Before Starting Ozempic, Wegovy, or Mounjaro: The 5-Step Supplement Checklist (2026)
Starting Ozempic, Wegovy, or Mounjaro? Do these 5 things before your first injection: (1) Get baseline bloodwork. (2) Start a multivitamin, magnesium, and protein supplement Day 1. (3) Set a protein target of 1.2-1.6g/kg/day. (4) Begin resistance training 2-3x/week. (5) Add biotin and collagen within the first month. 22.4% of GLP-1 users develop a nutritional deficiency within 12 months (PMID: 40584822) — starting supplements early prevents this.
Step 1: Get Baseline Bloodwork
Before your first injection, request these labs from your doctor. This establishes your starting point so you can catch depletions early:
| Test | What It Measures | Why Before Starting | Optimal Range |
|---|---|---|---|
| 25-Hydroxyvitamin D | Vitamin D status | 42% of Americans already deficient; 13.6% of GLP-1 users become deficient at 12 months (PMID: 40584822) | >30 ng/mL (optimal: 40-60) |
| Vitamin B12 | B12 status | Drops ~13% in 12 months on GLP-1 drugs (PMID: 41549912) | >400 pg/mL |
| Ferritin | Iron stores | Hair loss threshold; 3.2% develop anemia. Standard CBCs miss this — ask specifically. | >30 ng/mL (optimal: 50-100) |
| Serum Folate | Folate status | Reduced vegetable intake on GLP-1; severe deficiency case reports exist | >5.9 ng/mL |
| CBC with Differential | Blood cell counts | Baseline for anemia, B12/folate deficiency detection | Normal ranges |
| CMP | Kidney, liver, electrolytes, glucose | Baseline for dehydration monitoring and kidney function | Normal ranges |
| RBC Magnesium | Intracellular magnesium | Serum Mg is unreliable — only 1% of body Mg is in blood. Ask for RBC specifically. | 4.2-6.8 mg/dL |
| Zinc | Serum zinc | Zinc depletion causes hair loss, taste changes, impaired immunity | 60-130 mcg/dL |
| Thyroid Panel (TSH, Free T4) | Thyroid function | Baseline before biotin supplementation (biotin interferes with thyroid tests) | TSH 0.4-4.0 mIU/L |
| HbA1c | 3-month blood sugar average | Tracks metabolic improvement over time | <5.7% (non-diabetic) |
How to ask your doctor: "I'm starting [drug name] and want to track my nutritional status. Can you order a vitamin D, B12, ferritin, folate, RBC magnesium, zinc, CBC, CMP, thyroid panel, and HbA1c?" Most physicians will order these without issue — they are standard labs with well-established clinical utility.
Step 2: Start These Supplements on Day 1
Do not wait for bloodwork results to come back. Do not wait for deficiency symptoms. GLP-1 drugs suppress appetite within 24-72 hours of the first injection — nutrient gaps begin accumulating immediately. The joint advisory from ACLM, ASN, OMA, and TOS recommends starting nutritional support concurrent with therapy initiation (PMID: 40445127).
| Supplement | Product | Why Day 1 | Cost/Day | Buy |
|---|---|---|---|---|
| Protein Powder | ON Gold Standard Whey | Muscle loss begins week 1. Establish the habit before appetite drops. | $0.85 | Buy |
| Multivitamin | NATURELO One Daily | 30-40% calorie reduction begins immediately. Covers B vitamins, D, zinc, iron. | $0.47 | Buy |
| Magnesium Glycinate | Vitamin Shoppe Mg Glycinate | GI side effects deplete electrolytes from day 1. Also prevents cramps and supports sleep. | $0.24 | Buy |
Add Within the First Month:
| Supplement | Product | Why | Cost/Day | Buy |
|---|---|---|---|---|
| Biotin | Nature Made Biotin 2500 mcg | Hair loss prevention — starts 2-4 months after drug initiation. Get ahead of it. | $0.06 | Buy |
| Collagen | Vital Proteins Collagen | Hair, skin, and joint support during rapid weight loss. | $0.61 | Buy |
One click adds the complete Day 1 + Month 1 stack (90-day affiliate cookie)
Step 3: Set Your Protein Strategy
This is the single most important nutritional intervention. 25-40% of weight lost on GLP-1 drugs is lean mass (muscle, bone, organ tissue), not fat (PMID: 39431379). Adequate protein is the primary countermeasure.
Calculate Your Target
Per the joint advisory from ACLM, ASN, OMA, and TOS: 1.2-1.6g protein per kg bodyweight per day (PMID: 40445127).
| Your Weight | Minimum (1.2g/kg) | Optimal (1.6g/kg) | Supplement Needed* |
|---|---|---|---|
| 150 lbs (68 kg) | 82g/day | 109g/day | 25-50g (1-2 scoops) |
| 180 lbs (82 kg) | 98g/day | 131g/day | 25-75g (1-3 scoops) |
| 200 lbs (91 kg) | 109g/day | 145g/day | 50-75g (2-3 scoops) |
| 250 lbs (113 kg) | 136g/day | 181g/day | 50-100g (2-4 scoops) |
*Assuming 60-80g protein from food once appetite suppression kicks in.
Pro tip: Start your protein habit before the first injection if possible. Once GLP-1 nausea hits, the last thing you want is to figure out how to mix a protein shake for the first time. Practice for a few days so it becomes routine.
Step 4: Begin Resistance Training
A 2025 case series found GLP-1 users who combined protein with resistance exercise preserved significantly more lean tissue than those relying on protein alone (PMC: 12536186). Start before or concurrent with your first injection:
- Frequency: 2-3 sessions per week minimum
- Focus: Compound movements — squats, deadlifts, bench press, rows, overhead press
- Intensity: Moderate (RPE 6-8 out of 10) — you do not need to train to failure
- Duration: 30-45 minutes per session is sufficient
- Progression: Gradually increase weight or reps over time
If you have never resistance trained, consider 2-3 sessions with a personal trainer to learn proper form. Many gyms offer a complimentary session for new members. The investment pays for itself in preserved muscle mass.
