Rhodiola vs Ashwagandha: Which Is Better for Stress and Sleep?

By Matthew Atkins · Nov 5, 2026

The Short Answer

Both herbs are sold for stress, but they aren’t equals.

• Ashwagandha has more research and somewhat stronger results, especially for stress and sleep. A 2026 review counted 19 trials of ashwagandha against 5 of rhodiola (Łuszczak and Kocki 2026). The US government’s center for complementary health research (NCCIH) says some ashwagandha products may help with stress and insomnia.
• Rhodiola’s research is thin and mixed. NCCIH says there isn’t enough reliable evidence to say it helps with anything (NCCIH), and its fatigue trials contradict each other.
• Their risks are different. Ashwagandha has been linked to rare liver injury and isn’t recommended for people with thyroid or autoimmune conditions. Rhodiola’s main concern is how it mixes with antidepressants and some blood-thinning and anti-seizure drugs.
• Taking both together hasn’t been studied. We found no trial that tested the combination.

If your main goal is…

• Stress or anxiety: the evidence leans toward ashwagandha, though it’s still rated low quality. Rhodiola has one small positive trial for stress-related burnout.
• Better sleep: ashwagandha has a small but real effect across several trials. Rhodiola has almost no sleep research, and trouble sleeping is one of its side effects.
• More energy or less tiredness: neither has good evidence. Rhodiola’s trials point both ways; ashwagandha’s one fatigue trial found no difference from a dummy pill.
• Low mood or depression: neither is a treatment for depression. See a doctor.

Whichever you’re considering, read the safety section first, especially if you take any prescription medicine.

At a Glance

Is One Calming and the Other Energizing?

That’s how they’re usually sold: ashwagandha to wind down, rhodiola to perk up. There’s something to it, but it comes from tradition and side effects rather than from trials comparing the two.

Ashwagandha can cause drowsiness (NCCIH), and lab studies suggest it has sedating effects (MSKCC). Rhodiola was traditionally used to boost mental and physical performance (MSKCC), and trouble sleeping is one of its side effects.

The picture is messier than the marketing, though. Older studies suggest rhodiola may be stimulating at low doses but sedating at high ones (Drugs.com). And in one fatigue trial, described below, people on the “energizing” herb ended up more tired than people on a dummy pill.

What the Research Shows

Stress

Ashwagandha. In one trial, 60 stressed adults took 240 mg a day of ashwagandha extract or a dummy pill for 60 days. Anxiety dropped more on ashwagandha, and so did morning levels of cortisol, the main stress hormone (Lopresti et al. 2019). The lead researcher disclosed past funding from an extract maker for unrelated studies. In another trial of 60 stressed adults, both 250 mg and 600 mg a day lowered stress scores and cortisol over eight weeks (Salve et al. 2019).

When researchers pooled 12 trials covering about 1,000 people, ashwagandha lowered stress and anxiety scores on average. But results varied a lot between studies, and the reviewers rated their confidence in the finding as low (Akhgarjand et al. 2022).

Rhodiola. The main stress trial gave 60 adults with stress-related exhaustion 576 mg a day or a dummy pill for four weeks. Both groups improved, partly a placebo effect, but the rhodiola group did somewhat better on a burnout questionnaire and some attention tests (Olsson et al. 2009). One author, Alexander Panossian, was later thanked in another trial as working for the Swedish Herbal Institute, the company that supplied that trial’s extract; that trial says the company had no role in running or reporting it (Mao et al. 2015).

European regulators allow rhodiola to be sold for stress-related tiredness, but based on its long history of use, not on trial results (EMA).

More options: herbs for stress-related fatigue.

Sleep

Ashwagandha has the stronger case. A 2021 analysis of five studies, covering 372 adults who took 250–600 mg a day for 6–12 weeks, found a small but real improvement in sleep compared with a dummy pill. The effect was bigger at 600 mg, after at least eight weeks, and in people with insomnia (ODS).

Rhodiola has very little sleep research. Drugs.com mentions improved sleep, but the studies behind that were mostly about tiredness, not sleep (Drugs.com).

Tiredness and energy

Rhodiola’s results point both ways. A review of 11 trials found a benefit in about half, but all the trials had design flaws (Ishaque et al. 2012). In a later trial, 48 nursing students working shifts took rhodiola or a dummy pill for six weeks, and the dummy-pill group ended up less tired. The authors said rhodiola made fatigue worse, while warning that one small trial should be read with caution (Punja et al. 2014).

Ashwagandha hasn’t done better. In a trial of overweight men aged 40 to 70 with mild fatigue, energy improved over eight weeks in both groups, with no real difference between ashwagandha and the dummy pill (Lopresti et al. 2019).

Mood and depression

Rhodiola is often called a natural antidepressant. The best trial doesn’t back that up. Fifty-seven people with mild to moderate depression took rhodiola, the antidepressant sertraline (Zoloft) or a dummy pill for 12 weeks. All three groups improved a little, and the differences between them were too small to count (Mao et al. 2015). Rhodiola did cause fewer side effects than sertraline (30% of people against 63%).

An earlier, smaller trial of the same extract did find a benefit over a dummy pill (Drugs.com). Expert guidelines are split. A 2022 international taskforce doesn’t recommend rhodiola for depression (Sarris et al. 2022), while Canada’s 2023 guidelines list it as a third-line option for mild depression only (Lam et al. 2024).

For ashwagandha, NCCIH calls the evidence on anxiety unclear (NCCIH).

