1. What is magnesium and why does it matter so much?

Magnesium is the fourth most abundant mineral in the human body and is involved in more than 600 biochemical reactions. From energy production to DNA synthesis, from muscle relaxation to hormone regulation — virtually every process in your body requires magnesium to function properly.

Yet a large proportion of the population is deficient. Modern diets contain progressively less magnesium due to depleted agricultural soil, food processing and a diet high in sugar and refined products — all of which inhibit magnesium absorption. Stress, alcohol and intensive exercise further increase the body's demand while accelerating excretion.

The result: millions of people live with symptoms like poor sleep, muscle cramps, fatigue, headaches and stress — without realising the cause may lie in a single mineral deficiency.

At OMg Magnesium, we believe that access to pure, scientifically supported magnesium can make a real difference to how you feel every day. Our products are sourced from the Zechstein Sea — the world's purest source of magnesium chloride, deep underground beneath Groningen in the Netherlands. In this complete guide, we tell you everything you need to know.

2. Do you have a magnesium deficiency? Recognise the signs

A magnesium deficiency is deceptive: the symptoms resemble many other conditions and are therefore frequently overlooked. The most common signs include:

Physical signs

• Muscle cramps, especially at night in the legs
• Fatigue that doesn't resolve after sleep
• Headaches or migraines
• Heart palpitations or irregular heartbeat
• Restless legs and tingling sensations
• Increased muscle tension and stiffness

Mental and emotional signs

• Sleep problems — difficulty falling or staying asleep
• Irritability and mood swings
• Difficulty concentrating and brain fog
• Anxiety and heightened stress sensitivity
• Low mood or depressive feelings

Who is most at risk?

Certain groups have a significantly higher chance of magnesium deficiency:

• Athletes and physically active people
• Pregnant and breastfeeding women
• People under chronic stress or experiencing burnout
• Older adults (intestinal absorption decreases with age)
• People with type 2 diabetes
• People who drink alcohol regularly
• People taking certain medications (diuretics, proton pump inhibitors, antibiotics)

If you recognise several of these signs, there is a good chance you would benefit from magnesium supplementation. When in doubt, always consult a doctor.

3. What does magnesium actually do in your body?

Magnesium is involved in more than 600 enzyme reactions. These are its most important functions:

Energy production Magnesium is essential for the production of ATP (adenosine triphosphate) — the primary energy source of every cell. Without sufficient magnesium, your body cannot produce energy efficiently, leading to fatigue and reduced performance.

Muscle and nerve function Magnesium regulates the balance between calcium (which contracts muscles) and magnesium (which relaxes muscles). A deficiency leads to excessive muscle tension, cramps and restlessness.

Bone formation Between 50 and 60% of the magnesium in your body is stored in your bones. Magnesium activates vitamin D, regulates calcium and supports the formation of bone tissue. Without sufficient magnesium, even calcium supplementation becomes less effective.

Hormone regulation Magnesium plays a role in the production and regulation of hormones including cortisol (stress hormone), melatonin (sleep hormone) and insulin (blood sugar regulation). It is therefore a key player in your stress response, sleep rhythm and metabolism.

Cardiovascular health Magnesium regulates heart rhythm, supports normal blood pressure and reduces inflammation that contributes to cardiovascular disease.

Immune system and anti-inflammation Low magnesium levels are associated with elevated inflammatory markers (such as CRP). Magnesium supports the immune system and has a mild anti-inflammatory effect.

4. Magnesium and your health — condition by condition

OMg has written a detailed, scientifically supported article for each of the health topics below. Click on the topic most relevant to you for the full information.

Medical care & chronic conditions

Living with Ankylosing Spondylitis: The role of magnesium in joint inflammation Magnesium has anti-inflammatory properties and supports muscle relaxation and joint mobility. Read how magnesium can contribute as a complementary approach to ankylosing spondylitis.

A strong heart: Why magnesium is essential for your cardiovascular system Magnesium regulates heart rhythm, supports normal blood pressure and reduces the risk of cardiovascular disease. Read the science behind magnesium and your heart.

