Best Oil to Grow Eyebrows: Castor, Rosemary, and More

Castor oil is the most popular pick, and for good reason: it's thick, coating, and its main compound (ricinoleic acid) has some legitimate biological activity related to hair follicle pathways. But if you want the most evidence-backed option for actually stimulating eyebrow growth, rosemary oil is pulling ahead. A 2023 clinical study found rosemary oil comparable to 2% minoxidil for scalp hair density, and while that research was on the scalp, the follicle biology applies to brows too. The practical answer: use rosemary oil (diluted in a carrier like castor or jojoba oil) as your primary growth driver, and lean on castor oil for its conditioning and coating properties. Combined, they cover both stimulation and retention.

The best oils for eyebrow growth, broken down

Castor oil: the crowd favorite with honest caveats

Castor oil dominates the conversation around eyebrow growth, and it has been used in naturopathic and beauty practice for decades. Its main active component is ricinoleic acid, which makes up roughly 85–95% of the oil and drives most of its pharmacologic properties. Researchers have proposed that ricinoleic acid may inhibit prostaglandin D2 synthase (PTGDS), an enzyme associated with hair loss, and that it can activate prostaglandin EP3 receptors, which plays into hair follicle signaling pathways. That's a plausible mechanism on paper.

Here's the honest part: there are no controlled human studies proving castor oil directly causes eyebrow or hair regrowth. The PMC literature flags this clearly. What castor oil does well is moisturize the brow area, reduce breakage of existing hairs, and coat fine brow hairs so they look slightly fuller. That's still genuinely useful when your brows are sparse or recovering from over-tweezing, but you shouldn't expect it to resurrect completely dormant follicles on its own. but you shouldn't expect castor oil to resurrect completely dormant follicles on its own, which is a similar question to can shea butter grow eyebrows. Think of castor oil as a supportive base rather than the active engine.

Rosemary oil: the best-evidenced essential oil for growth

Rosemary oil (Rosmarinus officinalis) is where the stronger evidence sits. It's thought to work primarily by improving microcirculation to the follicle and inhibiting 5-alpha-reductase, the enzyme that converts testosterone into DHT (a key driver of follicle miniaturization). The 2023 comparison with minoxidil showed comparable hair count increases at the 6-month mark, which is a genuinely impressive result for a plant-based ingredient. Rosemary oil must always be diluted before applying near the brows, typically at a 2–3% concentration in a carrier oil. That works out to about 3–4 drops of rosemary essential oil per teaspoon of carrier oil. Never apply it straight: it can cause irritation and, critically, should never get into your eyes.

Carrier oils: jojoba, argan, and why the base matters

Carrier oils don't grow brows on their own, but they're not just filler. Jojoba oil is structurally similar to your skin's natural sebum, so it absorbs well and doesn't clog follicles, making it an ideal carrier for rosemary oil in the brow area. If you want the closest thing to a brow-growth ingredient in a jojoba-based routine, treat jojoba as the carrier that helps other oils sit well on the skin, not as a standalone growth treatment Jojoba oil. Argan oil is rich in vitamin E and oleic acid, which support skin barrier health and reduce inflammation around the follicle. Fractionated coconut oil is another clean, lightweight option. The carrier you choose affects how irritating or comedogenic the blend is near the delicate brow and eye area, so lighter oils like jojoba tend to be the safest bet for daily use.

Essential oils: which ones actually help, which to avoid

Not every essential oil that people tout for hair growth is safe or effective around eyebrows. The brow area sits dangerously close to your eyes, so any oil that causes mucous membrane irritation becomes a real problem. Here's a quick breakdown:

The rule for all essential oils near brows: always dilute, always patch test on your inner arm 24 hours before applying to your face, and keep the application precise. A thin eyeliner brush or a clean spoolie works better than your fingertip for keeping oil out of your eyes.

Does vegetable oil (or olive oil, coconut oil) actually help brows grow?

This comes up a lot, and the answer is: probably not directly. Plain vegetable oil (the kind in your kitchen) contains fatty acids like linoleic and oleic acid that can soften and condition brow hairs and the surrounding skin, but there's no evidence it stimulates follicle activity. The same applies to standard olive oil and unrefined coconut oil. These oils can help with hair breakage and the general health of existing brow hairs, which indirectly makes brows look a bit fuller over time. But if your goal is actual growth of new hairs or reactivation of follicles that have slowed down, plain vegetable oils are the wrong tool.

That said, if you're in the phase of recovering from heavy waxing or tweezing damage, applying a light nourishing oil to the brow area keeps the skin around the follicle healthy while you wait for regrowth. In that context, any gentle oil has some supportive value. Just don't mistake "my skin feels better" for "my follicles are being stimulated."

