My grandmother planted neat rows of red geranium as her garden borders. As kids, we disliked the furry green leaves and odd smell of the red flowers of the geranium and much preferred her roses, sweetpea, and fuschia.
Nowadays, geranium is marketed for infections, skin health, stress, depression, dementia. It seems odd to me that this everyday plant from my childhood can do so much? What does science have to say?
What Is Geranium Oil?
There is a little confusion when it comes to the word "geranium."
Geranium (with a capital G) is the botanical name of a genus of plants also known as cranesbills.
My grandmother's flowers were Pelargonium which are also known as geranium (with a small g).
For the purposes of this article, we will look at research relating to:
- Umckaloabo (a herbal extract of Pelargonium sidoides (P. sidoides) and comes as a tablet and liquid).
There are over 200 species of geranium and the two main types of geranium used for medicinal purposes are the South African geranium and the rose geranium.
The chemical composition of geranium oil includes: citronellol (21–28%), geraniol (14–18%), linalool (10–14%), geranyl acetate (0.3–4.5%), menthone (0.7–2.2%), limonene (0.1–0.6%), geranyl butyrate (0.5–1.3%), myrcene (0.2–0.4%), α-pinene (0.18–0.4%).
There are over 9000 geranium products for sale on Amazon currently.
Is There any Research?
There are 586 scholarly publications related to geranium which include only 17 clinical trials. To put this into context, there are over 100,000 publications for the search term 'rose' which includes over 6000 clinical trials. See, I am not the only one who prefers rose over geranium.
The vast majority of studies on geranium come from Iran.
Does Geranium Oil Help With Muscle Cramps?
Some other blogs make a connection between geranium oil and muscle cramps. They use an overview article on aromatherapy oils as the reference to support this claim (1).
This article does not state that geranium can help with muscle cramps or pains.
Furthermore, there are no studies linking geranium with muscle cramps or pains.
There is no proof that geranium oil helps with muscle cramps.
Does Geranium Oil Reduce Wrinkles?
There are no studies showing that geranium helps with wrinkles.
There are no studies proving that geranium oil helps with wrinkles.
Does Geranium Oil Fight Infection?
An Iranian study compared the antibacterial effects of an essential oil blend (Syzygium aromaticum, Lavandula angustifolia, and Geranium robertianum) with ciprofloxacin antibiotic drops in ear infections (2). A total of 70 patients were randomized to either the herbal blend or the antibiotic - three drops every 12 hours for a week.
The herbal treatment was as effective as antibiotics at reducing symptoms (tenderness, itching, erythema, edema, and discharge) and reducing the bacterial count.
Another study showed that geranium aerosol helped protect against influenza infection in mice (3).
There are thousands of infectious agents. There is just one study in 70 patients which showed that geranium helped treat ear infections (otitis externa). We cannot conclude from this that geranium is a general anti-infectious agent.
Does Geranium Oil Increase Urination?
There is nothing to back up this claim. No basic science. No clinical trials. Nothing.
There is nothing to support claims that geranium oils increase urination.
Is Geranium Oil a Natural Deodorant?
This is a long stretch. Other blogs claim that geranium oil has anti-bacterial activity and it smells nice (to some people but not me) and that adding these two together come up with the conclusion that geranium is a natural deodorant. Seriously?
There are no actual studies that show that geranium is a natural deodorant.
Does Geranium Oil Prevent Dementia or Alzheimer’s Disease?
Korean investigators have proposed that geranium may be a compound worth investigating in Alzheimer Disease.
They found that soluble fractions of Geranium thunbergii significantly inhibited the activity of an enzyme called β-secretase which is thought to play a role in the development of Alzheimer's Disease (4). Just to be clear, this was an experiment in which the activity of the enzyme was measured in a laboratory. That is it. That does not give us any clue as to whether this would be safe of actually work in real live humans.
There is no proof that geranium can prevent dementia or Alzheimer's Disease.
Does Geranium Oil Help Respiratory Infection?
A 2013 Cochrane review from Germany looked at 8 studies and found that Pelargonium may be effective in relieving the symptoms of colds, bronchitis, and sinusitis in adults and children (5). These were all patients in whom antibiotic therapy was felt to be unnecessary. The overall quality of the data was low (I wonder if Cochrane reviews ever say that the quality of the data was good?).
There is some evidence that geranium oil extract may help with the symptoms of respiratory tract infections.
Does Geranium Oil Fight Nerve Pain?
Neuragen PN® is an FDA registered homeopathic drug. It contains a blend of six homeopathic substances and five plant-based essential oils. The six homeopathic substances are St. John's Wort (Hypericum perforatum), Wolfsbane (Aconitum napellus), Club Moss (Lycopodium clavatum), phosphorus, Poison Ivy (Rhus toxicodendron) and Rye ergot (Secale cornutum).
