I've always discouraged taking 5-HTP for PMDD because of the many underlying reasons women experience PMDD in the first place. Food sensitivities, malabsorption, an autoimmune disease or just a bad diet. It's best to investigate those causes then to think a supplement may be a solution. The probability is 5-HTP or tryptophan in a powder or capsule may unexpectently trigger a cascade of adverse reactions with other medications.
If you think 5-HTP will help with PMDD or severe PMS, you may want to rethink it, especially if you're taking an SSRI.
Selective serotonin reuptake inhibitors are generally used for depression, premenstrual dysphoric syndrome (PMDD), bulimia nervosa, obsessive compulsive disorder, (OCD) and weight loss. 5-HTP is converted to serotonin, so medications that increase serotonin may increase the risk of developing a rare but serious condition called serotoninsyndrome-symptoms include confusion, muscle rigidity, hot flashes, changes in blood pressure and heart rate, and coma.