diff --git a/NEWS.md b/NEWS.md
index 5ddd7206..bb35245d 100644
--- a/NEWS.md
+++ b/NEWS.md
@@ -1,5 +1,9 @@
 # teal.modules.hermes 0.1.5.9002
 
+### Miscellaneous
+* Added placeholders for `assaySpec`, `adtteSpec` and `geneSpec` inputs when no option is selected.
+* Disabled the select input for `assaySpec` and `adtteSpec` when there are no options available.
+
 # teal.modules.hermes 0.1.5
 
 ### Bug Fixes
diff --git a/R/adtteSpec.R b/R/adtteSpec.R
index 9e3d33c5..5feca2a3 100644
--- a/R/adtteSpec.R
+++ b/R/adtteSpec.R
@@ -107,10 +107,14 @@ adtteSpecInput <- function(inputId, # nolint
 
   ns <- NS(inputId)
 
-  selectInput(
-    inputId = ns("paramcd"),
-    label = label_paramcd,
-    choices = ""
+  tagList(
+    selectizeInput(
+      inputId = ns("paramcd"),
+      label = label_paramcd,
+      choices = "",
+      options = list(placeholder = "- Nothing selected -")
+    ),
+    include_js_files("dropdown.js")
   )
 }
 
@@ -295,6 +299,12 @@ adtteSpecServer <- function(id, # nolint
       sort(unique(adtte_joined[[adtte_vars$paramcd]])) # Order should not matter.
     })
 
+    # Start by disabling selection, will be overriden if there are valid choices.
+    session$sendCustomMessage(
+      "toggle_dropdown",
+      list(input_id = session$ns("paramcd"), disabled = TRUE)
+    )
+
     # Once available endpoints change, we update choices (and also the selection
     # if nothing was selected earlier) and warn the user if previous endpoint is
     # not available.
@@ -310,11 +320,15 @@ adtteSpecServer <- function(id, # nolint
         ))
         ""
       }
-      updateSelectInput(
-        session,
+      updateSelectizeInput(
         "paramcd",
         choices = paramcd_choices,
-        selected = new_selected
+        selected = new_selected,
+        session = session
+      )
+      session$sendCustomMessage(
+        "toggle_dropdown",
+        list(input_id = session$ns("paramcd"), disabled = (length(paramcd_choices) == 0))
       )
     })
 
diff --git a/R/assaySpec.R b/R/assaySpec.R
index 55d4c7a3..9c72ab7d 100644
--- a/R/assaySpec.R
+++ b/R/assaySpec.R
@@ -16,10 +16,16 @@ assaySpecInput <- function(inputId, # nolint
   assert_string(label_assays, min.chars = 1L)
 
   ns <- NS(inputId)
-  selectInput(
-    inputId = ns("name"),
-    label = label_assays,
-    choices = ""
+  tagList(
+    selectizeInput(
+      inputId = ns("name"),
+      label = label_assays,
+      choices = character(0),
+      options = list(
+        placeholder = "- Nothing selected -"
+      )
+    ),
+    include_js_files("dropdown.js")
   )
 }
 
@@ -119,15 +125,18 @@ assaySpecServer <- function(id, # nolint
           hermes::h_short_list(removed_assays), "as per app specifications"
         ))
       }
+      if (length(remaining_assays) == 0) {
+        remaining_assays <- character(0)
+      }
       remaining_assays
     })
 
     observeEvent(choices(), {
       choices <- choices()
-      updateSelectInput(
-        session,
-        "name",
-        choices = choices
+      updateSelectizeInput(session, "name", choices = choices)
+      session$sendCustomMessage(
+        "toggle_dropdown",
+        list(input_id = session$ns("name"), disabled = (length(choices) == 0))
       )
     })
 
