Taking ashwagandha consistently for over two months may lead to lower stress and anxiety, better sleep quality, improved memory, and overall health. While many studies have shown ashwagandha to be safe for up to about three months, little is known of its safety beyond that.
Some studies suggest that taking ashwagandha for more than eight weeks may lead to a greater improvement in sleep quality than taking it for fewer than eight weeks.
Other reviews suggest you may need to take ashwagandha for at least eight weeks to see benefits in sleep quality, though six weeks may be sufficient.
Most studies supporting ashwagandha’s use in improving sleep reported no ‘serious’ side effects, with only mild to moderate symptoms such as abdominal pain and nausea observed. However, these studies are only based on short-term observations.
Long-term use of ashwagandha may also help relieve anxiety and stress because ashwagandha helps reduce cortisol levels and increase serotonin.
In one study, people who took ashwagandha for six to eight weeks saw a significant reduction in stress and anxiety levels.
In other studies, participants had to take ashwagandha for up to 90 days (12 weeks) to see a significant effect.
The researchers also reported that using ashwagandha for these periods (up to 12 weeks) was generally safe, with only mild side effects observed.
If you are taking a selective serotonin reuptake inhibitor (SSRI) or other serotonergic medication, talk to a healthcare provider before introducing ashwagandha. There is some belief that the combination may lead to serotonin syndrome, when you have too much serotonin in the body, but more research is needed on the connection.
Ashwagandha can also improve memory and cognition. A 2021 study found that taking ashwagandha once daily for 90 days improved memory and focus, without any significant adverse events reported.
Ashwagandha can help improve stamina, strength, and muscle recovery during or after exercise.
A 2021 research review found that taking an ashwagandha supplement daily for 14 days to about 12 weeks led to significant improvements in muscle strength and exercise performance in athletes. Mild to moderate side effects were reported.
Ashwagandha supplements may help boost sexual function in both men and women by reducing cortisol levels and increasing testosterone levels.
One 2025 study revealed that taking ashwagandha for eight weeks improved orgasm and overall sexual satisfaction without any significant adverse effects.
While ashwagandha appears to be well-tolerated for up to about three months, it may lead to some side effects such as:
- Diarrhea
- Nausea
- Drowsiness
- Abdominal pain
- Dizziness
- Headaches
- Vomiting
In most cases, these side effects often resolve on their own, even without intervention.
There is also a risk of more serious effects, as ashwagandha can affect liver and thyroid function.
There have been instances where people who took ashwagandha developed jaundice (yellow discoloration of the skin that may be due to liver injury or a bile duct problem). In these cases, there were also signs of liver injury, but not liver failure. Liver tests return to normal within one to five months.
However, in a 2025 study that examined ashwagandha use for 12 months, the researchers did not observe any harmful effects on the liver.
Ashwagandha appears to be safe and well-tolerated when used between doses of 300-600 milligrams for up to three months.
One study also found that ashwagandha is safe to take for longer than 12 months. However, this is the only study to examine ashwagandha’s use for up to one year.
Until more long-term studies with larger sample sizes are done, there is not enough evidence to suggest that ashwagandha is safe for long-term use. This is especially true for its potential effect on liver and thyroid function.
If you must take ashwagandha, it may be best to limit use to up to three months. If you want to take it for a longer period or have any underlying health conditions, talk to your healthcare provider first.
Do not use ashwagandha if you:
- Are pregnant or breastfeeding
- Are scheduled for surgery
- Have an autoimmune disease such as rheumatoid arthritis
- Have thyroid disorders
- Have liver failure
- Have a family history of prostate cancer
