Scientists have explored various uses of essential oils, from improving oral health and easing nausea to treating insomnia. And it’s no secret that since the dawn of time, people have been slathering concentrated plant extracts on their skin. But can essential oils improve hair health and even encourage growth? According to one of the latest TikTok trends, the answer is yes.

On TikTok the hashtag #hairoil has racked up more than 1.6 billion views, with individual videos getting millions of views a pop. Many of the clips feature influencers showing off gorgeous, long, and healthy locks, making claims that homemade concoctions of oils are responsible for not only shine but hair growth, with one influencer, @madelinewould, on the video-sharing site dubbing the trend “hair oiling.”

Marisa Garshick, MD, a dermatologist in New York City, says hair loss is a common concern, especially on the heels of peak COVID-19, when reports of hair loss from physical stress increased. “For this reason,” says Dr. Garshick, “many people are concerned about shedding and thinning and are looking for treatment options.”

The New York City– and Los Angeles–based celebrity hairstylist Sally Hershberger agrees that hair growth is a hot topic, noting that many of her clients lost hair during and after having COVID-19.

Yet what works for getting someone their luscious, thick locks back — and what’s simply social media chatter — is less straightforward. Here are seven oils to consider adding to your beauty routine, generally ranked by how much scientific evidence supports their use for healthy hair, from most to least.

Pumpkin seed oil, made by either cold or hot-pressing pumpkin seeds, is a nut-free oil, says Hershberger.

The Claim

The oil from pumpkin seeds is “scientifically proven to stop hair loss,” said Taylor Rose, a certified IAT trichologist (@thehealthyhur), in a TikTok video. “This oil is rich in unsaturated fatty acids, especially oleic and linoleic as well as vitamin E, all of which have the potential to aid in hair growth by reducing inflammation in the scalp.”

The Truth

Most of the research on pumpkin seed oil for hair loss is limited because the groups of people studied have been small, such as in a paper published in February 2021, or the oil has been analyzed in mice, as in a study published at the end of 2019.

The claim that pumpkin seed oil is good for hair regrowth may hold promise, though: One rigorous randomized controlled trial of 76 men with androgenetic alopecia, or male pattern baldness, found that 400 milligrams (mg) daily of pumpkin seed oil taken internally over 24 weeks led to 30 percent more hair growth than with placebo.

Pumpkin seed oil may promote hair growth in a way that is similar to finasteride (Propecia), says Blair Murphy-Rose, MD, a board-certified cosmetic and medical dermatologist at the Laser and Skin Surgery Center of New York. The oil contains phytosterols, or plant-derived fatty substances similar to cholesterol in humans, that may inhibit the effect of an enzyme called 5alpha reductase, which is associated with hormonal hair loss, she says. 5alpha reductase converts one form of testosterone to a more potent form of testosterone, “and it is that more potent form that is most highly associated with male pattern (hormonal) hair thinning,” she adds. The anti-inflammatory effect of pumpkin seed oil may also promote hair growth by reducing inflammation in the scalp that could contribute to hair shedding.

Another randomized controlled trial, this one in 60 women, found that pumpkin seed oil was as effective as 5 percent minoxidil foam for hair regrowth. Minoxidil, an oral and topical drug, is used to treat male and female pattern baldness, per the Mayo Clinic. In hormonal alopecia, the hairs miniaturize or become thinner, says Dr. Murphy-Rose. “When that happens, the diversity of the hair shafts' diameters increases — some are normal and some are thinner.” One way researchers can gauge the effectiveness of a drug for alopecia is by observing whether the drug promotes diversity of hair shaft diameters.

After three months of treatment in the latter trial, participants who were administered pumpkin seed oil saw improvement in hair growth (per their resulting hair shaft diversity) similar to those who took minoxidil. They also found that the number of vellus, or baby, hairs decreased and that the number of "regular" hairs increased, “also suggesting new hair growth and a favorable response to treatment,” Murphy-Rose says.

Rosemary oil is generally steam-distilled from the flowers, leaves, and twigs of rosemary, says Hershberger.

The Claim 

“It does help promote natural healthy hair growth and hair thickness, it helps promote circulation in your hair, which can again promote natural healthy hair growth,” the hair specialist Abbey Tameron (@abbets) said about rosemary oil in one of her videos.

The Truth

Rosemary oil is believed to increase blood flow to tiny blood vessels, which may lead to increased hair growth by supplying more nutrients, says Murphy-Rose.

In one six-month single blind clinical trial of 100 participants, 50 of whom were given rosemary oil lotion and the other 50 minoxidil 2 percent lotion, both groups experienced a significant increase in hair count. Those in the rosemary oil group were less likely to experience scalp itching.

“Rosemary contains carnosic acid, which may contribute to scalp health,” she says. Rosemary oil also has anti-inflammatory and antimicrobial properties “which can help to fight dandruff, a common cause of inflammation on the scalp, which can contribute to hair thinning,” she says.

Hershberger adds that it can hydrate and strengthen your hair. The celebrity stylist Sean James, who works at Matthew Preece Salon in Santa Monica, California, points to a study that found rosemary oil to be just as effective as 2 percent minoxidil after six months. The research also found that people who used the oil were less likely to experience an itchy scalp.

