When adult acne flares up, the usual suspects—hormones, stress, skincare routines—get most of the blame. But what's in your glass might be quietly making things worse. Dermatologists and registered dietitians have zeroed in on two specific drinks that can trigger or worsen breakouts in adults. Here's what the research and clinical experience suggest, and what you can sip instead.
The first culprit: sugary coffee concoctions
Your morning latte might be loading your system with more than caffeine. Many coffee-shop favorites pack 30–50 grams of sugar per serving—roughly eight to twelve teaspoons. High-glycemic foods and beverages spike blood sugar and insulin, which can increase sebum production and inflammation, two hallmarks of acne.
“One of the most common dietary triggers I see in adult acne patients is the blended coffee drink,” says board-certified dermatologist Dr. Melissa Piliang. “It’s not the coffee itself—it’s the sugar and dairy together.” The combination can be especially problematic for those who already have oily skin or hormonal acne along the jawline and chin.
To keep your coffee habit clear-skin friendly: skip the syrups, use a splash of unsweetened almond or oat milk, and consider a sprinkle of cinnamon for flavor without the spike.
The second drink: skim milk and dairy-heavy smoothies
Milk—particularly skim milk—has been linked to acne in multiple observational studies. The exact mechanism isn't fully understood, but researchers suspect that the natural hormones and growth factors in cow's milk can overstimulate oil glands. Whey and casein proteins may also raise insulin-like growth factor 1 (IGF-1), which promotes acne.
“I see this most often in adults who switch to fat-free dairy thinking it's healthier for their skin,” explains functional medicine nutritionist Jessica Cording, RD. “But the reduced fat content actually increases the relative concentration of bioactive proteins that could affect acne.” Smoothies made with milk or yogurt-based protein powders can deliver a triple hit: dairy, sugar, and whey or casein concentrates.
What about green smoothies?
A fruit-and-spinach blend can still be high in sugar if it relies on juice or banana for sweetness. Experts recommend sticking to whole fruits, adding a vegetable base (think cucumber or celery), and swapping dairy milk for unsweetened coconut water or a plant-based alternative.
Why these drinks affect adult acne differently than teenage acne
Adult skin has often developed sensitivities over time. The gut-skin axis plays a larger role after age 25—meaning that what triggers systemic inflammation (sugar spikes, dairy proteins) can show up as papules or cystic bumps within 24 to 48 hours. Additionally, adults tend to consume these drinks regularly, making the daily exposure a constant low-grade trigger rather than an occasional indulgence.
What to drink instead for clearer skin
- Water—plain or infused with lemon, cucumber, or mint. Staying hydrated helps flush toxins and supports skin cell turnover.
- Green tea—rich in antioxidants called catechins that may reduce sebum production and inflammation when consumed regularly.
- Herbal infusions like chamomile or spearmint. Some research suggests spearmint tea can lower androgen levels that contribute to hormonal acne.
- Sparkling water with a splash of hibiscus or pomegranate juice for flavor without excess sugar.
If you're not ready to give up your morning latte or afternoon milkshake entirely, try a half-size or a version with one less pump of syrup. Small reductions can still make a meaningful difference over the span of a few weeks.
The bottom line
Adult acne is often multifactorial, but diet—especially liquid calories—deserves a closer look. Sugary coffee drinks and skim dairy are two of the most cited triggers in both clinical research and dermatology practice. Cutting back on these beverages for two to four weeks may help you identify a hidden contributor to stubborn breakouts. As always, consult a dermatologist for a personalized plan, because what clears one person's skin may not work for another.
