Dr. Mercola Melatonin Spearmint Flavor

Our assessment

The evidence shows that the Dr. Mercola Melatonin Spearmint Flavor product is a dietary supplement, but data for this specific product is limited. Our assessment of the primary ingredient, melatonin, finds it is commonly used to support sleep. However, we must rely on general data for the key mineral calcium, which is not typically a primary ingredient in a melatonin product. The FDA has received 592059 total adverse event reports across all supplements [FDA data]. For calcium specifically, high intakes might increase the risk of heart disease and prostate cancer [NIH ODS].

How it works

Think of calcium as a structural builder — it supports bone mineralization and density, and also helps with neuromuscular relaxation and nerve signaling [NIH ODS]. For a melatonin product, the intended effect is to help regulate your sleep-wake cycle, but specific mechanism data for this product's blend is not available.

Safety profile

Data not available for this specific product's side effects. However, for calcium, high levels in the blood and urine can cause poor muscle tone, poor kidney function, low phosphate levels, constipation, nausea, weight loss, extreme tiredness, frequent need to urinate, abnormal heart rhythms, and a high risk of death from heart disease [NIH ODS]. Calcium can also reduce the absorption of several medications, including bisphosphonates, tetracycline antibiotics, fluoroquinolone antibiotics, levothyroxine, and phenytoin [NIH ODS]. Total FDA adverse event reports for all supplements is 592059 [FDA data].

Our recommendation

We recommend you consult your healthcare provider before starting any new supplement, especially if you take medications for thyroid conditions, osteoporosis, or infections. Without specific data on the melatonin content or additional ingredients in this Dr. Mercola product, it is safest to choose a supplement with transparent labeling and third-party testing. For sleep support, start with a low dose and monitor your response.

Supplement labels contain several key sections regulated by the FDA:

• Serving Size — The recommended amount per dose. Always check this — some products require multiple capsules per serving.
• Amount Per Serving — Shows the quantity of each nutrient in the product, typically in IU (International Units), mg (milligrams), or mcg (micrograms).
• % Daily Value (%DV) — Indicates how much a nutrient in a serving contributes to a daily diet. 5% DV or less is low; 20% DV or more is high.
• Other Ingredients — Lists inactive ingredients like fillers, binders, and capsule materials (e.g., gelatin, cellulose, magnesium stearate).
• Suggested Use — The manufacturer's recommended directions for taking the supplement, including timing and dosage.

Source: FDA Dietary Supplement Labeling Guide