So, you want longer hair and you’ve stumbled upon an internet hack that claims to help you do that. Yep, we’re talking about castor oil for hair growth. Many have cited the ingredient as the reason for their longer, thicker hair, but with little science or proof to back up their claims. So, we figured it was time to ask the experts — dermatologists and a cosmetic chemist — to weigh in.

First things first: If you’re struggling with hair loss or thinning, you’re far from alone. It’s extremely common, impacting an estimated 80 million Americans. It can occur for several reasons, including hormonal changes, alopecia, and stress, so it’s always best to visit your doctor to determine what’s going on before diving into any possible treatments.

Regardless of the reason, losing hair can be stressful, and we get the temptation of trying at-home remedies like castor oil. (Those before-and-after photos are so dramatic, whether they’re real or not). To get a real definitive answer on this popular hair growth method, we turned to the pros.

Meet the experts:

• Marisa Garshick, MD, is a board-certified dermatologist in New York City.
• Ife J. Rodney, MD, is a board-certified dermatologist and founding director of Eternal Dermatology in Fulton, Maryland.
• Perry Romanowski, a cosmetic chemist and the author of Beginning Cosmetic Chemistry.
• Adam Friedman, MD, is a board-certified dermatologist and program director at The George Washington University School of Medicine & Health Sciences in Washington, D.C.

In this story:

What is castor oil?

Castor oil is derived from castor beans and is rich in protein, antioxidants, nutrients, and fatty acids, explains New York City-based board-certified dermatologist Marisa Garshick, MD. Like many hair oils, castor oil has been used for centuries all thanks to its “active ingredient ricinoleic acid, a hydrating and lubricating fatty acid,” adds Ife J. Rodney, MD, a board-certified dermatologist in Fulton, Maryland.

What is cold-pressed castor oil?

Not all castor oil is created equal. The castor oil you see in your hair-care aisle is typically cold-pressed — produced mechanically through a “physical crushing of the beans to extract a lighter, cleaner, and thinner form of oil that is abundant in nutrients and vitamins,” Dr. Garshick explains.

Castor oil that is not cold-pressed is typically used as a food preservative or in vegetable oils. It’s extracted chemically, via a “high-temperature roasting of the castor beans or a refining that involves bleaching and filtering,” says Dr. Garshick. “While this process helps to remove impurities, it can also impact the moisturizing and antioxidant properties of castor oil.”

What are the benefits of using castor oil?

Though it’s often touted as an all-natural panacea for your hair troubles (go ahead, Google it: You’ll find article after article about how this viscous oil can help with a myriad of issues like shedding, breakage, and regrowth) that probably isn’t the case. Unlike other popular oils and vitamins like rosemary oil and vitamin B5, both of which have at least some studies that back up their aid in hair growth, Dr. Garshick says scientific evidence surrounding castor oil’s ability to reverse hair loss is lacking. That being said, there are lots of other benefits to castor oil, making it a worthwhile ingredient for the hair.