More than 300 million people throughout the world are estimated to live with depression. Symptoms include a persistent worsened mood, disinterest in activities that used to bring joy, feelings of worthlessness, and appetite and sleep issues. Many over the counter meds are touted as depression treatments, but how many of them are actually effective is unclear. A new study tried to identify which of these products are promising.

Research recently published in the journal Frontiers in Pharmacology looked at existing studies on the impacts of herbal medications and dietary supplements on depression in people aged 18 to 60.

Rachael Frost, the study’s first author and senior lecturer at Liverpool John Moores University, says, “Depression is increasingly common, to the extent that it is sometimes described as an epidemic… Many of us know someone who struggles with minor or moderate levels of depression, or we may struggle from depressive symptoms ourselves. Often, we will try many things to help, such as antidepressants, talking therapies, meditation, or exercise. One common treatment people try is OTC products which are widely available and accessible from supermarkets, pharmacies, health food shops, and online.”

The team whittled down the available studies to 209 trials that focused on 64 of these products, some of which had limited evidence. Of those with more robust coverage, St. John’s Wort, saffron, probiotics, and vitamin D were found to be more effective than placebo. Products with more limited evidence that still may be promising included lavender, zinc, tryptophan, rhodiola, and lemon balm. In two trials each, bitter orange, Persian lavender, and chamomile tea showed positive results, as well.

Because lavender, lemon balm, and chamomile are so commonly used, the researchers say more study into them is warranted. Echium falls into this category, too.

The team believes it’s important for future studies to determine how well these products work as a supplemental treatment to antidepressants, as well as with therapy, which wasn’t included much in the available literature. The safety of this approach must also be better understood.

Frost says, “It’s good news that very few safety concerns arose from any of these products, whether they were taken alone or in combination with antidepressants. However, a healthcare professional should always be consulted on whether a product might interact with something else you are taking. A higher standard of safety reporting in trials is essential – only 145 (69%) of the examined studies fully reported any side effects from the products.”