Jojoba oil comes from the seed of the jojoba shrub, Hershberger says. Like other oils, jojoba is usually cold-pressed. Garshick adds that jojoba oil is composed of 50 percent wax esters and “therefore closely resembles natural human sebum,” making it difficult for your skin and hair follicles to know the difference, and thus they're more likely to absorb it and be strengthened by it.

The Claim

Hershberger says jojoba oil is thought to help with hair thinning, preventing split ends and nourishing brittle hair. In one video, TikToker @melaniekms, a Maui, Hawaii–based hairstylist, claimed that jojoba is “rich in vitamins and minerals that nourish hair,” including vitamins C, B, E, and copper and zinc. “Jojoba can also moisturize your scalp and be a dandruff remedy,” she added.

The Truth

In addition to softening and smoothing the scalp, jojoba has antioxidant benefits and is anti-inflammatory and antibacterial, research published in the June 2021 issue of Polymers found. These properties may “help improve overall scalp health, which can promote a healthy environment for the hair,” says Garshick.

Jojoba is packed with vitamins A and D plus omega fatty acids, per research, and these characteristics are known to be “great for healthy hair and hair growth,” Garshick says. Another potential perk? “It can absorb easier into the scalp and hair follicle for maximum results,” she says. “It’s a lot lighter than other oils, so it would be great for fine to medium hair.”

Michelle Ornstein, an esthetician and the founder of Enessa Skincare in Los Angeles who uses jojoba oil in her Moroccan Argan Silk leave-on hair treatment, adds that it may protect against environmental damage to the hair, per the aforementioned research.

This essential oil is derived from the fruit of Argania spinosa, a tree native to Morocco, explains Garshick.

The Claim

Argan oil is traditionally used to improve the appearance of skin and hair, and to heal wounds, Garshick says. “Using the oil on your mids to ends can actually help with frizziness and breakage. Using it on your scalp can help with dandruff, and yes, hair growth,” said the TikToker @skalliessentials in a video.

The Truth

Argan oil is probably an ingredient you’re familiar with, as it’s a common one in popular hair products.

There’s some truth to the claim that argan oil is good for your hair. For one thing, it contains linoleic and oleic acid, two fatty acids associated with a slew of benefits from strengthening the skin barrier to moisturizing the scalp and fighting inflammation, as research suggests. Argan oil also contains squalene, which may help hydrate and protect hair, Garshick adds. The result? “Shinier and smoother hair,” she says.

Argan oil could also protect your hair against heat-related damage, such as from use of a hair dryer, curling iron, or straightener. In one lab study published in the October 2022 Journal of Cosmetic Dermatology, researchers found that pretreating hair exposed to heat with argan oil helped prevent protein loss. Similar to the way protein builds muscles, argan oil appears to promote hair strength, minimizing hair thinning and shedding.

“Because [argan oil] is a smaller molecule, it absorbs more easily into the scalp and hair follicles,” adds Ornstein.

What’s more, oleic acid and linoleic acid help improve the penetration of other ingredients into the hair and can reduce inflammation, Ornstein explains. Meanwhile, linoleic acid can help moisturize dry hair, thanks to its skin-barrier-strengthening effects.

“Additionally, argan oil contains antioxidants such as polyphenols and vitamin E, to help with free radical damage,” she says, and research supports that. Free radical damage is the result of oxidative stress upon the body, explains Ornstein. “When there is an imbalance of unstable oxygen atoms within the body, cellular disruption occurs and is followed by inflammation, premature aging, and illness.”

Lemongrass oil is derived from the leaves of the lemongrass plant, which contains citral, minerals, and vitamins, per Garshick.

The Claim

Tameron (@abbets) said lemongrass oil is great for hair health. “A lot of the time when you have a flaky scalp, lemongrass can go in there and clean it up a little bit, which helps with your scalp health, which [in turn] helps with natural healthy hair growth,” she remarked in her video.

The Truth

Lemongrass contains anti-inflammatory, antioxidant, antibacterial, and antifungal properties, research has shown. “While it does not itself cause hair to grow, it can strengthen the hairs to minimize the potential for hair loss,” Garshick says. According to a small study, the oil may significantly reduce dandruff when applied to the scalp, nodding to its antifungal properties.

Coconut oil is a fatty oil that is derived from coconuts that has been used in both skin care and hair care for its moisturizing properties, says Garshick.

The Claim

TikTokers such as Jenny Liu, MD, an East Brunswick, New Jersey–based dermatologist, have claimed that coconut oil “penetrates well into the hair shaft,” “helps to reduce breakage,” and “nourishes hair.”

The Truth

Coconut oil contains lauric acid, which may offer antimicrobial and anti-inflammatory properties, and these characteristics suggest it could promote healthy strands, per research. One 2003 study found that coconut oil was high in fatty acids with a low molecular weight, helping it penetrate the hair shaft, and was successful in reducing protein loss when used as a prewash treatment. “Because coconut oil can have moisturizing properties, it can help to nourish the scalp and the hair to improve overall hair health,” Garshick says. But while it has been shown to help strengthen hairs and reduce breakage, there is not enough evidence to suggest that it helps support hair regrowth, she says.