Dimethylglycine
An endogenously produced methyl-donor metabolite found in small amounts in food. Heavily marketed as 'vitamin B15' or 'pangamic acid' since the 1970s for athletic performance, autism, and immunity — none of these claims hold up in controlled trials. The FDA has explicitly stated B15 is not a vitamin.
Quick decision guide
May help most
Honestly: no specific use is well-supported by RCT evidence. The page exists to set the record straight on marketed claims.
Common dosing range
Common label dose 125-250 mg twice daily — but no dose has clear clinical justification.
When to expect effects
Not established. Trials lasting 4 weeks have been negative for autism and athletic-performance endpoints.
Watch out for
Mostly a marketing-driven product. Save your money for supplements with replicated trial evidence.
Evidence snapshot
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.
Is it worth it for you?
Use this as a quick fit check, not a diagnosis.
Worth considering if…
Probably skip if…
Evidence at a glance
| Goal | Effect | Best fit | Time |
|---|---|---|---|
Athletic performance / endurance Mixed Evidence | No measurable effect in controlled trials | Nobody — controlled trials are negative | Not established (4 weeks was negative) |
Autism spectrum disorder Mixed Evidence | No significant difference vs placebo in 2 double-blind RCTs | Nobody — controlled trials are negative; resources are better spent on behavioral interventions with evidence | Not demonstrated |
Immune support Mixed Evidence | Single unreplicated small-trial signal | Nobody — better-evidenced 'immune' options include adequate sleep, vitamin D (if deficient), and vaccination | Not established |
Seizure disorders Mixed Evidence | Anecdotal case reports only; no controlled trial | Nobody — there are well-evidenced anti-epileptic options | Not established |
Cardiovascular / homocysteine support Mixed Evidence | No direct human evidence of clinical cardiovascular benefit | Nobody — the biomarker even with proven methyl donors doesn't translate to clinical benefit | Not established |
Athletic performance / endurance
- Effect
- No measurable effect in controlled trials
- Best fit
- Nobody — controlled trials are negative
- Time
- Not established (4 weeks was negative)
Autism spectrum disorder
- Effect
- No significant difference vs placebo in 2 double-blind RCTs
- Best fit
- Nobody — controlled trials are negative; resources are better spent on behavioral interventions with evidence
- Time
- Not demonstrated
Immune support
- Effect
- Single unreplicated small-trial signal
- Best fit
- Nobody — better-evidenced 'immune' options include adequate sleep, vitamin D (if deficient), and vaccination
- Time
- Not established
Seizure disorders
- Effect
- Anecdotal case reports only; no controlled trial
- Best fit
- Nobody — there are well-evidenced anti-epileptic options
- Time
- Not established
Cardiovascular / homocysteine support
- Effect
- No direct human evidence of clinical cardiovascular benefit
- Best fit
- Nobody — the biomarker even with proven methyl donors doesn't translate to clinical benefit
- Time
- Not established
Evidence for 5 uses
AI-assisted evidence assessment — talk to your doctor before relying on any single supplement.
Athletic performance / endurance
Mechanism onlyMarketing built on 1970s Soviet-era reports (uncontrolled) of cardiovascular benefits in athletes. The Harpaz 1985 double-blind RCT in trained runners found no significant effect on lactate, treadmill time to exhaustion, or VO2max. Subsequent small trials have similarly not shown performance benefit. No good evidence for ergogenic effect at any studied dose.
Bottom line: Don't buy DMG for athletic performance. Better-evidenced options include creatine monohydrate and caffeine.
Autism spectrum disorder
Mechanism onlyHeavily marketed in the autism community based on anecdotal parent reports and uncontrolled case series in the 1990s. Two double-blind placebo-controlled RCTs (Bolman 1999 and Kern 2001) of DMG 100-250 mg twice daily for 4 weeks in children with autism found no significant difference vs placebo on standardized behavior measures. The anecdotal signal did not survive controlled testing.
Bottom line: Two double-blind RCTs were negative. The marketing predates the trials; the trials never replicated the anecdotal reports.
Immune support
Mechanism onlyA single small 1981 trial (Graber et al., n=20) showed modest increases in some lymphocyte responses to pneumococcal vaccine with DMG vs placebo. This single result has been used for decades to justify 'immune-boosting' marketing claims. It has not been replicated in better-controlled or larger trials.
