Labels
The Arithmetic Nobody Does
Two comfortable labels can add up to an uncomfortable total, and neither will warn you.
Published 2026-08-17 · 8 minute read · Gelagen Notes
Most people who overshoot a nutrient ceiling do not do it with one product. They do it with three, each of which is entirely reasonable on its own, none of which mentions the other two.
A Worked Example
Take somebody who is doing everything sensibly. A daily multivitamin. A skin supplement. A separate vitamin D through the winter because their doctor mentioned it. Liver once a week because it is cheap and nutritious.
| Source | Preformed vitamin A |
|---|---|
| Multivitamin | 900 mcg |
| Skin supplement | 630 mcg |
| Liver, one 75 g portion | Over 6000 mcg, on that day |
| Butter, cheese, eggs across a day | 150–250 mcg |
| Daily total, non-liver days | ~1700 mcg |
| Adult upper limit | 3000 mcg |
On ordinary days that total is inside the limit. On liver day it is several times over it, and nobody involved has done anything foolish. Every label was accurate. No label mentioned any other label.
The Four Nutrients Worth Adding Up
Vitamin A. The ceiling applies to preformed vitamin A only — retinol and its esters from animal foods and supplements. Beta-carotene from vegetables is regulated by your own conversion and does not count toward it. Our figure is 630 mcg and it is the number we ask people to add up.
Zinc. The ceiling is 40 mg from all sources. The problem is rarely acute; it is that months of high total zinc quietly displaces copper. Ours is 2.7 mg precisely so it adds very little to anyone's total.
Vitamin D. Stored, with a 100 mcg ceiling. If your doctor has you on a prescribed dose, add ours in rather than assuming a gummy is negligible.
Selenium and iron, if you take them separately. Neither is on our panel, and both have narrower windows between useful and excessive than most people realise.
What Does Not Need Adding Up
The water-soluble group is mostly forgiving. B12 and biotin have no established upper limits and the excess is excreted, and vitamin C has a ceiling of 2000 mg that a stack of ordinary supplements will not approach.
Biotin is the exception that is not about safety at all: the laboratory interference at 5000 mcg happens regardless of what else you take, so declaring it before a blood test matters even if it is your only supplement.
A Method That Takes Five Minutes
Put every jar you take on the kitchen table. Write down the four nutrients above, one per line. Go through each label and add the figures. Compare each total against the ceiling.
Most people find they are comfortably inside on everything, and the exercise is worth it for the one case in ten where they are not. Take the list to your next appointment; a pharmacist can scan it in under a minute.
This is also the practical argument for buying products that print their amounts. You cannot add up a proprietary blend, because the label has told you the total of a group and nothing about any member of it.
Quick Answers
Is it dangerous to take two multivitamins?
It depends entirely on which nutrients they contain and at what amounts. Vitamin A and zinc are where the doubling matters most.
Does food count toward the ceiling?
For preformed vitamin A, yes. Liver in particular is extraordinarily concentrated. Provitamin A from vegetables does not count.
Who should I ask?
A pharmacist. They can see every product at once and it is exactly the kind of question they answer quickly and for free.