Strong bones for life: Magnesium and the prevention of osteoporosis Without magnesium, calcium supplementation works less effectively. Read how magnesium is the key to healthy, strong bones at every age.

Ringing ears: Can magnesium help relieve tinnitus? Research shows a link between magnesium deficiency and tinnitus. Read what the science says about magnesium as a supportive approach to ear ringing.

Mental wellbeing

The stress solution: How magnesium calms your nervous system Stress depletes magnesium, and magnesium deficiency makes you more susceptible to stress. Break this vicious cycle. Read how magnesium supports your nervous system.

Deeper sleep: Natural support for a better night's rest Magnesium regulates GABA and melatonin — the key hormones for sleep. Read how magnesium helps you fall asleep faster and sleep more deeply.

Ageing well: Maintain your mental sharpness with magnesium Magnesium absorption decreases with age while the need increases. Read how magnesium supports vitality and mental clarity in later life.

Magnesium and migraine: a scientifically supported natural remedy The American Headache Society recognises magnesium as an option for migraine prophylaxis. Read how magnesium can reduce migraine frequency.

Hormones & vitality

Magnesium & pregnancy: Safety and benefits for mother and child Magnesium is essential during pregnancy for the development of the unborn child and the health of the mother. Read what is safe and what works.

Hormonal balance: Magnesium for menstruation and PMS symptoms Magnesium helps with cramps, water retention, irritability and fatigue around menstruation. Read how to use it effectively throughout your cycle.

Magnesium & movement

Optimal sports recovery: Back in action faster with magnesium Magnesium supports energy production, reduces muscle soreness and accelerates recovery. Read why magnesium is the most underrated supplement for athletes.

First aid for cramps: Why your muscles protest (and the solution) Muscle cramps are one of the clearest signals of magnesium deficiency. Read how magnesium relieves acute cramps and prevents recurrence.

Restless legs: Finally relief from restless legs syndrome Magnesium deficiency is directly linked to RLS. Read how oral and transdermal magnesium supplementation together give the best results.

Product science & safety

Is magnesium safe? Everything about side effects and contraindications Magnesium is safe for most people, but there are points to be aware of. Read everything about safe dosages, side effects and who should exercise caution.

Why magnesium bisglycinate? The science behind superior absorption Not all magnesium forms are equal. Read why bisglycinate is the most absorbable and gentlest form for daily use.

5. Which magnesium form is right for you?

There are dozens of magnesium forms. The most common ones and their properties:

OMg chooses magnesium bisglycinate for the oral capsules, and Zechstein magnesium chloride for the oil and flakes — both forms with the highest bioavailability and the least risk of side effects.

6. How to take magnesium — the complete usage guide

How you take magnesium is at least as important as which form you choose. Read our detailed Magnesium Usage Guide for full details. The key points:

Oral supplementation (capsules)

• Take 2 capsules daily, preferably in the evening before bed
• Always take with a glass of water, preferably after a light meal
• Consistency over several weeks matters more than perfect timing
• Effect on sleep: noticeable after 1–2 weeks. Full replenishment: 4–8 weeks

Transdermal application (oil spray)

• Apply to arms, legs or abdomen
• Leave on for at least 20–30 minutes before rinsing
• A mild tingling sensation is normal and fades within minutes
• Ideal in the morning as part of your morning routine or after exercise

Magnesium bath (bath flakes)

• Dissolve 2–3 cups in warm bath water
• Soak for 20 minutes
• Drink extra water afterwards
• Ideal for relaxation, recovery and a good night's sleep

Combine for best results Oral supplementation and transdermal application complement each other. Capsules provide systemic replenishment of magnesium levels; oil and flakes provide additional local and rapid absorption.