The five plant-based essential oils are geranium oil (Pelargonium graveolens), lavender oil (Lavandula angustifolia), bergamot oil (Citrus aurantium), tea tree oil (Melaleuca alternifolia) and eucalyptus oil (Eucalyptus globulus). A randomized, placebo-controlled double-blind trial compared the effect of Neuragen to placebo in 60 patients with neuropathic/nerve foot pain (6). The Neuragen was applied to the sore foot and was not taken orally.
As compared to the placebo, Neuragen PN® led to a statistically significantly greater pain reduction. According to the study "Fifty six of sixty subjects (93.3%) receiving Neuragen PN® reported pain reduction within 30 minutes. This reduction within 30 minutes occurred in only twenty one of sixty (35.0%) subjects receiving the placebo."
What I find fascinating here is that 35% of people responded within 30 minutes to a placebo. Some people interpret the placebo effect as meaning that the patient is suggestible and that maybe the pain was not real in the first place. That is not my take on the placebo effect. I think that the pIacebo effect may allow our own natural healing to occur.
In many ways, does it matter? Neuropathic pain can be awful (think tooth pain) and the person who gets pain relief probably does not care about how it happened. Statistics be damned.
On the other hand, for those of us without neuropathic pain and as part of the Healthy But Smart tribe, the question remains as to whether geranium fights nerve pain. Geranium is one of 11 ingredients used in this blend. We can hardly conclude from this that geranium oil fights nerve pain.
How could I honestly recommend geranium to someone with excruciating nerve pain based on this? Especially, when there are safe and effective alternatives.
There is zero proof that geranium fights nerve pain.
Does Geranium Oil Reduce Anxiety and Depression?
There is a single clinical study looking at the effects of geranium oil in depression. This study is not listed in PubMed and was published in the Zahedan Journal of Research in Medical Sciences (7). The study found that geranium aromatherapy massage, once weekly for 8 weeks and for 30 minutes per week, improved symptoms of depression in post-menopausal women.
So what is our take on journals such as the Zahedan Journal of Research in Medical Sciences? This is a journal which is not indexed in the large journal databases. Neither does this journal have an impact factor. The impact factor of a journal is used to measure the yearly average number of times articles in that journal are cited or quoted.
The impact factor of a journal helps us to assess the quality of research. Of course, it is totally possible that high-quality research will be published in journals with a low impact factor (or no impact factor as in this case). However, it is usually not the way of things.
On the other hand, I have to give a big shout out to Zahedan Journal of Research in Medical Sciences who responded to my question about their impact factor in under a minute. Top marks for customer service.
Let's look at anxiety.
One study looked at the effects of gernanium oil on anxiety in patients who were undergoing treatment for acute myocardial infarction (heart attacks) (8). Iranian investigators randomized 80 patients to either placebo oil or geranium oil.
The oils were added to oxygen masks and the patients were asked to breathe the oil for 20 min a day on two consecutive days. The geranium aroma caused significantly greater reductions in the anxiety scores as compared to placebo.
Another group of Iranian investigators studied the effects of geranium on anxiety in 100 first time moms during the first stage of labor (9). (An exciting but scary time). The women were randomly assigned to inhalation of either geranium oil or placebo. The study showed a statistically significant reduction in anxiety and blood pressure in the geranium oil arm of the study.
There is limited scientific data to show that inhalation of geranium oil can reduce anxiety. A small, short-term study showed that geranium aromatherapy massage may help depression in post-menopausal women.
Is Geranium Oil an Effective Anti-inflammatory Agent?
Algerian investigators found that rose geranium extract had a statistically significant anti-inflammatory effect on swelling in paws and ears of Swiss mice (10). This anti-inflammatory effect was comparable to the non-steroidal anti-inflammatory drug, diclofenac.
A study from Japan showed that application of geranium to the skin reduced white cell activation and swelling in mouse models (11).
There is no evidence in humans to support the claim that geranium oil is an effective anti-inflammatory agent
Does Geranium Oil Boost Skin Health?
There are no studies linking geranium to skin health. There is speculation on other blogs that goes as follows. If geranium has anti-bacterial properties and if geranium has anti-inflammatory properties, then it must be good for your skin? Now why would I follow speculation when there are plenty of proven ways to boost skin health? Do you really want me to use mouse data to decide what I put on my face?
The only thing linking geranium oil and skin health is speculation and not science.
Can Geranium Oil be Used as an Insect Repellent and Bug Bite Healer?
