For years, dermatologists dismissed any link between diet and skin breakouts, but pioneering research changed that view. Early observational studies, such as the Harvard Nurses’ Health Study led by Dr Walter Willett and published in the Journal of the American Academy of Dermatology, pointed to a surprising link. Female participants who drank more milk during their teenage years reported higher rates of severe, doctor-diagnosed acne.
Curiously, the association was strongest for skimmed milk rather than whole or semi-skimmed milk. Follow-up studies tracking thousands of teenage girls and boys directly confirmed this pattern, showing that drinking milk, especially skimmed milk, consistently correlated with clearer skin flare-ups regardless of gender.
While some initially wondered if added growth hormones in cattle were to blame, scientists realised that milk naturally contains a complex blend of bioactive hormones and growth factors designed by nature to help young animals grow.
Newer, comprehensive research has since shed more light on why skimmed milk appears to be a bigger culprit than full-fat milk. Comprehensive review papers and meta-analyses, such as a major study published in the journal Nutrients by Dr Christian Juhl and colleagues involving over 78,000 young adults, confirmed that consuming dairy products increases the likelihood of developing acne. Skimmed milk consistently showed a higher risk ratio compared to whole milk.
Researchers now understand the physiological mechanism behind this reaction. Milk triggers an increase in a hormone called insulin-like growth factor 1, or IGF-1, which stimulates the skin’s oil glands to produce excess sebum and promotes cellular growth that clogs pores. When milk is skimmed, removing the fat alters its protein balance and glycemic impact. Skimmed milk contains a higher concentration of whey proteins and carbohydrate lactose relative to fat, which causes a faster spike in blood sugar and insulin levels.
This rapid insulin surge further boosts IGF-1 production, making skimmed milk a potent trigger for skin inflammation. Interestingly, fermented dairy products like yoghurt and cheese show a much weaker or non-existent link to breakouts, likely because the fermentation process breaks down some of these stimulating compounds.
References:
1. Adebamowo, C.A., et al. (2005). High school dairy intake and teenage acne. Journal of the American Academy of Dermatology, 52(2), 207-214.
2. Juhl, C.R., et al. (2018). Dairy Intake and Acne Vulgaris: A Systematic Review and Meta-Analysis of 78,529 Children, Adolescents, and Young Adults. Nutrients, 10(8), 1049.
3. Melnik, B.C. (2015). Linking diet to acne metabolomics, inflammation, and comedogenesis: an update. Clinical, Cosmetic and Investigational Dermatology, 8, 371-388.
4. Shetty, V.H. and Swathi, D. (2017). Correlation of acne with dairy products – Fact or a Misconception. IP Indian Journal of Clinical and Experimental Dermatology, 3(2), 43-47.
5. Dhakal, B., et al. (2026). Association of fast foods and dairy products in acne severity and scarring: a cross-sectional study. Annals of Medicine and Surgery, 88(1), 205-210.