Supplement
B-Complex
All eight B vitamins in one capsule, sold mainly on energy and stress support.
A B-complex supplies the eight B vitamins (B1, B2, niacin, pantothenic acid, B6, biotin, folate, and B12) in a single product, usually at several times the daily value for most of them. We grade B-Complex C+ on evidence and C+ for worth-it at about $6-14 per month.
Evidence
Worth it
Typical cost: $6-14/month
What it does
A B-complex supplies the eight B vitamins (B1, B2, niacin, pantothenic acid, B6, biotin, folate, and B12) in a single product, usually at several times the daily value for most of them. Formulations vary enormously between brands, and no two products carry the same mix.
What the research says
Lowers homocysteine
Evidence: moderate. The folate, B6, and B12 trio inside every B-complex lowers homocysteine by roughly a quarter to a third across the large trials. The biomarker effect is reliable; what it buys is the open question below.
No demonstrated reduction in heart attack, cardiovascular death, or total mortality
Evidence: moderate. VITATOPS (8,164 patients after stroke or TIA, Lancet Neurology 2010) and HOPE-2 were null on their composite outcomes. A 19-trial meta-analysis (47,921 participants) found one exception: a modest stroke reduction (RR 0.88).
May slow brain atrophy in mild cognitive impairment with high homocysteine
Evidence: emerging. VITACOG (Smith et al., 2010): B vitamins slowed the rate of whole-brain atrophy by about 30 percent in mild cognitive impairment, concentrated in participants with high homocysteine. One trial, and its clinical meaning is still debated.
Corrects B-vitamin deficiency where it exists
Evidence: strong. Repleting a documented deficiency is established practice. In countries with folic-acid food fortification, outright deficiency in healthy adults is uncommon, and the energy claims made for the non-deficient have no trial support.
The category has been tested at scale under its own core recipe: the big outcome trials gave folate, B6, and B12 and watched homocysteine fall by a quarter to a third while heart attacks, cardiovascular death, and total mortality did not move; one large meta-analysis finds a modest stroke reduction. The one targeted positive, slower brain atrophy in MCI with high homocysteine, rests on a single trial. The product is sold mainly on energy, for which there is no trial evidence in people who are not deficient.
The week's longevity and biohacking news.
This grade for B-Complex rests on the record above. When a new result changes that record, the grade changes with it, and the Thursday email is where the change lands first: the week's longevity and biohacking news, in plain English, linked back to the reasoning on this page.
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Every grade follows a published rubric, and sponsors never change one. When the evidence moves a grade, Thursday is where you hear it first, before you renew a stack that stopped earning its cost.
Is it worth it?
Evidence (C+) sits below the leaderboard floor, so the worth-it grade is capped at C+ however inexpensive it is. About $10 a month at a common dose. Derived from the October 2026 worth-it model.
Typical cost
$6-14/month
Common form, not a brand recommendation
Dosage context established
One capsule daily per label is the common pattern. The outcome trials studied folic acid (0.5 to 2.5 mg) with B6 and B12, not the full eight-vitamin blends on shelves, and no trial supports the megadose end of the market (several ingredients at 1,000 percent of daily value or more). Methylated forms are marketed as superior; no outcome trial shows a difference.
Worth-it leaderboard
B-Complex sits outside the worth-it top 20.
B-Complex sits outside the current top 20 on the gated leaderboard. The leaders below clear an evidence floor of B- before price counts at all, so cheap alone never earns a rank.
See the full worth-it leaderboard →
When the evidence moves a grade, this ranking moves with it. Thursday is where you hear it first.
Safety notes
The B6 content is the live issue. Chronic high-dose B6 causes sensory neuropathy (tingling and numbness that can recover slowly or incompletely). EFSA cut the adult upper limit to 12 mg/day in 2023 on the neuropathy data; the US limit is still 100 mg/day, and many B-complex products carry 25 to 100 mg of B6 per capsule. Check the B6 line before buying. Nicotinic-acid forms of niacin flush and can strain the liver at gram doses. Biotin at supplement doses interferes with common lab tests, including troponin and thyroid panels (FDA safety communications, 2017 and 2019). High folic acid intake can mask a B12 deficiency; both records carry that interaction here.
Longevity Lab Report
B-Complex news. Graded when it happens.
The grade on this page stays free. The email carries the news on b-complex: expert moves, dose changes, and what is working, in plain English every Thursday.
Changelog
Last updated 2026-10-23
- 2026-10-23|Graded from the homocysteine outcome trials (VITATOPS, HOPE-2, and the 19-trial meta-analysis) and the VITACOG brain-atrophy trial. The energy claims made for people who are not deficient carry no trial support and are graded as such. The B6 safety note carries EFSA's 2023 upper limit of 12 mg/day.
- 2026-10-23|Also listed under cognition and heart, matching this record's graded findings on brain atrophy in mild cognitive impairment and the pooled stroke result.