5-Methylthioadenosine (MTA) is a naturally occurring sulfur-containing nucleoside present in all mammalian tissues. The major source of MTA in cells is formed from S-adenosylmethionine during the synthesis of the polyamines spermine and spermidine. In most cells MTA does not accumulate is significant amounts and is rapidly metabolized by 5-methythioadenosine phosphorylase (MTAP) to yield adenine (Ade) and 5-methylthioribose-1-phosphate (MTR1P). The removal of accumulating MTA by MTAP is necessary for the cell to carry out polyamine metabolism, since MTA is a strong inhibitor of spermine synthase. Intracellular fluctuations in MTA levels could participate in the regulation of the liver proliferative response, and administration of MTA have hepatorptective effect in a model of CCl4-induced chronic liver damage.

3-O-methyldopa (3-OMD) is a metabolite of L-3,4-dihydroxyphenylalanine (L-DOPA), a drug used for the treatment of Parkinson's disease patients. 3-OMD is formed by catechol-O-methyltransferase. 3-OMD may be responsible for the side effects of L-DOPA.

For people with MTHFR gene variations, supplementing with the already activated form of folate (5-MTHF/5- METHYLTETRAHYDROFOLATE/LEVOMEFOLIC ACID) is far more effective in providing this form of folate than introducing the pre-converted form to the body through typical folate supplements. L-Methylfolate (5-MTHF) supplements provide the active form of folate naturally present in the body and available for biological action. 5-MTHF—the “active” form of folate that is able to pass the blood brain barrier. However, without a properly functioning methylenetetrahydrofolate reductase, MTHFR this conversion cannot take place and folate is not converted to forms that can cross the blood brain barrier. That is where 5-MTHF supplements come in. Levomefolate calcium is structurally identical to L-5-methyltetrahydrofolate (L-5-methyl-THF), a metabolite of vitamin B9. Mean baseline concentrations of about 15 nmol/L are reached in populations without folate food fortification under normal nutritional conditions. Orally administered levomefolate calcium is absorbed and is incorporated into the body folate pool. Peak plasma concentrations of about 50 nmol/L above baseline are reached within 0.5 – 1.5 hours after single oral administration of 0.451 mg levomefolate calcium. Steady state conditions for total folate in plasma after intake of 0.451 mg levomefolate calcium. In red blood cells, achievement of steady state is delayed due to the long lifespan of red blood cells of about 120 days. Levomefolate calcium is a part of contraceptive tablets: SAFYRA. Safyral is an estrogen/progestin COC (Combined Oral Contraceptive) containing a folate, indicated for use by women to: prevent pregnancy and raise folate levels in women who choose to use an oral contraceptive for contraception. COCs lower the risk of becoming pregnant primarily by suppressing ovulation. Other possible mechanisms may include cervical mucus changes that inhibit sperm penetration and endometrial changes that reduce the likelihood of implantation.

Zankiren (A-72517) is a peptidomimetic renin inhibitor with high potency and specificity. The drug was shown to reduce blood pressure in healthy volunteers after oral administration. In another clinical trial, zankiren exerted a renal vasodilator action. Despite positive results from initial clinical trials, further development of zankiren was discontinued.