Natural topical treatments are far superior to pharmaceutical ones on average, but within the natural sect, there’s still massive variation in quality.
You cannot grab any plant extract from a health shop or any natural oil recommended on the internet and expect success. You have the topical treatments which are proven for acne or another secret power: cinnamon, grapeseed oil, tamanu oil, green tea, among many others.
Then there’s thyme oil, rose water, and lavender oil, lying on the brink of greatness. Such topical treatments could graduate to the inner circle at any moment, if just one more amazing study or compound turns up.
Finally, we have natural topical treatments with strong potential to clear acne, but equally strong potential to achieve nothing, the category of both mystery and opportunity, and that’s the category which neem falls into.
What is neem?
Neem oil is a fatty oil rather than an essential oil like tea tree oil. It’s the oil of the seed of the neem tree, whereas neem extract comes from the tree’s leaves.
Scientifically known as Azadirchata indica, this tree can grow to 50 feet (15 metres) tall and live for 200 years. The neem tree is native to India and Pakistan, but after transplantation, now grows in Africa, Australia, South America, and the Middle East.
It’s a highly adaptable tree which thrives in semi-arid conditions and the most nutritionally depleted soil, with temperatures as high as 50C and rainfall as little as 18 inches per year being sufficient. There’s three subspecies, with a Thai version called a.siamensis and the rare Malaysian a.excelsa, found deep within jungles, but the Indian a.indica is our interest for acne.
Neem’s medical history stretches back over 4500 years. It’s one of the many herbal remedies recommended in the ancient Indian school of ayruvedic medicine, with early references in textbooks dating back to 2nd century AD and 4th century AD. According to ayurvedic medicine, neem is a cooling, digestion-enhancing plant, but also has “Ahrudya”, meaning that it’s not so good for the heart.
Traditional theories include using neem leaves for ulcers, insect bites, eye problems, detoxifying the blood, and muscle aches. The bark is recommended for oral health, and even today, neem twigs are used as makeshift toothbrushes in rural India.
One of the coolest proven uses is neem oil’s natural insecticide properties. Neem oil is applied to fruit and vegetables in organic horticulture, because of a unique compound in neem called azadirachtin. This limonoid can deter aphids, grasshoppers, spider mites, caterpillars, and many chewing rather than sucking insects.
The other modern usage, of course, is neem’s popularity for acne, and here the direct evidence is extremely uncertain.
All the direct studies on acne
To start with, acne patients themselves cannot agree on which to use. Some use the neem oil, while others use neem leaf extract.
Each has strong but separate medicinal properties. Furthermore, the studies also test different products, so here’s every single study conducted directly on acne.
Firstly, we have a topical study which tested a newly invented cream consisting of neem extract, green tea, licorice, sweet holy basil, and an Indian herb called green chiretta. Applying this cream to human skin reduced colonies of p.acnes bacteria, and another strain of skin bacteria, staphylococcus epidermis.
This study was very interesting in itself, showing that a concoction of purely natural ingredients can reduce acne bacteria excellently. The problem is the four other ingredients, which cloud our vision; there’s no evidence that neem itself had any effect. Green tea reduces sebum production, while sweet holy basil has proven antimicrobial properties against p.acnes bacteria. Licorice can reduce oily skin by inhibiting androgen receptors, while green chiretta is identical to neem, unproven but promising.
Our next study did test neem in isolation. 31 patients were supplemented with neem for 6 months. There was no significant change in inflammatory acne lesions but a statistically significant reduction in overall acne counts.
The problem here? The study tested oral neem. Acne-clearing nutrients or supplements can work just as well topically, with vitamin C being a top example, but with vitamin C we know that increasing antioxidants is the dual power. Here we can only confirm that neem didn’t decrease inflammation strongly.
We now arrive at a topical study, a poor one though. Neem leaves were tested against three strains of skin-colonising bacteria. Neem reduced levels of staphylococcus epidermis and staphylococcus aureas very successfully, but failed to reduce p.acnes bacteria even slightly. High concentrations of two proven antibacterial compounds were detected in neem, α-terpinene and terpinen-4-ol, which is tea tree oil’s signature compound, but to no avail. The sweet holy basil was potentially the best ingredient in the first recipe.
But redeeming this topical treatment, we have our best study, saved until last. Once again, neem leaves were tested against bacterial strains found on human skin. This time, neem inhibited both s. epidermis and p. acnes highly effectively, leading to the conclusion that “azadirachta indica had a strong inhibitory effect on acne-inducing bacteria“.
What’s the lesson from these results? Massive uncertainty.
What about staphylococcus epidermis, a more consistently inhibited strain? Its role in acne is mysterious. It’s a natural member of human skin flora, but some studies have detected more expansive colonies in acne lesions. However, s. epidermis has also been shown to control p.acnes bacteria in skin pores, and prevent its dominance.
A possibility is that s. epidermis is like p.acnes and has multiple strains, some friendly and some malicious. Regardless, there’s no secret power for neem here, not yet anyway, but it adds potential, as do the high levels of terpinol-4-ol. Also, if you’re somebody wondering whether you actually have pityrosporum folliculitis, neem extract was tested against malassezia yeasts in this study and found to have no suppressing effect.
Neem may or may not curtail the p.acnes bacteria lurking in your pores, but what other powers does it have?