An article in Pest Management Sciences (what a great name) found that geranium oil extract could kill Stephanitis pyrioides (azalae lace bug) and Aedes aegypti (yellow fever) (12).
The only human clinical trial on the subject looked at a blend of olibanum oil, eucalyptus oil, geranium oil, citronella oil and isopropyl myristrate versus two different products containing diethyltoluamide (DEET) against mosquito bites in Tanzania (13). DEET is commonly used as an anti-mosquito agent in Africa.
The DEET containing products offered 98% and 87% protection against mosquitos as compared to only 48% protection in the geranium oil containing product. Who would choose 48% protection against a potentially lethal infection?
Malaria kills people every day. Essential oils blends containing geranium, citronella, and eucalyptus do not offer adequate protection. End of story. This is too serious to get wrong.
Does Geranium Oil Fight Candida?
There are 17 studies looking at the anti-fungal effects of geranium.
Non- clinical studies suggest that geranium has antifungal properties (14).
There is only one clinical trial (15). This Korean study compared an essential oil mixture consisting of geranium, lavender, tea tree, and peppermint versus a saline placebo in 43 patients with terminal cancer. Mouth care was performed twice daily for seven days.
Scores for subjective oral "comfortness" and numbers of Candida species were measured before and after the intervention. "Comfortness" was the term used in the paper. The score for subjective oral "comfortness" was significantly higher in the geranium oil arm as compared to the control group. The numbers of colonizing Candida albicans was significantly lower in the geranium arm of the study.
One small short-term clinical mouthcare trial suggests that geranium oil has anti-fungal properties. There are no trials looking at geranium oil for other for other infections caused by Candida (eg vaginal Candida) or other fungi for that matter.
Does Geranium Oil Reduce Hemorrhage Episodes?
In Andean medicine, geranium has been traditionally used to control bleeding. Venezuelan investigators studied the effect of geranium leaves in a bleeding rat model (yes, this means rats that were made to bleed in order to study blood clotting) (16). They found a statistically significant decrease in bleeding time with crushed geranium leaves. The anti-bleeding effect was comparable to the effect of commercially available sponges used to control bleeding.
Ear, nose and throat specialists in Johns Hopkins, Baltimore, USA studied the effect of rose geranium oil in people with hereditary hemorrrhagic telangiectasia (17). This is a genetic disorder that results in weakness in blood vessels that increases the risk of bleeding. The study group consisted of 20 patients who were followed for at least 3 months. The study subjects applied the rose geranium oil in a sesame carrier oil to the nose.
They found that there was a statistically significant improvement in nosebleeds and no side effects in the study cohort. There are two main limitations to this study. Firstly, there is no control or comparison arm of the study. Secondly, the study looked at a very unique cohort of patients and the results of this study cannot be generalized to other patients.
There is some evidence in the medical literature that geranium may have an anti-bleeding effect but this is limited to rat models and 20 patients with a rare genetic disorder. There is no evidence that geranium can be used to manage bleeding in the general population.
Is Geranium Oil Safe?
A German study of almost 500 patients who took either geranium or placebo for bronchitis for 7 days showed no significant difference between geranium and placebo in terms of safety (18).
A significant issue with the licensing of many herbal products relates to concerns over liver damage. Geranium is no exception.
German investigators decided to try to debunk the myth around geranium related liver toxicity (19). In medicine, there is a system known as pharmacovigilance (19). Pharmacovigilance people hate being called the drug police but that is a pretty good description. The idea behind pharmacovigilance is to capture data on drugs after drug licensing.
The studies that lead to drug licensing may involve tens, hundreds and rarely thousands of patients. Clinical studies deal with very controlled environments and patients. Most countries have national pharmacovigilance agencies. Doctors are supposed to report cases of side effects related to medicinal products to these agencies.
Pelargonium has been licensed as a medicinal herb for treating respiratory tract infections since 1976. The investigators took 13 possible cases of reported liver injury related to geranium and took a closer look at the data. They found no reason to suspect that geranium was to blame in any of the 13 cases.
The American Society for the Prevention of Cruelty to Animals lists geranium plants as toxic to dogs, cats, and horses (20). Geraniol and linalool can cause vomiting, depression, and dermatitis in animals.
There is very little scientific research on geranium oil. Looking at the research that we do have, we see some preliminary evidence to suggest that geranium oil may have a role in respiratory tract infections and relieving anxiety in acutely stressful situations.
What I find very difficult are the wildly false claims that other bloggers are making about this plant. Specifically, we have seen the lack of data for geranium in relation to nerve pain and malaria transmitting mosquitoes. It is just wrong to make false claims that could mislead people into trusting geranium instead of proven alternatives for serious conditions such as these.