The answer so far
Think of a protein drink as food in a convenient format. Whether it helps depends on what it replaces, the rest of the diet and the outcome being measured.
Protein drinks are packaged ways to consume protein, calories and other ingredients. They can be convenient, but a high protein number does not establish better muscle, weight or health outcomes. Compare the drink with ordinary food, the person’s total intake and the outcome actually measured.12
On this page
What is in the package?
A product may contain milk or plant proteins, sweeteners, fibre, fats, vitamins, stimulants or a proprietary blend. Serving sizes differ, so compare protein and calories per serving and per 100 grams when possible. ‘High protein’ describes composition; it does not describe absorption, satiety or clinical benefit. For practical handling, see storing powder, shakes and bars. To compare formats, see drinks, bars and powders.
Read caffeine in drinks and supplements, sleep and safety. See BCAAs and muscle evidence for amino acids sold separately. For the distinction between lean tissue and strength, see weight-loss medicines and muscle. For a separate quality question, see protein powders and metal testing.13
What the evidence can show
Trials can test a defined product in a defined population, for example alongside resistance training or during recovery from illness. They cannot automatically support claims about every brand, flavour or dose. For healthy people who already eat enough protein, adding a supplement may increase calories without improving the outcome they care about.2
Do more protein shakes improve strength?
In a 2024 trial, 171 healthy adults aged 50 and over were randomly assigned a daily plant-protein drink, dairy-protein drink or low-protein drink for 12 weeks; 141 completed the study. The researchers found no statistically significant differences between groups in handgrip strength or the other measured health outcomes. This does not prove that extra protein never helps: the trial studied particular drinks and participants for a limited period, and it cannot settle what happens in people with different diets, illness or training programmes. Two authors were affiliated with a food-ingredients company. A shake can be a convenient food, but more protein is not automatically a measurable improvement in strength. See how to compare protein products and how to interpret a study result.5
Where caution matters
Bars and shakes can contain substantial sugar alcohols, caffeine or total calories, and concentrated products may be unsuitable for some people with kidney, liver or metabolic conditions. Combining products can duplicate nutrients or stimulants. This page offers no personal intake target or product recommendation. For possible causes of digestive discomfort, see protein products and bloating.42
Further reading
Trusted external resources selected to help explain this page. They open in a new tab.
- Protein in the diet ↗A plain-language overview of protein’s role and where it comes from.
- A 12-week trial of plant and dairy protein drinks ↗Healthy adults aged 50 and over; specific drinks over 12 weeks, not a test of every protein product.
Sources, kept close.
Selected supporting sources; this is not a complete literature review.
- Protein in dietMedlinePlus · U.S. National Library of Medicine consumer reference
- Nutrition and athletic performanceMedlinePlus · U.S. National Library of Medicine consumer reference
- FDA 101: Dietary SupplementsU.S. Food and Drug Administration · Regulator consumer guidance
- Questions and Answers on Dietary SupplementsU.S. Food and Drug Administration · Regulator consumer guidance
- Impact of increased protein intake in older adults: a 12-week double-blind randomised controlled trialAge and Ageing / PubMed · 2024 randomized controlled trial; Ireland