screening QuizFrequently Asked Questions
Can a head injury affect hormones?
It can, in some people. The pituitary gland sits at the base of the brain and helps direct several hormone systems, and head trauma can affect it. Research describes a portion of people developing pituitary hormone changes after a traumatic brain injury, a pattern sometimes called post-traumatic hypopituitarism. It does not happen to everyone, and severity varies.
How long after a head injury can hormone problems show up?
There is no single timeline. Some changes appear in the months after an injury, while others may not become noticeable until later. Because the symptoms can be gradual and non-specific, it is common for them not to be connected back to an injury that may have happened years earlier.
I was never diagnosed with a concussion. Could this still apply?
Possibly. Plenty of meaningful head injuries are never formally evaluated at the time, especially with sports, falls, vehicle accidents, or events someone did not report. The HELPS screening tool was designed partly to surface these overlooked or downplayed injuries. A screen is a starting point for a conversation, not a diagnosis.
What does an evaluation involve?
Generally a review of your history and symptoms along with lab work that looks at the relevant hormone systems. The Millennium TBI Protocol, developed by Dr. Mark Gordon, is one structured framework for that kind of assessment. What happens next depends entirely on what the evaluation finds and is decided with a clinician on an individual basis.
Sources
- Acute and chronic hypopituitarism following traumatic brain injury: a systematic review and meta-analysis. Neurosurgical Review. 2024. PubMed 39527353
- Tanriverdi F, Schneider HJ, Aimaretti G, et al. Pituitary dysfunction after traumatic brain injury: a clinical and pathophysiological approach. Endocrine Reviews. 2015;36(3):305-342. PubMed 25950715
- Gordon M. Traumatic Brain Injury: A Clinical Approach to Diagnosis and Treatment. Millennium Health, 2018.
Last reviewed by Dr. Ian Strand, DO, FAAMM on . This article is for general education and is not medical advice. A positive screen is not a diagnosis. Please talk with a licensed clinician about your individual situation.
Curious whether an old injury is part of the picture?
Asymmetric Health offers TBI-focused hormone evaluations using the Millennium Protocol, with a clinician who reviews your history and labs together rather than treating symptoms in isolation.
Asymmetric Health is located in Lacey, WA. Telehealth available statewide in Washington.