Forums›Nutrition & Supplementation›Micronutrient deficiency risk on GLP-1 — my results so far

Micronutrient deficiency risk on GLP-1 — my results so far

Dr.SleepRoch Sat, Mar 28, 2026 at 4:51 PM 29 replies 856 viewsPage 1 of 6

Dr.SleepRoch

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Mar 28, 2026 at 4:51 PM#1

Read the primary source rather than the write-up and the two do not agree, so here is what is actually in it.

A sustained drop to 1,100 or 1,200 calories reliably under-delivers a predictable set: B12, vitamin D, iron, folate, zinc and magnesium. Two of those are worth testing rather than guessing because the tests are cheap and the symptoms overlap with everything else — ferritin and B12. The rest a decent multivitamin covers, and there is no benefit in megadosing any of them.

Where I think it is weakest: the completion rate deserves as much attention as the headline, because a large effect among those who finished is a different claim from a large effect among those enrolled.

What would genuinely help is knowing which deficiencies actually show up when intake drops this far, and which are worth testing rather than supplementing blind. Happy to be told the question itself is wrong.

Note on sourcing:
Figures above are from the primary publication rather than the press summary. If a number here disagrees with one you have, post yours and we will work out which of us is reading a secondary source.

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PurityPaulOR

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Mar 28, 2026 at 5:24 PM#2

Dr.SleepRoch said:
A sustained drop to 1,100 or 1,200 calories reliably under-delivers a predictable set: B12, vitamin D, iron, folate, zinc and magnesium.

Iron studies on micronutrients — important especially for women:

Marker	Baseline	Month 6	After Supplementation
Ferritin	79	27	54
Iron	109	59	87
TIBC	319	389	339
Transferrin Sat	29%	19%	28%

My ferritin cratered at month 6 from reduced dietary intake. Iron bisglycinate 36mg with vitamin C brought it back up. Don't wait for anemia symptoms — test proactively.

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DebRD_ATL

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Mar 28, 2026 at 5:57 PM#3

Dr.SleepRoch said:
A sustained drop to 1,100 or 1,200 calories reliably under-delivers a predictable set: B12, vitamin D, iron, folate, zinc and magnesium.

Vitamin and mineral labs to check while on micronutrients — my doctor orders these quarterly:

B12: Can drop due to reduced GI absorption. Mine went from 650 to 380 — now supplementing.
Iron/Ferritin: Reduced food intake = reduced iron. Ferritin dropped from 65 to 22. Supplementing.
Vitamin D: Was already low (24 ng/mL), now taking 5000 IU daily.
Folate: Stable, no issues.
Zinc: Slightly low, added a multivitamin with zinc.

Nutritional deficiencies are a real risk when you're eating significantly less. Don't skip your labs!

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NurseLeah_Nash

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Mar 28, 2026 at 6:30 PM#4

DebRD_ATL said:
Vitamin and mineral labs to check while on micronutrients — my doctor orders these quarterly: B12: Can drop due to reduced GI absorption.

Blood count monitoring for micronutrients: my doctor noticed my MCV (mean corpuscular volume) trending up at month 6: 91 → 97 fL. This flagged potential B12 or folate deficiency.

Sure enough, B12 had dropped from 620 to 340 pg/mL. Started B12 injections monthly and MCV normalized within 2 months. GLP-1 agonists can impair B12 absorption — this is a real clinical concern that deserves routine monitoring.

Last edited: Mar 28, 2026 at 7:30 PM

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kevin_tulsa

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Mar 28, 2026 at 9:31 PM#5

PurityPaulOR said:
Iron studies on micronutrients — important especially for women: Marker Baseline Month 6 After Supplementation Ferritin 79 27 54 Iron 109 59 87 TIBC…

Same experience, arrived at from the opposite direction.

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