How to Make Castor Oil Serum for Eyelashes

Step-by-step instructions and tips to use castor oil for eyelashes.

Castor oil with beans on wooden surface
Amawasri / Getty Images
  • Total Time: 15 minutes
  • Skill Level: Beginner
  • Estimated Cost: $5-$20

If you only associate castor oil with laxatives, it’s time to broaden your scope and consider its many beauty applications—especially this luxurious and sustainable DIY castor oil eyelash serum.

Derived from the castor bean plant, castor oil offers a heavier dose of vitamin E and fatty acids than many other popular plant oils. Its antibacterial and hydrating properties make it a great choice for your natural skin and hair care needs.

While claims of its lash-lengthening powers haven’t yet been scientifically supported, castor oil helps lay the foundation for healthy follicles and hair growth, which is, of course, essential for long, beautiful eyelashes.

What Is Castor Oil?

Castor oil is extracted from the beans or seeds of the Ricinus communis plant, a shrub native to areas of Africa and Asia that now grows abundantly in tropical climates.
Rich in triglycerides, castor oil is widely used in the beauty industry for its moisturizing properties, which help naturally remove dirt from skin and lock in hydration. The oil is clear with a slight yellow tint and mild scent.

What You'll Need


  • Small bottle and reusable applicators or an empty, sanitized mascara tube with wand
  • Dropper


  • 1 to 2 teaspoons castor oil
  • 1 to 3 drops lavender essential oil
  • 1 to 3 drops cedarwood essential oil
  • 1 to 3 drops vitamin E oil


Young caucasian woman applying serum for eyebrows and eyelashes growth in front of the mirror. Night time beauty routine.

Triocean / Getty Images

  1. Combine Ingredients

    Pour essential oils and vitamin E oil into a small bottle or empty mascara tube that has been thoroughly cleaned and sanitized (see instructions below).

    Add castor oil, ensuring that you leave enough space to insert the wand.

  2. Mix

    After replacing the cap, slowly invert to thoroughly mix the ingredients.

  3. Apply Serum

    Apply to eyelashes (as you would mascara) each night before bed. Take care to lightly coat lashes with only one or two brushstrokes to avoid getting serum in your eyes.


You can also use castor oil on its own to strengthen and moisturize your eyelashes. Pure, organic castor oil without any additives is your best bet.

Simply dip your clean applicator in the oil and apply a light layer to your eyelashes before going to bed. Start by using a small amount to prevent it from getting in your eyes. Be sure to wash it off in the morning.

Castor Oil for Eyebrows

For a slight deviation from lash care, you can apply castor oil serum to your brows for a similar effect. Castor oil-treated eyebrows may appear fuller and thicker—perfect for remedying any over-plucking incidents from the past.

Simply repeat the recipe from above, but change up the essential oils to differentiate your DIY products. Rosemary and tea tree make a lovely, aromatic addition.


Note that some people may experience an allergic reaction to castor oil, so be sure to do a patch test before applying this serum to your eyelashes, eyebrows, or skin.

How to Clean Your Mascara Tube and Brush

closeup of mascara wand and tube on wooden surface


If you're going to reuse an old mascara tube and brush to store and apply your serum, keep in mind that they should be thoroughly sanitized. This process will require a lot of soaking and scrubbing to remove all the remaining mascara. Follow these steps:

  1. Fill the tube with a water-based makeup remover. Allow it to soak overnight.
  2. Use your wand to help clean the inside of the tube. Pump the brush and swirl it around for a few minutes to further remove the material. Empty the tube.
  3. If your mascara tube has a rubber insert or stopper, remove it.
  4. Submerge the mascara tube, brush, and rubber insert in warm water with dish soap. Make sure that the tube is filled with soapy water. Let them soak for an hour or two.
  5. Use the wand to scrub the inside of the tube and then rinse with warm water. If the water comes out dirty (with mascara), scrub with soapy water again. If necessary, repeat this process until the water comes out clean.
  6. Use a gentle brush to scrub the wand and bristles and rinse with warm water.
  7. Once the tube is clean, sterilize it by filling it with rubbing alcohol. Place the brush in and close the container, shake it a little, and dump the alcohol.
  8. Allow all pieces to air dry completely before reassembling them.

Note that this process works best for mascara brushes made of synthetic material. Alcohol may degrade natural fibers.