When you eat significantly less food — as most people do on Mounjaro — your intake of essential vitamins and minerals naturally decreases. Over time, this can lead to deficiencies that affect energy, immunity, bone health, and more. Understanding which supplements may be helpful allows you to stay proactive about your health.
Common Deficiency Risks on Mounjaro
Research into GLP-1 receptor agonist therapy suggests several nutrients are particularly at risk during prolonged reduced-calorie intake:
- Vitamin D: Already deficient in a large proportion of the UK population due to limited sunlight, reduced food intake worsens this. Vitamin D is essential for bone health, immune function, and mood regulation.
- Iron: Especially relevant for women of childbearing age. Symptoms of deficiency include fatigue, shortness of breath, and pale skin.
- Vitamin B12: Found primarily in animal products. Those eating very little meat, fish, or dairy may become deficient. Symptoms include tingling, fatigue, and cognitive difficulties.
- Calcium: Critical for bone density, particularly during rapid weight loss when bone mineral density can decrease.
- Folate: Important for cell production and particularly vital for women who may become pregnant.
Recommended Supplements
The NHS already recommends that all adults in the UK take a vitamin D supplement of 10 micrograms (400 IU) daily, particularly during autumn and winter. On Mounjaro, this becomes even more important year-round.
A good-quality multivitamin and mineral supplement can provide a safety net. Look for one that includes vitamins A, C, D, E, B12, folate, iron, calcium, and zinc. These are available from any high-street pharmacy — Boots, Superdrug, and Holland & Barrett all stock reliable options, typically costing £3–£8 per month.
Supplements to Discuss with Your Doctor
Before taking anything beyond a standard multivitamin, consult your GP or pharmacist, particularly regarding:
- Iron supplements: These can cause constipation, which Mounjaro may already worsen. A blood test can confirm whether supplementation is needed.
- High-dose vitamin D: If blood tests show significant deficiency, your GP may prescribe a loading dose.
- Omega-3 fish oils: Generally safe but worth mentioning if you take other medications.
- Protein supplements: Whey or plant-based protein powders are safe for most people but check with your prescriber if you have kidney issues.
Timing Your Supplements
Take supplements with food for better absorption and to reduce stomach upset. Fat-soluble vitamins (A, D, E, K) are best absorbed with a meal containing some fat. If nausea is an issue, try taking your multivitamin with your largest meal of the day.
What to Avoid
Be cautious of "weight loss supplements" marketed alongside GLP-1 medications. Many contain unregulated ingredients, dubious claims, and may interact with Mounjaro. Stick to evidence-based supplements from reputable brands.
Regular blood tests through your GP can monitor your levels and guide supplementation. Prevention is far easier than treating an established deficiency.