Most yeast infections happen when a fungus called Candida, which normally lives in small amounts in the vagina, grows out of control. Preventing them comes down to keeping the conditions that hold Candida in check: an acidic vaginal environment, healthy bacterial balance, and minimal excess moisture. Here’s what actually works.
Why Yeast Infections Happen
A healthy vagina hosts beneficial bacteria, primarily Lactobacillus species, that produce lactic acid and keep the pH below 4.5. That acidic environment does two things: it limits how much Candida can grow, and it prevents the fungus from switching into its more aggressive, infection-causing form. When something disrupts this balance, Candida seizes the opportunity.
The most common disruptors are broad-spectrum antibiotics, hormonal changes (pregnancy, oral contraceptives), uncontrolled diabetes, and certain hygiene habits. Each of these shifts the vaginal environment in a way that gives yeast a foothold. Fewer than 5% of women experience recurrent yeast infections, defined by the CDC as three or more episodes in a single year, but even occasional infections are worth preventing if you can.
Keep Blood Sugar in Check
Candida feeds on sugar. When blood glucose runs high, sugar levels in vaginal secretions rise too, creating an environment where yeast proliferates faster. Elevated blood sugar also shifts vaginal pH upward, making it less acidic and less hostile to Candida. On top of that, chronically high glucose weakens immune function, reducing your body’s ability to keep the fungus contained.
This is why yeast infections are significantly more common in people with diabetes, particularly when blood sugar is poorly managed. But you don’t need a diabetes diagnosis for this to matter. Consistently eating large amounts of refined sugar and simple carbohydrates can cause blood sugar spikes that, over time, create a more yeast-friendly environment. Prioritizing whole grains, fiber, protein, and healthy fats helps keep glucose levels steadier throughout the day.
Be Strategic About Antibiotics
Broad-spectrum antibiotics are one of the most well-established triggers for yeast infections. They work by killing a wide range of bacteria, but they don’t distinguish between harmful bacteria and the Lactobacillus species that protect your vaginal environment. Once those protective bacteria are depleted, Candida can expand unchecked.
You obviously shouldn’t skip antibiotics you genuinely need. But if you’re someone who gets yeast infections after antibiotic courses, it’s worth asking your doctor whether a narrower-spectrum antibiotic could work for your situation. If broad-spectrum treatment is necessary, your doctor can sometimes prescribe a preventive antifungal to take alongside it.
Choose the Right Underwear
Moisture is Candida’s best friend after sugar. The fabric closest to your skin plays a surprisingly large role in how much moisture stays trapped against the vulva throughout the day.
Cotton is the clear winner. It breathes well and wicks away sweat and vaginal moisture that yeast thrives on. Be careful with underwear labeled as cotton blends, though. Some brands feel like cotton but still contain synthetic fibers. Even underwear with a cotton crotch panel doesn’t fully protect you, because the surrounding synthetic fabric still traps heat and moisture.
A few other clothing habits that help:
- Change underwear daily, and more often if they get damp from sweat or discharge.
- Skip panty liners when you don’t need them. Wearing them routinely decreases airflow and can cause irritation.
- Sleep without underwear, or in loose boxer shorts or pajamas. Increased airflow overnight gives the area time to dry out, which is especially helpful if you’re already prone to infections.
- Avoid sitting in wet swimsuits or workout clothes. Change as soon as you can after swimming or exercising.
- Use fragrance-free, hypoallergenic detergent. Many standard detergents leave residue on fabric that can irritate the vulva and make infections more likely.
Stop Douching and Skip Scented Products
Douching is one of the most direct ways to disrupt vaginal flora. It washes away the Lactobacillus bacteria that maintain acidity and can cause an overgrowth of harmful organisms, including Candida. The Office on Women’s Health states plainly that most doctors recommend against douching entirely. A healthy vagina is self-cleaning; the discharge you notice is part of that process.
Scented tampons, pads, powders, and sprays pose a similar risk. The fragrances and chemicals in these products can irritate vaginal tissue and shift the microbial balance. Plain, unscented versions of menstrual products are a safer choice. For external washing, warm water alone or a mild, unscented soap on the vulva (not inside the vagina) is all you need.
Watch for Hormonal Triggers
Estrogen promotes glycogen production in vaginal tissue, which Candida can use as fuel. That’s why yeast infections become more common during pregnancy, when estrogen levels surge. Oral contraceptives, particularly higher-estrogen formulations, can have a similar effect.
If you notice a pattern between starting or switching hormonal birth control and getting yeast infections, talk to your prescriber about lower-estrogen options. Some people also notice infections clustering around certain points in their menstrual cycle, which reflects normal hormonal fluctuations. Tracking when infections occur can help you and your doctor identify whether hormones are a factor.
Support Your Vaginal Microbiome
Not all Lactobacillus species are equally protective. Research has found that vaginal environments dominated by Lactobacillus iners are more vulnerable to both bacterial vaginosis and Candida infections compared to those with other Lactobacillus species. You can’t directly choose which bacteria colonize your vagina, but you can support conditions that favor a healthy mix.
Probiotic supplements containing Lactobacillus strains are widely marketed for vaginal health. The evidence is mixed on whether oral probiotics reliably colonize the vagina, but some studies suggest they may help restore balance after antibiotic use. If you want to try them, look for products with strains specifically studied for vaginal health, such as Lactobacillus rhamnosus and Lactobacillus reuteri. Fermented foods like yogurt, kefir, and sauerkraut provide dietary Lactobacillus as well, though their direct impact on vaginal flora is less well established.
What Recurrent Infections Look Like
If you’re getting three or more yeast infections within a 12-month period, that meets the clinical threshold for recurrent vulvovaginal candidiasis. At that point, over-the-counter treatments alone are unlikely to break the cycle. Recurrent infections sometimes involve Candida species that are resistant to standard antifungal treatments, or they may signal an underlying issue like undiagnosed diabetes or immune suppression.
Treatment for recurrent infections typically involves a longer initial course of antifungal medication followed by a maintenance regimen that can last six months or more. The goal is to suppress Candida long enough for the vaginal environment to stabilize. Even with treatment, recurrence rates are high once maintenance therapy stops, which is why the prevention strategies above become especially important for people in this category.