Chaulmoogra (Hydnocarpus) Oil: A Leprosy Remedy, Not a Sunscreen
Last updated November 2, 2026
Lab-tested at SPF 2.0 — it blocks only about half of UVB, which is virtually no protection.
Chaulmoogra oil, also sold as hydnocarpus oil and spelled chaulmugra or chalmoogra, is pressed from the seeds of Hydnocarpus trees native to India and Southeast Asia. Scientific research indicates an SPF value of 2.0, making it one of the lowest-performing oils tested, providing essentially no UV protection.
Origin and Production
Several Hydnocarpus species are sources of chaulmoogra oil. It appears that the chaulmoogra of early Ayurvedic texts and of South India came from Hydnocarpus wightiana, Tuvakara in Sanskrit; botanical databases now treat H. wightianus as a synonym of Hydnocarpus pentandrus, which is the name you will see in recent research. The "true chaulmoogra" seeds of the Calcutta bazaar and the Paris and London drug sellers were identified in 1901 as those of Taraktogenos kurzii, now Hydnocarpus kurzii, a tree of Burma and northeast India. In 1904 Frederick Power's laboratory at Wellcome in London pressed the seed kernels and found the shells, the oil and the remaining press-cake each made up about a third of the seed's weight. From the oil they isolated a new fatty acid, chaulmoogric acid, and a year later its lower homologue, hydnocarpic acid, from H. wightiana and H. anthelmintica seeds. These are cyclopentenyl fatty acids, the characteristic class of compounds in Hydnocarpus seed oil.
Sources: Parascandola J. Chaulmoogra oil and the treatment of leprosy. Pharmacy in History. 2003;45(2):47-57 (National Library of Medicine); Sahoo MR, et al. Hydnocarpus: an ethnopharmacological, phytochemical and pharmacological review. J Ethnopharmacol. 2014;154(1):17-25; GBIF Backbone Taxonomy, Hydnocarpus pentandrus.
Scientific Research on UV Protection
Kaur & Saraf Study (2010)
The SPF value of 2.019 for chaulmoogra oil was determined in Kaur & Saraf's study published in Pharmacognosy Research. This extremely low value indicates that chaulmoogra oil blocks only about 50% of UVB radiation, providing virtually no protection against sun damage.
Reference: Kaur CD, Saraf S. In vitro sun protection factor determination of herbal oils used in cosmetics. Pharmacognosy Research. 2010;2(1):22-25.
Minimal Photoprotective Properties
With an SPF of 2.019, chaulmoogra oil offers essentially no meaningful UV protection. This value is so low that it would provide less protection than simply wearing light clothing. The unique cyclopentenyl fatty acids that make chaulmoogra oil therapeutically interesting contribute nothing to UV absorption or reflection.
History: Leprosy, Alice Ball and the Sulfones
Parascandola, "Chaulmoogra Oil and the Treatment of Leprosy" (2003)
Chaulmoogra oil had been used in Asia against leprosy and other skin conditions for hundreds of years, including in Ayurvedic medicine, before British physician Frederic Mouat introduced it to Western medicine in 1854. He dressed patients' ulcers with the oil and gave the pulped seeds by mouth. Applied to the skin it had only limited value; swallowed it worked better, but effective doses were so nauseating that one Public Health Service doctor's patients told him they would rather have leprosy than take another dose. Injection avoided the nausea but was painful.
One answer came from India, where Leonard Rogers injected a water-soluble sodium salt of the oil's fatty acids from 1915. Another came from Hawaii, where the sequence of events is not entirely clear. It appears that at the suggestion of Harry Hollmann, a Public Health Service surgeon, Alice Ball, a young African-American chemist and the first woman to earn a master's degree in science from the College of Hawaii (1915), turned the oil's fatty acids into ethyl esters. She died on 31 December 1916, aged 24, before publishing, so exactly how far she got is not certain. Her supervisor Arthur Dean published the work between 1920 and 1922 without crediting her, and the esters, thin oils that were readily absorbed when injected into muscle, became known as "Dean's derivatives". In 1922 Hollmann gave her the credit, describing the preparation as "Ball's Method", and in 2000 a plaque in her honor was placed on the campus of the University of Hawaii-Manoa. In fiscal year 1921, 94 patients treated with the esters were "paroled" from Kalihi Hospital in Honolulu, though officials recognized that follow-up was needed to know whether the improvement would last.
The oil probably peaked in the 1920s and 1930s, but side effects were still a problem, treatment was long, and there was disagreement about how effective it really was: by 1942 George McCoy, director of the National Institute of Health, had come to doubt its value. The sulfone drugs, shown effective at the Carville leprosy hospital in Louisiana in the 1940s, ended its run. Carville officially abandoned chaulmoogra therapy in 1947, and by the 1950s it had "essentially become just a colorful relic of pharmacy's past."
Reference: Parascandola J. Chaulmoogra oil and the treatment of leprosy. Pharmacy in History. 2003;45(2):47-57. Full text (NLM).
Uses Today, and the Evidence
In Indian medicine Hydnocarpus pentandrus is used primarily for leprosy and other skin disorders, and related species are used for skin disorders in traditional medicine in China, Thailand, Malaysia and Myanmar. A 2014 review of the genus lists antibacterial, antileprotic, antitubercular, antipsoriatic and anti-inflammatory activity among those reported for its extracts and compounds; its abstract does not separate laboratory findings from human ones, and the authors call for further investigation. The animal research on leprosy only suggests the oil might harm the bacterium that causes it. For people, the Natural Medicines database rates the evidence on psoriasis, eczema and other skin disorders as insufficient to judge whether it works.
