When the guy manning the griddle at my local deli sees me walk in, he gets to work on my standard order: two eggs, cheddar, and avocado on a toasted everything bagel with hot sauce. I used to have to stay on top of him as, with several other orders being barked, he’d need at least one reminder of what I wanted. Now he’s got it down cold, I’ve got plenty of time to peruse the bounty of items the establishment stacks, floor to ceiling, while I wait.

A few weeks ago, I was absent-mindedly scanning the area behind the register and saw a line up of packages featuring images of samurai warriors, holographic rhinos, and the like. For a split second, I didn’t know what I was looking at but after reading the words “time,” “size,” and “stamina,” I figured out that they were, in fact, boner pills. I’d always seen products marketed as “male enhancement” in bodegas and gas stations but dismissed them immediately. I suppose I just found it hard to believe that anyone would take these herbal concoctions and expect anything to happen. “Horny goat weed”—often a top line ingredient in these pills—just sounded ridiculous.

“Yo, that’s good shit man,” the cashier said when he saw me eyeing up the selection of around half a dozen packets of pills.

“Come on,” I said. “That stuff’s bogus, right?”

“I swear to god man,” he said, eyes wide. “It’s no joke.”

Being the curious sort and in a somewhat silly mood, I forked out the $10 on the “Rhinozen Black Fire” just to make sure that these pills were snake oil and not, as the cashier suggested, potent. Though the packaging proudly stated that the product is made in the USA, phrases such as “gentleman entry begins” and “rock hard rerctions (sic)” didn’t instill me with confidence that these pills were in any way legit. This despite a graphic that read “100% Genuine Product” and another that suggested that the effect of a pill lasts up to 11 days! I mean, come on.

A few days later, I was just bored enough to give the pill a try, ingesting it on a Wednesday morning before heading off to the gym. Generally, I like to start off with a mile-long run but after just a few minutes on the treadmill, my heart felt as though it was trying to bust out of my rib cage. Feeling light-headed, I stumbled off of the treadmill and took a knee, hoping that the feeling would go away. Ten minutes later, however, it seemed to have gotten worse. By the time I got outside I was feeling pains in my chest. As my breath became shallower, I called a friend to try and calm myself down.

“What’s wrong with your voice?” he asked as I tried to avoid thinking about the prospect of keeling over. “It’s all quavery.”

Embarrassing as it was, I quickly fessed up to what I’d done, chiefly because I felt that this phone call might be the last one I’d ever make.

After returning home I did something I probably should have done prior to swallowing the pill, and googled what I’d just ingested. I quickly learned that the FDA has no fewer than twenty “rhino” branded products on a list entitled “Tainted Sexual Enhancement Products.” The specific formulation I’d foolishly taken, Rhinozen Black Fire, wasn’t on the list but I figured it was pretty safe to assume that, like “Boss Rhino,” “Krazzy Rhino,” and “Rhino Big Horn,” it too contained ingredients other than the innocuous-sounding ones listed on the back.

My experience certainly didn’t feel like it was the result of goji extract, licorice, or ginseng. Turns out that for virtually every male enhancement product it had analyzed, the FDA concluded that either sildenafil—the active ingredient in Viagra—or tadalafil—the active ingredient in Cialis—was present.

While regarded as being quite well-tolerated, both sildenafil and tadalafil require a prescription from a doctor. He or she will have to discern whether these drugs—which are called phosphodiesterase-5 (PDE5) inhibitors—could cause problems due to a patient’s existing health condition or interactions with other drugs they’re taking.

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A PDE5 inhibitor is a vasodilator, meaning that it opens blood vessels. “PDE5 inhibitors may result in a raging boner but at the same time, it’s dilating all the blood vessels in your body,” says Seth Cohen, a urologist at NYU’s Langone Health. This is why a headache, dizziness, flushed face and—as I’ve previously written about—a stuffy nose are common side effects, particularly in younger men. Nitrates, a type of medication used to treat or prevent heart pain, are also vasodilators. “Nitrates alone can cause dangerous drops in blood pressure and a double dose of vasodilators is, doubly dangerous,” he says.

Also, once you get a prescription for legit erectile dysfunction medication, you actually know how much you’re taking. There’s really no telling how much of these drugs are being added to these cornerstore pills, many of which are somehow available at Amazon. The issue with store-bought supplements is that they don’t comply with the same rules that drugs do, says Landon Trost, a urologist at the Mayo Clinic. “Supplements typically only get attention from the FDA if a certain number of severe injuries or deaths occur,” says. “Otherwise, they stay under the radar.” Trost also tells me that in unregulated supplements, the label doesn’t necessarily reflect what’s actually in there, and dosages will fluctuate from one sample to the next.

Cohen adds that the symptoms I reported could be due to a large dose of a PDE5 inhibitor, the interaction of the PDE5 inhibitor with whatever other ingredients found in the pill, or both. Again, there's no way to actually know because the supplement was not regulated or tested the way legit drugs are.

After about three hours of lying down and moving around as little as possible, the feeling that I was about to die in the most pointless way imaginable began to dissipate. I was still too shaken up to investigate whether the pill would do what it promised but the following morning, I awoke with an erection like a crowbar that didn’t fully subside for some 90 minutes. And for the next several days—though not quite 11—every boner I had seemed significantly more intense than normal. While that sounds like a positive outcome, my rather foolhardy self-experiment coincided with my girlfriend and me breaking up, so I didn’t even get to use Rhinozen Black Fire as intended.

I made a concerted effort to track down the entity that makes Rhino products for comment, but the best I could do was find someone at a Pennsylvania-based distributor of the product—Sassy Sensations. Though I was promised a call back from the firm’s owner, the only effect my inquiry had was the disappearance of the product from their website around an hour later. “Oops—we couldn’t find that one” reads the message on the page that still has Rhinozen Black Fire in the URL. Another result of my probing was the discovery of news that in October of 2018, a South Korean national was arrested in Fullerton, California after being suspected of illegally importing and selling erectile dysfunction drugs, including Rhino capsules. If that was the guy I needed to speak with, I can imagine that he wouldn’t be so eager to chat.

When I was sure that it was finally out of my system for good and all, I asked Trost if I was in any real danger. He told me that there was really no way of knowing. To illustrate his point, he recalled a recent case of a man taking four 100 mg viagra pills—four times the maximum recommended dose—and damaged his kidneys in the process. He contrasted this with a 2015 report of a 56-year-old who attempted to kill himself by taking 65 100 mg Viagra pills—the highest known dose. “It’s important to note though that just because one person survived such an extreme dose doesn’t mean that everyone would respond similarly,” he says.