9 Uses for Coffee Grounds You Didn’t Know About

Coffee beans contain high levels of antioxidants that exhibit potent disease-fighting activity in our bodies, according to 2020 research published in Molecules. But a closer look at coffee’s antioxidants looks a bit like an ingredient list for a trendy beauty product, too. Several of coffee’s strongest antioxidants—such as caffeic, chlorogenic, p-coumaric, and ferulic acids—and, of course, caffeine, have been shown in scientific studies to offer promising skincare benefits. From nitrogen to magnesium, coffee also contains elements and minerals that offer heavy-duty applications around your home. 

And here’s the thing: While some of these bioactive compounds make their way into your morning cup o’ joe, a large amount winds up in the used coffee grounds, according to 2022 Molecules research. Most people toss these coffee grounds in the trash, but this nutrient-rich waste may offer benefits from head-to-toe and in your household. 

Here’s what current research says about the benefits coffee grounds may provide.

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Promote hair growth

Research published in 2023 in the journal Foods found that the phenolic compounds, flavonoids (another group of plant-based antioxidants), and caffeine in coffee grounds may promote hair growth and reduce hair loss. The researchers found that these compounds stimulate hair follicles to produce new cells and enhance blood flow to hair follicles. 

Plus, lightly massaging your scalp with coffee grounds can remove product build-up and dead skin cells, spurring new hair growth. Make your own follicle facial by working brewed coffee grounds into your scalp with your fingertips for 60 seconds before rinsing with cool water, then finish with your regular shampoo and conditioner.

Other studies show that the quercetin in coffee grounds may help with eyebrow growth and thickness, too, according to a 2021 review of research published in Frontiers in Sustainability.

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Cover up gray hairs

Heads up, brunettes! The Frontiers in Sustainability research points to coffee grounds as a natural hair colorant, citing studies that show coffee can stain brown hair, effectively masking gray hairs. 

Mix one teaspoon (or two, depending on the thickness and length of your hair) of cooled coffee grounds into a handful of conditioner and apply it to recently shampooed hair. Let it sit for no more than five minutes, and then rinse thoroughly with cool water to seal the hair cuticle. The temporary stain is not recommended for lighter hair colors.

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Reduce the appearance of cellulite

Research published in the Aesthetic Surgery Journal in 2023 says that when applied to the skin, caffeine stimulates enzymes that break down fat and increase blood flow to the area of application. This review of studies found that there may be a moderate cellulite reduction in the thighs after using a caffeine-containing product, such as coffee grounds. Research published in the International Journal of Women’s Dermatology backs this claim up, adding that the exfoliating massage you get from coffee grounds may also reduce the look of cellulite. 

However, the research emphasizes that the effects of caffeine or massage on cellulite are temporary. The study authors say that effectively treating cellulite requires extensive fat, collagen, and connective tissue remodeling—and to date, no procedures have been proven successful long-term. 

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Treat under-eye puffiness

The skin around your eyes is delicate and thin, making it more susceptible to signs of aging, such as fine lines. Your eyes are also often the first to reveal a lack of sleep, allergies, or fluid retention thanks to dark under-eye bags and puffiness. 

The caffeine in coffee grounds can help temporarily relieve eye puffiness thanks to its anti-inflammatory properties and ability to reduce fluid retention and strengthen skin laxity, according to 2024 research published in the International Journal of Women’s Dermatology.

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Perk up your skin

Thanks to its ability to reduce blood flow in the skin, the caffeine in coffee grounds can temporarily make your skin appear brighter and tighter. However, caffeine may have lasting effects on the skin, too. Research published in Cosmetics in 2023 says that caffeine may help protect the skin against the effects of sun damage and promote collagen and elastin preservation, compounds that give your skin a youthful look.

The Frontiers in Sustainability research points to skin benefits behind other antioxidants in coffee grounds:

• Chlorogenic acids may reduce skin hyperpigmentation and promote skin wound healing.
• Triacylglycerols promote skin hydration.
• Its phenolic compounds have been shown to prevent accelerated skin aging. 

Licensed aesthetician Jennifer Phillips recommends trying this coffee ground mask: 

• 1 tablespoon raw cacao powder
• 1 tablespoon bentonite clay
• 1 teaspoon fresh coffee grounds
• 1-3 tablespoons aloe vera gel (or water)

Combine the following ingredients, apply to the face and neck, and leave on for 10 to 15 minutes—or until the clay starts to stiffen. Using warm water, remove the mask in a circular motion. Follow up with a toner and cleanser.

Just remember: This is a mask, not a scrub. Physical exfoliants like coffee grounds can work great to remove dead, rough skin on your arms, legs, and feet, but they can be harsh on the delicate skin on your face. Using gentle, circular motions to remove the mask is all the pressure you need to exfoliate away dead skin cells on your face.

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Deodorize your fridge

Coffee grounds are a great deodorizer, too, according to 2023 research published in the International Journal of Advance Research, Ideas and Innovations in Technology. This is because the nitrogen in coffee grounds absorbs foul-smelling odors, making them a great addition to your fridge to soak up strong-smelling or spoiled food. Simply fill a jar with used or fresh grounds and place it, uncovered, in the back of your fridge. 

You can also make DIY air fresheners by putting dried coffee grounds in a sock and putting it in the car, gym bags, or whatever else needs freshening up. The researchers also say to keep a bowl of coffee grounds by the sink. After cutting up onions or garlic, for instance, scrubbing your hands lightly with coffee grounds will help get rid of any lingering smell. 

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Fertilize plants

When you’re working in the garden, skip the commercial fertilizer and use old coffee grounds instead. The potassium, phosphorus, magnesium, and calcium in coffee grounds play important roles in improving soil nutrients, accelerating plant growth, and even upgrading the nutrient content in what you grow, according to 2022 research published in Waste. Past research indicates that so-called “spent” coffee grounds and charred spent coffee grounds absorb heavy metals that contaminate soil and water.  

“Commercial fertilizers contain nitrogen, potassium, and phosphorous, but they also can contaminate groundwater with runoff and have other negative implications,” says Gwenn Fried, who serves as vice president, New York, on the Mid-Atlantic Horticultural Therapy Network’s board of directors. “Coffee grounds used thoughtfully have similar benefits, are readily available, reduce waste, and smell good.” (She adds that the caffeine in coffee grounds helps repel pests such as snails and slugs, too.)

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Wash up

Because of their grittiness, coffee grounds can be used as an effective DIY cleaning scrub. And they may even help sanitize surfaces. Several studies have shown that coffee beans have strong antibacterial and antimicrobial activity, according to 2022 research published in Frontiers in Nutrition—plus, coffee grounds’ versatility makes them well-suited to homemade soap recipes.

“I love to make kitchen soap with fresh grounds,” says Fried. “It’s great for washing up after a day of gardening or getting pesky cooking smells off of your hands.”

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Boost compost

Since coffee grounds are rich in nitrogen, they’re perfect for an at-home compost. Just add the coffee grounds directly to your compost pile. How much? A study published in Waste Management showed that spent coffee grounds can be successfully composted in a variety of proportions. But researchers found that a batch containing 40% coffee grounds produced the lowest greenhouse gas emissions and best quality compost.

“In the home garden, I like to add used coffee grounds to compost that is ready to be applied to planters and garden beds,” Fried says. “I also will sprinkle used grounds directly around plants if I am trying to repel slugs. I’ve had some success with this pest-repellent method, but it is not foolproof.”

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