Whey

Studies in people

• Benefit

  Muscle strength in older adults²

  Whey protein helped older people who were frail or sarcopenic gain muscle and walk faster, but did nothing for healthy older people.

• Benefit

  Muscle mass as we age³

  Whey protein helps build and keep muscle, especially with exercise, and may slow muscle loss with age.

• Benefit

  Muscle strength in older women⁴

  In postmenopausal women, whey protein helped arm strength and leg muscle only when paired with resistance training.

• Benefit

  Muscle recovery after exercise⁵

  In young, healthy adults, whey protein had small to medium benefits for muscle function recovery after hard workouts.

• No harm found

  Acne severity in men⁶

  In men with acne, whey protein did not make acne worse over six months.

• Benefit

  Muscle soreness after exercise⁷

  In men who exercised hard, whey protein lowered blood signs of muscle damage, but soreness and fitness stayed the same.

• Benefit

  Muscle soreness after running⁸

  In runners, whey protein was linked to lower muscle damage markers after a marathon and longer distances at 9 and 12 minutes.

• Benefit

  Muscle soreness after exercise⁹

  In active women, four days of whey protein hydrolysate improved flexibility and strength recovery after hard exercise.

• Benefit

  Muscle strength and mass in older adults¹⁰

  In older people with muscle loss, whey protein plus leucine and vitamin D added muscle, but strength improved only with exercise too.

• Benefit

  Muscle loss with age¹¹

  In older adults, leucine-enriched whey protein plus resistance training increased lean muscle mass, strength and physical performance.

• Benefit

  Muscle building after exercise¹²

  In healthy adults, whey protein taken with exercise boosted muscle protein building, especially when taken before or right after a workout.

• Open question

  Kidney stone risk¹³

  In healthy people, whey protein did not change average kidney stone risk factors, but some individuals saw big shifts.

• Benefit

  Muscle and body fat after workouts¹⁴

  In people doing strength training, whey protein after workouts helped build lean muscle and lose fat.

• Open question

  Baby growth and stools¹⁵

  Babies fed whey formula grew the same as others, but their stools were different.

• Benefit

  Muscle mass in older adults¹⁶

  In older people in care homes, whey protein plus vitamin D and strength training improved muscle mass.

• Open question

  Blood pressure¹⁸

  Whey protein drinks lowered a blood enzyme in people, but blood pressure itself did not change.

Animal and lab studies only

• Benefit

  Cancer treatment support²⁴

  Whey protein has shown anti-cancer effects in lab and animal studies, but human studies are still in their early days.

• Benefit

  Muscle and liver cells²⁵

  In lab studies, whey peptides crossed a gut cell barrier and fought free radicals in muscle and liver cells.

• Benefit

  Thyroid health in rats²⁶

  In animal studies, whey protein raised antioxidant levels in rats with an underactive thyroid.

• Benefit

  Milk protein allergy²⁷

  In animal studies, whey-based baby formula with certain broken-down milk proteins reduced allergy sensitization, but not all whey formulas work the same.

Study type not stated

• Concern

  Kidney and liver health¹⁹

  Taking whey protein in large amounts for a long time may affect the kidneys and liver.

• Benefit

  Gut and brain health²⁰

  Acid whey may help gut health and babies' brain development, but scientists are still studying it.

• Benefit

  Dairy waste disposal²²

  Cheese whey, a byproduct of cheese-making, can be used to make health-promoting drinks and vinegar.

• Concern

  Mineral levels in protein powders²³

  Whey protein powders can carry minerals like calcium and sodium, and heavy daily scooping may push some past daily recommended amounts.

Allergies and intolerances

These are about people with an allergy, an intolerance or coeliac disease. The signal is about the ingredient itself, and these are about the person eating it, so the signal does not count them.

• Blood immune complexes¹⁷

  People allergic to milk had higher levels of immune complexes made against whey in their blood.

How it’s made and used

• Food texture and mixing²¹

  Whey proteins mixed with plant compounds can change how they foam, emulsify and act as antioxidants.

The signal at the top counts the findings in people and in animal and lab studies. A concern in studies of people outranks animal and lab studies, and “No concerns” needs at least one finding in people. When most findings in people point one way, the page leans that way (“Mostly”), and every finding is still shown. Findings whose study type is not stated are shown but not counted. This page is a reference, not medical advice. It describes what regulators and published research say. Talk to a doctor or dietitian about your own diet.