What Causes Acne, and How Can You Prevent It?

Jeff Hautala
By Jeff Hautala, Co-Founder of Exposed Skincare

The first thing we have to consider when treating acne is what causes acne. You hear a lot of claims about what causes acne, from dairy to steroids, even vaping. Some of these really can cause acne, but others definitely do not. Still, just knowing what can cause acne in general isn’t enough to treat your specific acne, because everyone’s acne is caused by a slightly different grouping of factors. So we’re here to help you find out why you have acne.

beautiful woman lying on the ground
Finding out what causes acne can help you find the best treatment for your skin.

Why Do I Have Acne?

Each individual with acne has it for a different combination of reasons, because there are nearly countless potential reasons for acne. Something that causes acne in one person may not cause it in another, and the answer to “why do I have acne?” may change throughout your own life as well. In the teenage years, hormones are typically what causes acne, while adult acne is more commonly caused by dry skin or slowing skin cell production. Although there are many large-scale causes for acne, at the skin-level, all of these causes can be simplified into three core reasons for acne: inflammation, bacteria, and oil production.

Reasons for Acne

When we search for reasons for acne, typically we want to know the factors in our daily life that could be contributing to our acne, because then we can change them. But why do those factors cause acne in the first place? It all comes back to three main reasons for acne: inflammation, bacteria, and oil production. All acne is a result of some combination of these three causes. Find out why these factors are so important to acne formation, what the main acne symptoms are, and how long acne lasts below.

The Most Common Acne Symptoms

Acne symptoms differ based on what kind of acne you have: blackheads, whiteheads, pimples, or cysts. It also depends on what your skin type is. For instance, if you have dry skin, acne may take the form of small white or red bumps that look almost like a rash, but it’s also possible you might have sporadic pimples. If you have oily skin, you could have widespread blackheads, but you might have large, painful cysts. Combination skin often has a variety of types of acne. We’ll explain the causes of each of these kinds of acne in a moment, but first, what do they look like? How do you know what kind of acne you have?

Blackheads are small, pore-sized dots typically dark brown in color, and whiteheads are small, pore-sized dots that are often skin colored or slightly white. It’s important to note that whiteheads are only the size of one pore, and are not inflamed. If you have a white bump that is red around the edges and maybe painful to the touch, that is most likely a pimple, or a pre-pimple, sometimes called a papule. Once there is a clearly defined white or yellow head, it’s officially considered a pimple. Cysts are inflamed, like pimples, but they don’t have a clear head. Instead, they have a blister-like appearance, but with a thicker layer of skin. Cysts are often soft to the touch, but they should never be popped at home, as this can cause serious scarring.

How Long Does Acne Last?

Like acne symptoms, how long acne lasts really depends on the person. If we’re talking about how many years a person has acne in general, that can be anywhere from zero to 90, though it is most common to get acne around age 11-14 and for it to fade around age 24-28. Still, this won’t apply to everyone. In fact, recent studies show that many women are experiencing higher rates of adult acne lasting into their 30s.

On a smaller scale, if you’re wondering how long individual acne lesions will last, it depends on what kind of acne it is. Blackheads and whiteheads can be tricky to get rid of, and sometimes last several weeks, or might appear to last for weeks because as the old ones fade, new ones take their place. Pimples typically become more inflamed over the course of a few days, come to a head, and then either pop or fade and the skin returns to normal after another few days. A dark mark may also be left behind, lasting anywhere from a day or two to several weeks. Cysts are typically considered the longest-lasting type of acne; one cyst might stick around for a few days or a few weeks, becoming more and more infected. But if you have cystic acne, there’s no need to panic. Dermatological care can greatly reduce the length of time cysts last, and can even prevent them entirely.

Inflammation: The Heart of It All

You may have heard of inflammatory and non-inflammatory acne, but the truth is, all acne starts with some degree of inflammation. The skin can become inflamed in a variety of ways, including irritation from harsh skin care products, picking at the skin, a fever, and an allergic reaction, among many others. Any time the skin becomes inflamed, it swells slightly and your pores start to constrict. This traps oil, dead skin cells, and bacteria in the pore, which can then cause all kinds of acne, from blackheads to cysts.

