Users Guide to Supplement Timing (Graphic)

User’s guide to supplement timing

By Cat, Jan 2018; updated Aug 2018 with additional  information from Better Nutrition magazine

This guide is from Dr. Mercola’s posting on 1/17/18 (1). You can also download a printable pdf (User’s Guide to Supplement Timing). If you take dietary supplements:  multi-vitamin/mineral, specific vitamins, specific minerals, antioxidants, etc., it’s very important to take them at the right time, and to pay attention to which should or should not be taken together, or with/without food. Taking them at the wrong time or wrong combination can minimize their effect. Also pay attention to which ones should not be taken if you are taking certain prescribed medications (this info is not on the graphic; see Mercola’s article (1) for more info).

Since writing this post, I found a related article in the Better Nutrition magazine by  Lisa Turner (Feb 2018 issue (2)), so I have added their information, below. Unfortunately, I cannot update Mercola’s guide.

See also 1. Misc. & Information Menu; 2. User’s Guide to Supplement Timing (pdf)


You can also print this as a pdf file: User’s Guide to Supplement Timing (pdf)

From Better Nutrition article by Lisa Turner(2)

Calcium & Magnesium:

High doses will compete with each other for absorption. Taking too much calcium and too little magnesium can contribute to calcification of the arteries. Recommended daily ratio if calcium to magnesium is 1:1 or 1:2. When to take:

  • Calcium twice a day (500 mg each, with breakfast and with lunch is their recommendation).
  • Magnesium: (not discussed in Better Nutrition article). Mercola’s guide recommends it at night, without food.


Do not take with magnesium, calcium or zinc, as it can inhibit the absorption of the other minerals.  [From my chemistry background, this possibility of inhibition is for all minerals with a +2 ionic charge, for which magnesium, calcium, iron and zinc all qualify.]

Best way to take: 60-75 mg chelated iron (such as ferrous gluconate) before breakfast, wash it down with orange juice (not coffee or milk), and 2-hours before taking vitamin E or a multivitamin. A second dose can be taken at a later time in the day.

[Cat’s Note: ferrous form (+2 charge) is easier on your body than ferric form (+3 form). Heme-iron (in bloody meats, and liver, most commonly ferrous form) is the easiest on the body. Free iron – not chelated – is a toxic heavy metal and can cause significant free-radical damage to your blood vessels and tissues.]

I take iron as desiccated beef liver powder (heme iron).

Vitamin D:

Best way to take is as Vitamin D3 (cholecalciferol), 4,000 IU with a meal that contains healthy fats.

I take it as D3-liquid with my morning smoothie that is rich in fats (coconut oil, whole raw milk, cream and cottage cheese, as well as fish and cod liver oil). The raw milk and cottage cheese also provide vitamin K, which is good to take with vitamin D.

Vitamin B Complex:

Best way to take: split the daily dose into several partial doses during the day, but not at night, because they can make it hard to sleep. They can be taken with or without food, but Mercola recommends without food. Your formula should not contain more than 100 mg of B6 (pyridoxine).

I take it as part of a whole food multi that I take with breakfast, lunch and dinner; the daily dose provides 4 mg of B6. I also take Doc’s Best B-Complex with breakfast; it provides 50 mg B6.

Vitamin C:

This is available as ascorbic acid or as ascorbate (a salt of ascorbic acid); the latter is easier on the body. Like other vitamins, it is best split the daily dose into 2-3 smaller doses during the day to prevent gastrointestinal distress that some experience with large doses.

Best way to take is 250-500 mg, twice a day, with breakfast and lunch. Mercola’s guide agrees with this.

I take it as part of the whole food multi I take with breakfast, lunch and dinner, with a bit extra added to my morning smoothie as liquid-C and dried acerola berry powder. and also as fruit/berries added to my smoothie, and apples with brie at lunch.


Supplemental probiotics are best taken on an empty stomach so they have the best chance of surviving stomach acid. Spore-based probiotics are best at surviving the acid. Take 30 minutes before a meal that contains some fat which buffers stomach acids. Some probiotics can be taken with a meal, but never after a meal.

Best strains include: L. acidophilus, B. Longum, B bifidum, L. rhamnosus and L. fermentum.

Best way to take: 5 – 25 billion CFUs of a broad-spectrum formula, 30 min before eating, or with a meal.

Mercola recommends taking most probiotics without food, but take spore-based probiotics with food.

Cat’s note: Fermented and cultured foods also provide an abundance of probiotics, and is considered the best way to take them daily as a single bite/spoon-full of fermented food with each meal. A bowl of plain, unsweetened yogurt with a bit of fresh fruit, or an ounce of real cheese (such as brie) is another way to get probiotics.

I take several different probiotics in rotation, including acidophilus, etc and also spore-based formulas, to avoid getting an overabundance of one or several species which can cause issues – our microbiome needs to be balanced for best activity. I also take S. boulardi, a type of yeast that keeps candida yeast in check, as part of my rotation.

Fish Oil:

This includes “fish” oil, krill oil, and cod liver oil. They should be taken in divided doses with food to avoid gastric distress.

Best way to take: 500 – 600 mg twice a day, with breakfast and lunch or with lunch and an early dinner. Fish and cod liver oil are rich in the Omega-3s DHA and EPA. DHA is actually more important than EPA, but we can make DHA from EPA. We cannot make EPA.

Cat’s note:  Most fish oils such as Carlson’s and Nordic brands are highly processed, so the oils are likely damaged. One site (3) recommends Rosita brand of fish oil because it is not as processed. Blue Ice brand of cod liver oil is cured the way the ancient Vikings did. Blue Ice calls it “fermented” but you can’t really ferment the oil; however, other constituents from the fish liver can be fermented. Krill oil is another possibility (that Mercola endorses).

I add Rosita fish oil and Blue Ice cod liver oil to my smoothie, of which I drink most for breakfast, and a lesser amount with an early dinner. I also eat a lot of wild salmon in season (summer and fall), which is an excellent source of quality fish oil.



  1. Mercola:
  2. Better Nutrition magazine, February 2018 issue, article by Lisa Turner:
  3. Beverly Meyer article:

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