Is your protein shake helping or harming you? Dietitians reveal the hidden ingredients that could make or break your health

Supermarket shelves are packed with glossy bottles and tubs promising muscle, energy, and recovery in the form of protein shakes. But with so many options, how do you know if what you’re sipping is actually helping you — or quietly working against your health? A recent EatingWell report, supported by insights from Mayo Clinic experts, breaks down the key ingredients to seek out and the red flags to avoid.

What Makes a Good Protein Shake?
Dietitians agree that quality protein is the foundation of any effective shake. For light snacks, around 10 grams is enough to curb hunger and balance blood sugar. Post-workout recovery, however, calls for 20 to 30 grams of high-quality protein, explains sports dietitian Amy Goodson. Whey and casein, both derived from dairy, remain top picks for their muscle repair and recovery benefits. Plant-based proteins — soy, pea, and rice among them — are excellent alternatives, provided you vary sources to cover all essential amino acids.

Watch Out for the Sweet Trap
One of the biggest pitfalls in protein shakes is added sugar. While natural sugars from fruit or milk can aid recovery, excess added sugar undermines the health benefits. The 2020–2025 Dietary Guidelines advise limiting added sugar to under 10% of daily calories, yet most adults exceed this. Nutritionists recommend checking labels carefully and opting for shakes with minimal added sweeteners.

The Power of Micronutrients
Beyond protein, shakes can be a source of valuable vitamins and minerals. Vitamin D supports bone health, while electrolytes like sodium aid hydration after sweat-heavy workouts. According to dietitian Jessica Isaacs, dairy-based shakes even outperform water in hydration thanks to their mix of protein, fluid, and electrolytes.

Safety First: Why Testing Matters
Not all protein powders and drinks are created equal. Because supplements are less regulated than medications, experts advise choosing brands certified by third-party testers such as NSF International or ConsumerLab. This step helps ensure products are free from harmful contaminants like heavy metals, which independent studies have found in nearly 40% of protein powders on the market.

A protein shake can tick every nutritional box, but if it tastes unpleasant or causes digestive issues, it won’t be sustainable. Many formulas use sugar substitutes or fiber isolates that may cause bloating or discomfort. Dietitians suggest experimenting until you find a shake that satisfies both your taste buds and your gut.

According to the Mayo Clinic, ready-to-drink protein shakes offer convenience, while powders provide flexibility for mixing into foods like oatmeal, smoothies, or even coffee. Both can work, but the key is choosing options that suit your lifestyle and dietary needs.

What to Avoid in a Protein Shake
Experts caution against multi-ingredient “performance blends” that add unnecessary calories or hard-to-digest fillers. Artificial sweeteners, sugar alcohols, and high levels of added sugar should also raise red flags. And while collagen supplements may help joints and skin, Mayo Clinic notes they are not complete proteins and shouldn’t be relied on to preserve muscle strength the way whey or soy can.

For older adults, the stakes are even higher. Research from Mayo Clinic shows nearly half of people over 71 don’t consume enough protein, which can accelerate muscle loss and impair daily functioning. In such cases, shakes or powders can be a practical solution to meet daily needs, especially when appetite or chewing difficulties make whole foods harder to consume.

Protein shakes can be a powerful ally in recovery, nutrition, and even aging well — but only if chosen wisely. Look for products with 20–30 grams of protein, minimal added sugar, third-party safety testing, and a taste you enjoy. And remember, as dietitian Tony Castillo explains, the best time to drink one is often right after a workout: “Protein shakes help refuel with carbs, repair with protein, and rehydrate with fluid and electrolytes.”