The strong stat restore potion is a one dose potion only available in Daemonheim. Using the potion restores stats (excluding Prayer and Summoning) by 10 + 24% of skill level.
It is made by adding Buckthorn and Red moss to a Vial of water. This requires level 78 Herblore and grants 173.5 experience in Herblore. This potion can only be made in dungeons with complexity level ≥5.