Depression And Supplements: What Really Works?

Depression is a common and growing mental disorder that can cause profound sadness, lack of energy, changes in sleep and appetite, among other symptoms. It has several causes, including genetics, stress, and physical illness, and affects both mental and physical health. In addition to medications and therapies, many people use natural products, such as herbs and supplements, to alleviate symptoms. Studies show that substances such as omega-3s, St. John's wort, and vitamin D have promising effects, but more research is still needed to confirm their effectiveness and safety.

Depression is a fairly common mental disorder that is on the rise worldwide. Depending on the country and how it is measured, so-called major depression can affect 2% to 21% of the population. It is characterized by symptoms such as profound sadness, lack of interest in previously enjoyable activities, changes in appetite, difficulty sleeping, constant fatigue, and difficulty concentrating.

To be considered a clinical case, a person must experience at least five of these symptoms for two weeks or more, and these symptoms must have a significant impact on their life. In other words, it's not just "feeling sad," it's something deeper and more persistent, disrupting personal, professional, and social life.

In the United Kingdom, for example, about 11% of the population reports mild symptoms of depression, while 4% have moderate symptoms and 3% have severe symptoms. Depression can arise from a combination of factors, such as genetic predisposition, trauma or intense stress, chronic physical illness, and others.

Science is also trying to understand what happens in the body of people with depression, and it is already known that there are changes in brain chemicals, such as serotonin and dopamine, as well as hormonal changes and signs of persistent inflammation in the body. There is also evidence that the gut microbiota (the good bacteria in the gut) can influence the brain through an "axis" that connects the intestine and nervous system.

Depression doesn't just affect emotional well-being. It can worsen physical health, increasing the risk of heart disease, diabetes, and other chronic conditions. It also causes social and economic harm, as many people with depression end up taking time off work.

Worldwide, it is estimated that depression is responsible for 16% of the loss of quality life years, a cost to the global economy of trillions of dollars. This highlights the urgency of finding more effective ways to prevent and treat depression.

Currently, health guidelines in the United Kingdom recommend that treatment for depression begin, whenever possible, with the least invasive approaches. These include therapy (individual or group), physical exercise, and even self-help techniques. If necessary, your doctor may also suggest antidepressants.

Ideally, treatment should be decided jointly with the patient, taking into account what makes the most sense for each case. However, in practice, less than 14% of people with depressive symptoms in the UK receive any type of treatment. Many face difficulties, such as long waits for therapy sessions.

Therefore, it's not uncommon for people to try to manage their symptoms on their own. Many turn to natural products, such as medicinal herbs, vitamins, and supplements, which can be purchased without a prescription.

A famous example is St. John's wort (Hypericum perforatum), used for centuries for its potential antidepressant effects. Other products, such as lavender, chamomile, omega-3s, probiotics, and vitamin D, have also been studied for their positive effects on mood and mental health. These products are part of what we call self-care, strategies that people adopt themselves to improve their health and well-being.

But do these products really work? To answer this question, researchers at Liverpool John Moores University, UK, conducted a major scientific review to discover what has been studied so far.

They searched medical databases for all clinical trials conducted through December 2022 on over-the-counter products used to treat depressive symptoms in adults aged 18 to 60. In total, they found more than 23,000 studies, of which 209 were analyzed in detail.

The products with the most studies and the most evidence were:

1. Omega-3

   
   

2. St. John's wort (Hypericum perforatum)

   
   

3. Saffron

   
   

4. Probiotics

   
   

5. Vitamin D.

Other substances that have also shown promising results but still require further research include folic acid, lavender, zinc, tryptophan, rhodiola, and lemon balm.

The good news is that most of these products have been shown to be safe for use alone or as a complement to antidepressant medications. However, the studies themselves acknowledge that it is necessary to better report possible side effects and continue exploring how these products can help when combined with psychological therapies, offering a more comprehensive and personalized approach for those suffering from depression.

This type of research helps guide the next steps in science. Knowing which natural products have the most potential and which still need further study is essential to expanding treatment options, especially for those seeking more accessible, natural alternatives, or those that complement traditional medicine. Depression is a serious condition, but with proper information, support, and treatment, it can be addressed with a better quality of life.

READ MORE:

Understanding the research landscape of over-the-counter herbal products, dietary supplements, and medications evaluated for depressive symptoms in adults: a scoping review

Rachael Frost, Aiman Zamri, Silvy Mathew, Adriana Salame, Cini Bhanu, Sukvinder K. Bhamra, Juan Carlos Bazo-Alvarez, Michael Heinrich, and Kate Walters

Frontiers in Pharmacology. Volume 16 - 2025. 19 May 2025

DOI: 10.3389/fphar.2025.1609605

Abstract: 

Over-the-counter (OTC) products such as herbal medical products (HMPs) or dietary supplements are a valued part of preventative and supportive self-care for depressive symptoms, but there is a wide array of products available, with differing levels of clinical evidence. It is unclear what the optimal directions for future research in this field are. We aimed to explore the size and nature of the evidence base available for OTC products for depression in adults aged 18–60. We carried out a scoping review following Joanna Briggs Institute guidance. We searched MEDLINE, Embase, PsycINFO, AMED, and CENTRAL from inception to December 2022, and 10% of the results were screened by two authors and the remainder by one author. We included randomised controlled trials of products commonly available OTC in multiple countries in participants with symptoms or a diagnosis of depression. Results were narratively summarised by the product and volume of evidence available. Out of 23,933 records found, we screened 1,367 full texts and included 209 trials. The largest volume of evidence was for omega-3s, St John’s Wort, saffron, probiotics, and vitamin D. Among a range of herbal medical products with promising evidence, those most commonly used and thus warranting further research were lavender, lemon balm, chamomile, and Echium. For 41 products, we found only single trials. Few products presented safety issues, whether used alone or adjunctively with antidepressants. Products with limited but promising evidence included folic acid, lavender, zinc, tryptophan, Rhodiola, and lemon balm, and future research should focus on these products. There is a need for further evaluation of herbal medical products as adjuncts to antidepressants and for exploring their potential benefits when used adjunctively with psychological therapies to support a more integrative approach. Safety reporting in these trials needs to be further improved.