Does Castor Oil Actually Help Blepharitis? What a New Zealand Clinical Trial Found

Castor oil has been a folk remedy for tired, irritated eyes for generations. But does it hold up when it's actually put to the test? A clinical trial from New Zealand set out to answer exactly that question for people with blepharitis — and the results are worth knowing if you deal with red, crusty, uncomfortable eyelids.

What is blepharitis, quickly?

Blepharitis is chronic inflammation of the eyelid margins — the strip of skin where your lashes meet your eye. It leaves lids looking red and swollen, often with flakes or crusts at the lash base, and it's a leading driver of dry, gritty, burning eyes. It tends to be stubborn and recurrent, which is why so many people go looking for a gentle, natural option they can keep using long-term.

The study: a smart, self-controlled design

Researchers recruited 26 people with clinical signs of blepharitis (14 women and 12 men, average age 38). Each person applied a 100% cold-pressed castor oil formulation to the eyelids of one eye only, twice a day for four weeks. Their other eye received no treatment and acted as the control.

This "paired-eye" design is clever: because the treated and untreated eye belong to the same person, differences between the two are much more likely to come from the castor oil itself rather than from diet, age, environment or other factors. At the start, both eyes measured the same. After 28 days, the researchers compared them again.

What actually improved

The treated eyes showed clear, measurable improvements that the untreated eyes did not. Specifically, the study reported reductions in:

• Eyelid margin thickening — lids became less swollen and inflamed along the rim.
• Telangiectasia — the visible small blood vessels on the lid margin.
• Eyelash matting and cylindrical dandruff — the collar-like debris that builds around the lash base.
• Madarosis — lash loss associated with chronic lid disease.
• Lid wiper epitheliopathy — irritation of the inner lid surface that wipes across the eye with each blink.
• Staphylococcal and seborrhoeic eyelash crusting — the two classic types of blepharitis crusting both decreased more in treated eyes.

On top of the physical signs, participants' OSDI score — a standard questionnaire that measures dry eye symptoms — dropped significantly, meaning people actually felt better, not just looked better on examination. Importantly, no adverse events were reported.

Why castor oil might work

Castor oil is rich in ricinoleic acid, which has recognised soothing and antimicrobial-supporting properties. On the lid margin it can help loosen crusts, condition the skin, and create a less hospitable environment for the bacteria and debris that keep blepharitis simmering. Because it's an oil, it also sits comfortably on the oily lid margin without stinging the way some cleansers do.

What this does — and doesn't — mean for you

This was a small study, and the authors were careful not to oversell it. It doesn't prove castor oil "cures" blepharitis, and blepharitis is a chronic condition that generally needs ongoing management rather than a one-time fix. But it's genuinely encouraging: a simple, natural, well-tolerated treatment produced real improvements in both the signs and the symptoms of lid disease within four weeks.

The key details that matter if you want to try it: the study used 100% cold-pressed castor oil (purity matters — more on that in another post), applied as a thin layer to the eyelids twice daily, for external use only, avoiding getting oil directly in the eye.

Want a castor oil made for eyelids? Meibocare LidBoost+ is a 100% cold-pressed, pharmaceutical-grade castor oil with a precise roller-ball applicator designed for the lid margin — the same type of oil used in this kind of research. It's also part of our discounted dry eye treatment packages.

Frequently asked questions

Is castor oil safe to put on your eyelids?

In this trial, twice-daily eyelid application of 100% cold-pressed castor oil for four weeks produced no adverse events. Use a pure, cold-pressed product, apply a thin layer to the outer lids only, and check with your optometrist if you have an active infection.

How fast does castor oil work on blepharitis?

In the study, measurable improvements were seen after four weeks of twice-daily use. Blepharitis is chronic, so ongoing use is usually needed to maintain the benefit.

Educational information only, not medical advice. Consult your optometrist or doctor about persistent eyelid or eye symptoms. Reference: Muntz A, Sandford E, Claassen M, et al. Randomized trial of topical periocular castor oil treatment for blepharitis. The Ocular Surface. 2021;19:145–150. doi:10.1016/j.jtos.2020.05.007 (PubMed)