People with Tourette syndrome suffer significantly less from their tics when they take a daily supplement containing L-theanine and vitamin B6. This is shown in a small Italian trial published in Nutrients in 2022.

Study
Researchers from Catania University recruited 34 children and teenagers aged 4-17. All children had Tourette syndrome but were not taking any medication. The trial lasted eight weeks.

The researchers divided the participants into a control group and an experimental group.

The participants in the control group attended a weekly meeting with their parents where they received information about their condition.

The participants in the experimental group took a daily supplement containing 200 milligrams of L-theanine and 2.8 milligrams of vitamin B6. The participants were therefore aware that they were taking a supplement.

The researchers specifically tested this combination because L-theanine reduces feelings of stress. Vitamin B6 inhibits anxiety, possibly because the vitamin plays a role in the biosynthesis of dopamine, serotonin, and GABA.

Results
The Italians determined the severity of their subjects' tics using the Yale Global Tic Severity Scale [YGTSS]. This is a standardized questionnaire for physicians.

The table below shows how to interpret YGTSS scores. Click on it for a larger version.

In the control group, the average YGTSS score decreased by a non-significant 18 percent. The score remained within the mild-to-moderate range.

In the experimental group, the average score dropped by 44 percent. This decrease was indeed statistically significant. Moreover, the severity of the tics decreased from 'moderate' to 'mild'. The decrease was therefore not only statistically significant but also clinically significant.

The researchers also looked at the effect of supplementation on anxiety. No results were found.

Conclusion
"Complementary supplementation with vitamin B6 and L-theanine can help in the treatment of tic disorders", the Italians summarize. "Despite this finding, further placebo-controlled trials are needed."