Supplements to Lower Cortisol: What the Research Actually Shows

Search for supplements to lower cortisol and you will find long lists of herbs, vitamins and “adrenal” blends. Very few of them have been tested in a way that actually measured cortisol in people. This guide only ranks supplements where controlled human trials measured cortisol.

It is educational, not medical advice. Supplements can support a healthy stress response; they are not a treatment for any hormone condition.

Key Takeaways

• Ashwagandha has the most evidence. Several randomized trials and two meta-analyses found lower cortisol with 240 to 600 mg of root extract a day over about 8 weeks.
• Phosphatidylserine and omega-3 blunted the cortisol rise during stress tests, in small trials lasting 10 days to 4 months.
• L-theanine and vitamin C have single studies showing a smaller cortisol response or faster recovery after a stressful task.
• Magnesium and reishi are popular for cortisol, but their research has mainly looked at sleep and stress rather than cortisol itself.
• Sleep, daylight and caffeine timing matter as much as any capsule. If you suspect a real hormone problem, ask a doctor for testing.

For a fuller picture of the hormone itself, read our guide to what cortisol is.

What Cortisol Does, and Why You Would Want to Lower It

Cortisol is a hormone made by your adrenal glands. It is not the enemy: you need it to wake up, keep blood sugar steady and respond to challenges. It normally peaks within an hour of waking and falls through the day.

The problem is a stress response that stays switched on. When stress is constant, cortisol can stay higher in the evening or spike harder and longer during stressful moments, which many people notice as feeling wired, tired or unable to wind down. That is the pattern most “cortisol supplements” aim at. For the bigger picture, see how chronic stress affects aging.

Symptoms alone cannot tell you your cortisol level. If you have persistent weight changes, muscle weakness, easy bruising or very high blood pressure, see a doctor, who can measure cortisol in blood, saliva or urine.

Our guide to the signs of high cortisol explains which signs point to everyday stress and which need a doctor.

Supplements That Lowered Cortisol in Human Trials

Supplement	What cortisol did in trials	Dose studied	How long	Evidence
Ashwagandha	Lower morning or serum cortisol than placebo	240 to 600 mg root extract a day	About 8 weeks	Several trials and 2 meta-analyses
Phosphatidylserine	Smaller cortisol rise during a stress test or hard exercise	400 to 600 mg a day	10 days to 3 weeks	Small trials
Omega-3	19% lower overall cortisol during a stress test	2.5 g a day	4 months	One large trial
L-theanine	Smaller cortisol response to a stressful task, 3 hours after a drink	Single dose	Same day	One small trial
Vitamin C	Faster cortisol recovery after stress, not a smaller peak	3,000 mg a day	14 days	One trial
Rhodiola	Changed morning cortisol response in adults with stress-related fatigue	576 mg extract a day	4 weeks	One trial

1. Ashwagandha

Ashwagandha (Withania somnifera) root is the most studied supplement for cortisol. In an 8-week randomized trial of 60 stressed but healthy adults, 250 mg and 600 mg a day lowered serum cortisol compared with placebo, with the larger dose doing more (Salve et al., 2019). A 60-day trial of 64 adults under chronic stress taking 300 mg twice a day also found substantially lower serum cortisol (Chandrasekhar et al., 2012), and a 60-day trial of 240 mg a day found greater drops in morning cortisol than placebo (Lopresti et al., 2019).

Pooled results agree. A 2024 meta-analysis of nine randomized trials with 558 participants found lower perceived stress, anxiety scores and serum cortisol (Arumugam et al., 2024), and a 2025 meta-analysis of seven trials found a clear drop in cortisol (Albalawi, 2025).

• How to take it: 240 to 600 mg a day of a standardized root extract, with food. Give it about 8 weeks.
• Safety: usually mild stomach upset or drowsiness. Rare liver injury has been reported, and it can affect thyroid hormones. Avoid it in pregnancy, and check with a clinician if you take thyroid, blood pressure, blood sugar, immune or sedative medicines.

Our ashwagandha vs L-theanine guide compares the two most popular stress options, and the ashwagandha ingredient page covers the basics.

For the stress, sleep and dosage research on ashwagandha in one place, see our guide to ashwagandha benefits. For how ashwagandha compares with saffron, see saffron vs ashwagandha. For how it compares with GABA for stress, calm and sleep, see our guide to GABA vs ashwagandha.

2. Phosphatidylserine

Phosphatidylserine is a fat found in cell membranes, especially in the brain. In a study of 80 adults, three weeks of 400 mg a day of a soy-based phosphatidylserine complex clearly blunted the cortisol response to a public-speaking and mental-arithmetic stress test and reduced distress afterward. Oddly, 600 mg and 800 mg did not have the same effect (Hellhammer et al., 2004). In 10 healthy men, 600 mg a day for 10 days lowered peak cortisol during and after moderate to hard cycling by about 39% compared with placebo (Starks et al., 2008).

