Young women experiencing premenstrual syndrome are likely to benefit from supplementation with high doses of vitamin B1 or thiamine. Vitamin B1 has little effect on the physical symptoms of premenstrual syndrome, but a significant effect on the psychological symptoms.

Study
In 2013, researchers from the Jahrom University of Medical Sciences in Iran published a small trial in the Global Journal of Health Science, involving 80 female students with a mild form of premenstrual syndrome. The researchers divided the students into two equal-sized groups.

In the week before their period, the students in the experimental group took a supplement containing 100 milligrams of vitamin B1 twice a day. This meant they took 200 milligrams of vitamin B1 per day for seven days.

The students in the placebo group took a placebo.

The week before menstruation is the late luteal phase of the cycle. During this period, progesterone and estrogen concentrations drop sharply. According to gynecologists, this hormonal fluctuation causes the symptoms associated with premenstrual syndrome.

Results
The impact of supplementation on the physical symptoms of premenstrual syndrome was modest. The supplementation group reported, among other things, slightly fewer headaches and less bloating.

The effects of supplementation on the mental symptoms of premenstrual syndrome are shown in the table below.

The psychological effects of supplementation were significantly greater. The students experienced significantly less anxiety, depression, poor sleep, fatigue, and difficulty concentrating.

Conclusion
"Using vitamin B1 in luteal phase could reduce overall severity of physical and mental symptoms of the premenstrual syndrome - needless of using it in the entire menstrual cycle", the Iranians write.

"Furthermore, vitamin B1 has no side effect and does not change menstrual bleeding pattern. Therefore, vitamin B1 is recommended for treatment of the premenstrual syndrome."