Sundown · label read against the research

B Complex

One use holds up once you check the amounts against the research.

8 ingredients on the label1 at a studied amount

What it’s good for

1at a studied amount
0under it, untested
3only a trace
4nothing we can say

Supplement Facts

Serving Size 1 Tablet(s)


Amount Per Serving   % Daily Value

Thiamine1.5 mg125%
Riboflavin1.7 mg131%
Niacin20 mg125%
Vitamin B62 mg118%
Folate666 mcg DFE167%
as Folic Acid
Vitamin B126 mcg250%
Calcium Carbonate†
Vegetable Cellulose†

† Daily Value not established, or not stated on this label.

a trace of what was studiedform isn't statedenough to matterno claim either way

What the maker says

Their words, from the label. We show them so you can see what you’re being told. They’re Sundown’s claims, not our findings.

What they say it’s for

  • “B Vitamins aid in the conversion of food into energy”
  • “B Complex with 6 essential B Vitamins”
  • “For energy support & heart health”

How they say to take it

  • Directions: For adults, take one (1) tablet daily, preferably with a meal. As a reminder, discuss the supplements and medications you take with your health care providers.

Their own warning

  • Warning: If you are pregnant, nursing, taking any medications or have any medical condition, consult your doctor before use.
  • Discontinue use and consult your doctor if any adverse reactions occur.

These statements has not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure or prevent any disease.

Worth knowing about this bottle

Folate (5-MTHF) with Vitamin B12 (Methylcobalamin)

High-dose folate can correct the anaemia caused by a B12 deficiency while doing nothing about the nerve damage that deficiency also causes. The blood count comes back normal and the neurological injury carries on unnoticed.

What to do: If you take high-dose folate or folic acid and are older, vegan, or on long-term metformin or acid-reducers, have B12 measured directly. A normal blood count does not rule a deficiency out.

Vitamin B12 (Methylcobalamin) with Calcium

Calcium supplements may reduce vitamin B12 absorption, particularly from food sources.

What to do: If supplementing both, consider separating doses by a few hours, especially if you have low B12 levels.

Folate (5-MTHF) and Vitamin B12 (Methylcobalamin) work better together

Folate and B12 work synergistically in one-carbon metabolism, DNA synthesis, and homocysteine reduction.

Vitamin B2 (Riboflavin) and Vitamin B3 (Niacin) work better together

Riboflavin is needed for the enzyme that helps convert dietary tryptophan into niacin in the body. Low riboflavin status can reduce how much niacin the body makes on its own.

Vitamin B2 (Riboflavin) and Folate (5-MTHF) work better together

Riboflavin helps folate do its job of lowering homocysteine, an amino acid linked to cardiovascular risk when elevated. This effect is strongest in people with a common genetic variant (MTHFR 677TT) that makes their folate-processing enzyme depend more heavily on riboflavin.

Vitamin B2 (Riboflavin) and Vitamin B6 (Pyridoxine HCl) work better together

Vitamin B6 does not work until the body converts it to pyridoxal 5’-phosphate, and that conversion needs a riboflavin-derived cofactor. Low riboflavin means B6 you have taken stays in a form the body cannot use.

Vitamin B3 (Niacin) and Vitamin B6 (Pyridoxine HCl) work better together

Your body makes some of its own niacin out of tryptophan, an amino acid from food — and it needs vitamin B6 to do it. Low B6 means less niacin made, so more of it has to come from what you eat.

Vitamin B3 (Niacin) and Vitamin B6 work better together

The body can make a small amount of its own niacin from the amino acid tryptophan, but that process needs vitamin B6. If someone is low in B6, they convert less tryptophan into niacin, so their niacin status depends partly on B6 status.

3 present in trace amounts

Far under everything studied. No trial speaks to what this much does.

Thiamine1.5 mg
  • Supports chronic fatigue — dose is 97% short of the 50–100 mg tested.
  • Supports brain fog — dose is 97% short of the 50–150 mg tested.
Riboflavin1.7 mg
Vitamin B126 mcg
  • Some evidence for low mood — dose is 99% short of the 1000–2000 mcg tested.
  • Some evidence for headaches/migraines — dose is 99% short of the 1000 mcg tested.
  • Some evidence for eye strain — dose is 99% short of the 1000 mcg tested.
  • Some evidence for poor memory — dose is 99% short of the 1000–2000 mcg tested.

Label read from the NIH Dietary Supplement Label Database. Formulations change — check the panel on the bottle in your hand. Check a different product.