Boners are all about blood flow. So your heart—the organ that pumps your blood—has to be in tip-top shape for you to have A-plus erections. Anything that puts strain on your ticker, like being overweight or smoking, also tends to take lead out of your pencil.
Testosterone is the second factor that's crucial to a strong erection, and there are plenty of weird things that screw with its production. All the items on this list can mess with your manhood:
1. Grocery receipts. The types of thermal paper and ink used for most supermarket receipts contain high levels of bisphenol-A (BPA), a chemical that increases your body’s production of the female hormone estrogen. And that estrogen boost—along with some other BPA-triggered hormonal changes—harms your hardness, finds a study from Kaiser Permanente. ATM receipts, airport baggage tags, and lottery tickets are all printed on this BPA-heavy kind of paper. As you’ve probably heard before, hard plastics and canned foods are also common BPA sources.
2. Dessert. Consuming sugar, whether in a slice of cake or a can of soda, causes an uptick in your blood’s glucose levels, which stimulates the release of the hormone insulin. That torpedoes your body’s testosterone production, making it tougher for you to get it up, shows a study from Irish and American researchers. (This sugar-insulin-testosterone connection also explains why your T levels spike and you tend to pitch a tent first thing in the morning—when you haven’t eaten for hours.)
3. Crappy shuteye. Sleeping 5 hours a night (or less) for a few days was enough to sink T levels by 10 percent among a small group of healthy young guys, found a study from the University of Chicago. Sleep is essential for testosterone production. And so if you’re not getting enough of it—around 8 hours a night—don’t be surprised if you erection seems groggy, the study suggests.
4. A baby in your bedroom. Snoozing in close proximity to your newborn—like if you have him or her in a bassinet in your bedroom—lowers your testosterone production 7 percent or more, shows a study from Notre Dame and Northwestern University. You might think sleep disruption is to blame. But there’s evidence that hormonal shifts caused by spending the night next to your tyke triggers the drop in T, the study authors say.
5. Soy. Every vegan's favorite meal ingredient has “estrogen-like properties” that saps your body’s T store, finds a study from Harvard Medical School. A little soy won’t kill your libido. But a soy-heavy diet—think multiple daily meals that include it— could spell trouble for your erection, the study demonstrates.
