Wondering if a hair test for allergies could be the easy, no-needle test you’ve been looking for? Around 6% of UK adults have a food allergy [1]. Hair analysis tests are marketed as a way of identifying allergies or intolerances using just a few strands of hair.
While this method is convenient, painless, and can be performed at home, unfortunately hair analysis lacks any research to suggest it’s effective for identifying allergies. The good news? There are research-backed methods to identify the source of your reactions so you can avoid future symptoms. In this article, we’ll explore:
A hair test for allergies uses hair samples to test for allergies or intolerances. These may be related to certain foods, environmental substances, or chemicals.
Many companies selling hair tests for allergies do not offer an explanation of how they work. They simply invite you to submit a hair sample for “laboratory testing” without any further details on the specific testing procedure. According to Dr Adam Fox, an allergy specialist from Guy’s and St Thomas’ hospital, home allergy tests are not useful and only a blood test interpreted by a clinician can confirm an allergy.
Of the vendors that offer an explanation, some claim they can identify allergies through a process called bioresonance [2]. This entire process is a scam to make money, and there is not a shred of evidence to support this theory. According to these companies, information from living organisms is stored as resonance, or energy, in strands of hair, and these “frequencies” can be detected by machines.
There is no scientific evidence to suggest these machines can actually detect energy. Some of these companies acknowledge that this method does not make a medical diagnosis or offer a replacement for professional medical advice.
Unfortunately, there is no scientific evidence to support bioresonance as a method of identifying allergies. When briefly mentioned in a 2019 review article on laboratory tests in alternative medicine [3], authors commented,
“bioresonance testing… is widely available but has no basis in science whatsoever and will not be considered further here.”
However, it’s worth noting that bioresonance therapy has an established evidence base supporting it as a treatment for mild to moderate allergies [4-5]. This process works differently from diagnostic methods and does not involve using hair strands.
It involves passing an electric current through tissues or exposing them to a magnetic field. This may have some physiological effect but it has nothing to do with altering “frequencies” of the cells.
There is very limited research on the use of hair tests for diagnosing allergies. In one study, researchers contacted 22 direct-to-consumer (DTC) food allergy testing companies [2].
Each company was asked whether they had ISO15189 accreditation, a certification of quality and competence standards for medical laboratories. They were also asked about their methods of testing and the level of clinical input into their testing and interpretation procedures. Researchers found:
Another study tested the accuracy of hair and saliva allergy tests for dogs [6]. Samples from one allergic dog, one non-allergic dog, and one fake sample (fake fur for the hair test and water for the saliva test) were used.
Researchers tested for 128 food and environmental allergens. The results were no better than random chance at distinguishing between the samples, and results were inconsistent when repeated.
Further research is needed on this topic because the sample size was very small (two dogs), and animal research does not allow conclusions to be drawn about humans.
Many hair tests claim they can identify the sources of allergies, intolerances, or both. Here, we’ll explain the difference between the two.
An allergy describes an immune response to something that’s harmless to most people. Common allergens (things that cause allergic reactions) include [7]:
Allergy symptoms can range from mild to life-threatening. Here’s what you may experience during an allergic reaction [7]:
In some cases, allergies can even cause hair loss. One study described two cases of telogen effluvium that were caused by allergic contact dermatitis to hair dye [8].
The most severe allergies can cause anaphylaxis. This may cause rapid swelling, difficulty breathing, and a drop in blood pressure, and can be fatal if not treated as soon as possible. People with severe allergies often carry an EpiPen (epinephrine auto-injector). This delivers a shot of adrenaline to treat anaphylaxis.
Understandably, people with allergy symptoms are often keen to find the root cause to avoid future allergic reactions, and some of these people turn to hair tests.
A food intolerance describes difficulty digesting specific foods or ingredients [9]. It’s not as serious as an allergy, but it can make you feel ill.
Symptoms of a food intolerance usually appear several hours after eating something you’re intolerant to. These symptoms may include [9]:
There are many other potential symptoms, including fatigue, headaches, nausea, constipation, rashes or joint pain [9]. Your symptoms may only last several hours, or can persist for a few days.
There are several conventional and alternative methods to test for allergies. Hair testing falls into the bracket of alternative testing, but there is no evidence behind it. Here are some of the other options:
These allergy tests are evidence-based and used in clinical practice [10]. They are performed and interpreted under the supervision of a trained medical professional.