So then, is all acne inflammatory? Well, technically yes, but the terms “inflammatory acne” and “non-inflammatory acne” refer to inflammation that occurs (or doesn’t occur) after the acne forms. For instance, blackheads and whiteheads are considered non-inflammatory acne because the skin doesn’t become even more inflamed after they form. Pimples and cysts, on the other hand, are considered inflammatory acne because they become even more inflamed after forming. This is because of the bacteria that causes acne.

The Bacteria That Causes Acne

There is a particular type of bacteria that causes acne, called p. acnes, but it isn’t all bad. P. acnes is actually a natural part of the biome of bacteria that always live on the surface of our skin. They really only become a problem when inflammation traps them in a pore. Once trapped in the pore, these acne bacteria start to multiply, and eventually your body recognizes it as an infection. This is when pimples form. The skin triggers the inflammation response around the infected pore to prevent the infection from spreading, which is what makes pimples raised and often painful. The immune system sends cells to fight off the acne bacteria, often killing themselves in the process as well. All of the dead cells create pus, which is what gives pimples their white or yellow heads.

Typically, this is where the process ends, but sometimes our immune system struggles to kill the p. acnes infection. P. acnes have a special chemical they can release that attaches to our skin cells to make them seem like bacterial cells to our immune system, causing us to attack our own cells instead of the p. acnes. This allows the infection to spread deeper into the skin, creating a cyst.

Oil Production: When Normal Processes Go Awry

Similar to how we always host a certain amount of p. acnes bacteria, our skin is always producing oil. It’s absolutely necessary to the health and protection of our skin. Although we often think of oily skin being especially acne-prone, dry skin runs into many problems as well. In fact, many people who think they have oily skin may be over-drying their skin. Healthy skin always produces a certain amount of oil to provide a layer of protection between our skin and any potential irritants, like pollutants in the air or rough fabrics. This is a very good thing, because irritants cause inflammation, which we now know is where all acne starts. However, sometimes we produce a little too much oil, and that can cause problems.

Our skin can overproduce oil for any number of reasons, from hormonal fluctuations to genetic predisposition. When we produce too much oil, it gets backed up in our pores, causing clogs. If the pore is closed at the surface of the skin, the clogged pore forms a whitehead, a collection of oil trapped beneath the surface, leaving a small, slightly raised white bump. If the pore is open at the surface of the skin, it forms a blackhead, a collection of oil trapped in a pore, but exposed to the air. Although it is common belief that blackheads are caused by dirt, this is not true. Blackheads are just like whiteheads, except the pore is open to the air, which oxidizes the excess oil in the pore, turning it a dark color. Think of it like an apple that you cut up and leave on the counter. The exposure to the air turns it brown after a little while.

Wait, Is Acne Genetic?

Absolutely. Unfortunately, researchers haven’t discovered exactly how acne is passed down or what about our genetics makes us more or less prone to getting acne, but studies suggest genetics do play a large role. In attempts to answer the question “is acne genetic?” researchers have controlled for environmental factors and still found that parents with acne were more likely to have children with acne. Other studies have found that some people seem more generally predisposed to acne than others in the same environment, making researchers inclined to believe that there is a genetic component involved in acne.

It can be hard to wait for acne to fade, but it does eventually.

Is Acne Contagious?

One of the most common questions about what causes acne is whether or not acne is contagious. Generally, acne is not contagious and cannot be passed from person to person. This is an understandable worry, because acne is at least partially caused by bacteria, but p. acnes doesn’t quite work like that.

The first reason acne isn’t typically contagious is because everyone has p. acnes bacteria on their skin already. If you have acne and your skin touches someone else’s, some p. acnes bacteria could transfer from your skin to theirs, but they already have p. acnes as well, so it’s very unlikely to cause any change in their skin.

Second, the actual infection of p. acnes bacteria is contained beneath the skin in the head of the pimple or pimples. It can’t transfer to someone else because your own skin is in the way.

