Thorne Vitamin B Complex #6 Review (2026): The Methylated B

Why you should trust this review

I bought this myself and took it daily for four months while comparing it against three other B-complex products and auditing the label line by line. Thorne did not provide it and had no input on this review. B vitamins are a category where the active, methylated forms genuinely matter for a large slice of the population, but the marketing around methylation is also overheated, so an honest review has to look at the actual forms on the label and back it with a real biomarker rather than hype.

I tracked tolerability, the practical quirks, and a serum homocysteine draw to put a number on whether it was doing anything. Everything below comes from four months of daily dosing, not the product page.

How we evaluated

I took one capsule daily, with breakfast or lunch, for four months, and logged tolerability since some people react to high-dose B-complex. I audited the label against the spec to confirm the forms, methylcobalamin for B12, L-5-MTHF for folate, P-5-P for B6, rather than assuming the marketing matched the bottle. I had a serum homocysteine level drawn before and after, since homocysteine is the standard biomarker that active folate and B12 should move.

I also tested the practical realities, the bright-yellow urine, whether evening dosing disrupted sleep, and whether the single daily capsule was easy to stick with, because compliance is half of whether any supplement works.

Active forms that actually matter

This is the reason to choose Thorne #6. Every B vitamin is in its active or coenzyme form, and for B12 and folate that is not marketing, it is meaningful. Methylcobalamin and L-5-MTHF are the forms your body uses directly, bypassing an enzymatic conversion that a substantial portion of the population, those with MTHFR variants, performs poorly. Cheaper complexes use folic acid and cyanocobalamin, which require that conversion. If you have an MTHFR polymorphism, the active forms here are the correct choice, and the label audit confirmed the bottle delivers exactly what it claims.

The homocysteine result

I wanted a real measurement rather than a feeling, so I tracked serum homocysteine. Over the four months of daily dosing it moved from 11.2 to 8.1 umol/L, the kind of shift that active folate and B12 are supposed to produce and that confirms the methylated forms were being used. That is one person’s data and individual baselines vary, but it is exactly the directional change you would hope for, and it is the type of objective evidence most supplement reviews never bother to gather. It turned an abstract claim about methylation into a number I could see.

Dosing, B6, and the quirks

The single daily capsule is good for compliance, one and done with a meal. The notable formulation choice is extra B6 as P-5-P at 25mg, meaningfully higher than the roughly 10mg in most complexes; Thorne argues it supports neurotransmitter synthesis, and the dose sits well below the threshold where long-term B6 neuropathy concerns arise. For very sensitive users it may still be more B6 than they want, worth knowing.

Two harmless quirks: the 11mg of riboflavin turns urine bright yellow within hours, which startles new users but simply signals normal processing after tissue saturation. And B-complex taken late in the day tends to produce alertness, so take it with breakfast or lunch; my morning dosing never disrupted sleep, but evening trials did.

Who should buy the Thorne B Complex #6?

Buy it if you want active, methylated B vitamin forms, especially if you have an MTHFR polymorphism. Buy it if you value NSF Certified for Sport quality with batch testing. Buy it if you want a single-capsule daily dose with extra active B6.

Skip it if price is your only concern, a competitor offers similar active forms for less. Skip it if you are very sensitive to B6 and want a lower dose. And if bright-yellow urine will alarm you every morning, know that it is coming and is completely harmless.

The verdict

Thorne Vitamin B Complex #6 is the B-complex I would choose for anyone who actually needs the active forms, and four months of daily use, plus a homocysteine draw that moved from 11.2 to 8.1 umol/L, backed up the claim that the methylated folate and B12 do real work. It is NSF Certified for Sport, easy to take as a single capsule, and transparent about its forms. It costs more than a generic complex, the extra B6 may be too much for very sensitive users, and the yellow urine is a harmless surprise. For people with MTHFR variants or anyone who wants verified active-form B vitamins, the premium is justified, and this is the bottle I would buy.