The dose and form may matter. It is generally well tolerated. For its other uses, see phosphatidylserine for brain health.

3. Omega-3 Fish Oil

In a 4-month randomized trial of 138 sedentary middle-aged adults, 93 of them women, 2.5 g a day of omega-3 led to 19% lower overall cortisol during and after a stressful speech task than placebo, along with lower levels of the inflammatory marker IL-6 (Madison et al., 2021). A lower dose of 1.25 g a day was also tested. Omega-3 is a slow, background option: the effect was measured after months, not days.

4. L-Theanine

L-theanine is an amino acid from tea leaves. In a crossover trial of 34 healthy adults, an L-theanine-based drink reduced subjective stress during a multitasking test one hour after drinking it, and the cortisol response to the test was smaller three hours after the dose (White et al., 2016). A separate 4-week trial of 200 mg a day reduced stress-related symptoms and improved sleep quality (Hidese et al., 2019).

L-theanine is the as-needed option on this list, and it does not cause drowsiness. It can slightly lower blood pressure, so check with a clinician if you take blood pressure medicine.

5. Vitamin C

In a 14-day randomized trial of 120 healthy young adults, 3,000 mg a day of slow-release vitamin C led to smaller blood pressure and stress responses to a public-speaking test and faster cortisol recovery afterward. The overall cortisol response itself was not smaller (Brody et al., 2002). That is a high dose, above the 2,000 mg daily upper limit for adults, so it is not one to copy without advice.

For comparison, three quarters of a cup of orange juice, the base of the viral cortisol cocktail, has about 93 mg of vitamin C.

6. Rhodiola

Rhodiola rosea is an adaptogen used for fatigue. In a 4-week trial of 60 adults with long-term stress-related fatigue, 576 mg a day of a standardized extract improved fatigue and attention scores and changed the morning cortisol response compared with placebo (Olsson et al., 2009). Some people find rhodiola mildly stimulating, so take it earlier in the day; see our rhodiola ingredient page.

Other Supplements Popular for Cortisol and Stress

• Magnesium: helpful if your intake is low, and often recommended for stress.
• Reishi: a mushroom traditionally used for calm and sleep; research on it has looked at sleep and fatigue rather than cortisol. See reishi for sleep for what is known.
• “Adrenal support” blends: often built on marketing rather than trials. When researchers tested 12 of them, all contained thyroid hormone and several contained steroid hormones (Akturk et al., 2018), so avoid products that promise to “reset” your adrenals.
• Kanna: small studies show calmer responses to stress; cortisol was not among the measures.

Habits That Lower Cortisol Without a Supplement

• Keep a regular sleep schedule; short or irregular sleep can raise evening cortisol.
• Get daylight soon after waking to help anchor your body clock and daily cortisol rhythm.
• Move most days. Regular moderate exercise can improve how you handle stress, while very long or intense sessions raise cortisol for a while afterward.
• Keep caffeine to the morning, and limit alcohol, which disrupts sleep.
• Use a quick reset during stressful moments, such as slow breathing with a longer exhale.

Food plays a part too. Our guide to cortisol triggering foods covers what studies found on caffeine, alcohol, salt and licorice, and the foods linked to lower cortisol. For sleep, exercise, breathing and other habits, see how to lower cortisol naturally.

Supplements to Lower Cortisol for Women

Most of the trials above included women, and the omega-3 trial was two-thirds women, so the same options apply. Two cautions matter more for women: ashwagandha should be avoided in pregnancy and while trying to conceive, and very high doses of vitamin C are not advised in pregnancy. If cortisol questions come with irregular cycles or other hormone symptoms, a clinician can test rather than guess. For mood during perimenopause, a 12-week trial of saffron extract in women is covered in our guide to saffron supplement benefits. Our Saffron Mood and Calm Capsules pair 28 mg saffron extract with 200 mg L-theanine per serving; join the waitlist on the product page to hear when they launch.

To find out where your levels stand first, read our guide to how to test cortisol levels at home or with your doctor.

Where Our Products Fit

To be clear, our products are not intended to lower cortisol. Three of them contain L-theanine, the as-needed option above:

• Theanine Nasal Spray: 36 mg of L-theanine per two-spray serving, for stressful moments. It is absorbed through the lining of the nose instead of being swallowed like a capsule, so some of each dose skips digestion. The dose is lower than the 200 mg used in trials.
• Anandamide Supplement: 100 mg of L-theanine per serving, with anandamide, PEA and OEA.
• OEA Supplement: 200 mg of L-theanine per serving, the same amount used in the 4-week trial, alongside OEA, PEA and acetyl-L-carnitine.