The third and last reason acne is not really contagious is because p. acnes are anaerobic bacteria, meaning they can’t survive in the open air. Exposure to oxygen will kill p. acnes pretty quickly, so even if you have p. acnes on your hands from picking at your skin, other people can’t get p. acnes from touching your hand or things you’ve touched.

The one condition under which acne is likely to be contagious is when it comes to your own skin. You can easily spread acne bacteria from one part of your skin to another by picking at pimples and trying to pop whiteheads or blackheads. The bacteria can leave the oils in your face and move to the oils on your fingers and then immediately return to your skin as you continue picking. The short time the p. acnes are on your fingertips before they transfer to the next place you’re picking is so short, they typically don’t die from oxygen exposure.

Stress Acne: When Our Bodies Take Fight, Flight, or Freeze a Bit Too Seriously

Stress acne is a common occurrence largely because our bodies don’t distinguish between emotional threats, like the stress of a big presentation at work, and physical threats, like a charging lion. All threats are the same to our autonomic nervous system, the part of our nervous system responsible for our fight, flight, or freeze response. If you’re under a lot of stress, your autonomic nervous system will try to protect you.

The problem with this is that an elevated heart rate, quickened breathing, and increased sweating doesn’t help with emotional stress the way it might with physical stress. But the reason this response leads to stress acne is the negative way our body responds to chronic stress. When we experience constant or repeated stressors that trigger our fight, flight, or freeze response, our body becomes less sensitive to the hormones that regulate inflammation throughout our body, hormones like cortisol and adrenaline. This can lead to increased inflammation, which can kickstart all kinds of acne, but it can also lead to increased production of these hormones, which can contribute to increased oil production.

Non-Stress Related Hormonal Acne

Although stress hormones are one of the main culprits for acne, other hormones can be at fault as well. As we delve into some of the external causes of acne, it’s important to remember that all outside causes of acne only produce acne because they affect the three root causes of acne: inflammation, bacteria, and oil production. Generally speaking, hormonal shifts cause acne because they cause increased oil production, which also encourages accelerated bacteria growth. Menstruation, polycystic ovarian syndrome, having a baby, taking steroids, and using creatine can all affect hormones in such a way as to cause increased acne.

Steroid Acne

If you’ve ever taken steroids, you may have noticed an increase in acne. When you understand how hormones are related to acne, steroid acne makes a lot of sense. The term “steroids” is actually short for “corticosteroids,” a synthetic form of the hormone cortisol. If you remember from our discussion about stress acne, cortisol is integral to our body’s stress response, and overexposure to it can lead to dysregulation of the inflammation response, which causes stress acne.

Steroids work in much the same way. Instead of producing extra cortisol due to stress, steroids introduce extra cortisol artificially. This can improve performance, in body-building or in treating an injury or infection, but it also reduces the body’s ability to regulate inflammation, leading to increased acne.

So how can you tell if you have steroid acne? The best clue is to pay attention to when your breakouts start. If you were relatively acne-free before starting steroids, that is a big clue that they play a role in your recent acne. If you had acne before starting steroids, they could still be affecting your skin. There are a few signs to look out for to help identify steroid acne. First, although steroid acne can appear on the face, back, or arms, it is most common on the chest. Second, it can take the form of many different types of acne, from blackheads to cysts, but inflammatory acne like pimples, cysts, or nodules (hard cysts) is typically more common. If you think your steroids could be causing increased acne, speak with your doctor.

So…Does Creatine Cause Acne Too?

That’s a fair question. If steroids, typically used in body-building, can cause acne, then it’s possible that creatine, also used in body-building, could too. However, creatine is actually very different from steroids, and the research on the relationship between creatine and acne is much less clear. It’s important to note that no major research study has examined the relationship directly between creatine and acne. All the information we have on creatine and acne is based on its general properties and how we assume it will interact with acne.

Creatine is a supplement that increases the body’s capacity to store energy, which can boost performance in body-building and sports. While steroids are an artificial hormone, creatine simply manipulates hormones, rather than mimicking them. Some studies have shown that creatine can increase testosterone levels, which can boost oil production and lead to more acne. But creatine isn’t the only way testosterone levels can shift to cause acne.

