Quick Comparison

B-ComplexOmega-3 (DHA)
Half-LifeWater-soluble; excreted daily (except B12 which is stored)20-67 hours (plasma), but brain DHA turns over slowly over weeks
Typical DosageStandard: A quality B-complex providing 25-100 mg of B1, B2, B3, B5, B6, plus 400-800 mcg folate (as methylfolate) and 500-1000 mcg B12 (as methylcobalamin). Methylated forms preferred for B9 and B12 (folate → methylfolate, B12 → methylcobalamin). Take in the morning — B vitamins can be mildly energizing.Standard: 1-2 g combined EPA/DHA daily (aim for at least 500 mg DHA). For depression: 1-2 g EPA-dominant fish oil. Triglyceride form is better absorbed than ethyl ester. Take with a fatty meal.
AdministrationOral (capsules, tablets, sublingual). Methylated forms preferred for B9 and B12. Take with breakfast.Oral (softgels, liquid). Triglyceride or phospholipid forms preferred over ethyl ester for bioavailability. Take with food containing fat.
Research Papers10 papers10 papers
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Mechanism of Action

B-Complex

Each B vitamin serves specific neurological functions: B1 (thiamine) — cofactor for transketolase (pentose phosphate pathway), pyruvate dehydrogenase, and alpha-ketoglutarate dehydrogenase; essential for glucose metabolism and ATP production in neurons. B2 (riboflavin) — precursor to FAD/FMN, cofactors for Complex I and II of the electron transport chain, and glutathione reductase. B3 (niacin/niacinamide) — precursor to NAD+/NADPH via the salvage pathway; NAD+ is substrate for sirtuins, PARP, and 400+ dehydrogenases. B5 (pantothenic acid) — component of coenzyme A, required for acetylcholine synthesis via choline acetyltransferase and for fatty acid oxidation. B6 (pyridoxine) — cofactor for AADC (5-HTP to serotonin, L-DOPA to dopamine), GABA synthesis (GAD), and homocysteine metabolism. B9 (folate) — tetrahydrofolate donates methyl groups for dTMP and purine synthesis, and for homocysteine remethylation. B12 (cobalamin) — cofactor for methionine synthase (myelin maintenance) and methylmalonyl-CoA mutase.

Omega-3 (DHA)

DHA is a structural component of neuronal phospholipids (particularly phosphatidylethanolamine and phosphatidylserine in synaptic membranes), maintaining membrane fluidity which is essential for G-protein-coupled receptor function, ion channel gating, and synaptic vesicle fusion. DHA is metabolized by 15-lipoxygenase to specialized pro-resolving mediators (SPMs) including neuroprotectin D1 (NPD1), which actively resolve neuroinflammation by reducing NF-kappaB activation and pro-inflammatory cytokine production. DHA supports BDNF expression through modulation of the CREB pathway and promotes synaptic plasticity by enhancing long-term potentiation (LTP) and dendritic spine density. It also influences neurotransmitter receptor conformation and binding efficiency. Deficiency impairs membrane signaling, increases neuroinflammation, and accelerates cognitive decline.

Risks & Safety

B-Complex

Common

Bright yellow urine (harmless — riboflavin excretion), mild nausea.

Serious

Very safe at standard doses. B6 can cause peripheral neuropathy at >200 mg daily for extended periods.

Rare

Flushing from niacin (B3) if non-flush form is not used.

Omega-3 (DHA)

Common

Fishy aftertaste, burping, mild gastrointestinal discomfort.

Serious

High doses (>3 g/day) may increase bleeding risk — caution with blood thinners. Fish oil quality matters — choose products tested for mercury and oxidation.

Rare

Allergic reaction in people with fish/shellfish allergy.

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