According to the WebMD website, accessed on 16 January 2017,
“Dimethylglycine might be safe to use short-term, up to 28 days. The safety of long-term use is unknown.”
However, according to Xia (2011),
“DMG generally has a very safe record. A small percentage of children may exhibit hyperactivity which can be moderated by vitamins known as folates.”
There are no known contraindications (something which makes a particular treatment or procedure potentially inadvisable) for dimethylglycine.
However all nutritional supplements in the wrong doses can cause harm and may also interact dangerously with any medications that are being taken.
Therefore professional advice should always be obtained before embarking on a course of DMG supplements, especially if the individual is already taking a medication or is unwell physically in any way.