In 2023, 11.4% of US adults took a prescription medication for depression, according to the National Center for Health Statistics.
Many of them also reach for supplements from the same drugstore aisle, and a handful of popular ones do not mix with the pills at all.
The main concern is a reaction called serotonin syndrome.
The National Center for Complementary and Integrative Health, part of the NIH, warns that combining St. John's wort with certain antidepressants can lead to a potentially life-threatening increase of serotonin.
Also read: Women with endometriosis face a 46% higher risk of type 2 diabetes, even before menopause
Symptoms can start within minutes to hours and include agitation, fast heartbeat, high blood pressure, and elevated body temperature.
SSRIs (selective serotonin reuptake inhibitors) are the most commonly prescribed antidepressants.
The group includes sertraline (Zoloft), fluoxetine (Prozac), escitalopram (Lexapro), citalopram (Celexa), and paroxetine (Paxil), according to the Cleveland Clinic.
Four supplements that push serotonin too high
St. John's wort is a herbal antidepressant and is the highest-risk interaction on the list.
Also read: Why you should avoid taking ibuprofen on an empty stomach
NCCIH states plainly that interactions with St. John's wort can weaken the effects of life-saving medicines or cause dangerous side effects, and it flags antidepressants first among the drugs affected.
5-HTP is the direct precursor the body uses to make serotonin. Taking it alongside an SSRI stacks two serotonin boosters on top of each other.
A 2021 review in the International Journal of Molecular Sciences describes how excessive 5-HTP stimulation is the underlying mechanism of serotonin syndrome.
L-tryptophan is an amino acid that the body converts into 5-HTP and then into serotonin. Same pathway, same risk when added to an SSRI.
Also read: Poor sleep can trigger headaches: How to lower your risk
SAMe is marketed for mood and joint health, SAMe has its own serotonin-raising activity. Adding it to an SSRI stacks two serotonin-boosting agents and can produce the same syndrome, so any use should be cleared with the prescriber first.
Three more with different risks
Garcinia cambogia is a weight-loss supplement, sold as hydroxycitric acid (HCA), and has been linked in case reports published in The Primary Care Companion for CNS Disorders to serotonin syndrome when taken alongside an SSRI.
SSRIs already carry a small bleeding risk on their own because serotonin helps platelets clot. Ginkgo biloba can add to that risk.
NCCIH notes that ginkgo may increase the risk of bleeding in people who are taking anticoagulant drugs, such as warfarin, and advises talking with a provider before combining it with any medicine.
Also read: Four-year study links vitamin D to slower biological aging
Yohimbe (yohimbine) is a bark extract that is sold for erectile function and fat loss can spike blood pressure.
NCCIH warns that yohimbine, a component of yohimbe, has been associated with cardiac arrhythmia (irregular heartbeat), blood pressure problems, heart attacks, and seizures, and specifically cautions against pairing it with certain antidepressants.
What the FDA asks patients to do
The FDA does not review supplements before they hit the shelf, and its consumer guidance on antidepressants is blunt about the risk.
In its depression medicines page, the agency tells patients to not forget about cold medicines, supplements, and herbals like St. John's Wort when listing what they take, because some can interact with antidepressants and cause unwanted side effects.
Also read: Suspected poisoned alcohol has killed at least 48 people
If you take an SSRI, the safest step before starting any of the supplements above is to run the name past your prescriber or pharmacist.
Readers already on an antidepressant may also find these foods and drinks that can work against an SSRI useful for the same reason.
This article is made and published by Ida-Marie Palm Varbæk, who may have used AI in the preparation.