Does St. John’s Wort Cause Weight Gain?
Key takeaways:
St. John’s wort is a supplement that can help treat mild to moderate depression. There’s no evidence that St. John’s wort directly causes weight gain.
Appetite can increase when depression symptoms get better, which can lead to weight gain. But people may mistakenly attribute these appetite changes to St. John’s wort.
St. John’s wort can interact with many medications. Make sure to discuss your current medications and supplements with your care team before starting St. John’s wort.
St. John’s wort (Hypericum perforatum) is a small, shrubby plant with yellow flowers. Native to Europe and Asia, it has a long history in European herbal medicine, dating back to the ancient Greeks. St. John’s wort is commonly used to treat depression and symptoms of menopause.
Most often, people will take St. John’s wort in the form of powdered flowers in a capsule. But it can also be taken as a tea or tincture, or applied topically as a body oil or lotion.
Even though it’s a natural supplement, St. John’s wort can cause side effects. Some people have noticed weight fluctuations while taking St. John’s wort. But does it really cause weight gain? And can St. John's wort help with weight loss? Here’s how St. John’s wort can impact your weight.
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Can St. John’s wort make you gain weight?
There is no evidence that St. John’s wort causes weight gain.
In one study, researchers followed 440 people who were taking St. John’s wort for depression. Researchers also studied how St. John’s wort impacted their overall health, including possible weight changes. They found that people’s body mass index (BMI) did not change over the course of the year. This finding shows that St. John’s wort did not directly cause weight gain.
Also, research in mice showed that St. John’s wort did not change the mice’s:
Food intake
Body weight
Fasting blood sugar
Insulin levels
Animal research can give important insight into how medications may impact humans. While the correlation isn’t always perfect, this research is reassuring that St. John’s wort doesn’t lead to weight gain.
So, while St. John’s wort doesn’t directly cause weight gain, if you’re taking it to help manage depression, you may still notice a change in your weight. Depression can decrease your appetite. And once you start treatment, your appetite may return. So if taking St. John’s wort helps you manage depression, you may also notice a change in your weight.
Can St. John’s wort help with weight loss?
Right now, there is no evidence that St. John’s wort helps you lose weight.
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Some people have a decreased appetite due to depression. Others may experience overeating as a symptom. Once people with this symptom start treatment for depression, they may notice that they stop overeating. This can result in weight loss. So, it’s possible to lose weight while taking St. John’s wort for depression treatment. But it’s not the St. John’s wort that’s directly causing weight loss.
The research on the impact of St. John’s wort on weight is still evolving. But there’s a well-designed study currently in progress. It’s looking at whether St. John’s wort and acupuncture can support weight loss. But the results are not available yet.
Who should avoid St. John’s wort?
St. John’s wort can help treat depression. In fact, the best available evidence shows that St. John’s wort is as effective as antidepressants for mild to moderate depression.
But this doesn’t mean everyone with mild to moderate depression should try St. John’s wort.
St. John’s wort is known to interact with many medications including:
Monoamine oxidase inhibitors (MAOIs)
Migraine medications like Triptans and calcitonin gene-related peptide (CGRP) receptor blockers
Seizure medications like phenytoin, carbamazepine, and phenobarbital
HIV medications like protease inhibitors and non-nucleoside reverse transcriptase inhibitors (NNRTIs)
Talk with your psychiatrist or primary care provider if you’re taking any of these medications. Don’t start taking St. John’s wort until you’ve gotten approval from your care team.
The bottom line
St. John’s wort can be used to treat mild to moderate depression. St. John’s wort does not cause weight gain directly. But you may experience weight gain if your appetite improves as your depression symptoms improve. St. John’s wort can interact with many medications. Review all your medications with your care team before starting St. John’s wort.
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References
Brattström, A. (2009). Long-term effects of St. John's wort (Hypericum perforatum) treatment: A 1-year safety study in mild to moderate depression. Phytomedicine.
Fuller, S., et al. (2014). St. John's wort has metabolically favorable effects on adipocytes In Vivo. Evidence-Based Complementary and Alternative Medicine.
National Center for Complementary and Integrative Health. (2020). St. John’s wort.
Sahebkar-Khorasani, M., et al. (2020). Appetite and weight control by Hypericum perforatum and acupuncture added to lifestyle modification: Study protocol for a randomized clinical trial. Advances in Integrative Medicine.
Saper, R. B., et al. (2004). Common dietary supplements for weight loss. American Family Physician.
