How do you feel when you start taking magnesium? A look at benefits and side effects

October 25, 2025 •

4 min read

A significant portion of the adult population, potentially as high as 50%, does not meet the recommended daily intake of magnesium. This vital mineral plays a crucial role in over 300 biochemical reactions in the body, including nerve and muscle function, energy production, and bone development. So, how do you feel when you start taking magnesium, and what can you realistically expect from this popular supplement?

Quick Summary

Starting magnesium supplements can lead to a variety of feelings, from quicker relief of muscle cramps and improved sleep within a few weeks to mild digestive upset initially. Full benefits like reduced anxiety and balanced blood pressure are more evident with consistent, long-term use and depend heavily on the supplement form and individual health status.

Key Points

Initial vs. Long-Term Effects: Some benefits like relaxation and relief from muscle cramps may appear within days or weeks, while others like mood improvements and better blood pressure take months.
Supplement Form Matters: The type of magnesium you take, such as glycinate for sleep or citrate for constipation, dictates the primary effects and potential side effects.
Digestive Side Effects Are Common: Mild gastrointestinal issues, including diarrhea and nausea, are the most frequent side effects, particularly with high doses or poorly absorbed forms.
Consistency is Key: Taking magnesium consistently, rather than focusing on a specific time, is the most important factor for achieving and maintaining optimal levels and benefits.
Consider Your Diet First: A balanced diet rich in magnesium-containing foods like leafy greens, nuts, and seeds is the foundation for healthy levels.
Consult a Professional: Always speak with a healthcare provider before starting supplementation, especially if you have existing health conditions or take other medications.

Your Initial Experience with Magnesium

For many people, the effects of magnesium supplementation are not immediate, especially for issues that have developed over time due to a long-term deficiency. However, depending on the form of magnesium, some initial effects can be felt relatively quickly. Highly bioavailable forms, such as magnesium citrate, are often used as a laxative and can produce a noticeable effect on bowel movements within hours. Other users may notice a calming sensation or a relaxation of tense muscles within the first few days to a couple of weeks.

Potential Early Effects

Digestive changes: Certain forms, like magnesium citrate or oxide, are known for their laxative properties and can cause softened or more frequent stools, especially at higher doses. Starting with a smaller dose or taking it with food can help mitigate this.
Relaxation and calmness: Magnesium plays a role in regulating neurotransmitters that calm the nervous system. For those with anxiety or muscle tension, initial doses may provide a subtle, calming effect.
Improved sleep: By regulating brain chemicals like GABA, magnesium can help relax both muscles and the nervous system. Some individuals report improved sleep quality and reduced restlessness within a couple of weeks of consistent evening supplementation.

The Longer-Term Benefits of Consistent Magnesium Use

While initial effects may be noticeable, the more profound benefits of magnesium often take several weeks or even months to appear consistently, particularly for chronic conditions. This is because it takes time to replenish depleted magnesium stores in the body's tissues.

Comprehensive Health Improvements

Reduced anxiety and stress: Research shows that magnesium helps regulate cortisol, the stress hormone, and neurotransmitters that affect mood. With consistent intake, you may feel better equipped to handle stress and experience a more balanced mood.
Better blood pressure control: For those with high blood pressure, magnesium supplementation has been associated with small but significant decreases in blood pressure over time.
Improved bone health: As a mineral crucial for bone formation and density, long-term magnesium intake supports overall skeletal strength.
Migraine prevention: People who experience migraines may have lower magnesium levels. Consistent supplementation has shown promise in reducing the frequency and severity of migraine attacks.
Enhanced energy levels: Magnesium is vital for the production of adenosine triphosphate (ATP), the body's primary energy source. Long-term supplementation can combat fatigue and increase overall energy.

Choosing the Right Magnesium for You

Not all magnesium supplements are created equal. The type you choose will significantly influence the effects you feel, especially initially, due to varying absorption rates and purposes. Consulting a healthcare professional is crucial to determine the best form and dosage for your specific needs.

