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What Is DFE on a Supplement Label, and How Is It Worked Out?
DFE stands for dietary folate equivalents, a unit that puts food folate and folic acid on one scale. The Reviralis Complete label prints folate as 680 mcg DFE and adds that this is 400 mcg of folic acid. The two numbers describe the same ingredient, so folate should be counted once.
Written by the Reviralis label deskUpdated · 4 min read
The unit01
What does DFE mean on a supplement label?
DFE means dietary folate equivalents. It is a unit that lets food folate and the synthetic form, folic acid, be added on one scale.
Q: Why is a new unit needed? A: The body takes up folic acid and natural food folate differently. A plain microgram count would hide that. DFE weights each form so that a label reads the same whichever form a product uses (NIH ODS, Folate).
On the Reviralis panel the folate line reads 680 mcg DFE with 400 mcg of folic acid in brackets. The bracket names the form. The 680 is the weighted total.
The arithmetic02
How do 400 mcg of folic acid become 680 mcg DFE?
Multiply the folic acid by 1.7. That is 400 times 1.7, which is 680 mcg DFE. The 1.7 is the factor labels use for folic acid in supplements.
The factor is not a hidden extra dose. It is a conversion. If you read 680 as micrograms of folic acid you would overstate the folic acid by 280 mcg, because only 400 mcg of folic acid is in the capsules per serving.
The NIH fact sheet uses a slightly different timing-based factor of 0.6 for folic acid taken with food, which gives about 667 mcg DFE from the same 400 mcg (NIH ODS, Folate). The label's 1.7 is the printed convention, so we follow the label.
400 mcg folic acid x 1.7 = 680 mcg DFE. The Daily Value is 400 mcg DFE, so 680 / 400 = 1.7, or 170% DV, which is what the panel prints.
Three numbers03
Which folate number matters: DFE, folic acid or percent Daily Value?
Each number answers a different question, and the limit uses the folic acid figure, not the DFE.
| Number | Value | What it tells you |
|---|---|---|
| Folic acid | 400 mcg | The actual folic acid in two capsules |
| Folate | 680 mcg DFE | The same folic acid, weighted for absorption |
| Daily Value | 170% | 680 compared with the 400 mcg DFE reference |
| Upper limit | 1,000 mcg folic acid | Adult ceiling for folic acid from supplements and fortified food (NIH ODS, Folate) |
Because the limit is stated as folic acid, 400 mcg is 40% of it. Comparing 680 with 1,000 would give a wrong 68%.
Reviralis: from $49 a bottle60 capsules a bottle · 2, 3 or 6 bottles · free US shipping on 3 and 6 · 60-day money-back guarantee
See packsOn the panel04
Where do I find the folate line on the Reviralis panel?
The folate line sits in the vitamin block, between vitamin B6 and biotin. Tap the numbered spots to see it and its neighbors.
Tap a number to read that part of the label.
- Serving
Serving size 2 capsules; 30 servings per container.
- Vitamins A, C, D, E
Vitamin A 720 mcg RAE, C 125 mg, D 2.5 mcg, E 27 mg, each with its % Daily Value.
- B vitamins and choline
Thiamine, riboflavin, niacin, B6 (706% DV), folate (400 mcg folic acid), biotin, pantothenic acid and choline.
- Iron, magnesium, zinc, selenium
Iron 1 mg, magnesium 50 mg, zinc 10 mg (91% DV) and selenium 50 mcg (91% DV), plus calcium 20 mg above them.
- Copper to potassium
Copper 0.052 mg, manganese 0.4 mg, chromium 12 mcg, molybdenum 10 mcg and potassium 50 mg.
- Proprietary Blend 661 mg
The combined weight of 18 names, from DMAE bitartrate to phosphatidylserine. The dagger means no Daily Value is set. No single amount is printed.
- Other ingredients
The capsule shell and three fillers, outside the blend.
For all 22 printed lines, see the Reviralis supplement facts. The panel does not say whether the folic acid is an added form or a conversion for another form, so we do not guess.
Why it matters05
Does DFE change how many ingredients the label has?
No. DFE and folic acid are one ingredient written twice on one line, so the label has one folate entry. Counting both is how a headline reaches 41 from the label's 40.
Our post on what n-in-1 means walks through that count. The folate group is also covered on the B vitamins page.
Some seizure medicines interact with folate (NIH ODS, Folate). Tell a clinician or pharmacist what you take. Reviralis is not an antiviral. Herpes has no cure, and no source shows Reviralis prevents or reduces outbreaks. Keep any prescribed antiviral as directed.
FAQ06
Reviralis questions people ask
Is DFE the same as micrograms?
No, DFE is a weighted microgram. One microgram of folic acid counts as more than one microgram DFE on supplement labels, because folic acid is absorbed better than natural food folate. That is why 400 mcg of folic acid prints as 680 mcg DFE.
Why does the label show two folate numbers?
The label shows the weighted total in DFE and the actual amount of folic acid in brackets. They describe one ingredient, so a careful reader counts the folate line once.
Is 680 mcg DFE above the folate upper limit?
No, because the limit applies to folic acid, not DFE. The adult limit is 1,000 mcg of folic acid from supplements and fortified foods (NIH ODS, Folate), and the label shows 400 mcg, or 40%.
Is the 170% Daily Value a warning?
No, it is only a comparison. The 170% means 680 mcg DFE against a 400 mcg DFE reference. The share of the folic acid upper limit is 40%. Read the percent DV as a yardstick, not a limit.
Who wrote this07
Written and reviewed by
Pages built from the label, the order page and linked NIH, FDA, FTC, Mayo Clinic and peer-reviewed sources.
Last updated . Read our editorial standards and how we check reviews. This website is the information site for a USA Authorized Reviralis Retailer. It is not the manufacturer or the distributor named on the label. We earn money when you buy through our order links.
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