What is S-adenosylmethionine (SAM)? High and low values | Lab results explained

In literature, SAM is sometimes referred to as AdoMet.

SAM is found in every cell of the human body and serves an important biologic function as the sole methyl donor in more than 100 different reactions catalyzed by methyltransferase enzymes.

It also plays a key role in activating the transsulfuration pathway, resulting in glutathione synthesis and energy production.

S-adenosylmethionine (SAM) is formed from the essential amino acid methionine and adenosine triphosphate (ATP) using the enzyme methionine adenosyltransferase (MAT).

SAM levels are an important feedback mechanism throughout the body. For example, SAM inhibits methylenetetrahydrofolate (MTHFR), thereby reducing the availability of 5-MTHF as a methyl donor. SAM also has been shown to downregulate the BHMT enzyme leading to another form of feedback inhibition while upregulating the CBS transsulfuration enzyme.

SAM levels in the body depend on the availability of the essential amino acid methionine and the enzyme MAT. Diet alone cannot provide adequate SAM; therefore, the body must also rely on de novo synthesis. The liver tightly regulates SAM levels. However, it has been shown, that plasma SAM levels increase in proportion to adiposity and obesity.

Methionine and SAH levels are not associated with fat mass, suggesting increased conversion of methionine to SAM in obese individuals. The mechanism of this increased conversion is still being studied.

More on the supplement SAM-e:

Since March 1999, SAM-e has been available in the US as an over-the-counter nutraceutical supplement. SAM-e supplementation may be considered when methionine is low, or when the enzymatic conversion from methionine is dysfunctional.

SAM-e has been shown to improve patient outcomes in conditions such as cancer, cognitive decline, arthritis, depression, and liver disease. Treatment with SAM-e has been shown to be as effective as prescription tricyclic antidepressants. SAM-e was also as effective as non-steroidal anti-inflammatory drugs to treat osteoarthritis, and has been successful in treating some liver conditions. 

SAM-e is generally well tolerated, and no serious side effects have been observed. However, there have been rare case reports of bipolar patients developing manic episodes due to SAM-e supplementation.



– Low methionine due to decreased protein intake, or malabsorption/maldigestion

– MAT SNP or lack of cofactors (ATP, Mg, K)


– Supplementation with SAM-e

– High caloric intake, high BMI


Test results may vary depending on your age, gender, health history, the method used for the test, and other things. Your test results may not mean you have a problem. Ask your healthcare provider what your test results mean for you. 

The information on is NOT intended to replace a one-on-one relationship with a qualified health care professional and is not intended as medical advice.

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