Excess S-Adenosylmethionine inhibits methylation via catabolism to adenine

Kazuki Fukumoto, Kakeru Ito, Benjamin Saer, George Taylor, Shiqi Ye, Mayu Yamano, Yuki Toriba, Andrew Hayes, Hitoshi Okamura, Jean-Michel Fustin

Research output: Contribution to journalArticlepeer-review


The global dietary supplement market is valued at over USD 100 billion. One popular dietary supplement, S-adenosylmethionine, is marketed to improve joints, liver health and emotional well-being in the US since 1999, and has been a prescription drug in Europe to treat depression and arthritis since 1975, but recent studies questioned its efficacy. In our body, S-adenosylmethionine is critical for the methylation of nucleic acids, proteins and many other targets. The marketing of SAM implies that more S-adenosylmethionine is better since it would stimulate methylations and improve health. Previously, we have shown that methylation reactions regulate biological rhythms in many organisms. Here, using biological rhythms to assess the effects of exogenous S-adenosylmethionine, we reveal that excess S-adenosylmethionine disrupts rhythms and, rather than promoting methylation, is catabolized to adenine and methylthioadenosine, toxic methylation inhibitors. These findings further our understanding of methyl metabolism and question the safety of S-adenosylmethionine as a supplement.

Original languageEnglish
Article number313
Pages (from-to)1-15
Number of pages15
JournalCommunications Biology
Issue number1
Publication statusPublished - 5 Apr 2022


  • Adenine
  • Dietary Supplements
  • Liver/metabolism
  • Methylation
  • S-Adenosylmethionine/metabolism


Dive into the research topics of 'Excess S-Adenosylmethionine inhibits methylation via catabolism to adenine'. Together they form a unique fingerprint.

Cite this