Most supplements can’t actually boost your mood—but these might
From omega-3s to probiotics, researchers have tested dozens of “natural” treatments for anxiety and depression. Only a few show measurable benefits—and even those come with caveats.
Once meant to bridge nutritional gaps, supplements have become a booming market for mental wellness.
With an estimated 5.7 percent of adults suffering from depression worldwide, more people are turning to over-the-counter supplements like vitamins, minerals, herbal extracts, amino acids, and probiotics in hopes of finding relief. For many, the appeal lies not just in accessibility, but in perception.
“With medications there is a lot of stigma around mental health, and people can be very scared about what that looks like,” says Nicholas Fabiano, a researcher in the Department of Psychiatry at the University of Ottawa. “Which makes people want to try other things that are perceived to maybe be safer, or less intense, or maybe require a shorter duration of treatment.”
But do these “natural” remedies work as advertised? New research is beginning to separate the supplements that show real promise from those that don’t stand up to scientific scrutiny.
Which supplements for depression don’t work
Nature is touted to offer remedies to support depression symptoms, but a new review published in Frontiers in Pharmacology says that most supplements marketed for depression show little to no benefit.
Take the most common ones—multivitamins, vitamin Bs, calming herbal blends, and melatonin, also often used to help regulate sleep. They’re widely used, but the research just isn’t there.
“They had some trials available, but not enough to make really substantive conclusions,” says Rachael Frost, a researcher from the School of Public and Allied Health at Liverpool John Moores University, who led the review.
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Omega-3 supplements, long believed to boost mood, didn’t fare much better. Of the 39 studies Frost analyzed, 23 showed no real benefit compared to a placebo. In one trial, people took three capsules daily for 12 weeks—and saw no clear improvement in mood. While a few studies reported positive results, the overall evidence isn’t strong enough to consider omega-3s a reliable treatment for depression, according to Frost.
The supplements showing early promise
A handful of supplements show early signs of promise—but the evidence remains limited. Herbal supplements like lavender, rhodiola, and lemon balm, as well as micronutrients such as amino acid tryptophan, folic acid, and zinc, have produced encouraging results in small studies.
The problem? Most of those trials are tiny. Most lavender experiments, for instance, only test it on groups of up to 150 people. “That’s not a huge amount of people,” says Frost, adding that when trials are small, it becomes harder to generalize findings to broader or more diverse populations.
Plus, supplements come in a variety of different methods of administration, which are difficult to compare for effectiveness. “Some of these were tested as a tea, some as capsules, some as tinctures,” says Frost. “What we need to do is a bit more trials to understand which is the most effective out of these, what do people need to be taking, and at what dosage?”
What actually works, according to research
A few supplements do appear to make a measurable difference. The strongest evidence points to St. John’s Wort floral extract, probiotics, vitamin D, and saffron.
Frost found 16 out of 26 trials with positive results for St. John’s Wort. For example, one study found that people taking 600mg of St. John’s Wort extract once or twice a day improved nearly twice as much as those taking a sham pill. But the bulk of evidence for St. John’s Wort is for mild to moderate depression; its efficacy in severe depression is much less established.
Frost also found that nine out of 16 studies on probiotics suggest they help reduce depression symptoms. One study had people take a probiotic pill containing 900 billion live microbes every day for 31 days as an add-on to their usual treatment for major depression, and found that they felt significantly better compared to the group that hadn’t.
Similarly, Frost found that 6 out of 9 studies on vitamin D showed promising results. In one case, people with mild to moderate depression who took a high dose of vitamin D for eight weeks showed a significant drop in their depression scores, compared to those who took none.
How belief affects supplement results
Even when supplements appear to help, some of their benefits may come less from biology than from belief. A 2022 study found that feeling proactive about one’s health can lead to real improvements, even if these don’t come from a clinically proven effect. In other words, expectations matter; believing a supplement will work can actually influence depression scores.
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It’s very difficult, Fabiano says, to quantify the placebo effect because it varies from substance to substance and isn’t easy to measure. “That’s something to just take into account, and not to say that it’s just the biological changes of the supplements resulting in that change,” says Fabiano.
Why supplement regulation still falls short
Despite the initial positive results on some fronts, dietary supplements aren’t regulated like medications—and that gap raises serious questions about safety, effectiveness, and consumer trust.
“I’d like to see much more research on safety and long-term outcomes, especially as more people buy and use these products,” says Frost, noting that labels should clearly highlight possible interactions or risks. Regulations differ significantly between countries, and this lack of consistent oversight can cause problems, from contamination and high doses to undeclared ingredients.
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Even what’s printed on a bottle isn’t always guaranteed. “Doctors don’t know if what the patient is getting is actually what’s on the label,” says Fabiano.
These are all factors as to why supplements aren’t commonly recommended in clinical settings unless the doctor has specific experience or a research background in the area, says Fabiano.
And while they’re often marketed as “natural,” that doesn’t mean they’re risk-free—especially when taken alongside prescription drugs, which they can amplify or diminish. For example, St. John’s Wort can dangerously interact with SSRIs. “This is something important to be aware of and something that you should always speak to your doctor about openly,” Fabiano warns.
