Chelation (also known as detoxification or detox) is a medical procedure used to remove heavy metals like mercury or lead from the body.
Chelation involves using one or more 'chelators' (chemicals such as DMSA, DMPS and EDTA) to remove the metals from the body.
The chelators may be given orally, by intravenous infusion, or in the form of nasal sprays, suppositories or creams. Once in the body, they are designed to ‘bind’ to the metals, allowing them to be flushed out of the body through your urine.
Some people think that the core features of autism and other problems faced by autistic people (such as poor strength and coordination) are caused by, or made worse, by the presence of heavy metals.
They also think that chelation can be used to prevent or reduce those core features and those other problems.
The National Institute of Health and Care Excellence (NICE) made the following recommendations:
'Do not use chelation for the management of core symptoms of autism in adults.' (NICE, 2012)
'Do not use [chelation] to manage autism in any context in children and young people' (NICE, 2013)
There is no high quality research evidence to show that heavy metals (such as lead or mercury) cause autism or any of problems faced by autistic people.
There is no high quality research evidence to suggest that chelators (such as DMSA, DMPS or EDTA) prevent or reduce the core features of autism in autistic people.
There is no high quality research evidence to suggest that chelators (such as DMSA, DMPS or EDTA) prevent or reduce any of the problems faced by autistic people.
There is mixed research evidence on the benefits of N-Acetyl-L-cysteine which is sometimes used as a chelator. However there is no evidence to suggest that any benefits which may or may not have arisen from the use of N-Acetyl-L-cysteine were due to the effects of removing heavy metals.
There is some high quality research evidence which suggests that some chelators are potentially extremely hazardous.
For these reasons, we strongly recommend that chelation is not used as an intervention for autistic people.
Please read our Disclaimer on Autism Interventions
The proponents of chelation claim that it is suitable for most children with autism because ‘most children with autism suffer from mercury/metal toxicity.’ (DAN!, 1999).
However this claim is not accepted by the majority of academic researchers.
According to Davis et al (2013)
“Chelation treatment aims to eliminate specific metals from the body. However, empirical evidence has yet to support the hypothesis that the core ASD symptoms are caused by the presence of such metals in the body. Because empirical evidence does not support the hypothesis that the core ASD symptoms are associated with specific levels of metals in the body, the use of chelation to remove metals from the body in order to ameliorate ASD symptoms could be seen as unfounded and illogical.”
and
“Moreover, even if metal poisoning contributed to the ASD symptoms, it would still be unclear whether chelation treatment would have the ability to reverse existing neurological problems caused by such exposure, or whether it would only be able to prevent further damage (i.e., worsening of symptoms). In other words, even if the metal poisoning theories held true, it does not necessarily lead to an expectation that chelation would ameliorate current communication and social skills deficits and behavioral impairments, rather than prevent additional or more extensive impairments.”
There have been various claims for chelation as a treatment for autistic people. For example, Defeat Autism Now! (2005) claimed that
“Many DAN! physicians have reported good improvements with DMSA, although the improvements are sometimes accompanied by gut problems. Reported benefits include rapid progression of language ability, improved social interaction, improved eye contact, and decreased self-stimulatory behaviors (stimming). Children with motor problems have experienced significant improvement in both strength and coordination.”
Chelation involves using one or more chemicals or other substances to correct chemical imbalances in the bodies of individuals with autism.
There is a wide range of different chelating agents, each of which has different properties (such as effectiveness and side effects).
They include
However not all chelating practitioners agree as to which of these chelating agents is appropriate to use. For example, Defeat Autism Now! states that cysteine should not be used because it may worsen mercury intoxication by spreading it to other tissues. It may also promote or worsen intestinal candidiasis.
Different practitioners of chelation follow different processes. The following processes are those recommended by Defeat Autism Now! in its Mercury Detoxification Consensus Group position paper of 2005.
The purpose of the provocation test is to find out if a toxic metal is present in the body, and if the given chelating agent can remove it.
This is done by using a small dose of a given chemical, such as DMSA, followed by a collection of urine or stool depending on the mode of excretion.
The third and last stage of treatment is to give full doses of the chelating agent, along with supplements of minerals and vitamins.
Depending on the chelating agent, it may be given orally, by intravenous infusion, or in the form of nasal sprays, suppositories or creams.
The dosage is determined by the individual's reaction to the initial testing and to subsequent doses of the chelating agent.
