The VA disability claims process can be confusing and frustrating, and getting a ‘not service-connected’ letter from the VA even more so. So enters the nexus letter. Depending on who you ask, it’s either the missing piece that wins your claim or an expensive document you didn’t need.
Dr. Marshall Bahr, Xterra Health’s founder, CEO, and medical director, started the company for that express purpose. He served in the 1st Battalion, 75th Ranger Regiment, as a special operations medic for almost seven years before graduating from medical school and becoming a physician in 2015. He knows how stressful the VA disability claims process can be because he’s been through it himself.
“I ended up having to use one of these [veteran disability services] companies that provide nexus letters, and I had to pay like $2,000 to get it,” Dr. Bahr said. “It worked, but I didn’t know how anyone else could afford it. That kind of drove the mission to make this a better, more affordable, transparent way of getting veterans expert-level nexus letters.”
The problem remains: most veterans don’t begin seeking nexus letters until they’re already frustrated. Maybe the VA denied your claim, or your VSO suggested getting one. Maybe you found yourself digging through Reddit, Facebook groups, and YouTube videos trying to figure out what everyone else seems to know.
This guide cuts through the noise.
Quick Answer
A VA disability nexus letter is a medical opinion from a qualified healthcare provider that establishes a veteran’s current medical condition and its connection to their military service. While not every VA claim requires a nexus letter, it can be critical when the connection between your service and your disability isn’t already obvious or documented.
What is a Nexus Letter?
If you search the VA.gov website, you won’t find the term “nexus letter” anywhere. Instead, you will see references to medical nexus, nexus opinion, favorable nexus, negative nexus, and nexus evidence.
Dr. Bahr broke down the VA’s process of evaluating service-connected disability as a three-part sequence. First, a veteran must have a current diagnosis. Second, a veteran must have an in-service event that caused the claimed disability, or another service-connected condition. The third is establishing the nexus.
“They often need that third thing, the nexus, which is just a fancy word for the bridge that connects number one to number two,” Bahr said. “The diagnosis to either the in-service event or the other service-connected condition, and if it’s not explicitly laid out in their medical records, a lot of times the VA just doesn’t make that connection for the veteran.”
“At least as likely as not” is the standard the VA uses to determine whether a disability is connected to military service. It means a qualified medical provider believes there is a 50% or greater probability that your condition was caused or aggravated by your military service or another service-connected disability. When the evidence for and against a claim is approximately equal, VA policy directs that reasonable doubt be resolved in the veteran’s favor.
The VA isn’t supposed to approve claims based on assumptions or good intentions. Instead, they review the medical and service records available to determine whether your condition has a nexus to a veteran’s service. That’s where veterans often hear the phrase “nexus letter.” Unfortunately, it’s also where misinformation starts.
Some believe every veteran needs one. Others insist they’re a waste of money. The fact is, a nexus letter is just one type of medical evidence. Whether you need one depends entirely on your individual claim.
Understanding that difference can save you months of frustration—and potentially thousands of dollars spent chasing evidence you never needed in the first place.
When You May Not Need a Nexus Letter
It’s important to know when you do or don’t need a nexus letter. This surprises many veterans. Sometimes you don’t need a nexus letter at all.
“Our YouTube platform is free education meant to coach veterans on what they need, so they don’t need to use us if they don’t need a medical opinion, a nexus letter,” Dr. Bahr said. “The key is that you don’t need it if you have the connection documented in your medical records. Not just the diagnosis, but the ‘why you have that diagnosis.’ If you have this, you do not need it.”
Likewise, what the VA calls presumptive service-connected disability may not require the same type of medical evidence because the VA has already recognized the relationship under specific circumstances. Examples include ALS, certain cancers associated with toxic exposures, and other conditions recognized by the VA under specific presumptive rules.
If a veteran is seeking a nexus letter for a condition that lacks the necessary medical evidence, Xterra Health will not charge the veteran for the evaluation and will inform them that it cannot issue the nexus letter. Bahr said he doesn’t want veterans to waste their money if “it’s not going to work.”
