The AlgaeCal Strontium citrate dosage is 680 mg/day. I take it at night. I'm thrilled that my numbers have improved but having a hard time understanding why my ARNP endocrinologist is still pushing Reclast in spite of it. You are definitely right about the scary side-effects. Even though supposedly they are fairly rare, if you are the one that ends up with long bone fracture, horrid aches and pains or jaw osteonecrosis that isn't much comfort! I started OsteoStrong 15 months ago about the same time as the AlgaeCal so I have no idea if one was more efficacious than the other.