Soothing of p.acnes’ dangers – an excellent study tested topical neem extract against inflammation, but specifically, the inflammation caused by p.acnes colonies. P.acnes stimulated two pro-inflammatory chemicals which are strongly linked to acne, TNF-a and IL-8, but neem reversed the increase.
This study is actually the most promising and interesting one around. Malicious strains of p.acnes do have their own powers, such as secreting lipases which break down your skin’s fats and churn out inflammatory metabolites, and secreting hyaluronidases which destroy hyaluronic acid in your skin. However, the main problem is your immune system’s inflammatory response to p.acnes, as it detects the overgrowth.
Antioxidants – another promising feature, because neem contains both a high count of antioxidants and a high variety of them. Antioxidants detected in neem include quercetin, gallic acid, catechin, nimbin, nimbanene, 6-desacetylnimbinene, nimbandiol, nimbolide, ascorbic acid, 7-desacetyl-7-benzoylazadiradione, 7-desacetyl-7-benzoylgedunin, 17-hydroxyazadiradione, and nimbiol. Neem oil, meanwhile, is naturally rich in vitamin E.
The unique signature antioxidant, which is most abundant in neem, is nimbidin. According to this oral study, this compound inhibits the release of neutrophils, acne-causing pro-inflammatory chemicals which fire bursts of free radicals. All we need now is for a topical study to materialise.
Neem leaves have other unique antioxidants too (anything beginning with “nimb” ) while the oil contains gedunin and the insecticide, azadirachtin. Antioxidants are guaranteed, unique benefits from each are possible.
Collagen – a weak but interesting connection, as topically applied dried neem leaves inhibited enzymes called Matrix Metallo-Proteinases (MMPs) in this study. MPP is one of the enzymes which breaks down collagen in the skin, destabilising its structure, and the decrease in activity was large at 50%. Less MPPs would be beneficial, but MMPs are only a single collagen degrading enzyme. The jury is out.
Riskier than normal
Neem also has a disadvantage, a potential side effect which is again mysterious: contact irritation. Neem topical treatments have a much higher risk of irritating, inflaming, or even rashing up your skin than other natural staples.
Immediately under suspicion is azadirachtin, the natural insecticide. Can a toxin strong enough to deter insects wreak havoc on your skin? Azadirachtin primarily works by confusing insects into not reproducing properly. After eating neem oil, insects lose interest in mating, lay eggs which never hatch, and even forget to fly or eat, becoming the village idiots of insects.
This sounds exactly like a classic acne-causing pesticide with hormone disrupting properties like atrazine. However, unlike synthetic insecticides, where the insect merely has to make contact before fizzing away and dying, neem oil must be eaten when on the leaves.
Neem oil is also more specific than chemicals, as within the insect group, neem is harmless against humanity’s allies like bees, ladybirds and butterflies. Neem is completely safe among mammals and birds, except if eaten in very high doses, when it causes liver failure.
The true problem may lie within the oleic acid. A typical fatty acid content of neem oil is…
Oleic acid – 50%.
Stearic acid – 20%,
Palmitic acid – 20%.
Linoleic acid – 10%.
The oleic acid is climbing into the death zone. It’s much lower than olive oil or almond oil at 70% but far higher than grapeseed oil, while the soothing and strengthening linoleic acid is very low for a plant-derived oil.
The actual studies which observed irritation used undiluted neem oil, whereas with testimonials, we have a mixture of recipes, with some people actually using neem leaves. The oleic acid, which is linked to skin barrier dysfunction, could be the real menace.
However, there’s also massive variation between different regions and subspecies, probably depending on the weather and climate which stimulates certain fats above others. This study discovered that the oleic acid of 60 Indian neem oils varied from 25% to 58%, with the palmitic and stearic acids often being higher and the highest detected linoleic acid value being 17%. Some neem oils could inflame your skin while others could enhance it; the variation is huge and could easily account for the differing experiences acne-clearing enthusiasts have. Neem oil’s pore-clogging properties are much more straightforward though, with a 2 out of 5 comedogenic rating, equal to grapeseed oil.
Any other potential problems? With a complex natural substance with many unique compounds, there always is. My recommendation is thus to avoid undulated neem oil except as an experiment – combining neem oil with a low oleic, high linoleic acne oil like grapeseed oil is a smart move. Neem leaves are free from oleic acid, but share a portion of neem oil’s compounds, so the threat remains.
Is neem the ultimate natural solution for acne? No. Is it an excellent weapon nevertheless? The evidence is too thin to say, but my gut instinct is that neem has some strong acne-clearing properties which may come to light.
Strangely, the direct studies keep analysing p.acnes; they must be cemented in the old belief that bacteria is the main villain behind acne. Neem might not suppress p.acnes bacteria itself, but suppressing the inflammation of p.acnes is a far superior power. P.acnes is a natural inhabitant of human skin pores. A runaway inflammatory response along with particularly malicious strains are the real threats.
Which should you choose, neem oil or leaves? The study on p.acnes-induced inflammation examined the leaves, but both have potential. Neem leaves were actually recommended by Ayurvedic medicine for calming acne; this ancient Indian school has an endless well of mystical superstition, but generations of experience are always useful to draw upon.
Neem leaves and oil are not proven to clear acne, but the studies are promising enough and compounds dense enough that there’s a big opportunity.
Thanks for reading!