Remember, buying a nexus letter “just in case” isn’t always the best strategy. The strongest claims aren’t built by submitting the most paperwork; they’re built by submitting the right evidence.
When a Nexus Letter Can Strengthen Your Claim
A veteran must prove to the VA why their disability is service-connected, and when the nexus letter is relevant, it’s generally after the VA has denied your claim. But that isn’t always the case.
Veterans often consider obtaining one when:
- Their initial claim was denied because the VA couldn’t establish service connection.
- A condition developed years after leaving the military.
- They’re filing a secondary service connection claim.
- Their service treatment records are incomplete or missing.
- Multiple medical conditions make the relationship more complex.
- A Compensation and Pension (C&P) examination produced an unfavorable opinion.
In these situations, an independent medical opinion may provide additional medical evidence for the VA to consider.
Every claim is different, which is why it’s difficult to nail down a universal answer for when a nexus letter is necessary.
How Nexus Letters Help Address the Lack of Military Medical Records
It’s no secret that the military infuses a no-quit, drive-on kind of attitude into its service members. So when you get knocked out on your initial jump in Airborne School, you may not want to go to sick call and potentially get dropped or recycled. So it’s rarely documented.
“There is evidence-based literature, medical literature, and peer-reviewed studies that clearly show that the overwhelming majority of the time, the culture in the military is one in which it dissuades or deprioritizes asking for help or going to sick call out of fear of stigmatization, out of fear of being labeled as weak, out of fear of being dissociated from your unit,” Dr. Bahr said. “So a lot of guys don’t do it, and they get out, and they get hit with the well, nothing happened, there’s nothing documented in service.”
If your disability claim isn’t clearly established by your military records, or you don’t have a service-connected condition that caused the disability, you may need a nexus letter.
Xterra Health is uniquely qualified to write nexus letters for veterans. It is one of the few physician-led veteran disability service companies in the space. A majority of Xterra Health providers are veterans or spouses of service members—they know what to do because they have lived experience.
“The majority of our providers are service members, or if they’re not service members, they are the spouses of service members, so they have lived experience to be able to say, ‘Oh, I know what it’s like, because I know what it’s like to wear military boots. I know what it was like to hump 12 miles at a time.’ I know what it was like to eat shit on a PLF and be able to articulate that from both a veteran experience and a medical experience,” Dr. Bahr said. “So, they can really tie that story together and then back it up with the peer-reviewed literature that supports their disability claim.”
A nexus letter helps explain that connection through medical reasoning and evidence rather than speculation.
Conditions That Often Benefit From Additional Medical Evidence
While every claim is unique, certain medical conditions frequently involve questions about service connection.
Examples include:
- Sleep apnea
- PTSD with secondary conditions
- Anxiety and depression
- Migraines
- Tinnitus-related secondary conditions
- Chronic pain
- Orthopedic injuries
- Degenerative arthritis
- Radiculopathy
- GERD
- Fibromyalgia
- Toxic exposure-related illnesses
Many of these conditions involve delayed symptoms, multiple contributing factors, or secondary service connections that require detailed medical explanations.
That doesn’t automatically mean you need a nexus letter, but they’re often discussed during these types of claims.
What Makes Medical Evidence Strong?
A medical opinion carries the most weight when it’s supported by facts and written by a qualified medical provider. Dr. Bahr said some nexus letters fail because the person who wrote them doesn’t have the medical licensing and qualifications necessary to provide a medical opinion.
Strong medical evidence typically includes:
- A thorough review of relevant medical records.
- Consideration of military service history.
- A clear medical explanation supported by accepted medical principles.
- Logical reasoning that explains why the provider reached their conclusion.
- Consistent documentation that aligns with the veteran’s medical history.
The VA wants to understand the medical reasoning behind the provided opinion. Simply stating that a condition is “service-connected” isn’t enough.
That’s why quality matters far more than length.
Common Myths About Nexus Letters
“A Nexus Letter Guarantees Approval.”
