VA nexus letters: what they are, when you need one, and buyer beware

A nexus letter is a written medical opinion from a qualified clinician connecting your current condition to your military service. For many claims it is the single most decisive piece of evidence, which is also why a whole industry has grown up selling them, sometimes for a lot of money.

What a good nexus letter says

The key phrase is that your condition is 'at least as likely as not' related to your service, meaning a 50% or greater probability. The clinician should show they reviewed your records, state the diagnosis and the in-service event or service-connected condition, give the opinion at that standard, and explain the medical reasoning. An opinion with no rationale carries little weight.

When you do not need one

You generally do not need a nexus letter for a presumptive condition, because the VA already concedes the link. You may also not need one if your service records clearly document the condition starting in service with continuity since. Nexus letters matter most for direct claims with a gap, and for secondary claims.

Buyer beware

Be cautious with expensive, boilerplate nexus letters from a clinician who never examined you or reviewed your records, VA raters discount those. Your own treating provider, who knows your history, is often the best source. Bring a clear summary of your diagnosis and in-service event to your appointment, and remember an unsigned, AI-generated draft is not competent evidence on its own.