diff --git a/code/controllers/subsystems/chemistry.dm b/code/controllers/subsystems/chemistry.dm
index 549ac0de9b..82f6f824b3 100644
--- a/code/controllers/subsystems/chemistry.dm
+++ b/code/controllers/subsystems/chemistry.dm
@@ -35,6 +35,18 @@ SUBSYSTEM_DEF(chemistry)
 			if(!chemical_reactions_by_id[reagent_id])
 				chemical_reactions_by_id[reagent_id] = list()
 			chemical_reactions_by_id[reagent_id] += D
+
+	// Init addiction probabilities
+	// The calcualation for the value fed into prob every tick that an addictive chemical is
+	// metabolized is quite complex, but it is based off values that are constant post-start up.
+	// We'll initialize those values into a global list here.
+	for(var/path in subtypesof(/datum/reagent))
+		var/datum/reagent/R = new path()
+		if(!R.addictiveness)
+			continue
+		GLOB.addiction_probs_ += R.type
+		GLOB.addiction_probs_[R.type] = 100 * (1 - (Root(R.addiction_median_dose/R.metabolism, 0.5 )))
+
 	return ..()
 
 /datum/controller/subsystem/chemistry/fire(resumed = FALSE)
diff --git a/code/modules/reagents/Chemistry-Metabolism.dm b/code/modules/reagents/Chemistry-Metabolism.dm
index a9286fca89..7c25bf34e0 100644
--- a/code/modules/reagents/Chemistry-Metabolism.dm
+++ b/code/modules/reagents/Chemistry-Metabolism.dm
@@ -57,7 +57,7 @@
 	var/datum/reagent/addict_reagent = (ref_reagent.parent_substance ? new ref_reagent.parent_substance : ref_reagent)
 
 	if(!is_type_in_list(addict_reagent, addiction_levels))
-		var/add_addiction_prob = 100 * (1 - (Root(0.5, ref_reagent.addiction_median_dose/removed)))
+		var/add_addiction_prob = GLOB.addiction_probs_[ref_reagent.type]
 		if(prob(add_addiction_prob))
 			addiction_levels.Add(addict_reagent)
 			addiction_levels[addict_reagent] = 10
diff --git a/code/modules/reagents/Chemistry-Reagents.dm b/code/modules/reagents/Chemistry-Reagents.dm
index ea56176062..7e1ba3427a 100644
--- a/code/modules/reagents/Chemistry-Reagents.dm
+++ b/code/modules/reagents/Chemistry-Reagents.dm
@@ -1,3 +1,5 @@
+GLOBAL_LIST_EMPTY(addiction_probs_)
+
 /datum/reagent
 	var/name = "Reagent"
 	var/description = "A non-descript chemical."