Reviews of the evidence have shown that there is little meaningful evidence to support the use of evening primrose oil (EPO) for breast tenderness or dermatitis.1, 2 But one review has suggested a benefit (versus drugs used for treatment) for breast pain. It should be noted that the studies cited within these reviews still offer many conflicts.2
There is only limited data on the use of primrose oil for schizophrenia but a Cochrane review of this application found no clear effect of EPO supplementation on schizophrenia.3
1. Stonemetz D. A Review of the Clinical Efficacy of Evening Primrose. Holistic Nursing Practice. 2008;22(3):171-4.
2. Sarayloo K, Najmabadi KM, Ghazanfarpour M. EFFECTS OF THE EVENING PRIMROSE OIL ON WOMEN’S MASTALGIA: A SYSTEMATIC REVIEW OF RANDOMIZED CONTROLLED TRIALS. The Malaysian Journal of Nursing. 2017;9(2):28-35.
3. Joy CB, Mumby-Croft R, Joy LA. Polyunsaturated fatty acid (fish or evening primrose oil) for schizophrenia. The Cochrane database of systematic reviews. 2000(2):Cd001257.