# 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. Updated: 2026-07-24 Canonical URL: https://elevateglp.com/guides/glp-1-vitamin-deficiencies ## 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. ## FAQ ### Which deficiency causes GLP-1 fatigue? Iron and B12 are the most common drivers of fatigue on a GLP-1. Vitamin D and inadequate protein are close behind. A blood test is the only way to know for sure. ### How often should I get blood work on a GLP-1? Every 6–12 months is a reasonable cadence. Ask for ferritin, vitamin D, B12, CBC, and a comprehensive metabolic panel at minimum. ### Can a multivitamin cover everything I need? No. Multivitamins typically under-dose magnesium, vitamin D, and electrolytes. Add magnesium glycinate, vitamin D3+K2, and a daily electrolyte alongside your multi. ### Does GLP-1 cause vitamin deficiency directly? Not directly — the medication itself does not deplete vitamins. What causes deficiency is eating substantially less food while on the medication for months at a time. ### Can I fix a deficiency with food alone on a GLP-1? Sometimes, but it is hard on small portions. Supplements are a faster, more reliable way to correct a low result while you rebuild your eating patterns. --- Source: https://elevateglp.com/guides/glp-1-vitamin-deficiencies Publisher: Elevate GLP (https://elevateglp.com) — supplements for people on GLP-1 medications. Educational content only; not medical advice. Attribution required when quoting.