Neither herb replaces proper care for depression or anxiety. If you’re struggling, talk to a doctor.

Exercise

Both are mixed. For rhodiola, a few early studies suggested better endurance, but most recent trials found no effect (MSKCC; Drugs.com). For ashwagandha, NCCIH says there isn’t enough evidence (NCCIH), though MSKCC cites limited data suggesting a benefit (MSKCC).

Safety: How the Risks Differ

This is where the two herbs differ most.

Ashwagandha’s main risks

Liver. The NIH’s database of drugs and supplements that harm the liver (LiverTox) rates ashwagandha as a likely cause of liver injury. Cases are rare and usually show up 2 to 12 weeks after starting, often with yellowing skin or eyes (jaundice) and itching. A few severe cases, including deaths and emergency liver transplants, happened mostly in people who already had liver disease, and LiverTox says people with cirrhosis or advanced liver disease should avoid it (LiverTox).

Thyroid, immune system and surgery. NCCIH says ashwagandha isn’t recommended before surgery or for people with thyroid or autoimmune conditions (NCCIH). There are case reports of an overactive thyroid that cleared up once people stopped taking it (MSKCC).

Medicines. NCCIH lists possible interactions with drugs for diabetes, high blood pressure, seizures and thyroid conditions, with sedatives, and with drugs that suppress the immune system (NCCIH). MSKCC adds that people on sleeping pills or anxiety drugs like benzodiazepines should probably avoid it (MSKCC).

Pregnancy. NCCIH says to avoid it in pregnancy and while breastfeeding (NCCIH). MSKCC says high doses may raise the risk of miscarriage (MSKCC), though the American Herbal Pharmacopoeia disputes this (ODS).

Regulators. Denmark has banned the sale of ashwagandha products. Its food authority points to a Danish risk assessment that found negative effects on sex hormones and reproduction, and possible effects on the thyroid, the immune system and the nervous system (Fødevarestyrelsen). France’s food safety agency advises against it for some groups, including pregnant women and people with hormone disorders (ODS). The EU has no approved monograph for ashwagandha because there wasn’t enough evidence to write one (EMA).

Rhodiola’s main risks

Antidepressants. One woman developed a fast, irregular heartbeat after three days of taking rhodiola with her antidepressant, and lab studies suggest rhodiola could add to these drugs’ effects. MSKCC advises caution (MSKCC).

Warfarin and phenytoin. Rhodiola slightly slows a liver enzyme that clears the blood thinner warfarin and the seizure drug phenytoin, which could push their levels up. Both drugs have a small margin between the right dose and too much (MSKCC). This is based on one study in 13 healthy volunteers, which measured the enzyme using a blood pressure drug and didn’t test warfarin or phenytoin directly (Thu et al. 2016). NCCIH also says interactions with the blood pressure drug losartan have been reported (NCCIH). European regulators, by contrast, say no clinically important interactions have been seen (EMA).

Side effects and age. Usually mild: dizziness, dry mouth, headache, trouble sleeping, and less often nausea, stomach pain or rash. European regulators don’t recommend it for anyone under 18 (EMA).

Liver. LiverTox has no entry for rhodiola itself (LiverTox). It shows up as one ingredient in some SLIMQUICK weight-loss products linked to liver injury, but LiverTox says no single ingredient could be blamed (LiverTox).

Can You Take Rhodiola and Ashwagandha Together?

Nobody has tested the combination. A 2026 review of both herbs found no trial that gave them together (Łuszczak and Kocki).

If you take both, you take on both sets of risks, and some of them overlap: blood pressure medicines, drugs that act on the brain and nervous system, and pregnancy.

A pharmacist can check your situation. Bring:

• both product labels (which plant, which part, how much per serving, and any other ingredients)
• a list of every medicine and supplement you take, especially antidepressants, blood thinners, seizure, thyroid, blood pressure, diabetes and immune-suppressing drugs
• any liver, thyroid or autoimmune condition, pregnancy plans, and upcoming surgery

Side by Side: What Each Was Studied For

For the full picture on each herb, see our ashwagandha and rhodiola pages. Other options, such as holy basil, are on our adaptogens page, and we explain what “adaptogen” means separately.

Questions People Ask

Can I take ashwagandha and rhodiola together?

It hasn’t been studied, and each herb’s risks still apply. If you want to try it, check with a pharmacist first; see what to bring.

Which is better for lowering cortisol?

Ashwagandha has more evidence. Two trials in stressed adults found it lowered cortisol more than a dummy pill (Lopresti 2019; Salve 2019), though a trial in men aged 40 to 70 found no difference (Lopresti 2019). Rhodiola has one trial showing a changed morning cortisol pattern (Olsson 2009).

What shouldn’t you mix with rhodiola?

Mainly antidepressants, the blood thinner warfarin and the seizure drug phenytoin, and possibly the blood pressure drug losartan. Other blood pressure medicines and stimulants are a theoretical concern (MSKCC; NCCIH).

Sources

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4. Memorial Sloan Kettering Cancer Center. About Herbs: Rhodiola. Last updated April 16, 2026. https://www.mskcc.org/cancer-care/integrative-medicine/herbs/rhodiola
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Matthew Atkins

Matthew studied biology and has worked in conservation. He's been interested in medicinal herbs for many years. More about HerbsList

This page is for general information only and isn't medical advice. Talk with a doctor or pharmacist before taking any herb or supplement. Full disclaimer