Sources: Sahoo MR, et al. J Ethnopharmacol. 2014;154(1):17-25 (authors from The Himalaya Drug Company and JSS College of Pharmacy); Chaulmoogra monograph, RxList (Natural Medicines Comprehensive Database).
Buying Chaulmoogra Oil
- Check the botanical name. Look for Hydnocarpus wightianus (often printed wightiana), its current name H. pentandrus, or H. kurzii. "Gynocardia" on the label is a red flag: Gynocardia odorata was wrongly believed to be the source through the 19th century, and in 1905 chemists showed its oil contains neither chaulmoogric nor hydnocarpic acid.
- It is for skin, not for swallowing. The Natural Medicines database rates chaulmoogra unsafe by mouth, saying it contains cyanide and might cause cyanide poisoning.
- Skin safety is not established. The same monograph says its safety on skin is unknown and that it can cause skin irritation, and it advises avoiding it in pregnancy and while breastfeeding.
- Test before you use it. Dermatologists recommend testing any new skin care product first: apply it twice a day for seven to 10 days to a quarter-sized spot, such as the underside of the arm or the bend of the elbow, and stop if the skin turns red, itchy or swollen.
- It is not sun protection. At SPF 2.019 it blocks only about half of UVB.
Sources: Parascandola 2003; RxList chaulmoogra monograph; American Academy of Dermatology, How to test skin care products.
Comparison and Recommendations
Chaulmoogra oil's SPF of 2.019 places it fourth from the bottom among the 16 oils Kaur & Saraf tested, above only sesame (1.771), tea tree (1.702) and rose (0.248) oils. Its negligible UV protection combined with its strong odor and potential for skin irritation makes it completely unsuitable for sun protection applications.
If you want chaulmoogra oil for skin use, Therapeutic Cold Pressed Chaulmoogra Oil from dève herbes lists Hydnocarpus wightiana as its botanical name and cold pressing as its extraction method. Use it on skin only, test it first, and never rely on it as sun protection.
Our Verdict: 1/5
Chaulmoogra oil measured SPF 2.019 in Kaur & Saraf (2010), blocking only about 50% of UVB - virtually no protection against sun damage. It is a historic leprosy remedy still used in traditional medicine for skin conditions, not a sunscreen.
Pros
- The main leprosy remedy before the sulfone drugs of the 1940s, though results were inconsistent and side effects significant
- Still used in traditional medicine, including Ayurveda, for skin conditions such as psoriasis and eczema
Cons
- SPF 2.019 blocks only about 50% of UVB - virtually no protection against sun damage
- Its unusual cyclopentenyl fatty acids contribute nothing to UV absorption or reflection
- Its safety on skin has not been established, it can irritate skin, and its smell is unpleasant
- Rated unsafe by mouth by the Natural Medicines database, which says it contains cyanide and might cause cyanide poisoning
Recommended: Therapeutic Cold Pressed Chaulmoogra Oil — for external skin use only — not a sunscreen
Frequently Asked Questions
What is chaulmoogra oil?
Chaulmoogra oil, also sold as hydnocarpus oil, is pressed from the seeds of Hydnocarpus trees of India and Southeast Asia. Before the sulfone drugs of the 1940s it was the one leprosy remedy widely recognized as having value, though results were inconsistent. It is not a sunscreen: Kaur & Saraf (2010) measured its SPF at just 2.019.
What are other names for chaulmoogra oil?
Hydnocarpus oil is one. Spellings include chaulmugra and chalmoogra; it is Oleum Chaulmoograe in older pharmacy, da feng zi in Chinese, Tuvakara in Sanskrit and marotti in Malayalam. The old name "gynocardia oil" comes from a misidentification: in 1905 chemists showed that the oil of Gynocardia odorata is a different oil.
What is the biological source of chaulmoogra oil?
The seeds of several Hydnocarpus species. The south Indian tree used in Ayurveda is Hydnocarpus pentandrus, long known as H. wightianus (the two names are the same species); the "true chaulmoogra" of the Calcutta and London drug trade was H. kurzii (formerly Taraktogenos kurzii) of Burma and northeast India. All yield oil with the same characteristic cyclopentenyl fatty acids. The family is Achariaceae (formerly classed in Flacourtiaceae).
What is chaulmoogra oil used for?
Historically, leprosy: applied to the skin, swallowed, and later injected. It is still sold as a skin oil, and in traditional medicine it is used for psoriasis, eczema and other skin disorders, but evidence is insufficient to rate it for any of these. Sun protection is not one of its uses - its SPF of 2.019 blocks only about half of UVB.
Who was Alice Ball?
A young African-American chemist at the College of Hawaii, the first woman to earn a master's degree in science there (1915). It appears that at the suggestion of Public Health Service surgeon Harry Hollmann she turned chaulmoogra oil's fatty acids into ethyl esters that could be injected and absorbed. She died in 1916 aged 24; Arthur Dean published the work without crediting her and the esters became "Dean's derivatives", but Hollmann credited "Ball's Method" in 1922.
What are hydnocarpic and chaulmoogric acid?
The unusual cyclopentenyl fatty acids that, with gorlic acid, characterize chaulmoogra oil. Frederick Power's laboratory isolated chaulmoogric acid in 1904 and hydnocarpic acid in 1905, and the antileprotic effect is thought to come from these acids. They contribute nothing to UV absorption or reflection - which is why its measured SPF is only 2.019.
Does chaulmoogra oil have side effects?
Yes. The Natural Medicines database rates it unsafe by mouth, saying it contains cyanide and might cause cyanide poisoning; even as a leprosy medicine, effective oral doses were very nauseating. On skin its safety is unknown and it can cause irritation. Pregnant and breastfeeding women are advised to avoid it.