The costs of undertaking chelation will depend to a large extent on whether you undertake the chelation yourself and/or whether you consult any kind of CAM therapist.
If you undertake the chelation yourself you will need to buy the chelators. The cost of 100 chelating tablets varies between £10 and £100 in the UK depending on the supplier and the specific chelating agent.
If you consult a CAM therapist, the costs may include the chelators, consultation fees, plus any travel and accommodation expenses.
Different people suggest different amounts of time required to undertake chelation for autistic individuals. For example
Davis et al (2013) reported that “The duration of chelation treatment ranged from approximately 1.5–7 months. Frequencies of administration ranged from 1 to 12 times weekly.”
James et al (2015) reported that “One of the more commonly used chelating substances, oral dimercaptosuccinic acid (DMSA; also called succimer), is given on a cyclical basis at doses of 10 mg/kg/d every eight hours for three days, followed by 11 days with no DMSA. These two-weekly cycles are repeated up to six times, totalling approximately three months of treatment.”
According to Davis et al (2013)
“The chemical substances utilized in chelation treatment have a myriad of potential and potentially serious, side effects, including fever, vomiting, diarrhea, loss of appetite, hypertension, hemorrhoid symptoms, metallic taste, hypotension, cardiac arrhythmias, hypocalcemia, the latter of which can in turn cause fatal cardiac arrest. In 2005, for example, a 5-year-old boy with ASD died from cardiac arrest caused by hypocalcemia while receiving intravenous chelation. The potential safety risks associated with chelation recently resulted in a suspension of a clinical study of chelation treatment for autism. Additional safety issues arose from a rodent study that found lasting cognitive impairment.”
According to the American College of Medical Toxicology (2009) even some forms of testing for metal toxicity are potentially harmful.
“It is ... the position of the American College of Medical Toxicology that post-challenge urinary metal testing has not been scientifically validated, has no demonstrated benefit, and may be harmful when applied in the assessment and treatment of patients in whom there is concern for metal poisoning.”
There are a number of contraindications (something which makes a particular treatment or procedure potentially inadvisable) for different groups of people. For example
Arrhythmias (disturbed heart rhythm); cystinuria ( kidney condition); erythema multiforme aka Stevens-Johnson syndrome (potentially fatal skin condition), fibrosis (increase in fibrous tissue); hypocalcemia (low calcium serum levels in the blood; hypertension (low blood pressure); mesothelioma (cancer of the lining of the organs in the body); neutropenia (low levels of a type of blood cell); pneumoconiosis (respiratory disease); tetany (intermittent muscular spasms); thrombocytopenia (low amount of blood platelets); toxic epidermal necrolysis (potentially fatal skin condition).
Most of the substances used in chelation are widely available within Europe, the US and other countries. For example, some chelating agents, such as alpha lipoic acid, are available without a prescription in chemists and health food stores. However the National Capital Poison Center (2010) reported
“Several unapproved ‘chelators’ are marketed for home use. The U.S. Food and Drug Administration (FDA) recently warned several companies that they are breaking the law by marketing such ‘therapies’. FDA noted that all approved chelating drugs require a prescription.”
Some providers of chelation will have professional credentials and qualifications, while others will not.
The UK and the US governments do not strictly regulate herbs and supplements. Because of this there is no guarantee of strength, purity or safety of some chelating agents and their effects may vary.
Chelation, using synthetic chelating agents, has been practiced for over a century. Chelation was initially used by the military for treating acute exposure to heavy metals and other toxic substances. It has since been developed for use in other medical conditions, including cardiovascular disease, Alzheimer’s disease and cancer.
At the end of the 20th century various researchers suggested that chelating agents could be used to remove heavy metals, especially mercury, from autistic people.
We have identified six scientific studies of chelation for autistic people published in peer-reviewed journals, four of which examined the chelating agent DMSA. We have been unable to identify any studies which examined the use of alpha lipoic acid, EDTA or zeolite as chelators.
These trials included more than 180 individuals aged from three to 14 years old and included people with a diagnosis of Asperger syndrome and pervasive developmental disorder - not otherwise specified. 109 of these individuals came from the single study by Adams et al (2009).
The paper by Adams et al (2009) included 2 studies of DMSA, the first included 109 children in an open trial, the second included 65 of those children in a randomised controlled trial. It stated that DMSA appears to be generally safe, and possibly effective in reducing the symptoms of autism in some children. However it also reported that the DMSA appeared to decrease essential minerals, such as potassium, which is worrying.
