Purveyor of barely legal dietary supplements, often

• Health supplement retailer, familiarly
• Pill peddlers
• Bodybuilder's chain
• Muscle-building chain
• Health supplement co.
• Big health supplement chain, familiarly
• Protein powder purveyor
• Health food chain
• Big purveyor of vitamin supplements

Wikipedia Word definitions in Wikipedia
GNC Holdings Inc. is a Pittsburgh, Pennsylvania -based American commercial enterprise focused on the retail sale of health and nutrition related products, including vitamins , supplements , minerals, herbs, sports nutrition , diet, and energy products.