- No medical opinion can guarantee a favorable VA decision. The VA reviews the entire evidence package before making a determination.
“Any Doctor Can Write One.”
- Healthcare providers may be qualified to diagnose medical conditions, but not every provider is familiar with VA disability standards or understands how to write medical opinions that address the questions VA adjudicators must answer.
“More Pages Mean a Better Letter.”
- Longer doesn’t necessarily mean stronger. Clear reasoning supported by medical evidence is usually far more persuasive than unnecessary length.
There is no mention of “Nexus Letters” in 38 CFR
- This is a common claim that claim shark companies are making. It’s partially true that the CFR doesn’t mention “nexus letters” specifically, but it does say the veteran has to establish nexus between their disability and military service.
- How do you establish that though? You get a qualified medical provider to write a nexus letter explaining the nexus the VA requires!
Why Some Claims Get Denied
Receiving a denial doesn’t automatically mean your condition isn’t related to military service; it generally means you didn’t provide enough of the medical evidence the VA needs to see.
Claims can be denied for many reasons, including:
- Missing medical evidence.
- Incomplete documentation.
- Lack of a current diagnosis.
- Insufficient evidence connecting the condition to military service.
- Conflicting medical opinions.
- Unfavorable C&P examination findings.
Understanding why a claim was denied is the first step toward determining what evidence may be helpful moving forward.
Choosing the Right Medical Provider
If you determine that your claim could benefit from a nexus letter, experience matters.
Look for healthcare professionals who:
- Review your complete medical history.
- Understand VA disability claims.
- Base their opinions on accepted medical evidence.
- Provide detailed medical reasoning rather than unsupported conclusions.
- Take the time to understand your military service and current diagnosis.
A thorough medical evaluation and review of records are always better than a quick template. Dr. Bahr said it’s easy to spot a template nexus letter: if you remove your name and the letter applies to any veteran, it’s likely a bogus nexus letter.
Veterans should be wary of who they hire to write their nexus letters. There are several companies that claim to have the qualifications to write a medical opinion, but they don’t always have the legal or medical licensure required by the VA.
Whether it’s a specialist or a family practice physician writing it, there is an easy way to identify a good nexus letter from a bad one.
“What the VA looks for is, did they actually look at all the records, all the objective evidence, and does the objective stuff match the opinion that they’re opining on,” Dr. Bahr said. If that is the case, then a nurse practitioner who’s 24 years old, fresh out of school, could have a better opinion than the best Mayo Clinic-trained neurologist in the world.”
FAQs
Is a nexus letter required for every VA disability claim?
No. Many successful claims are approved without one. Whether you need a nexus letter depends on the medical evidence already available in your file.
Can the VA deny a claim even with a nexus letter?
Yes. A nexus letter is one piece of evidence the VA considers alongside medical records, service records, C&P examinations, and other supporting documentation.
Who can write a nexus letter?
Qualified healthcare providers, including but not limited to physicians, physician assistants, and nurse practitioners, may be able to provide medical opinions. The provider should have the expertise and qualifications necessary to evaluate the specific medical condition involved.
Is a nexus letter the same as a Disability Benefits Questionnaire (DBQ)?
No. A DBQ documents the severity of a condition, while a nexus letter focuses on explaining the medical relationship between your disability and military service.
Can a nexus letter help after a denial?
Depending on the reason for the denial, additional medical evidence can strengthen a supplemental claim or appeal. The key is addressing the specific issue identified in the VA’s decision.
Before you Request a Nexus Letter
The VA disability claims process can be stressful and confusing during a veteran’s most vulnerable experiences, and nexus letters are one of the most misunderstood parts of it.
The important thing is understanding your claim before spending time, money, or energy chasing documents that may not apply to your situation.
As you continue building your claim, focus on submitting clear, credible medical evidence that accurately reflects your service and your health. When additional medical opinions are appropriate, they should strengthen the evidence, not replace it.
Call us today or schedule an appointment to get the support you need for your VA disability claim. Let us help you secure the benefits you have earned through your service to our country.
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This story has been updated to include more information on .
