Dimethylglycine

non-nutrient/non-botanicalN,N-dimethylglycine

What is it

Dimethylglycine (DMG, sometimes marketed as vitamin B15) is a naturally occurring derivative of the amino acid glycine produced as an intermediate in choline and betaine metabolism. It is sold as a supplement claimed to support energy, immunity, and athletic performance, though clinical evidence is limited.

How it works

DMG is formed when betaine (trimethylglycine) donates a methyl group to homocysteine, regenerating methionine. DMG then donates another methyl group to become sarcosine (monomethylglycine), and eventually glycine. In this way, DMG participates in the one-carbon/methylation cycle that supports neurotransmitter synthesis, DNA methylation, and homocysteine recycling. Proponents of DMG supplementation argue it may support oxygen utilization, immune function, and energy production through its role in methylation. However, the body produces DMG naturally as part of normal metabolism, and there is no clear deficiency state. The clinical evidence for supplementation in humans is sparse and dated, with most studies showing little to no benefit beyond placebo. The label "vitamin B15" is a marketing term; DMG is not formally classified as a vitamin and is not essential for humans.

Evidence for 5 uses

AI-assisted evidence assessment — talk to your doctor before relying on any single supplement.

Athletic performance / endurance

Grade D

Mixed evidence

Older claims that DMG improves oxygen utilization and endurance are weakly supported. Controlled studies have generally not shown meaningful performance improvements in trained athletes.

Autism spectrum disorder

Grade D

Mixed evidence

Older anecdotal reports and small open-label studies suggested possible improvements in behavior or communication, but controlled trials have generally failed to confirm benefit.

Immune support

Grade D

Mixed evidence

Marketing claims for immune enhancement are weakly supported by limited animal and in vitro evidence. Direct clinical benefits in humans have not been established.

Cardiovascular / homocysteine support

Grade D

Mixed evidence

Theoretical role in methylation pathways suggests possible homocysteine effects, but clinical evidence specific to DMG is lacking.

Seizures (anecdotal claims)

Grade F

Limited evidence

Some older anecdotal reports suggested seizure reduction; later case reports raised concerns about seizure-promoting effects. Evidence is conflicting and unreliable.

2 commercial forms

Dimethylglycine HCl

Hydrochloride salt; the standard supplement form.

Common in tablets and chewable forms.

Dimethylglycine (free form)

Less common; similar absorption.

Used in some niche formulations.

Dosage

There is no RDA. Typical supplement doses range 125-1,000 mg/day, with some products providing higher amounts. Studies in autism (with conflicting results) have used 125-500 mg/day. No formal UL exists; doses up to several hundred milligrams daily appear well-tolerated.

When and how to take it

DMG can be taken with or without food. Most users take it in the morning or split across the day. Effects are subtle and may not be immediately noticeable. No strict preferred timing.

Food sources

Food	Amount	%DV
Beans and legumes	Trace amounts	—
Whole grains	Trace amounts	—
Meat and fish	Trace amounts	—
Liver	Modest amounts	—

Safety

DMG is generally well-tolerated at typical doses. Side effects are uncommon and usually mild (occasional headache, GI upset, restlessness). Long-term safety data are limited. The compound is naturally produced and present in foods.

Who should be cautious

Pregnant and lactating women should avoid supplementation due to insufficient safety data. Caution in seizure disorders given anecdotal reports. Avoid using as a substitute for evidence-based treatments for ADHD, autism, or athletic performance.

Interactions

Few significant drug interactions documented. May modestly influence homocysteine and methylation pathways; adequate B-vitamin status (especially B12 and folate) is helpful. Anecdotal interactions with anticonvulsants have been suggested but are not well-documented.

Frequently asked questions

Is DMG a vitamin?⌄

No, despite the older label vitamin B15. DMG is a naturally occurring metabolic intermediate that the body produces from betaine. It is not classified as a vitamin and is not essential.

Does DMG really boost athletic performance?⌄

Probably not in any meaningful way. Older marketing claims about oxygen utilization and endurance are not well-supported by controlled studies in trained athletes.

Will DMG help with autism?⌄

Older anecdotal reports and open-label trials suggested benefit, but controlled trials have generally not confirmed it. It is not part of evidence-based autism interventions.

Is DMG safe?⌄

Generally well-tolerated at typical supplement doses. Long-term safety data are limited. Avoid in pregnancy and lactation due to insufficient safety information.

How is DMG different from TMG (trimethylglycine)?⌄

TMG (also called betaine) has one more methyl group than DMG. TMG is the methyl donor for the BHMT enzyme that converts homocysteine back to methionine. DMG is the product of that reaction. TMG has more evidence for homocysteine reduction than DMG.

References

Dimethylglycine - Wikidata — Wikidata link

Track Dimethylglycine with Pilora

Set up dose reminders, check interactions, and join the community in the Pilora iPhone app.

Coming to App Store

Disclaimer: These statements have not been evaluated by the FDA. This page is educational, not a substitute for personalized medical advice. Evidence grades are AI-assisted assessments — talk to your doctor before starting any new supplement, especially if you're pregnant, breastfeeding, on medications, or managing a chronic condition.