Castor oil is derived from the seeds of the castor plant, which is native to India. It’s thought to be useful for everything from fighting allergic reactions on your skin to stimulating hair growth all over the body.

It contains ricinoleic acid. This is an omega-9 unsaturated fatty acid that’s been loosely linked to changes in two substances that are thought to affect hair growth:

  • PGD2, which can shrink hair follicles and has been associated with parts of your body that can experience hair loss
  • PGE2, an anti-inflammatory that’s thought to make hair more dense

Castor oil’s moisturizing and nourishing properties are why many laud its wide range of uses, including:

  • reducing inflammation, especially on skin rashes
  • stimulating hair follicles
  • improving blood flow
  • making hair shiny

It’s also been thought to be good for hair growth. Tons of products for your scalp and other parts of your body promise to stimulate hair health by lubricating the skin around follicles and protecting long hair shafts from damage.

But does it work for growing a beard? The research says no — but it may be helpful when used with other strategies to stimulate hair growth, like your diet and lifestyle.

That’s because facial hair is a secondary sex characteristic and is different from other body hair.

Types of castor oil

Before you choose an oil, it’s helpful to know the differences between the various types you can find in stores:

  • Castor oil. Fresh castor seeds are cold-pressed, meaning that the oil is extracted by applying extreme pressure with a pressing device similar to that used for juicing.
  • Black castor oil. Castor seeds are first roasted and then heated before oil is extracted.
  • Jamaican castor oil. Castor seeds are roasted, crushed, and ground with a mortar and pestle, heated in water until they’re boiling, and pressed with a pressing device.

Supposedly, Jamaican castor oil is the most beneficial of these three because it’s typically not processed, and its dark color, which results from the roasting process, can also make your beard look darker.

But there’s no research that has definitively proven that any one of these oils is more beneficial than the others.

Castor oil hasn’t been found to do anything substantial for hair growth.

But there are some effects that may indirectly help your beard hair grow.

Its ability to fight off bacteria or fungal growth on the skin may help protect your follicles from damage, which can keep your hair healthy and promote hair growth.

The inhibition of PGD2 may have some benefits for hair elsewhere on your body, and even for your eyelashes and eyebrows. But this capability hasn’t been tested on beard hair or other types of post-puberty hair.

There’s nothing wrong with using a little castor oil on your face, as it has many other anti-inflammatory and antibacterial benefits for your skin.

But be careful when you apply it, as it can irritate parts of your body if used improperly. Don’t put it on any open cuts or irritated skin.

Here are some possible side effects that can occur if you use it too much or too often:

  • Skin irritation. If you have dermatitis or any kind of active rash or irritation on the skin surface, you might experience skin irritation upon application.
  • Eye irritation. This might occur if castor oil gets in your eye or you accidentally rub against your eye while applying the oil to your face.
  • Stomach cramping, nausea, or vomiting. This might happen if castor oil is ingested.

Here are some best practices for helping your beard grow faster or look thicker:

  • Wash, trim, and moisturize your beard regularly to make it look thicker and healthier.
  • Try using olive oil and avocado oil in combination with castor oil to lubricate the hair and surrounding follicles to protect all of your precious beard hairs.
  • Try leave-in conditioners to keep beard hair moisturized. This can have similar effects to other natural oils.
  • Combine castor oil with a carrier oil, such as coconut oil or almond oil, to augment its moisturizing properties.
  • Increase circulation to the hair follicles, which can help beard hair grow faster. This can include exercise, massaging the face, or taking vitamin E and B supplements.
  • Keep your testosterone levels balanced with a good diet and regular exercise. Eat foods rich with protein, iron, healthy carbohydrates, and zinc.

Your doctor might recommend any one of the following treatments to stimulate beard hair growth:

  • Minoxidil (Rogaine). This is a common product for scalp hair growth that may work for your beard. Rogaine can have some uncomfortable side effects. It also needs to stay on the hair and skin for hours after each application, so it may be too disruptive to be a useful remedy for facial hair.
  • Testosterone. If you have low testosterone, testosterone treatments can help stimulate facial hair growth. Supplements can have drastic effects on your body, so only try them if you have symptoms of low testosterone and have been diagnosed by a doctor.
  • Beard implants. With beard implants, hair is surgically implanted into your follicles. If you’re not satisfied with your beard hair growth or have trouble growing facial hair, this procedure might help. It can be expensive, and it might not achieve the look you want, though.

Castor oil isn’t proven to do anything for your beard hair.

But it does have some benefits for other parts of your body, so don’t feel like you can’t use it at all. Put it on your face or anywhere on your body to help moisturize your skin and keep bacteria and fungi off your skin surface.