Underwear is often the most overlooked article of clothing, and many of us may never give a second thought to exactly what we wear down there.
However, experts agree that the underwear you choose can have positive or negative effects on the wellness of your genital area. For instance, underwear that makes you sweat more can lead to itching and yeast infections. Certain cuts of underwear, such as thongs, can increase the risk of bacterial vaginosis or other infections. Underwear that’s too tight can cause constriction, chafing and bacterial infections, and there is some evidence that it can affect fertility in men.
When selecting a pair of underwear, it’s important to consider the fabric, fit and cut. And you’ll want to think about when and how often you change or go without underwear.
We spoke with four experts — two OB-GYNs and two urologists — who gave us their best advice for choosing and wearing underwear.
Stick with cotton or other natural fabrics.
When selecting a pair of underwear, the fabric is a major consideration. “Generally speaking, the best fabrics for underwear are natural fabrics like cotton,” said Dr. Andrea Braden, a board-certified OB-GYN in Atlanta. “It really has to do with the breathability of that fabric. We do know that air circulates better with cotton underwear versus polyester. It is important for vulvar health to have good air circulation.”
Other good natural options include hemp, bamboo and linen, said Dr. Suzy Lipinski, a board-certified OB-GYN at Pediatrix Medical Group in Denver.
Urologists agree. Dr. Scott D. Miller, the medical director at Wellstar Urology in Atlanta, said that cotton stands out because “it is comfortable, cool, breathable, moisture-wicking and absorbent.” However, “these characteristics are dependent on the quality of the cotton fiber and various types of weaves,” he noted.
And there are instances where other fabrics might do better. “During times of increased perspiration, cotton can retain too much moisture, leading to bacterial and fungal overgrowth,” Miller added. “In these cases, a better choice may be a fabric made of a combination of cotton and a synthetic fiber.”
Avoid fabrics that don’t let you breathe down there.
Lipinski advised against “non-breathable fabrics,” including synthetics such as nylon and satin. Additionally, “woven, rather than knit, fabrics or thick fabric can also limit how much [the fabric] breathes,” she said.
Miller said pure polyester “is probably the worst fabric for underwear” and explained why.
“Although it is among the lightest materials, it is neither absorbent nor very breathable,” he said. “However, its durability makes it a good addition as a small proportion of [fabric blends].”
If you’re unsure of a particular fabric blend, Braden suggested that feeling the fabric can help you decide. “It should be soft and not slippery.”
Even underwear that isn’t made of a natural, breathable fabric will often “have a cotton panel in the crotch area or gusset,” she added. And that’s a good thing: “That is because cotton is the most ideal fabric to be sitting in your ‘nether regions.’”
Pick a cut that feels comfortable to you.
The doctors generally agreed that when it comes to picking a cut of underwear, there’s no real right or wrong. Rather, it’s about what feels comfortable to you and what allows your body to breathe.
“The key is a comfortable fit that is not constricting or chafing,” Lipinski said. “This means different underwear for different body types. … Ask yourself, does the underwear feel comfortable and move with you or tighten up and constrict? Does the underwear ride up or cause chafing? Even two pairs of underwear in the same cut but [from] different brands can fit differently.”
Dr. Fenwa Milhouse, a board-certified urologist with Down There Urology in Chicago, said that “loose-fitting underwear has long been recommended,” adding that “tight-fitting underwear reduces air circulation and may increase local moisture down there, which can cause skin irritation and cutaneous or skin yeast infections.” Therefore, she encourages her patients to pick cuts that are “most comfortable for them.”
However, there may be reason to believe that certain underwear styles are better for fertility than others. Milhouse noted that a 2018 Harvard study evaluating semen parameters from almost 700 men found that participants who primarily wore boxers had a 25% higher sperm concentration than those who did not.
Still, “briefs have the advantage of better support and protection,” Miller said. “Boxers have the advantage of freedom of movement, although the extra material may cause bunching. Boxer-briefs combine the features of both, although most of these designs are form-fitting in the style of briefs.”
Consider how often you wear thongs.
Breathability doesn’t necessarily mean less fabric, with Lipinski noting how thong underwear tends to be tighter and more constrictive.
“This doesn’t mean that you can’t ever wear it, just maybe minimize use or save for those special occasions,” she said.
Also, consider your medical history.
“If you are prone to infections, then you may want to avoid wearing a type of underwear that is a thong or sits very closely to the rear end,” Braden said, adding that it can increase risk for bacterial vaginosis. “The reason behind that is that you can have bacteria tracked from the rectal area forward when the fabric is lying that close to the rectum. So if you’re going through an infection or prone to infection, it is probably best to wear something like a bikini or brief, or even boy shorts.”
Change your underwear daily, at minimum.
The agreed-upon rule among the doctors interviewed is to change your underwear at least once per day to make sure things remain clean and dry and to decrease the bacteria load.
“Bacteria is normal. We all have normal bacteria that lives on the vulva or in the rectal area,” Braden said. “What you don’t want is growth of bacteria coming from your clothing or your underwear.”
Braden explained how wearing underwear for long periods of time can cause infections or odors because moisture mixes with the normal bacteria that’s down there.
So it’s important to change your underwear as frequently as you can. Some people may even want to consider changing their underwear more than once a day.
“If you are active and sweat a lot or struggle with incontinence, then you may want to change even more frequently,” Lipinski said.
Consider going commando when you sleep.
Although some doctors found no issue with sleeping in underwear when done properly, others felt it may be beneficial to go without.
“In general, I recommend sleeping without underwear,” Milhouse said, adding that it allows your private parts to get air ventilation, decreases moisture and reduces irritation to the skin.
“Even for my incontinent patients, at night I encourage them to sleep without underwear and pads and instead sleep commando on an absorbent towel or sheet,” she said.
Ultimately, the decision is more about personal preference. However, it’s important to pay attention to how your body reacts.
“If you’re having any complaints, such as itchiness issues, in general, the more air the better,” Braden said. “The less trapped everything is against your skin, the better the skin is, the healthier it is. Yes, you can sleep in your underwear, but make sure it is something breathable, and make sure you are changing that daily.”