Protein Supplement Brands

Detailed guides to the most popular protein supplement brands — what they make, how their products compare, and who each brand suits best.

Brand Guides

Optimum Nutrition

The world’s best-selling protein brand. Home of Gold Standard 100% Whey — the benchmark product that competitors have spent decades trying to match. Also makes casein, pre-workout, creatine, and weight gainers.

Key products: Gold Standard Whey, Gold Standard Isolate, Gold Standard Casein, Serious Mass, Micronised Creatine

Premier Protein

One of the most recognisable RTD (ready-to-drink) protein brands in the US. Widely available in grocery stores and warehouse clubs. Known for 30g protein shakes at mainstream retail pricing.

Key products: Ready-to-drink shakes, protein powder, protein bars

Isopure

Specialist in whey protein isolate — high protein, zero carb, very low lactose. Popular with those managing lactose intolerance or following low-carb diets.

Key products: Zero Carb Whey Isolate, Infusions, low-carb protein range

Muscle Milk

Performance nutrition brand with a focus on protein blends. Uses a milk protein blend (casein + whey) for sustained amino acid release. Available RTD and in powder form.

Key products: Muscle Milk Pro Series, Genuine Muscle Milk, RTD shakes

Quest Nutrition

Best known for protein bars with macros that stand out from the category. Also produces protein powder and chips.

Key products: Quest Bars, Quest Protein Powder, Quest Chips

GNC

Long-established US supplement retailer that manufactures several own-brand protein lines. AMP Wheybolic carries NSF Certified for Sport status.

Key products: GNC AMP Wheybolic, GNC AMP Pure Isolate, GNC Pro Performance Whey

Compare by Goal

Post-workout whey: Optimum Nutrition Gold Standard | Isopure Zero Carb

Convenient RTD shakes: Premier Protein | Muscle Milk

On-the-go bars: Quest Nutrition

Drug-tested athletes: Optimum Nutrition (Informed Choice) | GNC AMP (NSF Certified)