Here's the original site I pinned in the search for deodorant recipes. I admit, I am skeptical of this and will update once I've used it for a few days. I tweaked the recipe a bit based on reading several other online versions.
Here's my version:
1/4 cup arrowroot flour/starch (Bob's Red Mill brand from Whole Foods)
1/4 cup baking soda
4 Tbs coconut oil (Nutiva brand)
10 shakes grapefruit essential oil (from Whole Foods)
Mix the arrowroot powder and baking soda, stir in oils. Warm in microwave enough to liquefy the coconut oil and stir again. Pour into container, then put in fridge to solidify.
I put it in a container from The Container Store, but I've read that it works great poured into an empty deodorant package as well.