diff --git a/code/modules/cm_aliens/XenoStructures.dm b/code/modules/cm_aliens/XenoStructures.dm
index e78756f1eda6..88b7dd07b666 100644
--- a/code/modules/cm_aliens/XenoStructures.dm
+++ b/code/modules/cm_aliens/XenoStructures.dm
@@ -162,11 +162,11 @@
 	var/mob/living/carbon/human/H = AM
 	// Wait doesn't this stack slows if you get dragged over it? What's going on here?
 	if(istype(H) && !H.ally_of_hivenumber(hivenumber))
-		H.next_move_slowdown = H.next_move_slowdown + slow_amt
+		H.next_move_slowdown = max(H.next_move_slowdown, slow_amt)
 		return .
 	var/mob/living/carbon/xenomorph/X = AM
 	if(istype(X) && !X.ally_of_hivenumber(hivenumber))
-		X.next_move_slowdown = X.next_move_slowdown + slow_amt
+		X.next_move_slowdown = max(X.next_move_slowdown, slow_amt)
 		return .
 
 /obj/effect/alien/resin/sticky/proc/forsaken_handling()
diff --git a/code/modules/cm_aliens/weeds.dm b/code/modules/cm_aliens/weeds.dm
index 4be1ce63ac25..45c78b979105 100644
--- a/code/modules/cm_aliens/weeds.dm
+++ b/code/modules/cm_aliens/weeds.dm
@@ -186,7 +186,7 @@
 	SEND_SIGNAL(crossing_mob, COMSIG_MOB_WEED_SLOWDOWN, slowdata, src)
 	var/final_slowdown = slowdata["movement_slowdown"]
 
-	crossing_mob.next_move_slowdown += POSITIVE(final_slowdown)
+	crossing_mob.next_move_slowdown = max(crossing_mob.next_move_slowdown, POSITIVE(final_slowdown))
 
 // Uh oh, we might be dying!
 // I know this is bad proc naming but it was too good to pass on and it's only used in this file anyways