Onion peel tea is made by simmering 2 to 3 dry outer onion skins in 2 cups of water for 5 to 10 minutes, then straining. The result is a golden-brown tea with a mild, earthy flavor that’s surprisingly rich in plant compounds, particularly quercetin, a flavonoid with antioxidant and anti-inflammatory properties. The outer peel of an onion contains the highest concentration of phenolic compounds, flavonoids, and antioxidants of any part of the onion, making it an ideal candidate for a simple extraction like tea.
Step-by-Step Preparation
You only need two things: the papery outer skins from 2 to 3 onions and about 2 cups (roughly 500 ml) of water. Red onion peels are the best choice, but yellow onion peels work too.
- Rinse the peels. Hold them under running water in a strainer, rubbing gently to remove dirt and any pesticide residue. Running water is more effective than soaking, and soap or produce wash isn’t necessary or recommended.
- Bring water to a boil. Pour 2 cups of water into a small pot and bring it to a rolling boil.
- Add the peels and simmer. Drop in the clean peels, reduce the heat, and let them simmer for 5 to 10 minutes. The water will turn golden to light brown as the compounds release.
- Strain and serve. Remove the peels and pour the tea into a mug. Add a teaspoon of honey or a squeeze of lemon if the earthy taste is too plain on its own.
That’s genuinely all there is to it. The peels themselves aren’t eaten, just steeped and discarded.
Why Simmering Time Matters
The goal is to pull quercetin and other beneficial compounds out of the peel and into the water. Quercetin is stable in boiling water for a reasonable window, but it does begin to break down. Research published in Food Chemistry found that quercetin starts degrading after about 17 minutes of continuous boiling. The half-life at 100°C is around 170 minutes, so you’re not going to destroy everything by boiling a bit longer, but there’s no benefit to going past 10 to 15 minutes. A 5 to 10 minute simmer hits the sweet spot: long enough to extract color and flavor, short enough to preserve the active compounds.
If the tea looks pale after 5 minutes, let it go a few minutes longer. A rich golden or amber color is a good visual indicator that extraction has occurred.
Red Onion Peels vs. Yellow Onion Peels
Red onion peels are the stronger choice. They contain higher concentrations of phenolic compounds, flavonoids, and anthocyanins (the pigments responsible for their deep color) compared to yellow or white varieties. Research in Molecules found that red onions have the highest antioxidant capacity among common varieties, with the peel specifically outperforming both the whole onion and the inner flesh. Red onion peels also contain a greater diversity of flavonoid compounds, which broadens the range of potential benefits.
Yellow onion peels still contain meaningful amounts of quercetin and are worth using if that’s what you have on hand. White onion peels rank lowest and produce a much milder tea with fewer bioactive compounds. If you’re choosing onions at the store specifically for tea, go red.
What Onion Peel Tea May Do for Your Health
The interest in onion peel tea centers on quercetin, which has well-documented antioxidant, anti-inflammatory, and lipid-regulating properties. The outer peel of a red onion contains roughly 0.6 mg of quercetin per gram of dry weight, though some extraction methods have measured concentrations as high as 60 mg per gram depending on how the peel is processed.
A study in Experimental and Therapeutic Medicine tested onion peel tea in a diet-induced obesity model and found it suppressed increases in body weight and fat tissue. It also significantly reduced blood levels of total cholesterol at two weeks and glucose at four weeks. The researchers attributed these effects largely to quercetin’s ability to alter the expression of genes involved in cholesterol metabolism, including raising “good” HDL cholesterol and lowering “bad” LDL cholesterol.
A separate clinical trial gave obese women a small daily serving of onion peel tea (33 mg, roughly the weight of a grain of rice) after meals for six months alongside exercise. The combination targeted cholesterol levels and cardiovascular risk factors. This gives a rough sense of the amounts studied, though it’s worth noting that the concentration in your homemade cup will vary depending on peel quantity, simmer time, and onion variety.
Onion itself has a long track record in research for regulating lipid metabolism and suppressing high blood sugar. The tea is simply a convenient way to access compounds that are otherwise discarded.
Tips for Better-Tasting Tea
Onion peel tea doesn’t taste like onion soup. It’s mild and slightly earthy, closer to a light herbal tea than anything pungent. Still, some people find the flavor underwhelming or slightly bitter on its own. A few ways to improve it:
- Honey: A teaspoon rounds out any bitterness and adds body.
- Lemon juice: A few drops brighten the flavor and add a pleasant tanginess.
- Cinnamon stick: Simmered alongside the peels, it adds warmth and pairs naturally with the earthy base.
- Ginger slices: A few thin slices added during simmering create a more complex, warming tea.
Cleaning Peels and Pesticide Concerns
Since you’re brewing the outermost layer of the onion, the part most exposed to pesticides during growing and storage, cleaning matters. The National Pesticide Information Center recommends holding produce under flowing water rather than dunking it, as running water removes more residue. Rubbing the peels gently while rinsing helps further. No washing method removes 100% of pesticide residues, but water alone is as effective as commercial produce washes or soap (which the FDA does not recommend for produce).
If pesticide exposure is a concern, using peels from organic onions is the simplest solution. Either way, always discard peels that look moldy, discolored beyond their natural hue, or damaged.
Side Effects to Be Aware Of
Onion peel tea is generally well tolerated, but some people experience upset stomach, gas, or loose stools. These are more likely if you drink large amounts or have a sensitive digestive system. Allergic reactions to onion, while uncommon, can include skin irritation, swelling, or in rare cases wheezing and chest tightness. If you’re allergic to onions, the tea is not a workaround since it contains the same compounds. People taking blood sugar-lowering medications or blood thinners should be cautious, as onion compounds can influence both glucose levels and blood clotting.