diff --git a/src/gadgets/insert.rs b/src/gadgets/insert.rs
index 1f69cb24..f618eb2b 100644
--- a/src/gadgets/insert.rs
+++ b/src/gadgets/insert.rs
@@ -37,8 +37,7 @@ impl<F: Extendable<D>, const D: usize> CircuitBuilder<F, D> {
         self.sub(one, not_equal)
     }
 
-    /// Inserts a `Target` in a vector at a non-deterministic index. This is done by rotating to the
-    /// left, inserting at 0 and then rotating to the right.
+    /// Inserts a `Target` in a vector at a non-deterministic index.
     /// Note: `index` is not range-checked.
     pub fn insert(
         &mut self,
@@ -49,7 +48,11 @@ impl<F: Extendable<D>, const D: usize> CircuitBuilder<F, D> {
         let mut already_inserted = self.zero();
         let mut new_list = Vec::new();
 
-        for i in 0..v.len() {
+        // Add a dummy value at the end (which will never be used).
+        let mut new_v = v.clone();
+        new_v.push(ExtensionTarget([Target::PublicInput{index: 0}; D]));
+
+        for i in 0..new_v.len() {
             let one = self.one();
 
             let cur_index = self.constant(F::from_canonical_usize(i));
@@ -58,12 +61,14 @@ impl<F: Extendable<D>, const D: usize> CircuitBuilder<F, D> {
             let mut new_item = self.zero_extension();
             new_item = self.scalar_mul_add_extension(insert_here, element, new_item);
             if i > 0 {
-                new_item = self.scalar_mul_add_extension(already_inserted, v[i - 1], new_item);
+                new_item = self.scalar_mul_add_extension(already_inserted, new_v[i - 1], new_item);
             }
             already_inserted = self.add(already_inserted, insert_here);
 
             let not_already_inserted = self.sub(one, already_inserted);
-            new_item = self.scalar_mul_add_extension(not_already_inserted, v[i], new_item);
+            // On the last round, v[i] is the dummy value, but by that round not_already_inserted
+            // will always be 0.
+            new_item = self.scalar_mul_add_extension(not_already_inserted, new_v[i], new_item);
 
             new_list.push(new_item);
         }