Relaxium Sleep is a dietary supplement that combines melatonin, magnesium, ashwagandha, valerian root, L-tryptophan, chamomile, passionflower, and GABA. Most people tolerate it without serious problems, but each of these ingredients carries its own set of potential side effects, and together they can cause digestive issues, next-day drowsiness, headaches, and interactions with common medications.
The Most Common Side Effects
The side effects people report most often with Relaxium overlap with those seen across sleep supplements generally. Daytime drowsiness is the big one. Melatonin, valerian, and GABA all promote relaxation, and their combined effect can linger into the morning, leaving you groggy, unfocused, or slow to react. This “hangover” feeling can impair balance, motor coordination, and memory, especially if you didn’t get a full night’s sleep after taking the supplement.
Headaches are another frequent complaint. Melatonin alone commonly causes them, and the combination of multiple sedating ingredients can amplify this effect. Some users also report vivid or strange dreams, night sweats, dry mouth, and general irritability or restlessness, all of which are recognized melatonin side effects.
Digestive Problems
Relaxium contains magnesium citrate, a form of magnesium that draws water into the intestines. This is the same compound used in over-the-counter laxatives. At the dose in a sleep supplement it’s unlikely to cause dramatic effects, but loose stools, more frequent bowel movements, and stomach cramps are common. Some people are more sensitive than others, and taking it on an empty stomach tends to make things worse.
Beyond the magnesium, melatonin itself can cause stomach aches and nausea. Valerian root is also known for occasional digestive discomfort. If you notice gas, heartburn, or changes in appetite after starting Relaxium, one or more of these ingredients is the likely cause.
Ashwagandha and Thyroid Concerns
Ashwagandha is one of the more biologically active ingredients in Relaxium, and it comes with specific cautions. The National Institutes of Health recommends that people with thyroid disorders avoid ashwagandha because it can alter thyroid hormone levels. If you take thyroid medication, ashwagandha may interfere with how that medication works. It’s also not recommended for people with autoimmune conditions or those about to have surgery.
For people without these conditions, ashwagandha is generally well tolerated at typical supplement doses. But because Relaxium is marketed broadly as a sleep aid, many users may not realize it contains an ingredient with these specific restrictions.
Interactions With Medications
The ingredient that poses the most interaction risk is L-tryptophan, an amino acid the body converts into serotonin. If you take any medication that also raises serotonin levels, combining it with L-tryptophan can push serotonin dangerously high, a condition called serotonin syndrome that causes agitation, rapid heart rate, high blood pressure, and in severe cases, seizures.
The medications most affected include:
- SSRIs and SNRIs (commonly prescribed for depression and anxiety), including fluoxetine, citalopram, escitalopram, duloxetine, and venlafaxine
- Tricyclic antidepressants like amitriptyline and doxepin
- MAO inhibitors like phenelzine and selegiline, which are considered especially dangerous to combine with tryptophan
- Opioid pain medications including codeine, hydrocodone, and fentanyl
- Triptan migraine medications like almotriptan and frovatriptan
Melatonin adds another layer. It can stimulate immune function, which means it may interfere with immunosuppressant drugs. The Mayo Clinic also advises against melatonin use if you have an autoimmune disease, since boosting immune activity is the opposite of what your treatment is trying to do.
Less Common but Serious Effects
Serious side effects from the individual ingredients in Relaxium are rare but documented. Melatonin can occasionally cause short-lasting feelings of depression, mild tremor, anxiety, confusion, or disorientation. Blurred vision, fainting, and dizziness that feels like the room is spinning have also been reported, though in fewer than 1 in 1,000 people.
Concerns about liver damage sometimes come up with valerian root, but the evidence doesn’t support this at normal doses. Animal studies using doses far higher than what’s in a supplement (adjusted for body weight) showed no signs of liver or kidney stress. The risk changes, however, if you combine valerian with other substances that affect the liver, including alcohol.
An FDA Warning Worth Knowing About
In April 2025, the FDA issued a warning letter to American Behavioral Research Institute, the company behind Relaxium. The letter stated that the company conducted a clinical trial on 40 human subjects using Relaxium as a treatment for insomnia without submitting the required Investigational New Drug application. The FDA noted that this failure “raises significant concerns about the safety and welfare of enrolled subjects” and questioned the validity of the data collected during the study.
This doesn’t mean Relaxium was found to be unsafe, but it does mean the clinical evidence the company uses to market the product was gathered outside the standard regulatory framework designed to protect participants and ensure data integrity. As a dietary supplement, Relaxium is not required to go through FDA approval before being sold, and its ingredients are not evaluated for safety or effectiveness the way prescription drugs are.
Who Should Be Cautious
Certain groups face higher risk from Relaxium’s ingredient combination. People taking antidepressants, pain medications, or migraine drugs should be particularly careful because of the serotonin interaction risk from L-tryptophan. Those with thyroid conditions or autoimmune diseases should avoid Relaxium due to the ashwagandha and melatonin it contains. Anyone scheduled for surgery should stop taking it beforehand, as both ashwagandha and melatonin can affect immune function and blood clotting.
Because melatonin causes daytime drowsiness, you should avoid driving or operating heavy machinery within five hours of taking the supplement. This window matters: taking Relaxium too late at night, or on a night when you can only sleep a few hours, increases the chance you’ll still feel its effects in the morning.