Our Clarity capsules include 150 mg of rhodiola, less than the 576 mg studied. For the wider stress picture, see our guide to the best supplements for stress and mood and our mood and stress collection.

Sources

• Salve J et al. Adaptogenic and Anxiolytic Effects of Ashwagandha Root Extract in Healthy Adults: A Double-blind, Randomized, Placebo-controlled Clinical Study. Cureus, 2019. PubMed
• Chandrasekhar K et al. A prospective, randomized double-blind, placebo-controlled study of safety and efficacy of a high-concentration full-spectrum extract of ashwagandha root in reducing stress and anxiety in adults. Indian J Psychol Med, 2012. PubMed
• Lopresti AL et al. An investigation into the stress-relieving and pharmacological actions of an ashwagandha (Withania somnifera) extract: A randomized, double-blind, placebo-controlled study. Medicine (Baltimore), 2019. PubMed
• Arumugam V et al. Effects of Ashwagandha (Withania Somnifera) on stress and anxiety: A systematic review and meta-analysis. Explore (NY), 2024. PubMed
• Albalawi AA. Dual impact of Ashwagandha: Significant cortisol reduction but no effects on perceived stress: A systematic review and meta-analysis. Nutr Health, 2025. PubMed
• Hellhammer J et al. Effects of soy lecithin phosphatidic acid and phosphatidylserine complex (PAS) on the endocrine and psychological responses to mental stress. Stress, 2004. PubMed
• Starks MA et al. The effects of phosphatidylserine on endocrine response to moderate intensity exercise. J Int Soc Sports Nutr, 2008. PubMed
• Madison AA et al. Omega-3 supplementation and stress reactivity of cellular aging biomarkers: an ancillary substudy of a randomized, controlled trial in midlife adults. Mol Psychiatry, 2021. PubMed
• White DJ et al. Anti-Stress, Behavioural and Magnetoencephalography Effects of an L-Theanine-Based Nutrient Drink: A Randomised, Double-Blind, Placebo-Controlled, Crossover Trial. Nutrients, 2016. PubMed
• Hidese S et al. Effects of L-Theanine Administration on Stress-Related Symptoms and Cognitive Functions in Healthy Adults: A Randomized Controlled Trial. Nutrients, 2019. PubMed
• Brody S et al. A randomized controlled trial of high dose ascorbic acid for reduction of blood pressure, cortisol, and subjective responses to psychological stress. Psychopharmacology (Berl), 2002. PubMed
• Olsson EM et al. A randomised, double-blind, placebo-controlled, parallel-group study of the standardised extract shr-5 of the roots of Rhodiola rosea in the treatment of subjects with stress-related fatigue. Planta Med, 2009. PubMed
• Akturk HK et al. Over-the-Counter "Adrenal Support" Supplements Contain Thyroid and Steroid-Based Adrenal Hormones. Mayo Clin Proc, 2018. PubMed

Frequently Asked Questions

What is the best supplement to lower cortisol?

Ashwagandha has the most human evidence, with several randomized trials and two meta-analyses showing lower cortisol at 240 to 600 mg a day over about 8 weeks. Phosphatidylserine and omega-3 have smaller trials showing a smaller cortisol rise during stress.

How fast can supplements lower cortisol?

Ashwagandha trials measured changes after about 8 weeks, and omega-3 after 4 months. Phosphatidylserine worked within 10 days to 3 weeks, and L-theanine reduced the cortisol response to a stressful task within hours in one study.

Does magnesium lower cortisol?

We found no randomized trial showing that it does. Magnesium is worth getting enough of for sleep and stress in general, especially if your diet runs low.

Does reishi lower cortisol?

Research on reishi has looked at sleep and fatigue rather than cortisol. It is traditionally used for calm and sleep.

Does L-theanine lower cortisol?

In one crossover trial, an L-theanine-based drink led to a smaller cortisol response to a stressful task three hours later. It is better studied for how calm people feel than for cortisol itself.

Can I take ashwagandha and phosphatidylserine together?

They work in different ways and are often combined. Start one at a time so you can tell what helps, and check with a clinician if you take medication.

What are the signs of high cortisol?

Feeling wired but tired, trouble winding down at night and cravings are common with ongoing stress, but they are not specific. Only a test can show your cortisol level, so see a doctor if symptoms persist.

These statements have not been evaluated by the Food and Drug Administration. This content is for education and is not medical advice. Our products are not intended to diagnose, treat, cure or prevent any disease. Talk with a healthcare provider before starting a new supplement if you are pregnant, breastfeeding or taking medication.