Magnesium Supplement Comparison


Type of Magnesium	Primary Benefit	Absorption Rate	Potential Side Effect	Best For
Glycinate	Relaxation, better sleep, anxiety reduction	High	Minimal digestive issues	Those seeking calmness and improved sleep without laxative effects
Citrate	Constipation relief, muscle cramps	High	Laxative effect	Occasional constipation or muscle tension relief
Malate	Energy production, muscle recovery, fatigue	High	Energizing effect (avoid before bed)	People with fatigue or post-workout soreness
Oxide	Constipation relief	Low	Strong laxative effect	Severe, short-term constipation, not ideal for addressing a deficiency
L-Threonate	Brain health, memory enhancement, focus	High (crosses blood-brain barrier)	None noted in searches	Improving cognitive function and managing mental stress

Potential Side Effects and When to Be Cautious

While generally safe for most people, especially from dietary sources, high doses of magnesium from supplements can lead to side effects. Common side effects often involve the digestive system and include diarrhea, nausea, and abdominal cramps. These issues are more likely with less-absorbed forms like magnesium oxide and can often be minimized by adjusting the dose or taking the supplement with food.

In rare cases, very high doses can lead to magnesium toxicity, also known as hypermagnesemia, which can cause serious symptoms such as low blood pressure, muscle weakness, confusion, and irregular heartbeat. This is more of a concern for individuals with impaired kidney function. It is crucial to follow dosage recommendations and consult a doctor before starting supplementation, especially if you have kidney disease or are taking other medications.

Maximizing Your Magnesium Intake

Beyond supplements, incorporating magnesium-rich foods into your diet is a sustainable way to increase your intake. Excellent dietary sources include:

Leafy greens: Spinach, kale, and collard greens.
Nuts and seeds: Almonds, pumpkin seeds, and cashews.
Legumes: Black beans, lentils, and chickpeas.
Whole grains: Oats, quinoa, and brown rice.
Other foods: Avocados, bananas, and dark chocolate.

Taking your supplement consistently is more important than the exact timing. Many people take magnesium in the evening due to its relaxing effects, especially if using a form like magnesium glycinate for sleep. Others may prefer a morning dose for overall energy support, especially with forms like magnesium malate. For best absorption and to reduce digestive upset, taking it with a meal is often recommended.

Conclusion

When you begin taking magnesium, the effects can range from mild initial changes, like improved sleep and muscle relaxation, to more significant, long-term benefits for mood, blood pressure, and bone health. What you feel and how quickly you feel it depends heavily on the type of magnesium, your starting health status, and consistent usage. While side effects are generally manageable and related to digestive upset, it is always wise to consult a healthcare provider before starting any new supplement regimen to ensure it is the right choice for you.

Frequently Asked Questions

When you first start taking magnesium, you might notice initial effects like a calming sensation or relief from muscle cramps within days to weeks. Some individuals may also experience digestive changes, such as softened stools, especially if taking forms like magnesium citrate or oxide.

The time it takes to feel the effects of magnesium varies. While initial benefits like muscle relaxation may be felt quickly, more profound changes related to mood or blood pressure can take weeks or even months of consistent supplementation to become noticeable.

Key benefits include improved sleep quality, reduced anxiety and stress, better blood pressure regulation, enhanced muscle function and recovery, and improved bone health.

Yes, common side effects of magnesium supplements include digestive issues like diarrhea, nausea, and stomach cramps, particularly at high doses. Taking smaller doses or opting for more bioavailable forms like magnesium glycinate can minimize these effects.

Magnesium glycinate, citrate, malate, and L-threonate are generally considered to be highly bioavailable, meaning they are absorbed well by the body. Each form offers specific benefits, so the 'best' type depends on your individual health goals.

There is no single best time, as consistency is key. Some people take it in the evening for better sleep, while others take it in the morning for energy or to help manage stress throughout the day. Taking it with food can also help prevent digestive upset.

For most healthy individuals, taking magnesium daily within the recommended dosage is safe. However, those with kidney problems or taking certain medications should consult a doctor, as excessive accumulation can be dangerous.

Yes, magnesium is known to help with anxiety by regulating neurotransmitters that calm the nervous system and helping to lower the stress hormone cortisol. The form magnesium glycinate is often recommended for its calming properties.