We received this question from a reader…
“For eczema and acne, I have been using neem oil on my face at night for two years, since hearing the benefits on the Dr. Oz show. Now a friend who saw it in my bathroom said “you know neem is a male birth control, right?” My fiancé is using a facewash with it for his acne so I want to know if this is true. What I’m reading online seems alarming.”
In many Middle Eastern and African countries, it is actually considered a weed. Though in India, the neem tree leaves have been used in Ayurvedic medicine for hundreds of years, at least. Mostly by women for beauty purposes, but both genders have historically used it for skin disorders and in oral hygiene products like this.
Also called the nimtree and Indian lilac, if the way it’s typically used does have a contraceptive impact, it must not be doing a very good job. Consider the fact that India is expected to surpass China’s population within just a few short years!
Then again, it is mostly women who use it. They enjoy the purported benefits of using it for dry skin, cystic acne, wrinkles, under eye circles, and other cosmetic ailments which men care less about.
But guys too have been using it for athletes’ foot, nail fungus, warts, and jock itch.
At one time it was even believed – albeit wrongly – that neem oil could help hair loss. You can bet that back in the day, there were plenty of men slathering it on their scalp for that reason alone!
Can you eat neem oil or leaves? Even though it’s pressed from the seeds and fruit of the tree, the oil is a far cry from olive and other culinary types. What does neem oil taste like? Bitter and gross. It is not considered edible.
Neither it, nor the fresh raw leaves, have been used as food historically. Any ingestion of the plant came from purported therapeutic uses. Neem tea was one, but it wasn’t something you drank for enjoyment.
The fact that it normally is not eaten further minimizes how much of its active compounds people are exposed to.
Yes, it is true your skin act like a sponge, absorbing what comes in contact with it. Regardless, it’s still far less exposure than say, eating a salad of leaves!
Despite its prevalence in Ayurveda, there is potentially troubling research suggesting neem oil might make animals infertile. Though many of the studies involved some pretty heavy uses of it – ingesting the oil or even injecting it directly into the vas deferens of rats, which are the tubes that sperm travel along.
Contraceptive concerns in research
This is not a new topic. There is research on PubMed as early as the 80’s and 90’s about the possibility of neem oil being a spermicide and vaginal contraceptive (1).
A 1990 study evaluating it as a spermicide found that the effect was dose dependent (2). The minimum concentration needed to inhibit the motility of sperm was reported as:
- For human sperm: 0.25 mg of neem oil per milliliter of liquid
- For rat sperm: 0.25 mg per milliliter
That’s as little as a 2.5% concentration of oil when mixed with something else… not very much!
That was looking at the oil making direct contact with the semen. Unless you’re using neem oil for hair in your pubic region, that’s probably not happening.
In IVF experiments using sperm and eggs from mice, neem oil was found to have a toxic effect on their interaction with most concentrations that were tested (3).
A 1995 paper on male contraceptives said injections of neem oil were being studied in China and India (4).
As far as exactly why neem oil is bad for fertility, electron microscopic studies say it causes a gradual leakage of an enzyme (LDH) from the sperm, damaging their cell membrane structure (5).
The extract from both neem bark and leaves have shown adverse side effects in rat and mice studies (6) (7). So the compounds responsible are likely found throughout the entire plant.
Direct contact vs. topical absorption
Is neem oil safe for humans to use on their skin?
Transdermal absorption is effective. Aside from over the counter products like nicotine patches, many prescription drugs are administered using skin patches. Ortho Evra and Xulane even make prescription birth control patches, which claims to be “up to” 99% effective.
Drugs like those are in contact with your skin 24/7. Compare that to something like neem shampoo and condition for dandruff. Sure, some residue inevitably is left behind, but the vast majority is washed off within just a few minutes.
On the other hand, if you use neem leaves for acne and pimples, how you typically apply it involves making a paste. It’s left on your face and neck for up to 20 or 30 minutes at a time, before being washed off.
