Vitamin
Vitamin B-Complex
B6 · B9 (folate) · B12 and co-factors
The quiet co-factors your brain leans on to build its own neurotransmitters. When B12 or folate run low, fatigue and flat mood often follow — which is why they're worth getting right before reaching further.
Our pick, and why
Choosing a vitamin b-complex on iHerb
This is the table where form matters most. Thorne Basic B is our pick: methylcobalamin, Quatrefolic® methylfolate (the benchmark 5-MTHF form), and Pyridoxal 5'-Phosphate — all active, nothing to convert. Jarrow B-Right is a strong second: also methylcobalamin and 5-MTHF, with the bonus of pantethine and inositol — it only partially passes on B6 (a mix of active P5P and standard HCl). NOW B-50 fails on both critical forms: cyanocobalamin B12 and folic acid rather than methylfolate — the conventional forms that a subset of people struggle to convert, which is precisely what this criterion is designed to screen for.
How we judge these
B12 as methylcobalamin (not cyanocobalamin), folate as methylfolate/5-MTHF (not folic acid), B6 in active form.
| Product | Product | B12 form | Folate form | B6 form | Full spectrum | Meets it | Link |
|---|---|---|---|---|---|---|---|
| Our pick Thorne Basic B Complex | Methylcobalamin | Quatrefolic® 5-MTHF | Pyridoxal 5'-Phosphate | Yes | ✓ | iHerb → | |
| Jarrow Formulas B-Right | Methylcobalamin | 5-MTHF (6S form) | P5P + HCl mix | Yes + pantethine | ✓ | iHerb → | |
| NOW Foods B-50 | Cyanocobalamin | Folic acid | Pyridoxine HCl | Yes | — | iHerb → |
- Thorne Basic B ComplexOur pick
- B12 form
- Methylcobalamin
- Folate form
- Quatrefolic® 5-MTHF
- B6 form
- Pyridoxal 5'-Phosphate
- Full spectrum
- Yes
- Meets our criterion
- ✓
- Jarrow Formulas B-Right
- B12 form
- Methylcobalamin
- Folate form
- 5-MTHF (6S form)
- B6 form
- P5P + HCl mix
- Full spectrum
- Yes + pantethine
- Meets our criterion
- ✓
- NOW Foods B-50
- B12 form
- Cyanocobalamin
- Folate form
- Folic acid
- B6 form
- Pyridoxine HCl
- Full spectrum
- Yes
- Meets our criterion
- —
Specs verified against live listings at time of writing and can change — confirm on the product page. Links are affiliate links; details.
If neurotransmitters are the brain’s messages, B vitamins are part of the machinery that prints them. Folate and B12 in particular drive the methylation cycle that produces serotonin, dopamine and norepinephrine precursors — which is why a true B12 or folate deficiency can show up first as flat mood and fatigue rather than anything dramatic.
A B-complex is a low-cost insurance policy, with the clearest payoff for people whose diet or absorption makes deficiency likely.
What to look for
- Methylfolate and methylcobalamin (the active forms) over folic acid/cyanocobalamin if you want premium absorption
- Sensible doses — “mega-B” formulas with 5,000% RDA aren’t better
- Take in the morning; some people find B vitamins too energizing at night