Does ashwagandha support thyroid hormone levels?

If you often feel sluggish, tired, and experience unexplained weight gain, those may be symptoms of low thyroid hormones. Some people develop these symptoms even without a clinical diagnosis of hypothyroidism—a condition called subclinical hypothyroidism. For these people, could ashwagandha—a supplement with wide-reaching potential health benefits—support thyroid hormone levels? Read on to learn more. 

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Ashwagandha is a plant known as an adaptogen, which means many people believe it’s a supplement that helps combat stress. Adaptogens like ashwagandha (or Withania somnifera) may help your body deal with all kinds of stress, whether chronic stress from a job or physical stress from a grueling workout. 

It’s not exactly new, either. Ashwagandha, also known as Indian ginseng or winter cherry, has been used in Ayurvedic, Indian, and African traditional medicine. Traditional practices like Ayurveda used the root and berries of this plant to treat a wide range of health conditions, and modern research is finding evidence to support some of these uses.

The potential health benefits of ashwagandha root extract are surprisingly wide-reaching. Potential ashwagandha benefits range from cognition to joint health. But for many people who feel like they have a sluggish metabolism, this plant’s most exciting potential benefit may be how it interacts with your thyroid.

A quick note on how your thyroid works: It is part of the hypothalamic-pituitary-thyroid (HPT) axis, which means they all work together in a system. The pituitary gland produces thyroid-stimulating hormone (TSH), which essentially prods your thyroid to make its own hormones, triiodothyronine (T3) and thyroxine (T4). T3 is the more active of the thyroid hormones.

To see if you have hypothyroidism, your healthcare provider will run blood tests to look at your TSH levels. High TSH numbers mean your thyroid isn’t keeping up with demand—the pituitary gland is working harder and harder to get your thyroid to make hormones, with little to no success. This would mean you have hypothyroidism, although exact ranges for this diagnosis may differ between medical experts. In subclinical hypothyroidism, TSH levels are high, but T3 and T4 levels are normal.

The main types of thyroid diseases discussed with regards to ashwagandha are hypothyroidism and hyperthyroidism.  

Hypothyroidism

Hypothyroidism is an underactive thyroid that fails to produce enough thyroid hormone to keep the body running normally. People with hypothyroidism may have no symptoms or symptoms so mild that they don’t realize they have the condition, especially if they have subclinical hypothyroidism (Gosi, 2021). 

Common symptoms of an underactive thyroid include (Gosi, 2021):

• Low mood, depression

• Feeling cold most of the time and unable to warm up

• Forgetfulness

• Constipation—slowed bowel movements

• Dry skin

• Hair loss

• Weight gain

• Slow heart rate

• Irregular menstrual cycles and/or fertility problems

• Joint pain

Hyperthyroidism

Just as the thyroid gland can become underactive, it can also become overactive—a condition called hyperthyroidism (“hyper” or high thyroid, as opposed to “hypo” or low thyroid). Hyperthyroidism usually develops as an autoimmune disease. The immune system produces antibodies that stimulate the thyroid to make more thyroid hormone than it should (Mathew, 2021). 

Another name for hyperthyroidism is Graves’ disease. Symptoms include fatigue, fast heartbeat, nervousness, inability to tolerate warm temperatures, increased appetite, muscle weakness, diarrhea, eye problems, weight loss, and feeling shaky (Mathew, 2021).

Although some scientific evidence suggests ashwagandha may help thyroid function, it’s important to make a distinction here. People with hypothyroidism are likely on prescription thyroid hormone medication, in which case beginning a supplement regimen should be discussed with your prescribing healthcare provider. 

If you suspect you have hypothyroidism, it’s essential to first and foremost seek medical advice from a professional. Ashwagandha may interact with thyroid medication, which is why discussing your desire to add this supplement to your routine with a medical expert is important.