Studies show that acne may be caused at least in part by a genetic predisposition

PCOS Acne: Why Acne Can Be a Sign of Polycystic Ovarian Syndrome

PCOS, or Polycystic Ovarian Syndrome, is a hormonal condition that often includes testosterone fluctuations. But how does that lead to PCOS acne? When testosterone increases, it stimulates excess oil production, which can lead to clogged pores and increased acne.

It’s important to note that having naturally high levels of testosterone doesn’t necessarily lead to more acne, it’s only when testosterone levels rise above your personal natural level that acne can result. For instance, most men and some intersex folks naturally produce high levels of testosterone and low levels of estrogen, while most women and some intersex folks naturally produce low levels of testosterone and high levels of estrogen. Testosterone-related acne only occurs when testosterone levels increase from your normal level, no matter where that level is normally. Testosterone can increase for a variety of reasons (like creatine use), but one of the most common reasons for testosterone imbalance in women is PCOS.

PCOS is a common hormonal condition that affects 5-10% of women, but is still very poorly understood. For instance, despite its name, many women with the condition don’t actually have ovarian cysts. One of the most common symptoms is insulin resistance. PCOS interferes with the body’s ability to break down sugars, so it uses more insulin. Eventually, the body gets used to the increased insulin and needs to produce even more. This continues until the body develops insulin resistance and the body needs to find other methods for breaking down sugar. The ovaries respond to this problem by producing excess testosterone, which results in increased oil production that creates PCOS acne.

Estrogen, Testosterone, and Period Acne

It’s very common for people who menstruate to experience period acne the week before their period starts. Unlike PCOS or creatine, menstruation doesn’t encourage increases in testosterone, it leads to an increase in estrogen, followed by a relatively sudden decrease. Because estrogen typically balances out testosterone, when it decreases significantly, like it does the week before menstruation starts, there is a relative increase in testosterone. There’s less estrogen to balance it out, so your body reacts the same as it would if you had a spike in testosterone.

In the weeks following menstruation, the ovaries secrete increased amounts of estrogen to help the uterus build up the uterine lining to prepare for the possible implantation of a fertilized egg. Once the lining has reached appropriate thickness, estrogen drops off and period acne can occur. About one week later, the uterus recognizes that no egg has implanted and the uterine lining begins to slough off in menstruation.

Is Postpartum Acne Normal?

After you have a baby, there are approximately 18 million issues to juggle. There’s your new lovely peanut, of course, and their unpredictable, constant routine of feeding, then there’s your own care, recovering from the trauma of birth (yes, it can be incredibly and traumatic simultaneously), and fielding constant, sometimes unwelcome, visits from loved ones who touch you and your baby entirely too much. And on top of that, many people experience postpartum acne.

After pregnancy, the body no longer needs to maintain the intense hormonal levels it supported during pregnancy. As these hormones drop off back to their normal levels, the body undergoes some side effects, including postpartum acne and melasma, a skin condition sometimes referred to as “the mask of pregnancy.” This is the side effect of overproduction of melanin during pregnancy that can give the skin a grayish hue during pregnancy or after birth. Both melasma and postpartum acne are incredibly normal. The body is simply trying to find new normal hormone levels after pregnancy, and that can take some time and come with some side effects. It can be frustrating, for sure, but if you have postpartum acne, you definitely aren’t alone.

Everything You Need to Know About an “Acne Diet”

Genetics, bacteria, hormones, all of these things definitely cause increased acne…but what about your diet? You may have heard the old wives tale that chocolate causes acne, but could it be more than a wives tale? What about caffeine, or dairy? The truth is, there is no solid research on how diet affects acne, and there is certainly no magical “acne diet” that will prevent acne.

It’s not that researchers haven’t tried to study how diet affects acne, it’s just a difficult thing to study. To determine how diet affects a very specific problem, like acne, you would have to control for a million other environmental factors, like hours of sleep, stress levels, pollution levels, pollen count, and more. Diet studies also rely on the participants adhering to the study’s diet perfectly, which is rarely the case. Because of this, we just aren’t sure how diet affects acne. There are a few preliminary studies that suggest foods that may or may not cause acne, but many studies contradict each other or rely too heavily on the individual components of any given food, rather than studying the food as a whole.

