The best replacement for vitamin d3 is d2.

The best alternatives to vitamin d3 are rated as following:
★★★★★  d2
★★★  d
★★★  vitamin d
★★  vitamin d2
★  cholecalciferol
  vitamin d3
  d2 better
  other vitamin d
  flu shot
  d what is the difference

Your alternative for vitamin d3 is not listed? Suggest!
Speaking about vitamin d3, one probably shouldn't forget about calcium.

Other search terms related to vitamin d3 and their ratings are:

★★★★★ calcium
★★★★ k2
★★ calcium and magnesium
★★ fish oil
k1 and k2
vitamin k2
You have in mind a companion for vitamin d3 and it is not yet here? Propose!

Google Trends

Scale is based on the average worldwide traffic of vitamin d3 in all years. Click on graph for more.
vitamin d3