When considering the side-effects of herbal supplements, a number of factors should be taken into account. First and foremost, because herbal supplements are often combinations of many herbs, it can be difficult to know which herb in a product caused the reaction. Secondly, there are far more people taking supplements than there are scientific studies of those substances.
As an illustration, consider that over a third of all Americans take herbal supplements, while herbal supplements are only mentioned in about 100,000 studies, which doesn’t even mean the supplements themselves were examined, only talked about.
To determine the effects, if any, of Ashwagandha use, I combed through credible studies of human participants in trials, as well as consulted a respected cancer center and the National Library of Medicine’s Liver Toxicology report, and found no instances of any serious interactions with Ashwagandha.
Published in 2016, a team of clinical scientists conducted a study to determine the effects of Ashwagandha on patients with anxiety. They found the treatment effective, and they also did not find any adverse effects of the root on the people involved.
They used what’s called a Likert scale (where the participants choose their answer on a scale of 1 to 5) to determine how the people felt about their treatment. It should be noted that this was a double-blind, randomized trial, so no one knew who was taking Ashwagandha and who was taking a sugar pill–not even the doctors giving them the pills.
In the course of this study, no one reported any ill-effects, and no illnesses were detected.
Another clinical trial involving humans, this one from 2012, found that some participants reported “mild” symptoms, but at the same rate as people from the placebo group. The scientists also couldn’t detect any cause for the symptoms. Taken along with the fact that people taking a sugar pill (without knowing it) reported the same symptoms, we could call this a psychosomatic response. That is, sometimes when people think they’re taking medication, their mind can so powerfully convince them that there will be side-effects that they actually do have some, though not from the drug.
What the Rest of the Literature Says
As mentioned above, because many more people take herbal supplements in the real world than the number of people in trials, there will always be more literature from doctors and hospitals on any side effects. In the case of Ashwagandha, there are some reported symptoms of over-use.
From the Memorial Sloan Kettering Cancer Center, we have listed symptoms including headache and nausea, and some digestive discomfort. Meanwhile, the National Library of Medicine reports some diarrhea symptoms as well.
The Library of Medicine is also clear to point out three important factors for us to consider:
Any actual toxins in the body will always find their way to, and leave traces within, the liver. So no signs of any of that are a good thing.
While it appears from all the scientific literature that Ashwagandha is well-tolerated by healthy individuals, there are two things to keep in mind.
One, consult your doctor before beginning any supplement routine. And two, many of the problems doctors have had in identifying what herbs cause people illnesses stem from people taking inferior or mixed supplements; so if you choose to take Ashwagandha, choose the manufacturer carefully.