The Weak artisan's Potion is a one dose potion only available in the Dungeoneering skill. Using the potion boosts Smithing, Crafting, Fletching, Construction and Firemaking by 3 + 2% of levels. This effect does not stack. The boost is just 3 for skills under level 50, and from 50 upwards the boost is 4.
It is made by adding Valerian and Red moss to a Vial of water. This requires level 27 Herblore and gives 68.5 experience. This potion can only be made in dungeons with complexity level ≥5.