I've been taking Primal Harvest Collagen and Primal Harvest Mind Fuel. I've noticed a positive difference with both. It's not immediate, but gradual, which is to be expected. When I was taking another supplement, I called customer Service and they immediately stopped the auto-ship and went out of their way to do so. I've been very satisfied with Primal Harvest. Any questions I've had and sent an email were quickly answered.