diff --git a/R/geneSpec.R b/R/geneSpec.R
index deef6e21..f6ea0b9f 100644
--- a/R/geneSpec.R
+++ b/R/geneSpec.R
@@ -107,6 +107,7 @@ geneSpecInput <- function(inputId, # nolint
         multiple = TRUE,
         selected = 1,
         options = list(
+          placeholder = "- Nothing selected -",
           render = I("{
           option: function(item, escape) {
               return '<div> <span style=\"font-size: inherit;\">' + item.label + '</div>' +
diff --git a/inst/js/dropdown.js b/inst/js/dropdown.js
new file mode 100644
index 00000000..1937f1a4
--- /dev/null
+++ b/inst/js/dropdown.js
@@ -0,0 +1,26 @@
+// Toggle enable/disable of a dropdown
+//
+// This can be done by `{shinyjs::enable/disable}` R package if that package is
+// added to the dependecies.
+// Parameters
+//  `message` should have `input_id` string and `disabled` logical properties.
+Shiny.addCustomMessageHandler('toggle_dropdown', function(message) {
+  const input_id = message.input_id;
+  const disabled = message.disabled;
+
+  let el = document.getElementById(input_id)
+
+  if (el.selectize !== undefined) {
+    el = el.selectize;
+    if (disabled) {
+      el.lock();
+      el.disable();
+    } else {
+      el.unlock();
+      el.enable();
+    }
+  } else {
+    // Fallback in case selectize is not enabled
+    el.disabled = disabled ? 'disabled' : '';
+  }
+});
diff --git a/tests/testthat/_snaps/assaySpec.md b/tests/testthat/_snaps/assaySpec.md
index ddce3e42..d1dfc3af 100644
--- a/tests/testthat/_snaps/assaySpec.md
+++ b/tests/testthat/_snaps/assaySpec.md
@@ -6,8 +6,34 @@
       <div class="form-group shiny-input-container">
         <label class="control-label" id="my_assay-name-label" for="my_assay-name">Please select the best assay</label>
         <div>
-          <select id="my_assay-name"><option value="" selected></option></select>
-          <script type="application/json" data-for="my_assay-name">{"plugins":["selectize-plugin-a11y"]}</script>
+          <select class="shiny-input-select form-control" id="my_assay-name"></select>
+          <script type="application/json" data-for="my_assay-name">{"placeholder":"- Nothing selected -","plugins":["selectize-plugin-a11y"]}</script>
         </div>
       </div>
+      <script>// Toggle enable/disable of a dropdown
+      //
+      // This can be done by `{shinyjs::enable/disable}` R package if that package is
+      // added to the dependecies.
+      // Parameters
+      //  `message` should have `input_id` string and `disabled` logical properties.
+      Shiny.addCustomMessageHandler('toggle_dropdown', function(message) {
+        const input_id = message.input_id;
+        const disabled = message.disabled;
+      
+        let el = document.getElementById(input_id)
+      
+        if (el.selectize !== undefined) {
+          el = el.selectize;
+          if (disabled) {
+            el.lock();
+            el.disable();
+          } else {
+            el.unlock();
+            el.enable();
+          }
+        } else {
+          // Fallback in case selectize is not enabled
+          el.disabled = disabled ? 'disabled' : '';
+        }
+      });</script>
 
diff --git a/tests/testthat/test-adtteSpec.R b/tests/testthat/test-adtteSpec.R
index d70a2571..7a24c219 100644
--- a/tests/testthat/test-adtteSpec.R
+++ b/tests/testthat/test-adtteSpec.R
@@ -175,7 +175,15 @@ test_that("adtteSpecInput creates expected HTML", {
     label_paramcd = "Select right PARAMCD"
   ))
 
-  expect_tag(result)
+  expect_class(result, "shiny.tag.list")
+  expect_length(result, 2)
+
+  # First element is a div tag
+  expect_tag(result[[1]])
+
+  # Second element is the contents of a single js file
+  expect_length(result[[2]], 1)
+  expect_tag(result[[2]][[1]])
 })
 
 # nolint start