Step 5: Know What to Expect Month-by-Month
| Timeline | What Happens | Nutrient Impact | Action |
|---|---|---|---|
| Week 1-2 | Appetite drops noticeably. Nausea may begin. Food intake drops 20-30%. | Caloric and nutrient intake decline begins. Electrolyte losses from GI side effects. | Day 1 supplements in place. Track protein intake. Have electrolytes on hand. |
| Month 1-2 | First dose increase. GI side effects may return. Eating 30-40% less than before. | Muscle loss accelerates. Magnesium, B vitamins begin declining. Hair follicles start entering telogen phase (invisible yet). | Add biotin and collagen. Maintain protein target aggressively. Use electrolytes during GI flares. |
| Month 3-4 | Rapid weight loss phase. Body composition changing. First hair shedding may begin. | Iron stores declining (especially women). Zinc depletion affecting taste and immunity. Vitamin D stores from fat cells releasing but new intake low. | If hair thinning starts: check ferritin, ensure protein + biotin + zinc are adequate. Continue all supplements. |
| Month 6 | Significant weight loss achieved. GI side effects usually stabilized. | Get bloodwork now. 7.5% are vitamin D deficient. B12 has dropped ~7%. Hair loss peaks. | Repeat baseline labs. Add standalone vitamin D, B12, or iron if levels are low. Adjust protein target to new weight. |
| Month 12 | Approaching or at target weight. Maintenance phase beginning. | 22.4% have a nutritional deficiency (PMID: 40584822). 13.6% vitamin D deficient. B12 down ~13%. | Repeat bloodwork. Continue supplements indefinitely while on the drug. Hair regrowth should begin if nutrients adequate. |
Before vs After: Your Supplement Protocol Comparison
| Supplement | Before GLP-1 | On GLP-1 | Why the Change |
|---|---|---|---|
| Protein | Optional for most people | Essential — 1.2-1.6g/kg/day | 25-40% of weight lost is muscle without intervention |
| Multivitamin | Nice-to-have for most | Essential — daily with food | 30-40% fewer calories = 30-40% fewer nutrients |
| Magnesium | Beneficial (50% already deficient) | Essential — 200-400mg glycinate | GI losses compound existing deficiency |
| Biotin | Unnecessary unless deficient | Recommended — 2,500 mcg | 14-25% experience hair loss; cheap insurance at $0.06/day |
| Collagen | Optional for skin/joints | Recommended — 10-20g/day | Hair, skin, and joint support during rapid weight loss |
| Electrolytes | Only if active/sweating | As needed — during GI symptoms | 3.5% develop clinical dehydration from GI side effects |
Frequently Asked Questions
What should I do before starting Ozempic?
Five things: (1) Get baseline bloodwork — vitamin D, B12, ferritin, folate, CMP, CBC, RBC magnesium, zinc, thyroid, and HbA1c. (2) Start a multivitamin, magnesium, and protein supplement Day 1. (3) Set a protein target of 1.2-1.6g/kg/day. (4) Begin resistance training 2-3x/week. (5) Add biotin and collagen within the first month. Total supplement cost: $2.26-3.11/day.
Should I take supplements before starting Ozempic?
Yes — start the same day as your first injection. GLP-1 drugs suppress appetite within 24-72 hours. Nutrient gaps accumulate from week 1. 22.4% of GLP-1 users develop a deficiency within 12 months (PMID: 40584822). Early supplementation prevents this.
What blood tests do I need before starting a GLP-1 drug?
Request: 25-hydroxyvitamin D, B12, ferritin, folate, CBC, CMP, RBC magnesium, zinc, thyroid panel (TSH, free T4), and HbA1c. These establish your baseline. Repeat every 6 months while on therapy.
When do GLP-1 side effects start?
GI side effects (nausea, reduced appetite) typically begin within 24-72 hours of the first injection, peak during weeks 4-8 and dose increases, then improve. This is why supplements need to start Day 1 — by the time nausea hits, your food intake has already dropped (clinical consensus).
How much protein do I need from Day 1?
Target 1.2-1.6g/kg/day from Day 1 (PMID: 40445127). For a 200 lb person, that is 109-145g/day. Establish the habit before appetite drops — it is much harder to start when nauseous.
Related
- GLP-1 Nutrient Depletion Guide — full evidence review
- Essential GLP-1 Supplement Stack — product picks and costs
- GLP-1 Supplement Calculator — personalized protocol
- Electrolyte Guide — managing GI side effects
- Cost Guide — budget breakdown by tier
- Best Protein for GLP-1 Users
Sources
- Butsch WS, et al. "Nutritional deficiencies in GLP-1 RA users: retrospective cohort of 461,382 patients." Obesity Pillars. 2025. PMID: 40584822
- Mozaffarian D, et al. "Nutritional Priorities to Support GLP-1 Therapy: Joint Advisory." Obesity. 2025. PMID: 40445127
- "Characterizing body composition modifying effects of GLP-1 RAs: A meta-analysis." 2024. PMID: 39431379
- "Micronutrient Deficiencies Associated With GLP-1 RA Therapy: A Narrative Review." 2025. PMID: 41549912
- "GLP-1 RA users with resistance exercise preserve lean mass." 2025. PMC: 12536186
- Forrest KY, Stuhldreher WL. "Prevalence and correlates of vitamin D deficiency in US adults." Nutr Res. 2011. PMID: 21310306