GNC Pro Performance Essential Amino Acids

Our assessment

The evidence shows that GNC Pro Performance Essential Amino Acids is a supplement designed to provide amino acids, but the data provided does not include specific clinical studies on this product. Our assessment is based on the ingredients listed on the label, and we must note that no ingredient data beyond the label was supplied. For general context, calcium is a common mineral in many supplements, but its role in amino acid products is not defined here. Data not available for specific product efficacy or ingredient breakdown beyond the label.

How it works

Amino acids are the building blocks of protein, and they support muscle repair and recovery after exercise. For calcium, which may be present in some formulations, the mechanism involves bone mineralization — supporting bone density and mineral deposition — as well as neuromuscular relaxation for muscle and nerve signaling [NIH ODS]. However, without specific ingredient data for this product, we cannot confirm its exact mechanism of action.

Safety profile

The FDA has received 592,059 total adverse event reports across all dietary supplements, but specific reports for this product are not available [FDA data]. For calcium, high intakes might increase the risk of heart disease and prostate cancer, and high levels in 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]. Data not available for side effects specific to this amino acid product.

Our recommendation

We recommend consulting your healthcare provider before starting any new supplement, especially given the lack of specific safety data for this product. If you are taking medications, note that calcium can reduce the absorption of bisphosphonates, tetracycline antibiotics, fluoroquinolone antibiotics, levothyroxine, and phenytoin [NIH ODS]. For a general audience, focus on whole food sources of protein and amino acids unless a deficiency is confirmed. Data not available for a confident dosage or benefit recommendation for this specific brand.

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