Is Costco or Sam's Club cheaper for protein?

Q: Cost of Membership: Worth It For Protein?

Costco Gold Star: $65/year. Sam's Club: $50/year. A serious protein buyer (3 tubs + 4 bar boxes per year) saves $80-120 per year over Amazon S&S on the same brands. Either membership pays for itself within the first quarter. Both clubs let non-members buy online with a surcharge (usually 5%), but selection is limited and the surcharge wipes out half the savings.

Q: What About Quality?

Both house brands publish their lab tests. Kirkland Signature whey is manufactured under Costco's quality spec and the protein content per scoop matches the label within tolerance in independent assays. Member's Mark whey performs the same. There is no quality penalty for going warehouse over name brand at the per-scoop level.

Question

Is Costco or Sam's Club cheaper for protein?

ProteinPrice Editorial · Accepted Answer

It depends on the SKU. Costco wins on Premier Protein 18-pack RTDs and its house brand Kirkland Signature whey ($30 for 5 lb). Sam's Club wins on Member's Mark protein bars and on Quest bar variety packs. Per gram of protein, Kirkland and the Premier 18-pack at Costco are the two cheapest mainstream options in the country.

Costco vs Sam's Club Protein: Which Warehouse Wins?