Unexpected breakouts. They’ve been a source of anxiety for generations, especially in our teen years when they appeared at the worst times. Like when we were getting ready for a big event—prom, a party, or picture day. Remember the panic setting in? Globbing on blemish remedies, hoping the pimple(s) would disappear by morning.
Even as adults, many of us still get acne. Whether it's a sometimes thing caused by hormonal changes or regular breakouts we can't shake, it can be frustrating to deal with. In the age of complexion-perfecting filters, we all want to feel comfortable in our skin.
What if we tackled acne from the inside instead of treating it on the outside? Research shows that gut health and acne are closely linked. So, let’s explore why our skin reacts the way it does and how understanding our gut health may be the path to clearer, healthier skin.
What is acne?
Acne is a common skin condition affecting around 50 million Americans yearly [1]. Causes include hormonal changes, stress, family history, certain medications, and, as we’ll discuss, poor gut health and diet.
Here’s how it forms:
- Sebaceous glands in your skin produce excess oil.
- Excess oil can cause the skin to produce new cells faster, which are stickier in people prone to acne.
- When these skin cells die, they don’t shed properly and can build up, clogging pores.
- Bacteria called Cutibacterium acnes infect clogged pores.
- Inflammation leads to the formation of acne lesions [2].
Standard acne treatments often include topical creams and antibiotics. But this approach often falls short [3]. Many people experience side effects, see only partial results, or find no relief at all. About 52% of people stop acne treatment because it’s ineffective [3]. Long-term antibiotic use for acne can also disrupt your gut microbiome [4].
The gut health and acne connection
Is acne a sign of poor gut health? Possibly. The exact link between gut bacteria and acne isn't fully understood yet. Still, it seems likely that your gut microbes play a role, similar to what’s suggested for skin conditions like eczema and psoriasis [5], [6].
Let’s check out what the research has to say about the gut health acne connection.
The gut-skin axis made simple
Scientists think the gut and skin communicate through the immune system, a process called the gut-skin axis [7]. How then does gut health affect acne?
Gut microbes can make immune cells send signals that either calm or inflame your skin. When your gut is out of balance, it can send more inflammatory messages. Imbalances in the gut microbiome can trigger inflammation, weakening your gut barrier and making it leaky. A leaky gut allows harmful microbes into your bloodstream, which may reach your skin and cause irritation and breakouts [7].
Decoding gut health and hormonal acne
Hormonal acne happens when changes in hormones like testosterone and estrogen cause breakouts. It's a common issue, especially for women during menstruation, pregnancy, and menopause [8].
Studies show that people with acne have less estrogen and more testosterone and insulin than those with clear skin [9]. Scientists think the gut microbiome might play a role in these changes. Some gut microbes can make hormones like testosterone [10]. Others make beta-glucuronidase, an enzyme that can change estrogen levels in your body [11].
The scoop on tryptophan digestion and acne
Animal research suggests that tryptophan, an amino acid in foods like chicken, eggs, and dairy, might be linked to acne. Researchers transferred gut microbiomes from people with and without acne to rats. The study showed that rats with gut bacteria from people with acne had a lower ability to make indoles from tryptophan [12], [13]. Indoles are helpful compounds from gut bacteria that reduce inflammation and help clear up acne.
Your gut, the mTOR pathway, and clear skin
Gut bacteria interact with the mammalian target of the rapamycin (mTOR) pathway, a signaling system inside your cells. The science is complex, but think of this pathway as your body's way of managing resources and keeping everything running smoothly. One way it does this is by helping control skin cell growth and oil production. Research shows that this pathway works differently in people prone to acne [14]–[16].
Gut microbes make beneficial metabolites like short-chain fatty acids (SCFAs) and indoles. They also make harmful ones like trimethylamine (TMA)—which is linked to heart disease. These substances can affect the mTOR pathway in our body [17]–[19]. If there's an imbalance, it can possibly worsen acne.
Microbes and acne: what's different and why it matters
Research shows key differences in the gut microbiome of people with and without acne. Those who suffer from acne usually have:
- Lower diversity - Their gut microbiome is less varied [20].
- Fewer beneficial bacteria - They have lower levels of SCFA-making bacteria like Bifidobacterium, Lactobacillus, Ruminococcus, and Blautia [20]–[24].
- Higher levels of Bacteroides [20], [24], [25] - This includes species like Bacteroides fragilis and Phocaeicola vulgatus, which often overpopulate the gut in people with obesity, insulin resistance, or inflammatory conditions [26]–[28].
- Increased potential for LPS production [20] - Harmful bacteria like Escherichia coli and Klebsiella pneumoniae make LPS. A weak gut barrier can let LPS into the bloodstream, causing inflammation.
How your diet shapes acne and gut health
A diverse fiber-rich diet helps keep your gut microbes healthy and your gut barrier strong. A typical Western diet does the opposite. Studies have found that eating the following foods can trigger acne:
- Dairy
- Chocolate
- Saturated fats (found in fried foods, pizza, and red meat) [29]
Alcohol, salted products, biscuits, sweets, and soft drinks may also worsen acne, but more research is needed [29].
These foods negatively impact your gut microbiome:
- Saturated fats decrease gut diversity [30]–[32] and lead to higher levels of LPS [33]–[35].
- Processed meats can fuel pro-inflammatory bacteria that make hydrogen sulfide (HS) [36]–[38]. Excess HS can damage your gut barrier.
- Ultra-processed foods like chocolate, ice cream, and frozen desserts have emulsifiers that can harm the gut and gut barrier [39]–[41].
Studies have also linked diet to the mTOR pathway. High-glycemic foods that spike blood sugar can interfere with the mTOR pathway and potentially worsen acne [15]. These include white bread, sugary cereals, candy, and sweetened drinks.
Can probiotics help curb acne?
There's limited research on probiotics and acne, but clinical trials on Lacticaseibacillus rhamnosus and Lactiplantibacillus plantarum show promise. Studies have found that these probiotics can reduce the number of acne lesions [42]–[44]. One clinical trial discovered that probiotics decreased harmful bacteria (Cutibacterium acnes and Staphylococcus aureus) on the skin while increasing a beneficial species (Staphylococcus epidermidis) [44].
Face creams with postbiotics (substances made by probiotic bacteria) may also help reduce acne [45].
The path to clearer skin
Next time you spot a breakout, you’ll have a better idea of how things like hormones and diet might be behind it. While there's still much to learn about the gut-skin connection, looking inward at the trillions of microbes in your gut is a great place to start.
If you haven't already taken a Gut Health Test, it will be helpful to see your levels of beneficial and disruptive bacteria. The test will look at this balance and check for potential production of LPS, SCFAs, beta-glucuronidase, and more. Based on your results, you'll get personalized recommendations for supplements, specific foods, and probiotics.
In the meantime, adopting a gut-friendly diet is always a good idea. Fermented foods like kombucha, kimchi, and yogurt are great options. Also, add more fiber-rich foods to your plate: whole grains, beans, and lentils, to name a few. While we need more research for the best probiotic strain for acne, those with Lacticaseibacillus rhamnosus or Lactiplantibacillus plantarum show promise for clearer skin.