Generally, the best way to treat acne is not with an acne diet, but with a gentle skin care routine, like the Exposed Skin Care routine. Our Basic, Expanded, and Ultimate skin care kits make good, healthy skin care available to everyone, from acne treatment newbies to skin care gurus.

At Exposed, we’ve developed skin care kits that range from simplistic to intensive so you can find the perfect skin care routine for you.

Does Sugar Cause Acne?

The question of whether or not sugar causes acne is a bit more complicated than simply looking at how much sugar food has in it. First, sugar does not “cause” acne. If you don’t have acne-prone skin, sugar will not make it appear out of nowhere. However, sugar can contribute to acne, so if you experience some of the other possible acne triggers, like menstruation, inflammation, or clogged pores, sugar could worsen acne.

Second, it’s important to consider both a food’s sugar content and how quickly that particular food causes a spike in blood sugar. Significant spikes in blood sugar are likely to increase acne because they require the body to produce more insulin and androgens to break down the sugar, which can lead to excess oil production. The best way to determine whether or not a food is likely to cause a blood sugar spike is to look up its glycemic load, rather than its glycemic index.

Glycemic index is a measure of how quickly a food releases sugar into the bloodstream, which would seem like the most important number for acne, but this number doesn’t reflect how much sugar the food releases. The best example of this is watermelon. It has a glycemic index of 72, which is very high, higher than soda even. Based on this number alone, it might seem like a good food to avoid in order to decrease acne. However, if you take a look at its glycemic load, you’ll find that watermelon presents almost no threat to acne at all. Watermelon has a glycemic load of 8, which is incredibly low. What this tells us is that although the sugar in watermelon releases into the bloodstream very quickly, it doesn’t contain much sugar in the first place, so it doesn’t cause much of a spike.

Does Caffeine Cause Acne?

In many ways, it makes sense that caffeine would increase acne, but there is currently no research to support this. The main reason some dermatologists suspect caffeine could contribute to acne is because of how it heightens the autonomic nervous system. As we discussed earlier, when the body is stressed, it becomes inflamed, and caffeine makes the body even more sensitive to stress, potentially increasing inflammation and increasing acne.

Although this theory makes sense, it’s important to remember that it is just a theory. There is no research confirming or denying caffeine’s role in acne formation, so for now at least, there’s no need to cut it out of your diet cold turkey.

Does Chocolate Cause Acne?

This is probably the most popular question about acne and diet, and the answer is hotly contested. In the first half of the 20th century, it was common knowledge that chocolate could lead to acne, but in the 60s, a study determined that chocolate did not cause acne. For the next 50 years, the wives tale that chocolate causes acne lived on, but it also grew to be known as “just a wives tale.” But recently, researchers have found that the study from the 60s was conducted rather poorly, and research from the 2010s suggests that the wives tale that chocolate causes acne may be more than “just a wives tale.” So what’s the truth? Does chocolate cause acne?

Right now, the best answer dermatologists can give us is this: chocolate may contribute to acne, but cutting chocolate out of your diet will not get rid of your acne. Unfortunately, we can’t pinpoint exactly why chocolate could lead to increased acne. Some sources claim it’s because of its high sugar levels or dairy products, but it’s important to avoid this logical fallacy. It’s easy to break food down to its component parts and claim that the food has all of the properties of those individual parts, but that’s just not how it works. When all of the ingredients in chocolate combine, the individual properties of each ingredient can change, shift, or even disappear.

The reason we suspect chocolate may cause acne is because reasonably well-controlled studies have found that when participants consumed half a chocolate bar every day for two weeks, they had more acne than when they abstained from chocolate for two weeks. However, their acne did not go away when they stopped eating chocolate, so there’s no need to cut yourself off completely.

Does Dairy Cause Acne?

