Guide
Magnesium glycinate without fillers: capsules, stearates and "clean" labels
Almost every capsule needs a shell and a small amount of a flow agent or lubricant to be manufactured consistently. Here's what those ingredients are, what "filler" usually means, and our own label measured against it.
A truly "pure" magnesium glycinate capsule — nothing in it but the active ingredient — is close to impossible to manufacture at any scale. Every capsule needs a shell, and most powders need a small amount of a flow agent or lubricant to fill consistently on production equipment. What matters is the difference between a functional processing aid used in a small amount and an ingredient added mainly to bulk out a serving. Here's what each of the common ones actually is, and where our own label stands.
What "filler" usually means
"Filler" is typically used for an ingredient added mainly to take up space — to make a capsule a standard size, or a tablet a standard weight, when the active ingredient alone wouldn't fill it. That's different from a processing aid used in a small percentage to make manufacturing work at all. The two get lumped together in marketing copy, which is why "filler-free" claims are worth reading carefully: check what's actually listed under "other ingredients," not just the word on the front of the bottle.
The common excipients, one at a time
| Ingredient | What it is | Why it's used |
|---|---|---|
| Hypromellose | A plant-cellulose-derived capsule shell | Holds the powder; a common vegetarian and vegan alternative to a gelatin shell |
| Gelatin | An animal-derived capsule shell | The traditional capsule material; not vegan or vegetarian |
| Magnesium stearate | A salt of stearic acid, a common fatty acid | A lubricant that keeps powder from sticking to manufacturing equipment, used in small amounts |
| Silicon dioxide | A mineral compound, also called silica | A flow agent that keeps powder from clumping so it fills capsules evenly |
| Rice flour | Milled rice | Often used as a bulking or anti-caking agent to standardize fill weight |
Magnesium stearate in particular gets singled out in "clean label" marketing, but it's listed as generally recognized as safe (GRAS) at the small amounts used in supplement manufacturing (21 CFR 182.6733), and it's a lubricant, not a bulking agent — it makes up a small fraction of a capsule's total weight, not the padding a "filler" usually refers to.
Checking any label for yourself
The "other ingredients" line on a Supplement Facts panel is required to list everything in the capsule besides the active ingredient, in descending order by amount. That line, not the front-of-bottle marketing copy, is where to check what a product actually contains. If a label claims "no fillers" or "clean," the other-ingredients line will either back that up or contradict it — and a completely empty other-ingredients line on a capsule product is worth a second look, since a shell has to be made of something.
Our own label
Our other ingredients are hypromellose, magnesium stearate, silicon dioxide, and rice flour. That's a capsule shell, a lubricant, a flow agent, and a bulking agent — all four of the categories above, at whatever amounts our manufacturer uses to keep the fill consistent across every capsule. If your bar for "pure" is zero excipients of any kind, our capsule doesn't clear it, and very few in this category do. What we can say plainly: the capsule shell is plant-derived, not gelatin, and the product is labeled vegan, gluten-free and allergen-free by Supliful, who manufactures it.
Questions people ask
Is magnesium glycinate vegan?
Ours is labeled vegan: the capsule shell is hypromellose, a plant-cellulose derivative, not gelatin. Vegan status is specific to the actual ingredients on a given label — a gelatin-shell capsule from any brand is not vegan regardless of what else is inside it.
Why does my magnesium glycinate have magnesium stearate in it?
It's almost always there as a lubricant, to keep the powder from sticking to the equipment during manufacturing, not as a bulk filler. It's used in small amounts and is listed as generally recognized as safe for that use.
What does "clean label" actually mean for a supplement?
There's no regulated definition. In practice it usually points at a shorter "other ingredients" list, or the absence of a specific excipient someone wants to avoid. It's worth checking the actual list on any label making this claim, ours included, rather than taking the phrase itself as a guarantee.
Can you get magnesium glycinate with absolutely no other ingredients?
In a capsule, essentially no — a shell is required at minimum, and most manufacturing also needs a small amount of a flow agent or lubricant. A loose powder sold without a capsule removes the shell, but typically still uses an anti-caking agent for the same reason a capsule needs a flow agent.
Is rice flour a filler in magnesium glycinate?
It's commonly used to standardize capsule fill weight, functioning more like a bulking agent than a lubricant. Whether that counts as a "filler" in the way you mean the word is a fair question to ask any brand, including us, and the honest answer is that it's there to make each capsule consistent, not to pad the serving with something inert and unnecessary.
Sources
- 21 CFR 182.6733 — Magnesium stearate, generally recognized as safe.
- Electric Tiger Magnesium Glycinate Supplement Facts and other ingredients: product page.
- How to choose a good magnesium glycinate.
- Third-party testing for magnesium glycinate.
*These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.
