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A study testing magnesium aspartate to prevent long-term low parathyroid hormone levels in patients after thyroid surgery

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What is this trial about?

A plain-language summary of the goals, design and what participants do

This study involves patients who are scheduled to undergo thyroid surgery, specifically a procedure where the entire thyroid gland is removed. After this type of surgery, some patients may develop a condition called postoperative hypoparathyroidism, which occurs when the parathyroid glands, small glands located near the thyroid, do not function properly. These glands help control calcium levels in the body, and when they are affected during surgery, calcium levels can drop too low. This condition can be temporary or long-lasting. The study will use magnesium aspartate, a form of magnesium given as an oral solution called TROFOCARD max, or a placebo to see if magnesium can help prevent this problem.

The purpose of the study is to find out whether taking magnesium aspartate by mouth for eight days can reduce the occurrence of long-term hypoparathyroidism six months after surgery. Participants will be randomly assigned to receive either the magnesium supplement or placebo, and neither the participants nor the doctors will know which treatment is being given. The magnesium or placebo will be taken starting before the surgery and continuing for several days afterward. During the study, doctors will monitor calcium levels and parathyroid hormone levels in the blood to check how well the parathyroid glands are working.

Throughout the study period, which lasts up to six months after surgery, participants will be checked at different time points to see if they develop hypoparathyroidism and whether they need additional treatments such as calcium or vitamin D supplements. The study will also track any side effects or unwanted reactions to the treatment and ask participants about symptoms they may experience related to low calcium levels. This information will help researchers understand if giving magnesium before and after thyroid surgery can protect the parathyroid glands and prevent complications.

The research process

The trial runs in 8 steps – from screening to follow-up. Each step says what happens and what the team monitors.

  1. Step 1

    Starting the treatment

    Your thyroid surgery has been scheduled. Before the operation, you will begin taking the study medication or placebo.

    The study medication contains magnesium aspartate, a form of magnesium that may help protect the parathyroid glands during surgery. The parathyroid glands are small glands near the thyroid that help control calcium levels in your body.

    You will receive either the active medication (TROFOCARD max) or a placebo. The placebo looks identical but does not contain the active ingredient. Neither you nor your doctor will know which one you are receiving during the study.

  2. Step 2

    Taking the medication before surgery

    You will take the study medication in the form of granules for oral solution. This means you will dissolve the contents of a sachet in water and drink it.

    The dose is 243 mg of magnesium per day, which comes in one sachet.

    You will take this medication daily for 8 days, starting before your surgery and continuing after the operation.

    The medication should be taken by mouth as directed.

  3. Step 3

    Undergoing thyroid surgery

    You will have your total thyroidectomy, which is the complete removal of your thyroid gland.

    The surgery may also include removal of nearby lymph nodes if needed.

    During this procedure, the parathyroid glands near your thyroid may be affected, which can sometimes lead to low calcium levels afterward.

  4. Step 4

    Continuing medication after surgery

    After your surgery, you will continue taking the study medication for the remainder of the 8-day treatment period.

    You will continue taking one sachet daily containing 243 mg of magnesium or placebo.

    Complete the full 8 days of treatment as instructed.

  5. Step 5

    First week follow-up

    Around Day 7 after your surgery, you will have a follow-up assessment.

    Your calcium and parathyroid hormone (PTH) levels will be checked. PTH is a hormone that helps regulate calcium in your blood.

    Your doctor will evaluate whether you need any replacement medications such as alfacalcidol (active vitamin D), calcium carbonate (calcium supplement), or cholecalciferol (vitamin D).

    Any side effects or symptoms you experience will be recorded.

  6. Step 6

    One month follow-up

    At 30 days (1 month) after surgery, you will return for another evaluation.

    Your calcium and PTH levels will be measured again.

    Your doctor will check whether you have developed temporary hypoparathyroidism, which means your parathyroid glands are producing less hormone than normal, leading to low calcium levels.

    Your need for calcium or vitamin D supplements will be assessed.

    You will be asked about any symptoms of low calcium, such as tingling around your mouth or in your fingers, muscle cramps, or unusual sensations.

  7. Step 7

    Three month follow-up

    At 3 months after your surgery, you will have another follow-up visit.

    Blood tests will be performed to check your calcium and PTH levels.

    Your doctor will review your need for any replacement therapy medications.

    Any ongoing symptoms or side effects will be documented.