Using the unrefined or refined neem oil for wrinkles or dry skin may involve a face cream or lotion. Those are typically worn all day or overnight, sometimes doing both for around the clock contact. Naturally, that means much more is probably being absorbed versus a two minute face wash regimen or shampooing your hair every night.
Whether skincare and haircare has any effect on male or female infertility is unknown. Human studies have not been done. Not even the animal studies evaluated applications in that manner – they involved direct injections, eating the extract, and mixing the neem with sperm and eggs in Petri dishes.
Even without studies to prove its safety or lack thereof, one has to keep in mind that when we eat something or it’s absorbed by our skin, our body immediately works to begin breaking it down.
So just because something proves to be toxic in a Petri dish, that doesn’t necessarily mean it’s a problem after your body digests or processes it.
For example, in lab experiments avocado extract has been found to cause human DNA mutations.
But when you eat avocado, your body is first digesting it before it comes in contact with your bloodstream, so the two scenarios are not equivalent (regarding that topic, read more about whether avocados are healthy for you).
What’s the latest?
Apparently it’s not just something which men should be thinking about.
A 2014 research paper published by a university in India said neem might be…
“…a potential candidate for the development of reversible herbal contraceptive for the control of female fertility in mammals.”
Not that you’re expected to make sense of it, but the diagram here was in their paper. It’s the proposed mechanism of how it may affect the level of follicle in mammalian ovary (8).
That’s not to be confused with similar sounding word; hair follicle. Rather, they are talking about the ovarian follicular fluid.
No doubt an earlier study in 2008 had some influence on this. Female rats were given neem flower extract by mouth for 3 weeks and it was found that (9):
“The estrous cycle of 80% of the rats was altered with a marked prolongation of the diestrus phase.”
They concluded it posed a potential as a contraceptive for women because it caused a partial block during the ovulation process.
Going back to the potential side effects in men, a couple studies actually used neem oil to intentionally cause infertility in male rats.
For example, a 2015 study gave rats a daily dosage for 40 days of Ipomoea digitata (a flowering herb). They wanted to see if it could improve/reverse things for “neem-oil induced infertile rats” (10).
In a 2012 study, it was said that the albino rats getting neem oil treatments had a “significant” reduction in sperm density and motility, testosterone levels, and even testicular weight (11).
To use or not use?
Even though it is not medically proven or approved for such uses, many people report positive results of using neem oil for skin rashes, blemishes like acne, and some even claim it soothes the side effects of scabies.
When it comes to hair, likewise you hear of many positive reviews of it being used for dry and flaky scalps (like dandruff) and helping with psoriasis of the head and neck.
In short, it’s been a popular herbal remedy in Ayurveda for centuries and today, it continues to be.
Without human studies though, no one can 100% guarantee neem is safe in all uses and dosages when it comes to the issues of fertility and pregnancy. In the same way – since only animal studies have been done – it would be premature for someone to claim that neem is dangerous or harmful to humans.
As we all know, what happens in lab rats does not always translate to people.
Plus, those rodents were eating neem or getting injections of it. As we explained, that’s quite a bit different than using it on your skin (with perhaps the exception of using it on your skin down there).
If you have or are trying to get pregnant – and likewise for the man participating in that act – then to be extra cautious, it might make sense to lay off the neem products during that period of time.
Is neem oil safe to use while pregnant? Since it has not been studied during pregnancy, it should be avoided during that time. No one knows if there are benefits or side effects during childbearing.
Likewise during breastfeeding. There is not adequate research to know whether or not neem oil is safe for babies or the lactating mother.
With those caveats said, there’s good reason why neem was brought up on the Dr. Oz show, as well as others in the media who have been talking about it in recent years.
It’s been popular for generations in Ayurveda practices in India, but the West is only just starting to learn about the many potential uses of this plant. Who knows, perhaps someday, derivatives of it will be developed into a form of natural birth control or other recognized medical treatment.
But for now, it remains a well-rated, albeit unproven, herbal remedy for acne, dry skin, warts, under eye circles, and other purported cosmetic benefits. On Amazon, this is a popular USDA certified organic brand.
These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.