7. How much magnesium do you actually need?

Read our detailed Dosage Guide for a complete overview. The basic guidelines:

Official recommended daily intake

• Men: 350 mg elemental magnesium per day
• Women: 300 mg elemental magnesium per day
• Pregnant women: 350–400 mg per day

Increased need with:

• Intensive exercise: +10–20% above the recommended daily intake
• Chronic stress or burnout: increased urinary excretion
• Pregnancy and breastfeeding: higher requirements for mother and child
• Older adults: reduced intestinal absorption requires higher intake
• Type 2 diabetes: higher renal excretion

Safe upper limit via supplements: 350 mg elemental magnesium per day for adults (European Food Safety Authority). Higher doses are possible under medical supervision.

8. Magnesium through the skin — how does it work?

Transdermal magnesium absorption — through the skin — is scientifically demonstrated and offers unique advantages for people sensitive to oral supplements or who want fast local results. Read the full article: The Science Behind Skin Absorption of Magnesium.

The skin acts as a semi-permeable membrane that allows magnesium ions to pass through. Magnesium oil (a solution of magnesium chloride in water) is rapidly absorbed and works locally on the affected muscles and tissues. Bath flakes provide systemic absorption through a large skin surface area during a prolonged bath.

Benefits of transdermal application:

• Bypasses the digestive system — no gastrointestinal side effects possible
• Fast local action for muscle pain and cramps
• Complementary to oral supplementation for optimal effect
• Ideal for pregnant women who are cautious about supplements

9. Pure magnesium from the Zechstein Sea — why the source matters

Not all magnesium is equal. The quality, purity and origin of the raw material determine the effectiveness of the final product.

OMg Magnesium exclusively uses Zechstein magnesium chloride — sourced from the Zechstein Sea, an ancient underground sea 1,600 metres deep beneath Groningen in the Netherlands. This source is 250 million years old and completely shielded from modern pollution, heavy metals and microcontaminants.

Read more about our source: The Source — The World's Purest Magnesium

Why Zechstein:

• Recognised as the world's purest magnesium chloride source
• No chemical cleaning required — pure by nature
• Sourced in the Netherlands — short, transparent supply chain
• Free from heavy metals, microplastics and modern pollutants
• Zechstein Original Inside® quality mark as guarantee of origin and purity

Our founders Roelof, Renske, Chris and Nina live directly above the Zechstein Sea in Groningen. That is not just a nice story — it means direct involvement in the origin of every drop of magnesium that OMg produces.

10. Frequently asked questions about magnesium

What is the difference between magnesium oil, capsules and bath flakes? All three contain magnesium chloride or magnesium bisglycinate, but work differently. Capsules are taken orally for systemic replenishment. Oil is absorbed transdermally for local and rapid action. Bath flakes provide a relaxing bath in which the whole body absorbs magnesium. The combination of capsules and oil or flakes gives the best results.

How quickly does magnesium work? The first effects — better sleep, reduced muscle tension — are often noticeable within 1 to 2 weeks. Full replenishment of magnesium levels takes 4 to 8 weeks with consistent use. For chronic conditions such as migraine or restless legs, 3 months is the recommended minimum period.

Can I take too much magnesium? Through food, an overdose is virtually impossible. Through supplements, high doses (above 350 mg elemental magnesium per day) can cause diarrhoea or stomach complaints. Serious toxicity is rare and occurs almost exclusively with kidney problems. When in doubt, consult a doctor.

Is magnesium bisglycinate better than other forms? For daily use and sleep support, magnesium bisglycinate is the most recommended form due to its superior bioavailability, minimal gastrointestinal effects and the additional calming effect of the glycine bond. Read more in our article Why magnesium bisglycinate?

Is magnesium safe during pregnancy? Yes, magnesium is an essential mineral that is particularly important during pregnancy. Always consult your midwife or doctor for personal advice. Read more in our article Magnesium & Pregnancy.

How do I know if I have a magnesium deficiency? A blood test measures magnesium levels in the blood, but this is not a reliable measure since only 1% of magnesium is in the blood — the rest is in cells and bones. The best indicator is your symptoms. Use our OMgenie chatbot for personalised magnesium advice based on your specific complaints.