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We Ask a Derm: How Often Should I Use Castor Oil for Hair Growth (and Other Questions Related to Hair Loss)
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Fact: The internet loves castor oil. A quick search of the words will yield millions of results (over 80,000,000 and counting), ranging from fervent Reddit threads to DIY recipes on Pinterest boards and beauty blogs from all corners of the world swearing by its ability to grow lush, long hair—and fast!

Based on the reviews (and some pretty convincing before and after photos), we were ready to promptly pour a large bottle of the stuff on our heads and let it work its purported magic, but we thought it would be wise to vet this beloved ingredient by an expert first. 

Enter Dr. Sheel Desai Solomon, a board-certified dermatologist at Preston Dermatology and Skin Surgery in North Carolina.

According to Dr. Solomon, "Women account for 40 percent of Americans who are struggling with hair thinning or loss. And because the options for treating this issue are often very costly, it is completely understandable why many women seek out natural remedies such as castor oil." Glad we’re on the same page, here, doc, but give it to us straight...

Does castor oil actually help with hair growth?  

In a word: no. "Scientific evidence surrounding castor oil for hair growth is lacking," says Solomon. The good news, she assures, is that it does not have any harmful effects and can "enhance and increase the absorption and effectiveness of other products," which can in turn provide "fertile ground" for hair to grow.

So again, to be crystal clear, castor oil itself does not cause new hair growth on its own. However, incorporating it into your routine can help create a healthier environment for hair to grow. (There’s a gardening analogy in there somewhere, but it’s early, guys, and we’ve been known to accidentally kill succulents.)

Are there any benefits to using it and what makes it a better option than, say, coconut oil? 

For starters, it’s incredibly moisturizing. Castor oil is loaded with fatty acids and antioxidants, which makes it a great treatment for dry or brittle strands. Well-conditioned strands equal more flexibility, and more flexibility means your hair will be less likely to snag or split. The extra shine is an added bonus.

It also has naturally antibacterial and antifungal properties that can help soothe an itchy scalp and reduce dandruff—especially when paired with a nice in-shower massage to boost circulation. (Um, scalp massage? Say no more, fam.) 

The most distinguishing characteristic of castor oil (over coconut or jojoba, which are also two commonly used ingredients in DIY hair remedies) is its dense and slightly sticky texture. By far the thickest of the bunch, a little dab of castor oil goes a much longer way than its counterparts. 

How—and how often—should I use castor oil in my hair?

Before you go and get your scalp massage on, Dr. Solomon has a quick word of advice: "As with any new product you’re introducing into your regimen, test a tiny amount on your inner arm for 24 hours first to make sure your skin doesn’t have an adverse or allergic reaction. While it’s rare, some people do experience irritation from castor oil."

On that note, we’d recommend looking for one that’s cold-pressed and organic, as any pesticides or GMOs could potentially increase the chances of irritation. Plus, a cold-pressed extraction ensures that you’re getting the purest and highest quality form of castor oil from the seeds since there are no chemicals or heat involved in the process. (Just brute force!) 

Once you’ve successfully survived your patch test, we’d recommend using it as a weekly or bi-weekly pre-shampoo treatment, as opposed to leaving it on overnight like some people suggest. (If for no other reason than to avoid getting it all over your sheets and pillowcases.)

And remember what we said about castor oil being dense and sticky? Through some experimentation, we’ve found that it helps to dilute it with a lighter carrier oil (like jojoba or grapeseed) before applying it to your head. It’s easier to spread and easier to wash out afterward.

Just mix a few drops of each together in the palm of your hand and work it evenly through your scalp and strands. Shampoo thoroughly afterward so no residue remains (which is especially important if your hair is on the finer side or tends to get greasy easily). 

Is there any ingredient that is scientifically-proven to help grow hair?

As of now, minoxidil (brand name Rogaine) is the only FDA-approved ingredient that can claim to grow hair. It stimulates growth by reactivating dormant follicles and causing them to go into the anagen, or active-growth phase faster than they would on their own.

Two things to note about using minoxidil: It requires patience and commitment. According to a report from Harvard Medical School, "You won’t see results until you use the drug for at least two months. The effect often peaks at around four months, but it could take longer, so plan on a trial of six to 12 months." And "if the minoxidil works for you, you’ll need to keep using it to maintain those results. If you stop, you’ll start to lose hair again."

While we’re on the topic of hair growth, knowing what causes loss and thinning might be helpful in figuring out your best plan of action.

"Though it tends to be most prevalent in your 40s and 50s, hair loss can occur much earlier for some women—and for a laundry list of reasons, including diet, hormonal changes, alopecia and stress," explains Solomon.

Postpartum hair loss, for example, is fairly common among new moms. (The good news? It typically resolves itself as your hormones self-regulate in the year after giving birth.) Other hormonal changes like switching up your birth control—or stressful lifestyle changes like moving to a new city, starting a new job or experiencing emotional trauma can trigger hair loss as well.

The most common culprit, however, is also one of the most unassuming: Your styling habits. Too much bleach (hello, highlights) and heat (courtesy of our lifelong pals, the blow-dryer and flatiron) can damage your hair and cause thinning over time.

Over-brushing—especially with an abrasive brush (i.e., ones with metal or natural bristles)—can snag at strands and cause breakage. And wearing your hair in tight ponytails, buns and braids too often puts tension on your follicles and can cause traction alopecia.

Luckily, the fix for styling-related hair loss is pretty straightforward: scale back the salon visits, use less heat, get yourself a gentler brush (preferably one that has a vented back and rounded tips over the bristles) and wear your hair down from time to time.

At what point do I need to see a professional?

If your hair is falling out at a rapid rate or you’re noticing other signs—like a wider part or a thinning ponytail—we’d recommend seeing a dermatologist who specializes in hair loss as soon as possible. As one derm told us recently, "It’s much easier to find ways to preserve what you already have than to try and grow new strands after they’ve already fallen out."

The dermatologist will start by asking you questions about your medical history, diet and lifestyle. They may also run some blood tests and, in some cases, do a scalp biopsy to examine whether the hair loss is related to low estrogen or iron levels, for example, or if it’s an infection or it’s genetic, as is the case with androgenetic alopecia. 

As anyone who has experienced hair loss knows, it can be isolating and overwhelming when you’re going through it, but you’re definitely not alone. (Recall the statistic about 40 percent of women?) It also helps that we have so many more resources and options for treatment than ever before—castor oil and beyond.

RELATED: The 7 Best Hair Loss Treatments (at Every Budget)

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