You know it as the sole reason you’ve been able to get out of bed for the past year, but caffeine’s got another job now: taking over the haircare industry. And unlike some of the other buzzy ingredients you see all over IG, this new glut of caffeine-spiked shampoos, conditioners, and treatments has powerful science behind it.The main takeaway is that caffeine stimulates blood flow to your scalp, explains Bridgette Hill, a trichologist and colorist at Paul Labrecque Salon and Skincare Spa in NYC and Palm Beach. And that’s crucial because blood is what feeds your scalp the oxygen and nutrients it needs to stay healthy.

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If it’s not getting enough—and this can def happen, mostly due to genetics or diet—your hair follicles and strands suffer, leading to dryness, thinning, or straight-up hair loss. Yeah, not ideal—and why caffeine-infused products might be an important addition to your routine. About that hair-loss thing: Caffeine naturally counteracts DHT, the hormone responsible for it, says dermatologist Dhaval Bhanusali, MD, founder of Hudson Dermatology and Laser Surgery in NYC.

Caffeine also encourages your hair to keep growing, kind of like how minoxidil—aka what’s in popular treatments like Rogaine—does. So basically, think of caffeine haircare as a form of prevention and as a proactive way to get longer, thicker, healthier hair. There’s just one caveat. Caffeine products take about three months of continual use to work. And no matter how much you’re chugging in the a.m., it’s not going to speed things along.