You’ll want to think twice before mixing your drink with these supplements.
Reviewed by Dietitian Madeline Peck, RDN, CDN
Key Points
- St. John’s wort, passionflower, vitamin A and melatonin should not be mixed with alcohol.
- Combining these supplements with alcohol can have dangerous and unpleasant side effects.
- Talk to a health care provider before starting a new supplement, and check that it is independently verified.
Alcohol interactions are often listed boldly on the label of both prescription and over-the-counter medications. But what about the supplements you take? Even if your supplement is something as unassuming as a natural herb or a vitamin, taking it along with a glass of wine or other alcoholic beverage could be dangerous.
“Drugs, supplements, herbs and even some foods may interact with each other in ways to increase chances of side effects and toxicity,” says Marina Buksov, Pharm.D. Alcohol can change how your body handles certain vitamins, minerals and herbs by either blunting the benefits you’re paying for or intensifying the effects, increasing the risk of organ damage or other dangerous side effects. Keep reading to learn which common supplements don’t mix well with alcohol, what actually happens in your body when they do, and expert-backed tips for taking any supplement safely.
St. John’s Wort
St. John’s wort is one of the most popular herbal supplements for supporting low mood, but it also interacts with many other substances, such as medications and alcohol. “St. John’s wort can induce a few cytochrome P450 enzymes in the liver, including CYP2E1, which can [increase the rate of] production of alcohol’s toxic metabolism intermediate, acetaldehyde, when co-administered,” Buksov explains. This means that drinking alcohol while also taking St. John’s wort will leave you feeling much worse than you would with alcohol alone, with increased hangover symptoms like dizziness, brain fog and drowsiness.
Passionflower
Passionflower shows up in a lot of relaxation and sleep supplements, often alongside ingredients like GABA, valerian or kava. On its own, passionflower may help suppress activity in the central nervous system, helping you relax and unwind. When combined with alcohol, which works on the same pathways, those effects can be amplified.
“Alcohol acts by binding and activating GABA-A, the body’s inhibitory neurotransmitter, and so do some herbs/supplements, including GABA, passionflower and kava,” says Buksov. The combination of alcohol and passionflower or any other supplement that acts on the same neurotransmitter can cause greater sedation and impair cognitive ability or motor reflexes more than you would expect with just one or the other.
Melatonin
Melatonin is one of the most popular sleep supplements, often taken just before bed to help reset your circadian rhythm after travel, during shift work or when you just need a sleep reset. If you also enjoy a nightcap in the hours before sleep, you could be canceling out some of the positive effects of melatonin while potentially increasing negative ones.
“If you take melatonin expecting better sleep, but pair it with alcohol, you’re essentially undoing the circadian rhythm–syncing benefits of the supplement, while adding on the sleep-disrupting effects of alcohol,” says Lauren Manaker, M.S., RDN, LDN. While alcohol may help you drift off to sleep more quickly, it fragments your sleep, causing more nighttime awakenings and less restorative REM sleep. So while melatonin mainly helps you fall asleep faster to gently reset your internal clock, it isn’t designed to override the sleep disruption caused by alcohol.
Vitamin A
Vitamin A is a fat-soluble vitamin often found in supplements that support eye, skin and immune health. Unlike water-soluble vitamins, the body stores vitamin A, mostly in the liver, the same organ that processes alcohol. “Regularly drinking alcohol depletes the liver of its vitamin A stores, increasing the risk of deficiency,” says Manaker.
But supplementing with even more vitamin A to cancel out the depleting effects of alcohol can have toxic effects as well. As alcohol depletes liver stores of vitamin A, it also causes dietary vitamin A to be sent to other tissues in the body, leading to a buildup in those tissues instead of the liver, where it’s meant to be. High levels of vitamin A in areas other than the liver can lead to hypervitaminosis A, with symptoms including hair loss, dry, cracked skin, fatigue, loss of appetite and liver damage. Because of the potentially severe effects of regularly combining alcohol and vitamin A supplements, taking one should only be done under the direction of a medical professional.
Other Safety Tips for Taking Supplements
- Always talk to a health care provider. A pharmacist or physician can cross-check a new supplement against your medications, your health history and your drinking habits to help catch any potential interactions before they have a chance to occur. Before you start a new supplement, it is wise to check in with a health care professional to ensure it is a safe and helpful fit for your routine.
- Check that it is independently verified. Supplements aren’t regulated in the same way as medications, so a seal from an independent verifier (like USP, NSF or Informed Choice) tells you the product actually contains what the label claims and isn’t contaminated with things that shouldn’t be there.
- Understand what’s in your supplement. “Not all supplements are the same—the dosage form, standardization of the extract and part of the plant used are important to understand,” says Buksov. Two products with the same herb on the label can behave very differently depending on how they’re made or what they’re combined with.
- Start low and go slow. Buksov recommends a “start low, go slow” approach and to have monitoring parameters in place for any new dietary or supplement change. Introducing one new supplement at a time, at a modest dose, makes it much easier to detect how your body responds and identify any potential side effects.
Our Expert Take
Alcohol can change how your body absorbs, processes and tolerates certain supplements. Some of these combinations simply blunt a supplement’s benefit, while others compound side effects or add stress to the liver. The safest approach is to use informed caution when taking supplements and to check with a pharmacist or physician if you have any questions or concerns. If you do decide to drink alcohol, understanding how it may interact with your supplement regimen is essential.