Do-It-Yourself
Milk of Magnesia (MoM)
Page Edition: 2023-07-17
Introduction
MoM was originally just a suspension of magnesium
hydroxide (a laxative) in filtered water.
The program Magnesium Water recipe uses CO₂ (from carbonation)
to convert the hydroxide to bicarbonate. The Mg bicarb
reaction transforms this 🧻 laxative to a
highly-absorbable 
Mg mineral supplement:
⌬ Mg(OH)₂ + 2 CO₂ → Mg(HCO₃)₂
In 2018, retail MoM in the U.S. market began
showing up with sodium hypochlorite (bleach) in the
Ingredients list. Now 5+ years on, unadulterated MoM
has vanished, and it doesn’t appear
that this situation is going to change. Bleached MoM
is unsuitable for making magnesium water (nor, frankly,
would I employ it for its labeled use, due to
its likely antiseptic effects on gut flora).
If you still have any unadulterated MoM, check the
expiration date, and if lapsed, discard the product.
See the ⇩final discussion
below for the apparent back-story of how things ended
up this way.
⟲
Mg Water Ingredient Choices Today
Although you can’t get clean MoM anymore, you can get simple
Mg hydroxide powder. With it, you can either:
- ⇩make
your own MoM, or
- ⇩just
add it more-or-less directly to carbonated
{seltzer} water.
The challenges with Mg hydroxide powder are that:
- a single day’s portion of it is merely 1.08 gram
(450 mg of Mg), which is too low a weight for
typical kitchen scales,
- the density of the powders varies, so the package
portioning amount (cc or tsp.) isn’t
sufficiently reliable for practical use with
kitchen measuring spoons, and
- even if the daily amount volume was reliable, at
~⅓ tsp., it’s very hard to measure precisely
by volume.
⟲ Product Sourcing
What is required for DIY MoM is food grade magnesium
hydroxide powder. It must be only Mg hydroxide
with no other ingredients, flow agents or preservative.
Topical or bath forms of Mg are unsuitable. All other forms
of Mg supplements (e.g. citrate, malate, glycinate, etc.)
are unsuitable for making Mg-water (those you consume directly).
You are unlikely to find Mg hydroxide at retail, or
at on-line food resellers. In some countries, it can be
hard to find, period. Check with a local chemist or
pharmacist. Beware of buying Mg hydroxide from
on-line “marketplace”⚠sites, as it’s expensive
enough to attract counterfeiters who take advantage of the
SKU co-mingling defect in the marketplace model.
Ordering directly from the brand might be ideal. Although
it may be a bit more expensive than at a reseller site,
the cost per portion is trivial: a 1 kg bag will
serve a single person for 2½ years. Seek a brand
that offers COAs. The numbers to check on the COA are
lead (Pb), cadmium (Cd) and arsenic (As).
If any of these are unreported, that may not be mere oversight.
You may need to have your bag in-hand to request a COA,
but you’ll then get a COA specific to the lot. As member
reports about COAs arrive, some brand biasing may emerge.
In the U.S, there are multiple brands offering suitable
products. Perhaps the top two in use by members are:
⎆PureBulk® Magnesium Hydroxide
⎆BULK SUPPLEMENTS.com®
Magnesium Hydroxide
⟲ DIY MoM
This approach allows ⎆the
program recipe (3 tbsp.
MoM in 2 liters of seltzer)
to keep working, and does so by employing larger amounts of
Mg hydroxide powder, that are practical to measure.
You will need:
🥛
one or more containers of known volume
⚖ a scale accurate to the nearest gram
🌢
a source of filtered or distilled water.
Tap water usually has serious problems.
The amount of Mg hydroxide powder needed
to make MoM
depends on the volume of water. Retail MoM is
1200 mg of Mg hydroxide per 15 mL
water (~1500 mg of elemental magnesium in 3 tbsp.
or 45 mL of MoM, used to make 2L Mg-water).
| DIY
MoM Amounts |
| Volume |
Mg hydroxide |
| 1 U.S. pint (473mL) |
38 grams |
| 1 U.S. quart (946mL) |
76 grams |
| 1 litre |
80 grams |
| 2 litres |
160 grams |
Add the measured amount of the Mg hydroxide
powder to the container. Fill with filtered or
distilled water to the level for the target volume.
