Strictly speaking, it depends on the situation. Astaxanthin in natural Haematococcus pluvialis can be taken for a long time, but it also depends on the culture method of Haematococcus pluvialis. If it is an open culture, it is easy to introduce impurities, and long-term use of astaxanthin containing impurities may cause allergies, phlebitis and liver damage. It is suggested to choose astaxanthin produced by closed culture, which has high purity and can be taken for a long time, such as astaxanthin in Japan and Algatech in Israel.