diff --git a/components/Onboarding.tsx b/components/Onboarding.tsx
index 630608a..3ae7e7a 100644
--- a/components/Onboarding.tsx
+++ b/components/Onboarding.tsx
@@ -68,35 +68,38 @@ export function Onboarding({ onComplete }: Props) {
 
           <form onSubmit={handleSubmit} className="space-y-4">
             <div className="space-y-1">
-              <Label htmlFor="pi">PI first name</Label>
+              <Label htmlFor="pi">
+                PI first name <span className="text-muted-foreground font-normal">(optional)</span>
+              </Label>
               <Input
                 id="pi"
                 type="text"
                 value={piFirstName}
                 onChange={e => setPiFirstName(e.target.value)}
-                required
                 placeholder="e.g. Smith"
               />
             </div>
             <div className="space-y-1">
-              <Label htmlFor="bldg">Building code</Label>
+              <Label htmlFor="bldg">
+                Building code <span className="text-muted-foreground font-normal">(optional)</span>
+              </Label>
               <Input
                 id="bldg"
                 type="text"
                 value={bldgCode}
                 onChange={e => setBldgCode(e.target.value)}
-                required
                 placeholder="e.g. EER"
               />
             </div>
             <div className="space-y-1">
-              <Label htmlFor="lab">Lab</Label>
+              <Label htmlFor="lab">
+                Lab <span className="text-muted-foreground font-normal">(optional)</span>
+              </Label>
               <Input
                 id="lab"
                 type="text"
                 value={lab}
                 onChange={e => setLab(e.target.value)}
-                required
                 placeholder="e.g. 3.822"
               />
             </div>
diff --git a/server/src/db/schema.sql b/server/src/db/schema.sql
index d514253..a8b5d2a 100644
--- a/server/src/db/schema.sql
+++ b/server/src/db/schema.sql
@@ -112,10 +112,16 @@ CREATE INDEX IF NOT EXISTS protocols_user_id_idx ON protocols(user_id);
 -- User profile — lab defaults pre-filled on chemical entries
 CREATE TABLE IF NOT EXISTS user_profile (
   user_id TEXT NOT NULL PRIMARY KEY REFERENCES "user"("id") ON DELETE CASCADE,
-  pi_first_name TEXT NOT NULL,
-  bldg_code TEXT NOT NULL,
-  lab TEXT NOT NULL,
+  pi_first_name TEXT,
+  bldg_code TEXT,
+  lab TEXT,
   contact TEXT,
   created_at TIMESTAMPTZ DEFAULT NOW(),
   updated_at TIMESTAMPTZ DEFAULT NOW()
 );
+
+-- Allow existing deployments to have nullable profile fields.
+-- DROP NOT NULL on an already-nullable column is a no-op in Postgres.
+ALTER TABLE user_profile ALTER COLUMN pi_first_name DROP NOT NULL;
+ALTER TABLE user_profile ALTER COLUMN bldg_code DROP NOT NULL;
+ALTER TABLE user_profile ALTER COLUMN lab DROP NOT NULL;
diff --git a/server/src/routes/profile.ts b/server/src/routes/profile.ts
index 95103b9..c323c58 100644
--- a/server/src/routes/profile.ts
+++ b/server/src/routes/profile.ts
@@ -21,9 +21,8 @@ router.get('/', requireAuth, async (req, res) => {
 
 router.post('/', requireAuth, async (req, res) => {
   const { pi_first_name, bldg_code, lab, contact } = req.body;
-  if (!pi_first_name || !bldg_code || !lab) {
-    return res.status(400).json({ error: 'pi_first_name, bldg_code, and lab are required' });
-  }
+  // Coerce empty strings to null so the DB stores a clean null rather than "".
+  const toNull = (v: unknown) => (typeof v === 'string' && v.trim() !== '' ? v.trim() : null);
   try {
     const result = await pool.query(
       `INSERT INTO user_profile (user_id, pi_first_name, bldg_code, lab, contact)
@@ -35,7 +34,7 @@ router.post('/', requireAuth, async (req, res) => {
          contact = EXCLUDED.contact,
          updated_at = NOW()
        RETURNING *`,
-      [req.user!.id, pi_first_name, bldg_code, lab, contact || null]
+      [req.user!.id, toNull(pi_first_name), toNull(bldg_code), toNull(lab), toNull(contact)]
     );
     res.json(result.rows[0]);
   } catch {