What's the best protein powder for men over 40?

Whey protein concentrate or isolate remains the most evidence-supported protein supplement for muscle protein synthesis in men over 40, it has the highest leucine content per gram (approximately 10–11% leucine), is rapidly absorbed, and has more direct human trial evidence than any other protein source, but for men with lactose intolerance or dairy avoidance, whey isolate (lactose-removed) or a combination of pea + rice protein (matching whey's amino acid profile) are clinically reasonable alternatives (Tang et al., Am J Clin Nutr, 2009).

The protein powder market is enormous and overwhelmingly oriented toward marketing over evidence. The relevant checklist for a protein supplement: (1) third-party tested (NSF Certified for Sport, Informed Sport) to verify contents match label; (2) whey (concentrate, isolate) or a pea+rice blend for plant-based; (3) minimal added ingredients (sugars, artificial flavors are preference-based, not harmful); (4) 25–30 g protein per serving. The "proprietary blend," "hydrolyzed," "mass gainer," and "anabolic matrix" categories add cost without adding muscle.

Honesty Scale: Solid (1) for whey protein as the evidence-leading protein supplement for muscle protein synthesis.

What to do: Buy an NSF Certified for Sport or Informed Sport certified whey protein powder. Costco's Kirkland Signature Whey protein and Thorne's Whey Protein are examples of high-quality, independently tested products. Do not pay premium prices for proprietary protein blends.

For the full picture, read The Supplementation Deep Dive