Algas calcareas powder comes from mineralized algae, mostly Lithothamnion species. It supplies calcium plus the other trace minerals naturally present in the algae.
People take it as a daily calcium source, especially when diet falls short. Taking it with a meal helps the body absorb it better. A typical day's serving provides 500 to 800 mg of elemental calcium, but check your product label because amounts differ between brands.
Space calcium doses at least 2 hours away from certain antibiotics like tetracyclines or fluoroquinolones, since calcium can block their absorption. Too much can lead to kidney stones or high blood calcium. If you have kidney trouble or a history of stones, speak with a healthcare provider before use. Sticking to recommended daily amounts makes it generally safe during pregnancy.