Alongside the massively effective and well researched kings of natural topical treatments like grapeseed oil, and green tea, one which stands out as remaining highly mysterious is castor oil. It’s an oil which has been experimented with endlessly, but analysed by very few studies related to acne.
What is castor oil? It’s the fat extracted from the castor bean, the fruit of the ricinus communis plant. Humanity has been using it for thousands of years; castor beans were found in Egyptian tombs dating back to 4000BC. In the Ebers Papyrus medicinal book of Egypt which dates back to 1500BC, castor oil was recommended for lowering eye irritation.
Topically, castor oil is gaining popularity rapidly as a hair regrowth solution. However, among everyone else, the castor plant is most famous as the natural source of ricin, the deadly, incurable poison featured in TV shows and delivered in envelopes to politicians everywhere. Castor oil is also a laxative, and was dished out by Mussolini and his fascist henchmen as a punishment back in the 1930s.
Castor oil is therefore distrusted by many, particularly the Italians. So understand right now that when applied to the skin, it’s completely safe. In 2002 it was found in over 769 cosmetic products, with lipstick accounting for 81% of them.
There are no studies directly on pimple counts and acne. However, rumours circulate the internet that it contains vitamin E, lowers inflammation, and is a top notch moisturiser.
The truth is that we don’t know the truth, because the research is too thin. But castor oil definitely has some promising powers for acne.
Use castor oil – get 56 more minutes in the sun?
By far the best of them is an ability to act as a natural protection against inflammation and irritation from UV radiation. Several natural topical treatments have this power, such as aloe vera, but not all of them – lemon juice contains natural furocoumarins which weaken your defences.
Our promising study for acne analysed the sun protection factor (SPF) of a wide assortment of carrier oils and essential oils. The SPF is a scientific measurement of the effectiveness of a sunscreen formulation, and how effectively it prevents both sunburn and other skin irritation.
Here’s how it works. If your starting point is 10 minutes lying on the beach in the sun, applying a rose oil cream with an SPF score of 1 will give you an extra ten minutes free from burning. Applying a revolutionary new sunscreen with an SPF of 150, meanwhile, would give you an extra 1500 minutes.
In our study on castor oil, the scientists tested both fat-based carrier oils (like olive oil) and essential oils, which are a separate part of a plant such as the petals distilled into a liquid (like tea tree oil or rose water).
Out of the ten carrier oils tested, castor oil received the sixth highest SPF, ending up with a score of 5.687. The two strongest oils were olive oil with 7.549 and coconut oil with 7.119. Almond oil came in at 4.659. Two poorly performing carrier oils were sesame oil with 1.771 and mustard oil scoring 2.105.
Overall, castor oil placed at around the middle. At first glance it looks average. However, 5.687 is an excellent score; it basically equals 56 minutes and 53 seconds of time on the beach before pimples explode from nowhere (bring your watch or else).
What’s more, coconut oil and olive oil are riddled with flaws. The former has a comedogenic rating of 4 out of 5 while the latter leads to irritated skin itself.
The signs are strong for castor oil as a natural sunscreen. On the surface, it’s unclear how castor oil provides these benefits. The two oils which came first, olive oil and coconut oil, consist of 97% lauric acid and 70% oleic acid respectively. The average castor oil contains just 4% oleic acid with a 2-6% range, with no lauric acid at all.
So what’s the explanation then? Possibly that castor oil is a unique oil in nature. 90% of its total fats are the monounsaturated omega 9 fat called ricinoleic acid. Ricinoleic acid is found in high quantities exclusively in the ricinus communis plant. It isn’t extensively researched, not compared to common fatty acids like oleic acid and linoleic acid.
Nobody knows what powers ricinoleic acid has. Therefore, UV ray protection could easily be one of them and that could explain the sunscreen abilities of castor oil as a whole.
Overall, photo-protection is the most notable power for acne that castor oil has by far, and definitely the most proven. If you were going to use castor oil on your skin, a sunny day would be the best day to do it.
Can castor oil enhance every other topical treatment?
Next though we have a completely fake power: vitamin E, and the claim that castor oil is rich in it. There’s a strong tendency on skincare blogs to assume that any natural oil is rich in vitamin E, whether it’s jojoba oil or sesame seed oil, but castor oil contains precisely none.
This study on an assortment of plant oils commented that “analyses of vegetable oils or fats from 17 different plant types showed as low as zero ug of a-tocopherol/g of castor bean and linseed oils and as high as 1276ug/g of wheat germ oil”. Alpha tocopherol is the main natural form of vitamin E. That theory is laid to rest, and while we’re on the subject, we’ll get to wheat germ oil as a topical treatment another time.
However, the tables turn with our next study which revealed that ricinoleic acid had potent anti-inflammatory properties. When applied to rat skin, ricinoleic acid exhibited strong anti-inflammatory effects compared to the red chilli compound capsaicin. Lowered inflammation equals lowered painful and red pimples; the ricinoleic acid content of castor oil varies from 85-95%.