These tests are for IgE-mediated allergies, the most severe type of allergy. A test measures the amount of IgE antibodies to a suspected allergen in your blood. Your doctor can organise this test, which is called a Radioallergosorbent Test (RAST).
Under medical supervision, a diluted amount of allergen is placed on your skin and then your skin is pricked with a needle. The allergen is chosen based on your clinical history. If a small swollen bump appears, you may be diagnosed with an IgE-mediated food allergy.
Food challenges are considered the gold standard in food allergy testing [11]. They involve eating small amounts of the suspected food under close medical supervision. You may be blinded, meaning you don’t know which food you’re eating.
Resuscitation equipment is on hand in case it’s needed. Your clinician can gradually increase the amount of food while monitoring any symptoms.
This method is often used for non-IgE-mediated allergies, or food intolerances because they can’t be detected by blood tests. You stop eating the suspected food or having contact with the suspected substance (e.g. latex) for a set period, while monitoring your symptoms by keeping a log or diary.
You then reintroduce the substance if your symptoms improve. A return of your symptoms suggests you may have an allergy or intolerance to that substance.
Besides hair tests, several other tests claim to identify allergies or intolerances but are not supported by research [10]. They can negatively impact your health if food groups are excluded unnecessarily or reintroduced without medical guidance. One of these is IgG testing, which is easy to confuse with IgE testing, but the two are very different.
Some companies that sell home tests for allergies offer IgG testing as an explanation [2]. IgG — or immunoglobulin G — is a type of antibody produced by your body, but there is no evidence to suggest IgG tests can detect allergies.
IgG antibodies are part of your natural defence against food antigens (substances that trigger an immune response). However, these antibodies also help your body build tolerance to antigens so they can be accepted without causing an immune response [12].
Research shows the presence of IgG antibodies indicates your body has been exposed to certain foods over a long period and is responding normally, not showing signs of allergy [12].
Although they sound similar, IgG antibodies are not to be confused with IgE antibodies. Blood tests for IgE antibodies are a clinically recognised test for identifying allergies to food and other substances [13].
However, not all food allergies involve IgE antibodies. Allergies not involving IgE tend to be less severe and symptoms come on slower [10]. Blood testing does not help to diagnose these types of allergies.
There are a few other alternative tests for allergies that are not backed by research. These include:
Hair tests cannot identify allergies at all. They may be harmful for your health if they cause you to eliminate important food groups unnecessarily, or misdiagnose the true cause of your allergic reactions.
If you think you or your child may have an allergy, speak to your doctor. They can refer you to an allergy clinic where you’ll receive a detailed medical assessment and evidence-based tests, delivered by a clinician, to identify the cause of your symptoms.
Hair tests at the Wimpole Clinic do not check for allergies. However, our hair doctors use several (evidence-based) diagnostic trichology tests to assess the health of your hair. These include blood tests for hair loss, and a hair pull test to assess male or female pattern baldness, as well as other types of alopecia.
Struggling with hair loss or dry, brittle hair? Find your nearest clinic location and book a consultation with a trichologist.
Most companies offering hair tests for allergies only require 3-4 strands of hair if it’s longer than an inch. It’s okay to use hair treated by dye or other treatments. Samples should ideally include the root or be cut as close to the root as possible. But remember, even if you follow all instructions to the letter, your results are unlikely to be conclusive or accurate with a hair test for allergies.
Research indicates hair tests are not an accurate way to diagnose allergies or food intolerances. Be wary of companies promising an allergy diagnosis using just a few strands of hair.
According to the American Academy of Allergy, Asthma, and Immunology, skin tests are usually the most accurate way to diagnose an allergy [15]. In some situations, blood tests, food challenges, and the exclusion and reintroduction of foods may be more appropriate.
Blood testing for IgE antibodies is backed by research and considered far more accurate than hair testing. If you suspect you have an allergy, visit your GP or local allergy clinic to arrange blood tests or a skin prick test.
A hair dye patch test is an important part of safely colour-treating hair. This involves dabbing a small amount of the dye you plan to use on your inner elbow or behind your ear. Symptoms of an allergic reaction usually appear within 48 hours, although in some cases, it can take several days [16]. If you have any adverse reactions within 48 hours, do not use the hair dye — consider adding colour to your hair without chemicals instead.
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