How to actually use oils to grow thicker, fuller brows

The routine that works

Consistency beats quantity here. Applying a large amount of oil once a week does far less than a small, precise application every night before bed. Here's the routine I'd actually recommend:

1. Make your blend: 3–4 drops of rosemary essential oil per teaspoon of castor oil or jojoba oil. Mix in a small dark glass bottle to protect the rosemary oil from light degradation.
2. Cleanse your face first so there's no makeup or sunscreen creating a barrier over the brow area.
3. Dip a clean spoolie brush or an eyeliner brush into the blend and apply a small amount directly along the brow line, working in the direction of hair growth.
4. Massage gently with a fingertip for 30–60 seconds. This isn't just for absorption: the massage itself may improve local blood circulation to the follicle.
5. Leave it on overnight. No need to wash it off before bed.
6. Apply once daily, or at minimum 5 nights per week. Rinse off in the morning with your normal cleanser.
7. Patch test before your first use: apply a small amount to your inner arm, wait 24 hours, check for redness or irritation.

Realistic timeline: what to expect and when

The eyebrow hair growth cycle runs in three phases: anagen (active growth), catagen (transition), and telogen (resting/shedding). At any given time, most brow hairs are in the resting phase, which is why eyebrows grow slowly compared to scalp hair. Realistically, here's what to expect with consistent nightly use of a rosemary-castor oil blend:

Three to four months is the honest minimum before judging whether oils are working for you. Anyone promising results in two weeks is selling you something. Age, genetics, the extent of previous waxing or tweezing damage, and underlying health conditions all affect how quickly (or whether) follicles respond.

What works for both eyebrows and eyelashes

If you're trying to improve both brows and lashes at the same time, castor oil is the safest crossover option. It's gentle enough to use along the lash line (applied carefully with a clean mascara wand or cotton swab), and it provides the same conditioning and coating benefits for lashes as it does for brows. Some people use it directly on the lash line at night. Rosemary oil, while excellent for brows, carries more risk near the actual lash line and eyelid because of proximity to the eye's mucous membranes. If you want to use rosemary oil for eyelashes, keep the dilution very low (1% max) and apply only to the outer base of the lashes, not the inner lash line.

For lashes specifically, there's also a prescription option worth knowing about: bimatoprost (sold as Latisse) is FDA-approved for eyelash growth and has solid clinical evidence behind it. It's not approved for brows, but some dermatologists use it off-label in that context. That's a conversation worth having if you're dealing with serious lash loss.

When oils aren't enough: stronger options and when to get help

Minoxidil for eyebrows

If you've been consistent with oils for four to six months and haven't seen meaningful change, minoxidil is the next logical step. Originally developed for scalp hair loss, minoxidil (typically 2–5% solution or foam) is used off-label for eyebrow growth and has a reasonable body of evidence supporting it in that context. It works by prolonging the anagen (growth) phase of the hair cycle and improving blood flow to follicles. A small 2021 study found that 2% minoxidil applied twice daily led to significant eyebrow hair count and density improvements compared to placebo over 16 weeks. The key risks: skin irritation, and the possibility of unwanted facial hair growth if the product spreads beyond the brow area. Apply precisely, use minimal amounts, and wash hands immediately after.

When to see a dermatologist

Some eyebrow thinning has nothing to do with how much you tweeze or what oil you use. Thyroid disorders (both hypothyroidism and hyperthyroidism) commonly cause brow thinning, especially at the outer third of the brow. Alopecia areata, nutritional deficiencies (particularly iron and biotin), and certain medications can all cause eyebrow loss that oils simply cannot reverse. If your brows have been thinning without a clear cause, or if you notice patchiness spreading, hair loss in other areas, or associated symptoms like fatigue or skin changes, see a dermatologist or your GP before spending more time and money on topical oils. A blood panel can rule out systemic causes quickly.

Other options a dermatologist might discuss include platelet-rich plasma (PRP) injections, which have emerging evidence for eyebrow regrowth, and microblading or powder brow tattoos as cosmetic solutions if follicle activity is permanently reduced. These aren't replacements for addressing the root cause, but they're real options worth knowing about when you've exhausted the topical route.

Your practical next-step plan

To pull it all together: start with a rosemary-in-castor-oil blend applied nightly to clean brows. If you are trying to answer whether can hair growth oil grow eyebrows, the most evidence-backed option in this category is rosemary oil for stimulation, while castor oil mainly helps condition and protect existing brow hairs. Give it a genuine three to four months before assessing. If you see improvement, keep going. If you see nothing by month four or five, move to 2% minoxidil (and consider a dermatology consult to rule out systemic causes). If your brow thinning came from over-tweezing or waxing, follicles are likely still viable and oils plus patience genuinely do work. If it came from nowhere with no obvious cause, get checked before assuming a topical fix is the answer.