Nexus Letters
100% free · provider reference
What a strong nexus letter actually looks like.
A nexus letter isn’t strong because it has a doctor’s signature at the bottom. It’s strong when each section gives the VA something it can actually weigh. Here’s the anatomy — and free templates your provider can use as a structural reference.
These are educational examples for licensed medical professionals, not scripts veterans fill out themselves. The provider owns the opinion because the provider makes the medical judgment.
When you actually need one
Not every claim needs an outside nexus letter. The strongest claims rely on the service treatment records, presumptive rules, or a clear VA C&P opinion. A nexus letter starts mattering when:
- •The condition was diagnosed after service and the connection isn’t obvious from the STRs
- •Service records are thin, lost, or silent on the in-service event
- •The VA issued a negative C&P opinion and you need a counter-opinion
- •The claim is a secondary or aggravation claim where the medical chain needs explaining
- •The VA acknowledged the diagnosis but denied the link to service
The seven sections of a strong nexus letter
The VA reads nexus letters for specific elements. Missing or weak sections give the rater a reason to discount the opinion. Each section below shows what belongs there and why.
Provider Credentials
Why the VA cares: The VA weighs medical opinions by the provider's qualifications. A specialist treating the condition carries more weight than a primary-care signature.
Strong example
"I am Dr. Jane Smith, M.D., board-certified in pulmonology and licensed in Texas. I evaluated the veteran on March 4, 2026, and reviewed the records below."
Weak version
A signature with no credentials, specialty, license, or context for the provider's role.
Records Reviewed
Why the VA cares: The VA needs to see the opinion is tied to the actual file — service treatment records, VA records, imaging, lay statements, prior decisions — not a five-minute summary.
Strong example
"I reviewed the veteran's STRs from 2010-2014, VA treatment records from 2016-2025, the February 2025 sleep study, medication history, spouse's lay statement, and the May 12, 2025 rating decision."
Weak version
"I reviewed the veteran's history" — no list, no specificity.
Current Diagnosis
Why the VA cares: Service connection requires a current diagnosed disability. A letter that talks about symptoms without naming the diagnosis leaves a major gap.
Strong example
"The veteran is currently diagnosed with obstructive sleep apnea, confirmed by polysomnography dated February 18, 2025."
Weak version
"The veteran has trouble sleeping" — that's a symptom, not a diagnosis.
Service Connection Theory
Why the VA cares: Direct, secondary, and aggravation are different claim theories. The opinion needs to pick one and address it explicitly so the rater isn't playing detective.
Strong example
"This opinion addresses whether the veteran's obstructive sleep apnea is secondary to, or aggravated by, the veteran's service-connected PTSD."
Weak version
"The veteran's condition is related to military service" — no theory specified.
Medical Opinion Statement
Why the VA cares: VA-friendly probability language ("at least as likely as not") signals 50%+ probability — the standard the rater weighs. Vague hedging gets discounted.
Strong example
"It is my medical opinion that the veteran's obstructive sleep apnea is at least as likely as not aggravated by the veteran's service-connected PTSD."
Weak version
"These conditions could be connected" — too vague to satisfy the standard.
Medical Rationale
Why the VA cares: A conclusion without reasoning gets discounted. The rationale is where the provider shows why the connection makes medical sense based on the specific facts.
Strong example
"This opinion is based on the veteran's documented sleep disturbance history, weight changes after psychiatric medication, chronic PTSD symptoms, and the absence of OSA symptoms prior to the progression of the service-connected psychiatric condition."
Weak version
"The veteran has sleep apnea and PTSD, and I believe they are connected" — conclusion without reasoning.
Signature & Date
Why the VA cares: A signed and dated opinion makes the authorship and timing clear. Unsigned or undated letters look incomplete and lose weight.
Strong example
"Respectfully submitted, Dr. Jane Smith, M.D., Board-Certified Pulmonologist, License #000000, March 4, 2026."
Weak version
An unsigned template, undated opinion, or no contact information.
Sample templates by secondary connection
Below are nexus letter templates for the most-claimed secondary connections. Each opens a structured starter that a qualified provider can adapt — not a copy-paste shortcut. Keep them as a reference for what a strong opinion includes.
PTSD → Sleep Apnea
The most-claimed mental health → respiratory secondary connection. PTSD-related sympathetic arousal, weight changes from psychiatric medication, and sleep fragmentation all support OSA causation/aggravation.
Back / Lumbar Strain → Radiculopathy
Nerve root involvement from a service-connected back condition is the textbook secondary spine claim. Lumbar imaging plus neurological findings carry the connection.
Tinnitus → Migraines
The noise-injury chain. Tinnitus is documented as a migraine trigger and aggravator in the literature, especially for blast-exposed combat veterans.
Chronic Service-Connected Pain → Depression
Persistent pain is one of the most-cited causes of secondary depression. Strong opinion ties the depressive symptoms timeline to the pain trajectory.
Knee → Hip
Altered gait from a service-connected knee condition is a recognized cause of hip arthritis and dysfunction. The opinion connects biomechanics, not just timeline.
What weak nexus letters do that you should avoid
- ×No clear diagnosis — symptoms only
- ×No list of records reviewed
- ×Hedged language: “could be” / “possibly connected”
- ×Conclusion without medical rationale
- ×Wrong claim theory (direct when it should be secondary)
- ×No discussion of competing causes or obvious risk factors
- ×Generic template not adapted to the veteran’s specific facts
Pair this with the C&P prep tools
A nexus letter establishes the connection. The C&P exam decides the percentage. Use these in tandem:
Educational content only — not legal or medical advice. The sample templates on linked pages are educational examples for licensed medical professionals, not scripts veterans should fill out themselves. The provider must own the opinion because the provider is the one making the medical judgment. Consult a VA-accredited representative for help filing your claim.