diff --git a/cf-lib/data/Technology.lua b/cf-lib/data/Technology.lua
index d1d1dbb..d6d82f1 100644
--- a/cf-lib/data/Technology.lua
+++ b/cf-lib/data/Technology.lua
@@ -132,6 +132,11 @@ end
 --- Adds a recipe unlock to the technology
 --- @param recipeName string The name of the recipe to unlock
 function Technology:addRecipe(recipeName)
+    for _, effect in pairs(self.prototype.effects) do
+        if effect.type == "unlock-recipe" and effect.recipe == recipeName then
+            return
+        end
+    end
     table.insert(self.prototype.effects, { type = "unlock-recipe", recipe = recipeName })
 end