Greater blue mutagen is an alchemy ingredient in The Witcher 3: Wild Hunt that is used to augment abilities and are more effective than their lesser and regular counterparts. When placed in the diamond-shaped slot in the character panel, they give +10% to sign intensity, which increases by 10 up to a max of +40% if all 3 skills attached to it are blue.
Like all greater mutagens they can only be crafted outside of the Blood and Wine expansion.
Blood and Wine expansion[]
With Blood and Wine, the player can now craft these with other ingredients that don't include blue mutagens. One can also be found as non-monster loot during the quest Turn and Face the Strange.
Crafting Requirements 
Crafting Requirements
Notes[]
- In an undocumented change for Patch 1.08, all mutagen icons were changed. However, there was still a bug for those on Steam and Origin that didn't reflect this and was later fixed in Patch 1.22. Despite this, some may still see the original icons instead, even with a fully patched game.