Along with their convenience, whey protein supplements do offer a number of benefits. They contain high levels of essential amino acids, which play an important role in stimulating muscle growth. What's more, the various protein fractions in whey (such as alpha-lactalbumin and glycomacropeptide) would be difficult to get from food alone.
However, there's no evidence to show that a whey protein isolate is any better than a whey protein concentrate.
Because it contains less lactose, a whey protein isolate may be more suitable for people who have difficulty digesting lactose. When choosing a whey protein supplement, make sure you use one processed using cross-flow microfiltration rather than ion exchange, as the microfiltration process preserves several important protein fractions. Suitable products include Precision Protein™ (EAS) and Micro Whey (Reflex Nutrition).
Protein supplements that contain a blend of both whey protein concentrate and whey protein isolate are better value for money. Suitable products include MyoPro® Whey (EAS) and Instant Whey (Reflex Nutrition).
While the extra ingredients included in many whey protein supplements sets them apart from the competition in the mind of the consumer, there is little or no evidence to show they have any real effect on muscle growth or fat loss.