Like chocolate, no one is quite sure how dairy affects acne. Some studies have provided evidence that dairy increases acne, while others have found that dairy has no effect whatsoever. Like all diet studies, research examining any possible link between dairy and acne is limited by uncontrollable outside factors and unreliable participants, which could account for the lack of agreement among dairy-acne studies.

Similar to chocolate, some people suspect dairy could cause acne due to some of its individual components, specifically the hormones it contains. Pasteurized milk contains insulin-like growth factor (IGF-1) and androgens, both hormones that can increase oil production (testosterone is a type of androgen, for example). However, just because a food contains something that might increase acne, that doesn’t mean the food itself will do so.

Ongoing research is being conducted on the effect of dairy on acne, but in the meantime, dermatologists don’t recommend cutting dairy out of your diet to prevent acne because there is insufficient evidence to suggest that it will actually work.

Does Coffee Cause Acne?

It’s complicated to determine if coffee contributes to acne or not. It contains caffeine, and is often mixed with dairy, sugar, and sometimes chocolate, all of which are factors that may or may not cause acne by themselves. It’s difficult enough to determine how individual ingredients effect acne, but when they are combined, it’s nearly impossible.

As with the other foods on this list, dermatologists don’t recommend cutting coffee out of your diet entirely just to get rid of acne. Even if coffee is linked to acne, it wouldn’t cause it, it would merely contribute.

Does Peanut Butter Cause Acne?

There is almost no reliable data on whether or not peanut butter causes acne, so for now, we recommend continuing to consume peanut butter as normal. There was one study conducted in the 70s that was meant to examine the effect of different foods on acne, including milk, chocolate, peanut butter, and Coca-Cola. However, the results were not divided based on which food was consumed, so the data was not overly helpful in determining whether or not peanut butter causes acne.

Does Soda Cause Acne?

Like peanut butter, there is relatively little research on whether or not soda causes acne, and like coffee, it contains many different ingredients that could have a potential impact on acne. Soda typically contains caffeine, and has a high glycemic index and a high glycemic load. If sugar and caffeine really do contribute to acne (and that’s still a big if), then it’s likely soda could contribute to acne as well. Until more research on any possible link between diet and acne becomes available, there’s no need to cut soda out of your diet.

Do Eggs Cause Acne?

Many people have the same concerns about eggs causing acne that they do about dairy causing acne: hormones. It’s important to note that growth hormones have not been proven to increase acne, but even if they did, you wouldn’t have to worry about it with your eggs, because chickens are not given hormones. Generally speaking, we feel confident in saying that eggs do not usually cause acne.

We say usually because there is one significant caveat we want to add as we wrap up this discussion of diet and acne: foods you are sensitive to have the potential to increase acne. It all comes back to inflammation. If you’re slightly allergic to a food, resulting in redness, hives, or any kind of swelling, your pores may constrict and acne could increase.

If you suspect a correlation between eating certain foods and your acne, you don’t need to wait for official research to come out. Do your own. Make everything else about your day as consistent as possible for two weeks and make sure to eat that food every day. Then, eat normally for a week, while keeping all other factors like skin care and stress as stable as possible, then cut out that food entirely for two weeks. Get specific, count the number and type of acne lesions you have at the beginning and end of each week, and if you find a connection that seems significant, then maybe consider cutting back on that food. We don’t recommend cutting foods out entirely, and we definitely don’t recommend cutting out entire food groups, like all carbs or all sugars. These kinds of restrictive diets can cause immense amounts of anxiety and stress, which could actually increase your acne. As with all dietary changes, it’s all about moderation.

Does Smoking Cause Acne?

Like the relationship between diet and acne, the relationship between smoking and acne is still unclear. Although smoking involves many components that seem likely to increase acne, the actual research that has been conducted so far remains inconclusive. Still, research is ongoing, because based on what we know about how nicotine affects the body, there is a good chance it could also affect acne.

Nicotine is known to decrease the flow of oxygen and increase the speed with which our cells die, and these issues could significantly impact acne. When oxygen flow decreases, inflammation increases, along with the likelihood of acne. Additionally, the healing process slows down, meaning that any acne that does form will take longer to heal and is more likely to result in acne scarring. Increased cell death could also have a detrimental effect on your skin because when skin cells die too quickly, they’re likely to get trapped in your pores, causing clogs that lead to blackheads and whiteheads.