Please note: we have not included any other studies of N-Acetyl-L-cysteine in our evaluation of chelation because, in none of those studies, was it used as a chelating agent.
There are limitations to all of the studies of chelation and autistic individuals identified to date. For example
According to the Cochrane Review - James et al. (2015) - the study by Adams et al (2009) is actually deeply flawed.
“Only one trial was included in this review, and we judged it to have high or uncertain risk of bias and methodological problems that limited the interpretation of outcomes presented. Of particular concern are the trialists’ questionable data analytical approach and interpretation of findings. It is interesting that trialists found differential directions of heavy metal excretion and change in ASD indices, yet they attempted to convince the reader not to read too much into these differences. Given the deleterious effects of chelation, misinterpretation and misuse of the study of Adams et al to justify the use of chelation for ASD is unethical and potentially places children unnecessarily in harm’s way. Moreover, if these findings are in fact valid, they actually undermine the heavy metal toxicity theory and the rationale for chelation treatment, suggesting that it should not be used in the first place."
For a comprehensive list of potential flaws in research studies, please see ‘Why some autism research studies are flawed’.
There is no high quality research evidence to show that heavy metals (such as lead or mercury) cause autism or any of the associated problems faced by autistic people.
There is no high quality research evidence to suggest that chelating agents (such as DMSA, DMPS or EDTA) prevent or reduce the core features of autism in autistic people.
There is no high quality research evidence to suggest that chelating agents (such as DMSA, DMPS or EDTA) prevent or reduce any of the problems faced by autistic people.
There is mixed research evidence on the benefits of N-Acetyl-L-cysteine which is sometimes used as a chelating agent. However there is no evidence to suggest that any benefits which may or may not have arisen from the use of N-Acetyl-L-cysteine were due to the effects of removing heavy metals from the body.
There is some high quality research evidence which suggests that some chelating agents (whether used in treatment or in provocation tests) are potentially extremely hazardous.
We agree with the authors of the Cochrane Review of chelation for autism spectrum disorder (ASD) - James et al (2015) - which made the following recommendations
“At the present time, the theory that heavy metals may cause autism or might worsen symptoms has not been established. This underlying theory needs to be tested and confirmed before future trials that assess chelation for ASD symptoms are implemented. However, the numerous side effects of chelation therapy, including hypocalcaemia, renal impairment, musculoskeletal and gastrointestinal symptoms and even death (Morgan, 2002; Brown, 2006; Kosnett, 2010), have led to the withdrawal of at least one planned study. It is therefore unlikely that institutional review boards will approve future trials for chelation for ASD unless safety in children can be assured through the current approach to research.
“If evidence emerges that supports a causal link between heavy metals and autism, further trials with methods suitable to ensure safety and to demonstrate that chelation removes heavy metals, improves social communication and reduces restricted repetitive behaviours seen in autism will be needed.”
This section provides details of scientific studies into the effectiveness of this intervention for people with autism which have been published in English-language, peer-reviewed journals.
If you know of any other publications we should list on this page please email info@informationautism.org
Please note that we are unable to supply publications unless we are listed as the publisher. However, if you are a UK resident you may be able to obtain them from your local public library, your college library or direct from the publisher.
This section provides details of other publications on chelation.
You can find more publications on this topic in our publications database.
If you know of any other publications we should list on this page please email info@informationautism.org
Please note that we are unable to supply publications unless we are listed as the publisher. However, if you are a UK resident you may be able to obtain them from your local public library, your college library or direct from the publisher.
According to Goldman and Woolf (2012)
“Sometimes chelation therapy is recommended based on the results of non-standard laboratory tests for multiple elements performed on samples of hair, blood, urine or other specimens. Such testing may show levels of chemicals above the laboratory’s reference range, but these are not necessarily levels that cause health problems. Sometimes a laboratory test known as “provocation testing” is used which involves giving a chelation medicine to "provoke" and measure the excretion of toxicants. This type of testing is not recommended. It does not reliably show high or toxic levels in the body nor prove the benefit of taking chelation therapy. It is also misleading to compare test results after taking “provoking” chelation medicine to test results from the reference population who have not taken the medicine. In standard medical practice, chelation therapy is given after carefully considering the results of standard laboratory tests, clinical factors, and scientific evidence.”