It’s a hormone your body releases in order to help you fight back or flee the scene in the face of a threat. But when your life is so high-stress that you’ve got cortisol coursing through your veins at all times, it can lead to high blood sugar, high blood pressure, excess weight and diabetes—all of which raise your risk for a slew of long-term health conditions. 

So it’s no wonder you might want a pill that could lower cortisol. 

Here’s what’s known about dietary supplements that may affect how your body handles stress and, as a result, lower your cortisol.

Magnesium

A 2020 review in the journal Nutrients supports the theory of a magnesium-stress vicious cycle. Turns out, many common signs of stress are also symptoms of low magnesium, such as fatigue, trouble sleeping, upset stomach, nervousness, irritability and headache. Research shows that stress may deplete the body of this essential nutrient and that low magnesium may make the body more sensitive to stress. Boosting magnesium with a supplement, some studies show, can relieve symptoms of stress, such as irritability, fatigue and poor sleep, and decrease cortisol levels. 

If those symptoms sound like just another Tuesday to you, it may come as no surprise that “A lot of people in the U.S. are a little low on magnesium,” says Cydney McQueen, PharmD, a clinical professor at the University of Missouri-Kansas City School of Pharmacy and an expert on dietary supplements. 

If you want to try a supplement for its possible effects on your body’s stress and cortisol levels, McQueen says magnesium would be a good one to start with. Over-the-counter magnesium supplements at the recommended dose are known to be safe and could bring other benefits, too. Magnesium through food or supplements may help prevent diabetes, migraine headaches, and osteoporosis, and it could help lower blood pressure, too. 

“Adding a reasonable dose through a supplement could have beneficial effects and we know it’s safe at those doses.” 

Omega-3 polyunsaturated fatty acid

The healthy fat found in seafood and soybeans, among many other sources, may play a role in biological markers of stress, including cortisol. 

A 2018 study of 2,724 middle-aged adults in the journal Psychoneuroendocrinology found that those with high cortisol levels had low blood levels of omega-3. Some research finds that when people with this biological sign of stress take omega-3 supplements, cortisol levels and other stress indicators improve. 

Omega-3 is another one that McQueen highlights as a well known supplement that’s generally safe and may have other benefits. 

“These supplements can be anti-inflammatory, and that can treat some of the negative effects of elevated cortisol,” she says. “They may benefit blood flow and your lipid profile, too,” she says. 

But before you try these supplements, the National Institutes of Health (NIH) advise that there’s conflicting evidence as to whether boosting omega-3 could also boost risk for prostate cancer. People who take medications that affect blood clotting or who have fish or shellfish allergies should talk to their doctor before taking this supplement. 

Vitamin C

A 2017 research analysis, published in JBI Database of Systematic Reviews and Implementation Reports, concluded that high-dose sustained release vitamin C helped blunt blood pressure spikes and anxiety in response to stress in women. That doesn’t mean it wouldn’t have the same effect on men. The study simply didn’t include men. 

Vitamin C is a known antioxidant, so it may bring other health benefits. But, be careful, there are real risks to getting too much vitamin C, especially in certain groups, such as postmenopausal women with diabetes and people at risk for kidney stones. The upper limit for all adults is 2,000 mg/day. 

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Ashwagandha

This green shrub found in India, Africa and the Middle East has been used as a medicine for thousands of years. Ashwagandha is known as an adaptogen—a plant or mushroom that helps the body respond to stress, anxiety or fatigue. 

Some clinical trials show that the evergreen may help ease stress and insomnia. 

“If you’ve got a supplement that’s helping you sleep a little better at night, that’s a way of dealing with stress, so naturally your cortisol will go down,” McQueen says. 

There’s less evidence, according to the NIH, to support a role for ashwagandha in anxiety. 

Keep in mind, most formal scientific research into medicinal plants tends to run up against the same problem—very small sample sizes. Research into this particular plant is no different. That said, “it’s looking promising for helping people with anxiety and stress. As part of that, you’d decrease cortisol,” McQueen says. 

As far as safety goes, research hasn’t tracked people taking ashwagandha for more than three months. There could be as-yet-unknown long term effects. You shouldn’t take it if you’re pregnant, breastfeeding, going to have surgery, or have autoimmune or thyroid disorders. It also interacts with a number of medications. If you take prescriptions, clear this supplement with your doctor or pharmacist first. 

The bottom line

These supplements may help move the needle on your cortisol levels. But remember, McQueen emphasizes, “Cortisol is a symptom, not the disease.” 

What’s causing your high cortisol levels is stress. 

“Anything you can do to lower stress—yoga, meditation, better sleep, a healthier diet—will bring cortisol down, too.”

More on nutrition and supplements:

• 4 best supplements for an energy boost, according to experts
• 8 healthy fast food picks for when you’re eating on the go
• It’s not 8 glasses a day anymore. Here’s how much water you should drink each day
• The 5 best supplements for healthy aging, according to a longevity expert