Capsaicin is the spicy compound found in Chilli Peppers, which despite the burning and heat that make you vow never to eat one again, is strongly anti-inflammatory. Ricinoleic acid even reduced the compound called substance P, a master regulator in acne which cranks up inflammation, sebum production, and skin cell turnover.
Even more promisingly, castor oil and ricinoleic acid might enhance the transdermal penetration of other skincare chemicals.
I first discovered that power in this review and it turned out that the origin was a study on rats performed in 1952. Therefore unless you’re a giant rat sitting at a computer desk, the power is completely unconfirmed. However, if castor oil can enhance skincare ingredient penetration, the implications would be excellent.
Antibacterial peptides and compounds from raw honey would clear acne better. Mixing castor oil with witch hazel would enhance the skin’s absorption of its endless antioxidants. Combining castor oil with green tea would allow the latter to downregulate sebum production more efficiently. The possibilities would never end.
Last on the menu we have castor oil’s powers as a moisturiser. No direct studies exist, but castor oil lacks the side effects of olive oil or coconut oil. The oleic acid concentration is extremely low at 4%; oleic acid irritates skin and disrupts the skin barrier by increasing trans-epidermal water loss.
Furthermore, castor oil has a comedogenicity score of only 1 out of 5, indicating a “very low” chance that it will clog skin pores. The fatty acid composition might turn out to be ideal for moisturising, because like we said earlier, ricinoleic acid is an unexplored entity. If miraculous results occur then there’ll be less disastrous results than many natural “moisturisers”.
It’s possible that castor oil can come at your acne from many directions, in addition to defending your skin from the sun.
The ricin scare story disproven
Now we have the ultimate question about castor oil – is it really laced with ricin and can using it bring about an untimely demise? The answer is no.
You don’t even need science. Egyptians applied castor oil to their eyes back in 1500BC, Indian women used it since 2000BC. If castor oil contained ricin, an incurable poison which is among the most easily manufactured chemical warfare agents, there’d be a bloody trail carved throughout the history books. Indeed there would be a bloody catalogue of tales on the internet, but there isn’t.
The fact is that ricin is derived from the castor bean. Castor oil is also derived from the caster bean. But ricin is extracted from the crushed pulp once the oil has been separated.
In the traditional castor oil products which have been heated for purification in a factory, all the ricin is deactivated anyway. I actually recommend that you buy cold-pressed or expeller pressed castor oil, but there’s still no problem. Ricin doesn’t partition into the oil during the initial separation from the bean; studies have confirmed this.
In fact, the FDA has deemed castor oil to be “generally recognised as safe” when taken orally. Topically, there’s even less danger.
You will not come to a sticky end by using castor oil for acne. The bigger question is the milder side effects, such as skin irritation. This giant review of castor oil’s safety concluded that castor oil was safe in the concentrations normally used in cosmetics and skincare.
Poor reactions do occur: “the clinical experience suggests that sensitization reactions are seen infrequently”. The main reactions occurred among those with existing dermatitis (an inflammatory skin condition), where castor oil and ricinoleic acid were mildly irritating and sensitising. In everyone else, however, castor oil caused no adverse sensitisation, photosensitisation, or irritation.
The scientists also considered data on ricinoleic acid to be fair game for their review, since it comprises 90% of castor oil. The result: “the available data demonstrate few toxic effects”.
Castor oil has no specific compounds with irritating potential, like the 8-cineol of tea tree oil. In the real world of testimonials, I’ve seen several negative testimonials speaking of new pimples, but no more than with grapeseed oil or jojoba oil.
The only much-feared side effect from castor oil is dry skin; it’s said to be a “drying oil” which can suck all the moisture away. However, nothing of the sort was mentioned in the study above.
Whether castor oil will clear acne remains to be seen, but overall, there’s little risk in trying it.
Is castor oil a miracle hair-growth tonic?
If you believe some, however, any castor oil applied to your face is a waste anyway. A large subset of the hair loss community has identified castor oil as a potential natural alternative to harsh drugs like finasteride.
Quite simply, it’s believed that rubbing unheated castor oil into your scalp will stimulate the inactive hair follicles to start growing again. It’s gaining popularity rapidly. People are even using it regrow their eyebrows (hopefully they won’t become a metre long).
Is there any truth to it? There’s definitely some evidence. One of the factors in hair loss is a compound called prostaglandin E2 (PGE2). This study found that higher levels of PGE2 had a stimulatory effect on hair growth. Specifically, it acted in co-ordination with another compound called PGF2alpha; PGE2 didn’t convert inactive hair follicles to active ones, but it did accelerate the development of those in early stages of rebirth.
The connection to castor oil? This study found that eating castor oil increased PGE2 levels significantly in rats.