With that said ashwagandha may be able to help those with low thyroid function. Supplementing with 600 mg of ashwagandha daily for eight weeks improved blood levels of TSH, T3, and T4 in patients with subclinical hypothyroidism in one small placebo-controlled study found (Sharma, 2018).

Researchers hypothesize that ashwagandha’s effect on thyroid hormone levels may have something to do with the relationship between TSH and cortisol levels. This is an area in which more research is needed. Not everyone with subclinical hypothyroidism needs treatment (Biondi, 2019).

However, people with Hashimoto’s thyroiditis, the most common cause of hypothyroidism in the U.S., should not take ashwagandha. Hashimoto’s thyroiditis is an autoimmune disease, which means it’s connected to the immune system. Research suggests that ashwagandha may boost immune system activity in animal studies—this may potentially make Hashimoto’s thyroiditis worse (Priyanka, 2020).

Since ashwagandha may increase levels of thyroid hormones, it’s not suggested for patients with hyperthyroidism who are already overproducing T3 and T4 (Sharma, 2018). 

The potential health benefits of ashwagandha go beyond the thyroid. Research suggests that ashwagandha supplements, such as powders and extracts, may (Mandlik Ingawale, 2021):

• Boost testosterone

• Boost male fertility by increasing sperm count

• Reduce blood sugar levels

• Reduce cortisol levels

• Reduce anxiety and depression

• Decrease inflammation

• Increase muscle mass and muscle strength

• Improve sleep

• Help lower cholesterol

The potential effects of this plant are thought to come from beneficial compounds, including withanolides (like withaferin A), glycowithanolides, and alkaloids. Withanolides are most well-known for their anxiolytic (anti-anxiety) properties and potential ability to improve the effects of stress (Mandlik Ingawale, 2021).

Clinical trials on the effects of this adaptogenic herb in humans show remarkably low rates of side effects, but they do happen.

Side effects of ashwagandha tend to be mild. Many studies on the supplement showed it was well-tolerated and noted high compliance and low dropout among subjects (Pérez-Gómez, 2020). 

Small studies looking at people who experienced adverse effects from ashwagandha note constipation, nasal congestion (rhinitis), drowsiness, cough and cold, change in appetite, and increased libido (Chandrasekhar, 2012; Raut, 2012). 

Although everyone should speak to a healthcare provider before starting a new supplement regimen, there are certain people for whom this is even more important. 

If you’re taking medication for high blood pressure, blood sugar, or thyroid function, be sure to talk to a healthcare provider about ashwagandha. Also, those who are pregnant or breastfeeding should avoid ashwagandha (MedlinePlus, 2020). 

People with an autoimmune disease—such as rheumatoid arthritis or lupus—should consult with a healthcare provider before taking ashwagandha, as it may potentially increase immune system activity and worsen symptoms  (Priyanka, 2020). 

If you are following a diet that eliminates the Solanaceae or nightshade family—a group of plants that include tomatoes, peppers, and eggplants—you should also avoid ashwagandha since it’s part of this family of plants. 

Ashwagandha is considered a supplement, a class of products only loosely regulated by the U.S. Food and Drug Administration (FDA). So, although products like ashwagandha powder, extracts, and capsules are readily available at health stores and online, it’s important to buy from a company you trust.

The evidence still isn’t strong enough to recommend ashwagandha to treat any medical condition. However, if you’re interested in adding ashwagandha to your supplement routine, speak with your healthcare provider, who can offer more insights based on your personal health status.

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Every article on Health Guide goes through rigorous fact-checking by our team of medical reviewers. Our reviewers are trained medical professionals who ensure each article contains the most up-to-date information, and that medical details have been correctly interpreted by the writer.

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Current version

August 31, 2021

Written by

Linnea Zielinski

Fact checked by

Mike Bohl, MD, MPH, ALM

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About the medical reviewer

Mike Bohl, MD, MPH, ALM

Dr. Mike is a licensed physician and a former Director, Medical Content & Education at Ro.