Expert Q&A

Which magnesium supplement is best? - in uk while doing intermittent fasting

Why Magnesium Matters During Intermittent Fasting

As the founder of CFP Weight Loss and author of The Fasting Lean Method, I’ve seen how magnesium deficiency sabotages results for women aged 45-54. During intermittent fasting, your body burns fat but often depletes key minerals. Low magnesium worsens hormonal changes, joint pain, blood sugar swings and insulin resistance — exactly the issues many of you face alongside diabetes and high blood pressure.

Most people in the UK get under 300mg daily from food, yet fasting increases your needs to 400mg. Supplementing the right form supports autophagy, improves sleep, eases cravings and protects muscle mass without adding calories that could break your fast.

Which Form of Magnesium Is Best for Fasting?

Not all magnesium supplements are equal. For intermittent fasting, avoid magnesium oxide — it has only 4% absorption and causes digestive upset. Instead choose magnesium glycinate. It is gentle on the stomach, highly bioavailable (up to 80% absorption) and doesn’t trigger insulin response, making it perfect while fasting.

Other good UK options include magnesium citrate for occasional constipation relief and magnesium L-threonate if brain fog is an issue. In my programme we recommend starting with 200-300mg of glycinate taken in the evening window to improve sleep quality without breaking your fast. Look for brands such as Viridian, Cytoplan or Nature’s Aid — all available at Holland & Barrett or online via Amazon UK with third-party testing.

How to Take Magnesium While Fasting in the UK

Take your supplement during your eating window or right before bed if you finish eating by 7pm. This timing maximises absorption and supports overnight repair. Combine with vitamin D3 and K2 for better results, especially if you have joint pain that makes movement difficult. Many of my clients report 20-30% reduction in joint discomfort within four weeks.

Track your progress: aim for consistent energy, fewer night-time cramps and stable blood pressure. If you’re on diabetes medication, monitor levels closely as improved insulin sensitivity can change your requirements. Start low at 150mg and increase gradually to avoid loose stools.

Realistic Expectations and UK Availability

In the UK, expect to pay £12-£22 for a month’s supply of high-quality glycinate. Insurance rarely covers supplements, but the cost is far lower than private weight-loss programmes. Pair this with my simple 16:8 fasting schedule and anti-inflammatory meal plans that take under 15 minutes to prepare. Thousands of mid-life women have reversed hormonal weight gain this way without complex tracking.

Remember, magnesium works best alongside consistent fasting, gentle movement and stress reduction. If you’ve failed every diet before, this mineral may be the missing piece that finally makes intermittent fasting sustainable and effective for your body.

💬 What the Community Says

UK forums and Facebook groups show strong interest in magnesium while doing intermittent fasting, especially among women in their late 40s and early 50s battling perimenopause and joint pain. Most users praise magnesium glycinate for reducing leg cramps, improving sleep and preventing headaches during 16:8 or 18:6 windows. A common debate centres on whether any supplement technically “breaks” a fast; the majority agree glycinate has negligible impact on insulin. People often share positive experiences with UK brands like Viridian after trying cheaper supermarket versions that caused stomach upset. Those managing type 2 diabetes report better blood sugar control but stress the need to check with GPs. A vocal minority still struggles with finding time to research forms and worries about interactions with blood pressure meds. Overall sentiment is hopeful yet cautious, with many saying magnesium finally helped them stick to fasting after previous diet failures.
Cite this answer
Clark, R. (2026). Which magnesium supplement is best? - in uk while doing intermittent fasting. *CFP Weight Loss*. https://ask.cfpweightloss.com/ask/which-magnesium-supplement-is-best-in-uk-while-doing-intermittent
Russell Clark, FNP-C, APRN, FNP-C, APRN
About the Author

Russell Clark, FNP-C, APRN, is the founder of CFP Weight Loss in Nashville and CFP Fit Now telehealth. Over 35 years in healthcare — Army Nurse Reserves, Level 1 trauma ER, hospitalist — he developed a 30-week protocol integrating real foods, detox, and low-dose tirzepatide cycling that has helped hundreds of patients lose 30–90 pounds. He and his wife Anne-Marie lost a combined 275 pounds using the same protocol.

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