Does whey protein cause acne?

Whey protein

Whey is the liquid protein left when milk is made into cheese, then dried into powder for shakes.

In a 2024 study of 201 men at gyms in Jordan, 100 with acne and 101 without, 47% of those with acne had taken whey in the previous 3 months, against 27.7% of those without (p = 0.0047). After adjustment, the odds of acne were 2.94 times higher in whey users (95% CI 1.11 to 7.82) (Muhaidat et al., 2024).

A 2026 review lists whey protein supplements among the foods observational studies have linked to acne (Dessinioti and Dreno, 2026). Case notes go the same way: five teenage athletes flared after starting whey, and lesions fully cleared in 4 after they stopped (Silverberg, 2012). Five male bodybuilders developed acne after whey too (Simonart, 2012).

The only randomised trial found no worsening. 49 men with mild to moderate acne took 30 g of whey a day (n = 25) or a non-whey supplement (n = 24) for 6 months. The between-group difference in facial lesions was −5.99 (95% CI −13.18 to 1.19, p = 0.09) and in truncal lesions −2.18 (95% CI −11.83 to 7.48, p = 0.65). The authors called whey non-inferior (Sompochpruetikul et al., 2024). We still grade the human evidence Limited: one gym survey plus case notes, against one trial of 49 men. More on dairy and acne and the wider breakout foods list.

Casein powder

IGF-1 (insulin-like growth factor 1) is a growth signal in your blood, and whey is often blamed for raising it. The trial that split milk proteins found otherwise.

In 57 eight-year-old boys, whey raised fasting insulin by 21% (P = 0.006), with no change in IGF-1 (P = 0.27). Casein raised IGF-1 by 15% (P < 0.0001), with no change in fasting insulin (Hoppe et al., 2009). So the insulin rise is measured for whey. The IGF-1 rise is measured for casein.

A 2015 review still groups dairy protein supplements with milk as foods to restrict if you want to calm the insulin and IGF-1 signal in oil glands (Melnik, 2015). In the Jordan gym study, casein-and-whey blends did not differ between men with and without acne (Muhaidat et al., 2024). We found no trial of casein powder and acne. For another high-leucine food, see eggs and acne.

Whey isolate

A 2022 review found no interventional study linking whey or casein ingestion with acne severity or prevalence (Meixiong et al., 2022). The 2024 trial used whey protein, not a head-to-head of isolate versus concentrate (Sompochpruetikul et al., 2024). We found no trial that compared those forms for skin. Isolate is still whey.

Pea and other powders

We searched PubMed on 16 September 2026 for pea protein and acne and found no study. Reviews still call for more diet trials rather than naming a safe powder (Dessinioti and Dreno, 2026). When the American Academy of Dermatology updated its acne guidelines in 2024, available evidence was insufficient to develop recommendations for dietary changes (AAD, 2024). Pea is a swap because it is not dairy whey, not because a trial cleared it. The acne plate itself is on foods for clear skin.

How long to give a swap

We found no trial of stopping whey that reported a timeline. The closest guides are acne diet trials: 12 weeks in 43 young men (Smith et al., 2007) and 10 weeks in 32 people (Kwon et al., 2012). The American Academy of Dermatology says a treatment that works should show some improvement in 4 to 6 weeks, and clearing can take two to three months or longer (AAD, 2023). Our "about 12 weeks" comes from those timelines, not from a whey-withdrawal study. Low-GI eating is the diet those trials actually tested; see the low-glycemic guide.