Cap and shake well. It may take some time for all
the clumps of hydroxide to break up.
Store in refrigerator until needed. There is
no preservative, so this suspension is at some
risk of contamination.
Shake well before use. This is a suspension, not a
solution. Make Mg-water per program recipe,
using this home-made MoM.
⟲ Direct to Mg-Water
| You will need: |
| ⚖‰ |
a gram scale accurate to the nearest
10 milligrams (0.010 grams) |
| 🍾🫧 |
carbonated filtered water (seltzer) or
a home carbonator and a source of filtered
or distilled water. Do not use sweetened,
flavored, colorized, mineral or otherwise
fortified sparkling waters. |
| 🌢 |
a source of filtered or distilled water
if you need to make a MoM slurry. |
| Direct
to Mg-Water Amounts |
| Volume |
Mg
hydroxide |
MoM Slurry
Water |
Elemental Mg
in Volume |
| 1 U.S. pint (473mL) |
0.85 grams |
¾ tbsp. (2+ tsp.) |
354 mg |
| 620 mL* |
1.1 grams |
1 tbsp. (3 tsp.) |
458 mg |
| 1 U.S. quart (946mL) |
1.7 grams |
1½ tbsp. (4 tsp.) |
708 mg |
| 1 litre |
1.8 grams |
1½ tbsp. (5 tsp.) |
750 mg |
| 2 litres |
3.6 grams |
3 tbsp. (9 tsp.) |
1500 mg |
| *
this is the size of the smaller
sodastream brand glass carafes. |
Note: ⇛⌛⇚
Regardless of how made, the Mg-water process is a
non-trivially hypobaric (negative pressure) physical
chemistry reaction. If using a glass bottle, the cap
may be hard to remove. If using a polymer bottle, it
is likely to dimple, weakening it over time. If using
a single-use retail seltzer bottle, the dimpling may
be of no real consequence.
If you are doing your own carbonation, ignore the
Slurry column. You can add
the table amount of Mg hydroxide directly to the
filtered water, shake well, carbonate, cap,
shake again, and allow 20 minutes or so to
react.
If you are not doing your own carbonation, and are
using pre-carbonated water (seltzer), adding
the powder directly to seltzer starts a spitty
irregular immediate reaction. So make a
single portion of MoM by first mixing the shown
amount of Mg hydroxide powder with the shown
amount of slurry water, in a separate small
container. Shake well, then pour into the seltzer.
Cap, shake, and let react for at least 20 minutes.
⟲ Why Bleach?
Why is the sodium hypochlorite in current MoM products?
I have several bottles of now-expired pre-bleach MoM, and
they have this interesting statement under
Other Information
■ does not meet USP requirements for
preservative effectiveness
Current products omit this advisory.
Back in the 2010s, there were at least two instances
of recalls of contaminated MoM … and two of these were
for professional unit-dose MoMs intended for clinical use. Here’s
a ⎆forum mention of one
of those cases. Clearly there is potential liability
here that the MoM industry would like to shoo away,
particularly for multiple-use containers of MoM.
Further, the usual customer for MoM is someone
on a standard diet, with constipation, and thus almost
certainly with SIBO. An antiseptic added to the MoM
is likely to clobber {all} microbes in the GI tract.
For the usual customer this might actually knock
down the SIBO a bit {along with any beneficial microbes}.
If so, the MoM producers could even possess trial data that let
them cluelessly conclude that the bleach made the product
both safer and more effective.🙄
If these observations and conjectures are correct, don’t
expect a suitable MoM to return to store shelves anytime soon.
___________
Bob Niland [⎆disclosures] [⎆topics] [⎆abbreviations]