Although these theories make sense, they have not yet been proven. Studies on acne and smoking are still very inconclusive.

Does Vaping Cause Acne?

Vaping, or inhaling the vapors of various heated liquids through a vaping pen, presents an even more complicated scenario than regular smoking because of the wide variety of ways to vape (with or without nicotine, as a replacement for real tobacco or as a new habit, frequency, etc.). Some studies have found that vaping could increase acne, but others have found that it could help decrease acne in very specific situations. So what’s the truth? We just don’t have enough information to tell yet.

If you start vaping, you might see an increase in acne for two reasons, both of which have less to do with the actual vapor and more to do with the habits surrounding it. For instance, one of the lines of reasoning for why vaping could increase acne is that it releases a great deal of moisture around the mouth, which people may then wipe away. Touching the face too much can transfer extra oils to the face, causing clogged pores. The second possibility is that when people transition from smoking to vaping with less or no nicotine, they may get more acne simply because of the major shift in habits. Although nicotine is bad for the body, if it gets used to it, it will still react when that nicotine suddenly disappears. This acne is usually temporary and fades after a week or two without smoking.

Limited research also suggests that vaping could decrease acne slightly, in the exact same situation. It’s possible that switching from nicotine cigarettes to low-nicotine vaping or vaping with no nicotine could reduce acne by restoring proper blood flow through the body and decreasing inflammation. This is in direct opposition to the previous theory, which just reinforces the fact that we truly don’t know enough about vaping and acne to say anything definitively.

The research on dairy and acne is inconclusive now, though further studies are being conducted.

Does Smoking Weed Cause Acne?

Similar to vaping, not many studies have been conducted on how smoking weed affects acne. Some sources claim that weed itself doesn’t increase acne, but eating a bunch of greasy or sugary foods because of “the munchies” can, but as we’ve already investigated, the link between acne and diet is also tenuous and under-researched. Limited research has also found that marijuana may increase testosterone and other androgens, which can increase oil production and lead to increased acne. Still, these are theories based on minimal research, so for now, we can’t say decisively how smoking weed will affect acne.

Does Sweat Cause Acne?

Sweat and acne are frequently associated with each other, so much so that we have a specific name for sports-induced acne: acne mechanica. Contrary to popular belief, acne mechanica is not actually caused by sweat, and it is not limited to sports or exercise.

Acne mechanica would be better described as friction-induced acne, and instead of being caused by the sweating that occurs during exercise, it’s typically caused by tight uniforms or sports equipment. Acne mechanica is also common among flute and violin players, and can sometimes appear on the breasts during menstruation when the breasts swell and bras fit tighter than usual. This friction can irritate the skin, leading to inflammation and clogged pores.

Sweat, on the other hand, does not contribute to acne. A 2008 study divided participants into three groups: one that did not exercise at all, one that exercised five days a week and showered within one hour of exercising every time, and one that exercised five days a week and waited at least four hours to shower every time. At the end of the two week study, there was no significant difference in acne between the groups. This suggests that sweat does not actually contribute to acne the way many of us assume it does. However, even if sweat doesn’t cause acne, tight clothing or equipment can, so if you do wear tight uniforms or sports bras to work out, showering right away in cool water may help soothe irritation and prevent inflammation.

Is It Possible to Get “Pillowcase Acne”?

If you’ve heard of something called “pillowcase acne,” you may think it sounds silly, but it’s actually one of the more reasonable explanations for what causes acne on this list. It’s true, your pillowcase could be contributing to your acne if you aren’t washing it often enough. Oil, bacteria, and dead skin cells can transfer from your skin to your pillowcase, then when you lay your head back down at night, they can transfer right back to your skin. This perpetuates a cycle of acne that’s only broken when you wash your sheets again. To avoid “pillowcase acne,” we recommend washing your sheets once a week if possible.

If you have acne, it’s a good idea to wash your pillowcase once a week to prevent a buildup of acne-causing bacteria, oil, and dead skin cells.