We don’t know whether this would translate when applied topically, or in humans; we know even less about whether the increase in PGE2 would be enough. But the purported benefits of castor oil on hair growth all came from testimonials originally and this could be an explanation.
There’s also a similar compound called prostaglandin D2. PGD2 was shown to prevent hair follicle activation, and it’s speculated though not proven that ricinoleic acid can inhibit it. Another theorised explanation is the vitamin E found in castor oil, since this study found that naturally occurring forms of vitamin E called tocopherols could stimulate hair growth. However, as we discussed earlier, there is no vitamin E in castor oil.
Overall, the jury is out on whether castor oil will give you a head of hair like Conan the barbarian, or Rapunzel if you’re a woman with hair loss.
The jury isn’t out on two much more common foods though: garlic and onions.
Apparently, onion juice is one of best treatments for hair loss around, hidden right in front of eyes. This study performed an extremely basic yet interesting experiment. 38 patients with hair loss were divided into two groups and supplied with either crude onion juice or plain old tap water. They were all told to apply their respective treatment to their head twice daily for two months.
In the onion juice group, regrowth of hair commenced after just two weeks. After four weeks hair regrowth was seen in 17 or 73.9% of patients, and after six weeks 20 (86.9%). Meanwhile, among those stuck in the tap water group, only two or 13% experienced hair growth after 8 weeks.
Why on earth could this effect have occurred? It could have been anything. Onion is a highly nutritious food; quercetin is one phytonutrient which it is rich in.
But the onion is in the same botanical family as the garlic bulb, and that too has been shown to stimulate hair growth. This study compared a placebo and garlic gel. With 20 patients in each group, 19 members of the garlic group experienced a “good” increase in hair regrowth and 1 experienced a “moderate” increase. The results were significantly better than those in the placebo group.
If you want to restore your long lost hair then just open your cupboard door and get some onions, garlic and a chopping board.
Other great strategies include taking zinc supplements to maintain the integrity of the hair follicles, and increasing your intake of glycine to provide more structural proteins. Zinc also happens to be excellent for acne.
The verdict on castor oil
Overall, castor oil is an interesting natural topical treatment for acne, which I won’t pass judgement on yet. Castor oil remains shrouded in mystery. There could be anti-inflammatory effects due to the ricinoleic acid, and it could be a great moisturiser.
However, we know for certain that the vitamin E content is a myth. We know that it has a good to great safety record. The only risk is that you’ll wake up and be the Wolfman, if you apply it to your face and the hair loss community turns out to be overly accurate.
The positive power we can be most sure of is its photo-protective properties. If it doesn’t clear acne solely through topical application, castor oil might successfully prevent it.
Castor oil could thus be a handy oil to keep in your cupboard over the summer, or to bring on a beach holiday where the sun beats down on you mercilessly. Remember: use castor oil and you increase your time spent in the sun without irritation by 56 minutes per 10 minutes. That’s a pretty interesting power.
I won’t issue an official Supernatural Acne Treatment recommendation for castor oil, but it has a lot of promise, not least because its main fatty acid ricinoleic acid has so little research covering it.
Classic vs Jamaican black castor oil
Now it’s time to become an expert on the different types of castor oil. To get maximum skin-enriching value there are a few unique twists and turns compared to say, jojoba oil.
Specifically, you have the choice of either classic castor oil or Jamaican black castor oil. Classic castor oil is the norm. The cold-pressed variety which you should purchase has a yellowy colour; compared to cold pressed oils like sea buckthorn or jojoba oil it isn’t that dark, but it will have that natural glow to it. It should have a light gold colour.
Organic cold pressed is optimal, since conventional factory refined oil features the usual cocktail of hexane and pesticides. During cold-pressing, the temperature never rises above the safe level of 50 degrees. Meanwhile, refined castor oil is blasted with heat until it’s swimming with free radicals, dreaming of giving you acne.
Refined castor oil is also bleached with chemicals to remove the colour. Why the manufacturers would want to remove the colour is unknown – if I were the CEO I’d retain the colour to make some extra sales based on appearance. Regardless, the chemicals will deliver inflammation and free radical mayhem to your skin.
As for black Jamaican castor oil, avoid getting dealt this stuff. This is called black castor oil because that’s what it is – the Jamaican manufacturers roast the castor beans for an extended period of time to produce a black colour and burnt smell. It is still manufactured in the Jamaican heartland and is a centuries old tradition.
Unfortunately, foreign items such as ash are introduced to the mix during production. An added acne risk has never been confirmed, but heating an oil for extended periods of time is never a smart idea; the longer the exposure the greater the morphing or oxidation of fats and nutrients.
It’s also possible that roasting the beans causes beneficial phytonutrients and antioxidants to release from molecular bindings, like with when you steam broccoli. One change which has been confirmed is an increased PH compared to normal castor oil.
Overall though, if you do decide to experiment with castor oil as a topical acne treatment, your choice is clear – cold-pressed classic castor oil.
Thanks for reading!