  8. Step 8

    Six month final evaluation

    At 6 months after surgery, you will have your final study evaluation.

    Blood tests will measure your corrected calcium and PTH levels to determine if you have developed chronic hypoparathyroidism. This is defined as persistently low calcium and PTH levels that have not recovered after 6 months.

    Your doctor will assess whether you still need calcium or vitamin D replacement therapy, or if you have been able to stop these medications.

    This visit marks the completion of your participation in the study.

    All symptoms and any adverse events throughout the study period will be reviewed.

Who can join the trial?

8 criteria

  • You must be an adult between 18 and 90 years old
  • You are scheduled to have total thyroidectomy, which means complete removal of your thyroid gland through surgery
  • Your thyroid surgery may or may not include removal of nearby lymph nodes, which are small glands that are part of your immune system
  • Your thyroid surgery can be for any reason, whether the condition is not cancerous or cancerous
  • You must be able to understand the study and sign a written informed consent form, which is a document showing you agree to participate after learning about the study
  • You must not have had any problems with your parathyroid glands in the past, which are small glands near the thyroid that help control calcium levels in your body
  • You must not have had any problems with how your body processes calcium, which is a mineral important for bones and nerves
  • You must not have had any problems with how your body processes magnesium, which is a mineral important for muscles and nerves

Who cannot join the trial?

8 criteria

  • Pregnancy or breastfeeding: Women who are pregnant or nursing a baby cannot participate in this study.
  • Known allergy to magnesium: If you have had an allergic reaction to magnesium or magnesium aspartate in the past, you cannot join this study.
  • Severe kidney disease: If you have serious problems with your kidneys that make it hard for your body to remove magnesium, you cannot participate. The kidneys are organs that filter waste from your blood.
  • Chronic diarrhea: If you have long-lasting diarrhea, which means loose or watery bowel movements that continue over time, you cannot join this study.
  • Pre-existing hypoparathyroidism: If you already had hypoparathyroidism before your thyroid surgery, you cannot participate. Hypoparathyroidism is a condition where your body does not make enough parathyroid hormone, which helps control calcium levels in your blood.
  • Permanent hypoparathyroidism from previous surgery: If you had thyroid surgery before and developed permanent hypoparathyroidism that has lasted more than 6 months, you cannot join this study.
  • Unable to take oral medication: If you cannot swallow pills or take medicine by mouth, you cannot participate in this study.
  • Participation in another clinical trial: If you are currently taking part in another research study that involves taking medication, you cannot join this study at the same time.
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Investigated drugs

Magnesium aspartate is a supplement that contains magnesium, which is an important mineral that helps your body work properly. In this trial, it is being tested to see if taking it before surgery can help protect the parathyroid glands, which are small glands in your neck that control calcium levels in your body. The goal is to find out if this supplement can prevent problems with low parathyroid function after thyroid surgery.

What is already known about the treatment

Magnesium Aspartate – Magnesium aspartate is a mineral supplement that combines magnesium with aspartic acid, typically taken orally in tablet or capsule form. This medication is being studied in clinical trials to determine if taking it before thyroid surgery can help prevent a condition called hypoparathyroidism, which occurs when the parathyroid glands don't produce enough hormone after surgery, leading to low calcium levels in the blood. Magnesium works at the cellular level by supporting the parathyroid glands' ability to function properly and helping regulate calcium balance in the body. It belongs to the pharmacological class of mineral supplements and electrolyte replacements, commonly used to treat or prevent magnesium deficiency and support various bodily functions including nerve and muscle activity.

Investigated diseases

Postoperative Hypoparathyroidism – Postoperative hypoparathyroidism is a condition that occurs after thyroid surgery when the parathyroid glands are damaged or accidentally removed during the procedure. The parathyroid glands are small glands located near the thyroid that control calcium levels in the blood. When these glands stop working properly, the body cannot maintain normal calcium levels. This leads to low calcium in the blood, which can cause various symptoms. The condition may be temporary, lasting a few weeks, or it can become chronic and persist for six months or longer. Symptoms typically include tingling sensations, muscle cramps, and other signs related to low calcium levels in the body.
Trial detailsLast updated 7 Oct 2026
Age18+ yearsPhasePhase IIITrial ID2025-522839-33-00Protocol codeMAGNEFFICIENTEstimated enrolment500 patientsSponsorHenry Dunant Hospital Center

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