GLP-1 Vitamin Deficiencies and How to Prevent Them
The most common vitamin and mineral deficiencies on GLP-1 medications — and the supplements that prevent them.
Key takeaways
- Iron, B12, vitamin D, and magnesium account for the majority of 'GLP-1 fatigue' complaints.
- Ask for ferritin, vitamin D, B12, CBC, and a CMP every 6–12 months while on a GLP-1.
- A daily multivitamin does not cover magnesium adequately — supplement it separately.
- Protein deficiency accelerates hair shedding and slows wound healing.
- Electrolytes cover potassium and sodium that a multivitamin does not.
Sustained calorie restriction on a GLP-1 medication is the perfect setup for nutrient deficiencies. The earliest signs — fatigue, brain fog, hair shedding, leg cramps, mouth sores — are often blamed on the medication when the real cause is a missing vitamin or mineral.
Here are the deficiencies that show up most often on GLP-1 medications, the symptoms to watch for, and how to head them off before they become a problem.
The top GLP-1 deficiencies
- Iron — fatigue, pale skin, hair shedding, cold hands and feet
- Vitamin B12 — fatigue, brain fog, tingling in hands or feet
- Vitamin D — low mood, muscle weakness, frequent illness
- Magnesium — leg cramps, poor sleep, constipation, anxiety
- Potassium — leg cramps, weakness, heart palpitations
- Sodium — headaches, dizziness, fatigue (especially on hot days)
- Protein — muscle loss, hair shedding, slow wound healing
- Calcium — bone density loss during rapid weight loss
How to prevent them
A daily multivitamin covers most baseline needs. Add magnesium glycinate at night, a daily electrolyte for sodium and potassium, and a protein source with every meal. Vitamin D3 + K2 covers a common gap that most multivitamins under-dose.
Ask your provider for a basic blood panel — ferritin, vitamin D, B12, CBC, and a CMP — every 6–12 months while on a GLP-1. Treat any low result with a targeted supplement rather than a broad approach.
What to test and when
- Baseline (before or within 30 days of starting): ferritin, vitamin D, B12, CBC, CMP, HbA1c, lipid panel
- 3–6 months in: repeat ferritin, vitamin D, B12 if any symptoms
- Every 6–12 months on maintenance: full panel above
- Anytime symptoms appear (fatigue, cramps, hair loss, tingling): test rather than guess
Reading your results
Ferritin under 50 ng/mL often causes fatigue and hair shedding even when hemoglobin is normal. Vitamin D under 30 ng/mL is common and worth correcting to 40–60. B12 under 400 pg/mL benefits from supplementation. Bring your numbers to your prescriber and treat them collaboratively.
Frequently asked questions
Elevate GLP-1 Dosage Tracker
Log your weekly injections, weight, hydration, and key milestones with a simple dashboard that helps you stay consistent throughout your GLP-1 journey.
Supplements for this plan
Formulated for the nutrient gaps GLP-1 medications create.