The best replacement for whey is soy protein.

The best alternatives to whey are rated as following:
★★★★★  soy protein
★★★★★  casein
★★★★  soy
★★★★  creatine
★★  egg protein
★★  muscle milk
★★  casein protein
★  whey isolate
★  soy protein powder
★  hemp protein
★  mass gainer
★  hemp
★  casein in the morning
★  milk
★  isolate
★  protein
  pea protein
  plant protein
  rice protein
  casein bodybuilding
  syntha 6
  weight gainer
  egg white protein
  soy better
  vegetable protein
  soy protein shake
  isolate protein
  casein allergy
  meat protein
  whey protein
  protein powder
  soy protein isolate
  protein shakes
  cow whey
  vegan protein
  hemp protein powder

Your alternative for whey is not listed? Suggest!
Speaking about whey, one probably shouldn't forget about creatine.

Other search terms related to whey and their ratings are:

★★★★★ creatine
★★★★★ casein
★★★★ milk
★★★ soy
★★ bcaa
casein protein powder
stevia protein powder
amino acids
You have in mind a companion for whey and it is not yet here? Propose!

Google Trends

Scale is based on the average worldwide traffic of whey in all years. Click on graph for more.
soy protein