It is an essential mineral for our bodies. It plays a fundamental role in more than 300 biochemical reactions.
Magnesium notably contributes to the proper functioning of various physiological systems, such as nerve transmission, muscle contraction, and blood pressure.
However, the daily requirements recommended by ANSES – 300 mg/day for women and 380 mg/day for men – are rarely met. This study even shows that nearly 70% of the French population does not reach this daily quota.
To prevent this deficiency, supplement regimens are sometimes recommended. But how long do they take to work?
Also read | A pharmacist gives her tips for buying the best magnesium
There is no set time frame for feeling the effects of magnesium.
From a few days to several months
Whether magnesium is taken to address insomnia, muscle cramps, stress, or anxiety, there is no single set duration after which this mineral will take effect.
The various factors I discuss below, as well as overall lifestyle, can affect the benefits felt during a supplement regimen.
Thus, one person may notice the benefits of magnesium a few days after taking it, while a 2-month regimen may be necessary for their neighbor.
In any case, it is recommended to continue taking magnesium for several weeks to achieve medium-term effects.
What studies say
Some studies on the effects of magnesium on anxiety show results after 8 weeks of use, while other research report initial benefits for insomnia after 20 days of consumption.
However, the scientific evidence in the reviews I share here is far too limited to make definitive claims about the onset and effectiveness of the mineral.

Factors that influence its absorption
The time it takes for magnesium to begin working depends in part on the absorption of the dietary supplement. This is influenced by various factors such as:
- the type of magnesium consumed: some forms of magnesium may potentially have lower bioavailability than others, as shown by this study.
- interactions with other minerals or vitamins: calcium, for example, can limit the absorption of magnesium, whereas vitamin D promotes its assimilation, as shown by this scientific research
- digestive health: gastrointestinal problems (Crohn’s disease, functional bowel disorder, etc.) or taking certain medications such as antacids can hinder the proper absorption of magnesium
- age, sex and general health status: depending on these factors, magnesium needs vary
My tips to optimize the effects of magnesium
To maximize the benefits of magnesium, there is no miracle cure. However, you can ensure the following:
- Choose a highly bioavailable form of magnesium: a supplement based on malate, bisglycinate, or a liposomal form
- Take the right dose: avoid taking too much
- Pay attention to consistency and take your supplement every day
- Favor a varied and balanced diet to provide all the other nutrients the body needs

