Horsetail oil is made by infusing dried horsetail herb in a carrier oil, either slowly over several weeks or quickly using gentle heat. The process is simple, requires only a few supplies, and yields an oil rich in natural silicon that many people use for hair and scalp care. Here’s how to do it from start to finish.
Why Horsetail Makes a Useful Infused Oil
Horsetail is one of the most silicon-rich plants available. That silicon content is the main reason people infuse it into oil. A 2016 study found that daily silicon intake over nine months improved hair’s resistance to breaking, and a 2015 study concluded that oral supplements containing horsetail-derived silica improved both hair strength and growth. Silicon also supports collagen production, which plays a role in the structural health of hair, skin, and nails.
When you steep horsetail in oil, fat-soluble compounds transfer into the carrier oil over time. The result is a concentrated topical oil you can massage directly into your scalp or skin, delivering those compounds where you want them.
What You Need
The supply list is short:
- Dried horsetail herb: Available loose from herbal suppliers or health food stores. You need it fully dried, not fresh (more on that below).
- Carrier oil: Olive oil is a popular choice because it’s affordable and extracts plant compounds well. Jojoba oil is another strong option, especially for hair use, since its structure closely resembles the oil your scalp naturally produces. Sweet almond oil works too and absorbs quickly without feeling heavy.
- A clean glass jar with a tight lid: Mason jars work perfectly.
- Cheesecloth or a fine mesh strainer
The standard ratio is 1 part dried horsetail to 2 parts carrier oil. So if you’re using 1 cup of dried herb, add 2 cups of oil.
Drying Horsetail Properly
If you’re starting with fresh horsetail, you must dry it thoroughly before infusing. Any moisture left in the plant can introduce bacteria or mold into the oil, ruining the batch and shortening its shelf life dramatically. In laboratory settings, horsetail stems are dried at around 115°F (45°C) for 48 hours, then ground into a fine powder.
At home, you have a few options. Spread the stems on a drying rack in a warm, well-ventilated room out of direct sunlight for about one to two weeks, until they snap cleanly rather than bend. A food dehydrator set to around 110 to 120°F speeds this up to one or two days. Once fully dry, crumble or chop the stems to increase the surface area that contacts the oil. The more surface area exposed, the more effective the infusion.
Cold Infusion Method (4 to 6 Weeks)
This is the hands-off approach and the one most herbalists prefer because low temperatures preserve delicate plant compounds.
Place the dried horsetail in your glass jar and pour the carrier oil over it, making sure the herb is fully submerged. Seal the jar tightly to keep air out. Store it in a cool, dark place, like a cupboard or pantry, for 4 to 6 weeks. Every few days, give the jar a good shake to redistribute the plant material and encourage extraction.
After the infusion period, the oil will have deepened in color and taken on a mild herbal scent. At that point, pour it through cheesecloth or a fine strainer into a clean bowl or jar. Squeeze the cheesecloth firmly to press out every last drop of oil trapped in the plant material. Discard the spent herb.
Heat Infusion Method (2 to 3 Hours)
If you don’t want to wait a month, a double boiler setup lets you infuse the oil in a single afternoon. The key is keeping temperatures low so you warm the oil without cooking it.
Fill the bottom pot of a double boiler with a few inches of water. Place your jar (lid loosely on, or use a heat-safe bowl) containing the horsetail and oil into the top section, or set it directly in the water bath. Bring the water to a very gentle simmer and maintain that low heat for 2 to 3 hours. Check periodically to make sure the water hasn’t evaporated. The oil should feel warm to the touch but never approach a boil.
Once the time is up, remove the jar and let it cool completely. Then strain through cheesecloth the same way you would with a cold infusion. The finished oil is ready to use immediately.
Choosing Between the Two Methods
Cold infusion produces a slightly more delicate oil because no heat is involved, which means heat-sensitive compounds remain intact. It’s ideal if you’re patient and want to make a large batch you’ll use over several months. Heat infusion is better when you need the oil soon or prefer to get the project done in one session. Both methods yield a usable oil, and the difference in final quality is modest for most home applications.
Storage and Shelf Life
Homemade infused oils are vulnerable to oxidation from the moment they’re made. Light, heat, and oxygen all accelerate rancidity. Store your finished horsetail oil in a dark glass bottle (amber or cobalt blue) with a tight seal. Keep it in a cool spot, or ideally in the refrigerator, where it will stay fresh longest.
Expect a shelf life of roughly 6 to 12 months depending on your carrier oil. Jojoba oil is extremely stable and lasts toward the longer end. Olive oil falls in the middle. Sweet almond oil oxidizes faster and tends to go rancid sooner. If the oil develops an off smell, looks cloudy, or feels tacky rather than smooth, it has turned and should be discarded. Adding a few drops of vitamin E oil (a natural antioxidant) when you bottle the finished product can extend its usable life by a few weeks to months.
How to Use Horsetail Oil
Most people make horsetail oil for their hair and scalp. To use it, warm a small amount between your palms and massage it into your scalp for several minutes, working it through to the ends of your hair. Leave it on for at least 30 minutes, or overnight for a deeper treatment, then wash it out with your regular shampoo. Two to three times per week is a common frequency for people targeting hair strength or scalp health.
The silicon in horsetail is associated with reduced breakage, improved hair texture, and better scalp circulation. Results are gradual. The studies showing measurable changes in hair strength involved consistent use over many months, so this is a long-game approach rather than an overnight fix. Some people also apply horsetail oil to their nails, cuticles, or dry patches of skin, where the same collagen-supporting properties can be beneficial.