Ashwagandha does not typically cause hot flashes, but it can in certain circumstances, particularly by pushing thyroid hormone levels too high. For most people, ashwagandha has the opposite effect: one clinical trial in menopausal women found it reduced hot flash frequency from about 14.5 episodes to 10.6 over eight weeks. But the supplement has real hormonal activity, and that same property can backfire depending on your thyroid status, dosage, and what else you’re taking.
How Ashwagandha Affects Thyroid Hormones
Ashwagandha raises thyroid hormone levels. A clinical trial of 50 people with underactive thyroids found that 600 mg daily of root extract for eight weeks increased both T3 and T4 (the two main thyroid hormones) and lowered TSH compared to placebo. A separate study found that even 500 mg daily caused small T4 increases in healthy men. For someone with a sluggish thyroid, this can be helpful. But if your thyroid is already functioning normally, or if you’re on thyroid medication, the extra push can tip you into excess territory.
When thyroid hormones climb too high, the result is a condition called thyrotoxicosis. Its hallmark symptoms include heat intolerance, sweating, palpitations, weight loss, fine tremors, and anxiety. In at least one documented case published in Cureus, a woman with a history of hypothyroidism developed thyrotoxicosis and a dangerous heart rhythm after replacing her thyroid medication with ashwagandha. Her symptoms resolved after she stopped the supplement. The heat intolerance and flushing she experienced would feel nearly identical to a hot flash.
The Difference Between Heat Intolerance and Hot Flashes
Classic menopausal hot flashes come from hormonal shifts in the brain’s temperature-regulation center. They tend to arrive in sudden waves, often with flushing across the chest and face, and pass within a few minutes. Thyroid-driven heat intolerance is more persistent. You feel consistently overheated, sweat more easily, and tolerate warm environments poorly. Both can cause flushing, sweating, and a sensation of internal heat, so it’s easy to confuse them.
If you started ashwagandha recently and your “hot flashes” came with a racing heart, unexplained weight loss, trembling hands, or a general feeling of being wired, that pattern points more toward thyroid overstimulation than a hormonal fluctuation.
Who Is Most at Risk
The people most likely to experience heat-related symptoms from ashwagandha fall into a few groups:
- People already on thyroid medication. Adding ashwagandha on top of levothyroxine or similar drugs can push thyroid levels beyond the target range. Even if you stopped your medication and switched to ashwagandha, the supplement’s thyroid-stimulating effect can overshoot.
- People with undiagnosed thyroid conditions. If your thyroid is borderline overactive and you don’t know it, ashwagandha can amplify that imbalance enough to produce symptoms.
- People taking high doses. Clinical studies have used anywhere from 300 to 600 mg of standardized root extract daily. Higher doses increase the likelihood of hormonal effects. Because ashwagandha products vary widely in their extraction methods and potency, it’s difficult to compare doses across brands.
How Ashwagandha Affects Reproductive Hormones
Beyond thyroid activity, ashwagandha also influences reproductive hormones, though the picture is less clear-cut. In aging men, it has been shown to raise DHEA and testosterone, possibly by stimulating the release of gonadotropin-releasing hormone (GnRH), which signals the body to produce more sex hormones. In the menopausal study, women taking ashwagandha saw meaningful increases in estradiol and progesterone and decreases in FSH and LH over 56 days.
These hormonal shifts generally work against hot flashes, not in favor of them. Rising estradiol tends to stabilize the brain’s thermostat and reduce vasomotor symptoms. However, hormonal fluctuations during the adjustment period, particularly in the first few weeks of supplementation, could theoretically trigger transient flushing in some individuals. This hasn’t been formally studied, but it’s a plausible explanation for people who notice brief hot-flash-like episodes early on that resolve with continued use.
Liver Stress as a Rarer Possibility
Ashwagandha has been linked to liver injury in a small number of cases, typically appearing two to 12 weeks after starting the supplement. The primary symptoms are jaundice (yellowing of skin and eyes), itching, nausea, and fatigue. While liver dysfunction can sometimes cause flushing and sweating as part of a broader inflammatory response, this would come alongside clearly abnormal symptoms like dark urine, pale stools, or visible yellowing. It’s not a likely explanation for isolated hot flashes, but it’s worth knowing about if you develop multiple unusual symptoms after starting ashwagandha.
What to Do if You Suspect Ashwagandha Is the Cause
The simplest test is to stop taking ashwagandha for two to three weeks and see if the hot flashes resolve. In the documented thyrotoxicosis case, symptoms cleared after discontinuation. If you’re also taking thyroid medication, your thyroid levels may need rechecking, since ashwagandha could have shifted your baseline.
Pay attention to the timing. Hot flashes or heat intolerance that started within a few weeks of beginning ashwagandha, or after increasing your dose, strongly suggest the supplement is involved. Symptoms that predated the supplement by months are more likely related to menopause, perimenopause, or another cause entirely. If stopping ashwagandha doesn’t help and you’re experiencing frequent or severe hot flashes, a thyroid panel and hormone check can clarify what’s driving them.