Ashwagandha and Cortisol: What the Science Shows

The cortisol obsession that took over social feeds, with hundreds of millions of views on stress-and-cortisol content, sent a lot of people toward ashwagandha. The 2025 evidence on it is honest and a little unflattering, and it lands in a place the marketing never mentions: the supplement can lower the hormone without changing how stressed you actually feel.

Ashwagandha is an adaptogen, a plant traditionally used to help the body handle stress. Modern trials have tested whether that translates into measurable changes. The newest data lets us separate the biochemical claim from the experiential one, and those two things have come apart.

What the 2025 meta-analysis found

A 2025 systematic review and meta-analysis of randomized controlled trials found a statistically significant drop in cortisol, about 1.16 micrograms per deciliter at doses around 500 to 600 mg per day, but no significant change in perceived stress (Albalawi, 2025, Nutrition and Health, PMID 40746175). The hormone moved. The feeling of being stressed did not, at least not reliably across the pooled studies.

That gap is the whole story. A lower cortisol number on a lab test is not the same as feeling calmer or coping better. The thing most people buy ashwagandha for, feeling less stressed, is the thing this analysis did not find. It is worth noting other reviews using different study sets have reported some benefit on stress and anxiety scales, so the picture is not unanimous. But the cleanest recent read shows a real biochemical effect and a missing experiential one.

This is a useful reminder more broadly. A supplement moving a biomarker is not proof it improves your life. Cortisol is a number; how you feel and function is the outcome that matters.

Safety is not nothing

Ashwagandha is not risk-free. There are published case reports of liver injury associated with its use, uncommon but documented enough that regulators in some countries have flagged it. It can also interact with thyroid medication and is not recommended in pregnancy. These are reasons to treat it as a real compound, not a harmless herbal tea, and to consider cycling off rather than taking it indefinitely.

The cortisol-belly trap

A lot of ashwagandha buying is downstream of a bigger myth: that high cortisol is the reason for stubborn belly fat, and that lowering it will melt the fat away. This is mostly wrong. True cortisol disorders are rare. For the average stressed person, chronic stress influences body composition indirectly, through worse sleep, more snacking, and less movement, not through a cortisol number you can supplement down.

That matters here because even if ashwagandha lowers cortisol on a lab test, the data did not show it changing how stressed people feel, and there is no good evidence it drives fat loss. Buying it to fix a “cortisol belly” is paying for a biomarker shift that does not connect to the outcome you actually want. The fat responds to a calorie deficit, protein, and training, the same as always.

What this looks like in coaching

When a client asks about ashwagandha, I start by naming what actually moves stress, because the supplement is far down that list. Sleep is first. Short sleep raises stress hormones and cortisol on its own, and the research on this is more consistent than anything on adaptogens. Regular training, especially resistance work, reliably improves mood and stress resilience. And the unglamorous work of reducing the actual stressors, the schedule, the overcommitment, the doomscrolling, beats any capsule.

If someone has the basics handled and still wants to try ashwagandha, I treat it as an optional, time-limited experiment. A standardized extract around 500 to 600 mg a day, for a defined period of a few weeks to a couple of months, then a break, while watching for any sign of liver issues and clearing it first with their physician if they take thyroid or other medications.

I am also direct about the safety piece, because the “harmless herb” framing leads people to take it casually and indefinitely. The liver-injury case reports are uncommon but real, which is why I favor a defined trial with a clear end date rather than an open-ended habit. Anyone on thyroid medication should not start it without their physician, since ashwagandha can push thyroid hormone levels, and it is off the table in pregnancy.

The broader lesson I want clients to take from ashwagandha applies to the whole adaptogen and “cortisol support” aisle. A supplement that moves a number on a lab panel is not the same as a supplement that improves your life. The studies here are unusually honest about that gap, showing a real hormone change and an absent feeling-of-stress change. Most products are not studied that carefully, and you should assume the same gap exists until proven otherwise.

The honest framing is the one the trends avoid. Ashwagandha can lower a stress hormone in your blood and may do little for the stress in your head. Fix the sleep, lift the weights, manage the actual load. Then decide whether a bottle is worth it.