Chlorotrianisene-d 9 is the deuterium labeled Chlorotrianisene. Chlorotrianisene is a long-acting non-steroidal estrogen and an orally active estrogen receptor modulator. Chlorotrianisene exhibits antiestrogenic activity. Chlorotrianisene potently inhibits the enzyme COX-1 and inhibits platelet aggregation in whole blood.