Scientists may have found a natural anti-anxiety supplement

This post originally appeared on Medical News Bulletin.

There may be a natural anti-anxiety supplement available, according to a recent study. Beta-sitosterol, an already established natural cholesterol-lowering supplement, has shown promising anti-anxiety effects.

In the study published May 18, 2021, researchers from the Weizmann Institute of Science tested the effect of beta-sitosterol on the anxious responses of mice placed in stressful settings. Although their findings are preliminary, the authors state that beta-sitosterol may have the potential to be used as a natural anti-anxiety supplement, but clinical trials will first need to test these effects in people.

Anxiety is a natural part of the “fight-or-flight” response in humans; it helps produce a survival response to dangerous situations. But in some individuals, the anxious response can be overactive and become debilitating.

There are anxiety medications available that alter hormones and transmission systems used by the nervous system. But these medications can have unwanted side-effects. To reduce adverse side-effects, studies have investigated different pharmaceutical targets called importins, which transport messages from the cell cytoplasm into the nuclei.

The research group at the Weizmann Institute of Science previously identified that importin alpha 5 plays a role in anxiety response.1 When the importin alpha 5 gene was inactivated in the hippocampus of mice – the area of the brain that controls emotional responses – there was a significant decline in anxiety-related behaviours. They used genetic mapping tools to identify a compound that induced similar genetic expression, beta-sitosterol.

What is beta-sitosterol?

Beta-sitosterol is a phytosterol that is naturally found in grains, cereals, and fruits, including avocados. It is already sold as a nutraceutical used for lowering cholesterol.

Beta-sitosterol was administered in mice and researchers noted downregulation of the Fos gene.1 High expression of the Fos gene in the hippocampus, blood, and amygdala – the area of the brain that triggers the “fight-or-flight” response – has been associated with anxiety.

Mice injected with beta-sitosterol were less hesitant to respond to fearful conditions compared to those that were not. The mice given beta-sitosterol also showed reduced expression of Fos in the prefrontal cortex and hippocampus, but not the amygdala. The researchers suggested that beta-sitosterol may reduce the contextual fear associated with anxiety.

Beta-sitosterol and anti-anxiety medication

A known anti-anxiety drug, fluoxetine, a selective serotonin reuptake inhibitor, was tested with beta-sitosterol. When used together, the dose of fluoxetine could be reduced while achieving the same anti-anxiety effect.1 They also observed that lower doses of fluoxetine and beta-sitosterol given together were more impactful than if each medication was given alone. These results suggest that a synergistic effect may be at play, where fluoxetine and beta-sitosterol work together to reduce anxiety.

The researchers suggest that beta-sitosterol may also act synergistically with other selective serotonin reuptake inhibitors. If true, this could provide relief for those struggling with adverse effects from their anti-anxiety medications.

Beta-sitosterol needs to be tested for effectiveness and safety in humans before it can be prescribed as a true natural anti-anxiety supplement. If you are looking for anxiety relief, speak with your doctor before taking any medication or supplements.


  1. Panayotis, N. et al. (2021). Beta-sitosterol reduces anxiety and synergizes with established anxiolytic drugs in mice. Cell Reports Medicine; 2(5): 100281. Doi:10.1016/j.xcrm.2021.100281.
  2. Image by newsong from Pixabay 

This post originally appeared on Medical News Bulletin.

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