Protein powder

Is protein powder safe?

For healthy adults at normal intakes, yes. Protein powder is concentrated food protein, usually from milk (whey or casein), soy, pea, rice or beef, and the body handles it the same way as protein from a meal. The concern people search for most, kidney damage, is not supported in healthy people. The real problem is what else is in the tub. In October 2025 Consumer Reports found that more than two-thirds of 23 popular powders and shakes contained more lead in one serving than its experts consider safe for a whole day.

That makes protein powder a quality question more than a dose question.

Does protein powder damage your kidneys?

Not if they work normally. A 2018 meta-analysis in The Journal of Nutrition pooled 28 randomised trials with 1,358 adults who ate a high-protein diet (at least 1.5 grams per kilogram of body weight, or 100 grams a day) or a normal one. Kidney filtration did not change differently between the groups. Filtration rises a little after a protein-heavy meal, which is a normal response, not injury.

People with chronic kidney disease are different. They are often told to limit protein to slow the disease, and a powder can push intake well above that. Ask your doctor before using one if you have kidney disease, diabetes affecting the kidneys, or a single kidney.

The usual target for people who train is 1.4 to 2.0 grams of protein per kilogram of body weight a day from all sources, according to the International Society of Sports Nutrition's 2017 position stand. For a 75 kg adult that is about 105 to 150 grams. Many people reach that from food, so one scoop of 20 to 40 grams is usually plenty.

How much lead is in protein powder?

Consumer Reports tested several samples of 23 products bought between November 2024 and early 2025. It used a strict yardstick: 0.5 micrograms of lead a day, the California Proposition 65 limit. Key results, as reported by NPR:

• More than two-thirds of products exceeded 0.5 µg in a single serving.
• Naked Nutrition Mass Gainer had 7.7 µg per serving and Huel Black Edition 6.3 µg. Naked said its serving is larger than most.
• Plant-based powders averaged about nine times the lead of dairy-based ones and twice that of beef-based ones.
• Lead levels were higher on average than in the organisation's previous test 15 years earlier.

Earlier in 2025 the Clean Label Project tested 160 products from 70 brands and found 47% above Proposition 65 thresholds for toxic metals.

Context matters. The FDA's interim reference level for lead from food is 2.2 µg a day for children and 8.8 µg for women of childbearing age, and most powders sit below that. But lead builds up over time, and a daily shake adds to what comes from other foods. Plants such as rice and pea absorb metals from soil, which is why plant powders tend to test worse.

What about other quality problems?

Protein powders are dietary supplements in the US, so the FDA does not check them before sale. The common complaints are less dramatic than lead: added sugars and sweeteners that cause stomach upset, and lactose in whey concentrate that bothers people with lactose intolerance (whey isolate has much less). "Mass gainer" products often carry large servings, which multiplies any contaminant per scoop.

Athletes in tested sport face one more risk: contamination with banned substances in a shared factory. NSF Certified for SportThird-party testingTesting of a supplement by an independent lab to check that it contains what the label says and is free of set contaminants.More in the glossary and Informed Sport screen batches for both banned substances and contaminants, and these seals are easy to find on protein powders.

Who should be careful

• People with kidney or liver disease, who may need to limit protein. Talk to your doctor first.
• People taking carbidopa-levodopa for Parkinson's disease. The drug label notes that a high-protein diet may impair levodopa absorption, because they compete for the same transport in the gut. A doctor or pharmacist can advise on timing.
• Pregnant women and children, who are most sensitive to lead. Food is the better source of protein for them unless a doctor advises otherwise.
• People with milk or soy allergies, who should read labels closely, since allergen recalls are among the most common for these products.

How to choose a safer protein powder

1. Check whether you need one. If you already eat protein at most meals, a powder adds little.
2. Prefer whey or other dairy protein if you tolerate it; it tested lowest for lead.
3. Look for a third-party seal (NSF Certified for SportThird-party testingTesting of a supplement by an independent lab to check that it contains what the label says and is free of set contaminants.More in the glossary, Informed Sport) and avoid products carrying a Proposition 65 warning.
4. Use it a few times a week rather than several times a day, and rotate brands if you rely on plant protein.

How we scored it

Protein powder scores well on dose safety (85), organ toxicity (85) and interactions (88), because protein itself is ordinary food. Product quality (58) pulls the score down: lead above strict limits is common, especially in plant powders. Regulatory record (80) reflects no bans but an open call for FDA limits. Compare creatine, a sports supplement with cleaner testing results, and calcium, another supplement where the source of the powder affects lead content.