Activated charcoal has been buzzy in the wellness world for years, popping up in a whole bunch of products—from facial cleansers to deodorants—and promising a slew of benefits, from unclogging pores to “detoxing” your body.
Now, we’re seeing it play a different role: turning various foods and drinks pitch-black for Halloween. There are charcoal-colored sprinkle cookies, spooky black margaritas with an orange Tajin rim, charcoal-and-turmeric bagels, and even pumpkin pizza with a charcoal crust. The natural black food coloring seems to turn everything into the perfect shade of inky black.
But the treats may come with an unintended trick: Activated charcoal can interact with certain medications, causing them to work less effectively…or not at all. If you’re thinking about whipping up black cocktails or cupcakes this Halloween, here’s what you need to know about the possible risks of using activated charcoal to get the job done.
What is activated charcoal…and what’s it doing in your icing?
Activated charcoal is a fine black powder that’s made by burning various substances like coconut shells, nut shells, or wood, then “activating” it by heating it along with a gas. This processing creates a bunch of pores in the charcoal, which can help trap chemicals that come into contact with it.
That brings us to its main benefit: “Activated charcoal is sometimes used in the treatment of acute poisonings or after unintended ingestion of medications or other substances,” Sarah Mersek, PharmD, a drug information pharmacist at the Cleveland Clinic, tells SELF. Basically, it soaks up the bad stuff and prevents it from getting absorbed into your bloodstream. The same pores make activated charcoal a helpful ingredient in beauty products, too, since they help substances stick together and “act like a magnet for dirt, oil, and other impurities,” Sejal Shah, MD, a dermatologist at Real Self in New York City, previously told SELF. (What it won’t do? Remove toxins from your body, as SELF debunked back in 2017—your liver and kidneys do a good job of that on their own.)
Then there’s activated charcoal’s most seasonal use as a food coloring. Typically, the powdered form sold for this is made from coconut shells, and its inky, saturated color is simply great for turning things black—a spooky-season benefit that doesn’t have anything to do with its behind-the-scenes absorption work.
What are the potential risks of using activated charcoal in food?
Eating activated charcoal in the short-term is “likely” safe, and consuming it regularly in the long-term is “possibly” safe too, according to the National Institutes of Health. Though in either case, it can cause not-so-pleasant side effects like constipation and black poop.
But just because activated charcoal is probably safe, doesn’t mean it’s risk-free for everybody. “Activated charcoal can reduce the absorption of other medications,” Dr. Mersek says. Because of its porous structure, activated charcoal binds to certain drugs in your stomach and stops them from entering your bloodstream to do their job, she explains.
What medications can activated charcoal mess with?
According to Dr. Mersek, activated charcoal can interact with the following meds:
- Acetaminophen: a pain reliever and fever reducer
- Aminophylline: used to treat wheezing, shortness of breath, and difficulty breathing caused by asthma, bronchitis, and other lung conditions
- Amiodarone: used to treat and prevent serious, life-threatening abnormal heartbeat or arrhythmia
- Aspirin: used to prevent and reduce the risk of heart attack and stroke in high-risk people, treat the symptoms of arthritis, relieve pain, and reduce fever
- Atenolol: a beta blocker used to treat high blood pressure and prevent chest pain
- Carbamazepine: used primarily to control seizures in people with epilepsy
- Digoxin: used to treat heart failure and arrhythmias
- Fluoxetine: a psychiatric medication used to treat depression, obsessive-compulsive disorder, some eating disorders, and panic attacks
- Indomethacin: used to treat severe arthritis pain
- Phenytoin: used to control and prevent certain types of seizures
- Valproic acid: used to treat certain types of seizures
- Verapamil: used to treat high blood pressure and chest pain
The National Institutes of Health (NIH) says that activated charcoal can make all types of oral birth control pills less effective as well. (When in doubt, talk to your doctor or pharmacist to see if your meds may be affected.)
Okay, but can the amount of activated charcoal used for food coloring actually mess with these meds?
“Activated charcoal doses of 25 to 100 grams in adults and 10 to 50 grams in children can prevent the absorption of other drugs,” Dr. Mersek says. That’s generally the therapeutic dose given in cases of overdoses or poisonings.
Food coloring generally uses much less than that: For example, an entire batch of Halloween cookies or a pitcherful of inky black margaritas may only contain about a teaspoon or two. And one teaspoon contains just about two grams of activated charcoal, Charles Michael White, PharmD, department head of the UConn School of Pharmacy, tells SELF. (However, the exact amount will differ depending on the actual charcoal product, Dr. Mersek says.)
In most cases, these small amounts bring less cause for concern. A one-teaspoon dose “would only have a modest effect on the absorption of drugs from the intestine to the bloodstream,” Charles Michael White, PharmD, department head of the UConn School of Pharmacy, tells SELF.
And timing your activated charcoal treats helps reduce the risk even more. The NIH recommends waiting at least an hour after you take your meds before eating them. As for birth control pills, you should either eat or drink activated charcoal at least 3 hours after or 12 hours before taking your meds to make sure your dosage is as effective as possible, the NIH says. This gives your meds enough time to make their way from your digestive tract to your bloodstream.
The modest absorption issues likely seen with a teaspoon-size dose “would be dramatically reduced if you avoid taking activated charcoal products for [about] three hours before or after the activated charcoal is taken, and is safe for most people,” Dr. White says.
Still, he says, if you’re taking what are called “narrow therapeutic index drugs”—in which small differences in blood concentrations can be serious, like with certain meds for epilepsy, arrhythmias, or organ transplants, among others—you should be more cautious. (If you’re not sure if your drug is considered one, ask your pharmacist.)
“It’s well known that even small changes in epilepsy drug blood concentrations can cause breakthrough seizures,” Dr. White says. “If I was taking a narrow therapeutic index drug, I would simply skip the activated charcoal altogether.”
Additional reporting by Ashia Aubourg
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