If you’ve been reading the 4-Hour Body by Tim Ferriss, you probably know one of the things he recommends is a fermented cod liver oil, vitamin rich butter combination.

This combination is unique for several reasons:

• The butter is a special vitamin rich butter that comes only from grass-fed cows eating fast-growing spring grass. It turns out to be rich in Vitamin K, and it one of the only food sources for Vitamin K.
• Cod liver oil normally has some great health benefits, and fermented cod liver oil is even higher in vitamin D.

This hard to find combination can be found on Amazon with Green’s Pastures’ Blue Ice Royal Butter Oil / Fermented Cod Liver Oil Blend – Capsules.