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Calcium Carbonate Supplement: Absorption, Timing and the 20 mg Line
A calcium carbonate supplement is absorbed best with food, because the stomach acid made at meals helps it dissolve. Reviralis prints calcium as calcium carbonate, 20 mg per two capsules, 2% of the Daily Value. Adults need 1,000 to 1,200 mg a day, so this line is a trace, not a source.
Written by the Goreviralis label deskUpdated · 4 min read
How much calcium is in a calcium carbonate supplement like this one?
Here it is 20 mg per serving, which is 2% of the Daily Value.
Adults need 1,000 to 1,200 mg a day, and the upper limit is 2,000 to 2,500 mg (NIH ODS, Calcium). A glass of milk holds roughly 300 mg, so the capsules add about what a spoonful of it would. Dairy foods, canned fish with bones and fortified drinks carry the real load.
| Measure | Amount | Share the label line fills |
|---|---|---|
| Label line (2 capsules) | 20 mg, 2% DV | Printed |
| Adult need | 1,000 to 1,200 mg | 1.7% to 2% |
| Upper limit | 2,000 to 2,500 mg | 0.8% to 1% |
Does a calcium carbonate supplement need food to absorb?
Usually yes: carbonate dissolves with stomach acid, and meals bring the acid.
NIH advises taking carbonate with food, while citrate works either way (NIH ODS, Calcium). The Reviralis directions say two capsules daily with 8 oz. of water, 20 to 30 minutes before a meal. That timing sits at odds with carbonate's usual advice. At 20 mg the gap hardly matters, but it shows why timing questions are worth putting to a pharmacist, not guessing.
Slide the dial on the how to use page to see the label's window around a meal.
For an 8:00 am meal, take 2 capsules with 8 oz of water between 7:30 am and 7:40 am.
- Two capsulesThat is the label's serving: two (2) capsules, not one. The pack and sales page say one capsule; this site follows the label.
- One 8 oz. glass of waterThe label asks for 8 ounces of water with the capsules.
- 20 to 30 minutes before a mealThe label says this timing gives the best results, "or as directed by your healthcare professional."
- Your clinician's direction winsIf your healthcare professional gave you other directions, follow those and keep every prescribed medicine, including any antiviral, going.
The timing comes from the label's suggested use. A dial is a reminder aid, not a promise of any result.
Which medicines does calcium affect?
Calcium can lower the absorption of thyroid hormone and some antibiotics when taken at the same time (NIH ODS, Calcium).
At 20 mg the effect is small, but a gap is cheap to ask about. Calcium from antacids and fortified drinks counts too. Keep taking every prescribed medicine, including any antiviral, and ask your pharmacist before changing the schedule.
- Thyroid hormone tablets
- Some antibiotics
- Calcium-rich antacids you use often
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 packsWhat should I ask my pharmacist about calcium?
Ask whether your total calcium is in range, not whether 20 mg is enough.
Add the calcium on every label and antacid. Then ask: Is my total near 1,000 to 1,200 mg from food and pills combined? Do any of my medicines need a gap? No source tests Reviralis Complete itself, so the label is the guide.
More on the minerals is in the major minerals group; see also the antibiotics and minerals post.
FAQ01
Reviralis questions people ask
How much calcium is in Reviralis?
The label prints calcium as calcium carbonate, 20 mg per two capsules, or 2% of the Daily Value. Adults need 1,000 to 1,200 mg a day, so the line is a trace. Food and fortified drinks supply the bulk.
Should calcium carbonate be taken with food?
Usually, yes. NIH advises taking carbonate with food because stomach acid helps it dissolve. Citrate absorbs with or without food. The Reviralis label asks for two capsules 20 to 30 minutes before a meal, so ask your pharmacist about your own timing.
Is 20 mg of calcium useful for bones?
Not on its own. A day's need is 1,000 to 1,200 mg, so 20 mg is about 2%. Bone health depends on total intake from food and any other supplements, plus vitamin D and activity.
Can calcium carbonate cause constipation?
It can in larger doses, since carbonate is a common cause of gas and constipation. At 20 mg that is unlikely. If a calcium product binds you up, tell your pharmacist which one you use.
Does calcium interfere with thyroid medicine?
It can lower thyroid hormone absorption when taken together, according to NIH. Ask your pharmacist how far apart to take them. Do not change a prescribed dose on your own.
Who wrote this02
Written and reviewed by
Pages built from the label, the sales page and linked NIH, CDC, 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 U.S. stocking partner for Reviralis. 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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