Bottom line: Built on a single 1981 trial that no one has replicated in 40+ years. Don't take DMG for 'immunity'.
Seizure disorders
Mechanism onlyAnecdotal claims and case reports going back to the 1980s suggested DMG might reduce seizure frequency in some children with refractory epilepsy. No controlled trial has demonstrated efficacy, and the anti-epileptic community has not adopted DMG into any practice guideline.
Bottom line: No reliable evidence. Discuss anti-epileptic options with a neurologist, not a supplement manufacturer.
Cardiovascular / homocysteine support
Mechanism onlyDMG is a one-carbon methyl donor in metabolism that intersects with the homocysteine remethylation pathway via betaine-homocysteine methyltransferase. Mechanistic plausibility exists. Controlled human trials demonstrating that DMG supplementation meaningfully lowers homocysteine or improves cardiovascular endpoints do not. For homocysteine, the evidence-based options are folate, B12, and B6 — none of which have shown CVD-event benefit despite reliable biomarker reduction.
Bottom line: Mechanistic story without human evidence. Standard CV risk management beats DMG by orders of magnitude.
How it works
How to take it
What to track
Bottom line: No dose has clear clinical evidence. If you trial it, set a 4-8 week limit and a specific objective measure before deciding to continue.
2 commercial forms
Compare the main delivery options and what they’re best suited for.
N,N-Dimethylglycine (free DMG)
Standard formPure DMG. The form used in clinical research (including the negative autism and athletic-performance trials). Typically sold as 125-500 mg capsules or tablets.
Well absorbed orally; rapidly metabolized.
Calcium pangamate / 'Vitamin B15'
Avoid — FDA misbrandedOlder Soviet-era formulation marketed as 'B15' or 'pangamic acid.' FDA has explicitly held these products misbranded since the 1970s; product identity is unreliable and ingredient lists vary.
Inconsistent formulations; FDA position is that these products are misbranded.
Safety
Know the common side effects, key cautions, and who should avoid it.
Common side effects
Serious risks
No serious risks reported at typical doses. Long-term safety beyond 6 months is not well characterized.
Who should avoid it
- Pregnant or breastfeeding people — insufficient safety data.
- Anyone considering 'vitamin B15' or 'pangamic acid' products — FDA has held these as misbranded since the 1970s, and product identity / purity is unreliable.
- Anyone using DMG as a substitute for evidence-based treatment of a serious condition (autism, epilepsy, immune deficiency) — discuss with the treating clinician.
Pregnancy & breastfeeding
Insufficient safety data in pregnancy and breastfeeding. Avoid unless specifically directed by a clinician.
Bottom line: Pure DMG appears well tolerated at typical doses. The bigger concern is paying for a supplement with no replicated benefit, or relying on it instead of evidence-based therapy.
Interactions
Theoretical interaction since DMG has been anecdotally claimed to alter seizure frequency. No documented PK or PD interaction; conservative monitoring is reasonable if used alongside.
Food sources
| Food | Amount | %DV |
|---|---|---|
| Beans (lima, navy, pinto) | 1 cup cooked (trace) | — |
| Brown rice | 1 cup cooked (trace) | — |
| Beef liver | 3 oz (trace) | — |
| Pumpkin seeds | 1 oz (trace) | — |
| Cereal grains (whole) | 1 cup (trace) | — |
| Sunflower seeds | 1 oz (trace) | — |
Beans (lima, navy, pinto)
- Amount
- 1 cup cooked (trace)
- %DV
- —
Brown rice
- Amount
- 1 cup cooked (trace)
- %DV
- —
Beef liver
- Amount
- 3 oz (trace)
- %DV
- —
Pumpkin seeds
- Amount
- 1 oz (trace)
- %DV
- —
Cereal grains (whole)
- Amount
- 1 cup (trace)
- %DV
- —
Sunflower seeds
- Amount
- 1 oz (trace)
- %DV
- —
Choosing a product
What to look for on the label — and what to be skeptical of.
Look for…
Be skeptical of…
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 by claim
Track Dimethylglycine with Pilora
Set up dose reminders, check interactions, and join the community in the Pilora iPhone app.
Coming to App StoreDisclaimer: 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.