Caffeine (1,3,7-trimethylxanthine) is a naturally occurring alkaloid found in coffee, tea, and cocoa. In skincare, it is used for its potential vasoconstrictive, antioxidant, and lipolytic properties. It is commonly included in formulations targeting under-eye puffiness, dark circles, and cellulite.

Clinical Evidence of the Effects on Under-Eye Puffiness

A randomized, double-blind, placebo-controlled study evaluated the efficacy of a 3% caffeine gel in reducing under-eye puffiness [1]. The study involved 34 volunteers who applied either the caffeine gel or a placebo gel. Both groups experienced reduced puffiness, but the difference between them was not statistically significant. However, 23.5% of participants responded better to the caffeine gel than to the placebo, suggesting individual variation. The authors concluded that the reduction in puffiness was more likely due to the cooling action of the gel base than to caffeine itself.

Cellulite and Lipolysis

Caffeine is frequently used in topical products marketed for the appearance of cellulite. Mechanistically, it is thought to promote lipolysis (the breakdown of stored fat) by inhibiting phosphodiesterase (an enzyme that deactivates fat-burning signals), which increases intracellular levels of cyclic adenosine monophosphate, or cAMP (a chemical messenger that activates fat metabolism). Elevated cAMP levels can trigger the breakdown of triglycerides (fat molecules stored in cells). [2].

Clinical studies evaluating its effect on cellulite include:

• Byun et al. (2015): In a six-week open-label study, 15 women applied a cream containing 3.5% water-soluble caffeine and xanthenes to their thighs and upper arms twice daily. Statistically significant reductions in thigh (−0.7 cm) and upper-arm (−0.8 cm) circumference were reported, along with improved cellulite grading scores. The study lacked a control group and had a small sample size [3].

• Dupont et al. (2014): In a double-blind, randomized, placebo-controlled trial, 44 women applied a topical gel containing caffeine and multiple other actives twice daily for 84 days. Compared to the placebo group, the active gel significantly improved skin tonicity and reduced the orange-peel appearance and stubborn cellulite. Circumference measurements also decreased. No adverse events were reported. The contribution of caffeine alone could not be determined due to the presence of multiple actives [4].

The current evidence suggests that topical formulations containing caffeine may improve the appearance of cellulite in some users, but results depend on formulation, treatment duration, and the presence of additional ingredients. Studies specifically isolating caffeine’s contribution are limited.

Antioxidant Activity

Caffeine has demonstrated antioxidant activity in both in vitro and in vivo models. It can scavenge reactive oxygen species (ROS) and reduce oxidative stress in skin cells exposed to ultraviolet radiation or pollution [5].

Safety and Irritation

Topical caffeine is generally well tolerated. Mild irritation or dryness may occur, particularly in alcohol-based formulas or at high concentrations. No systemic effects have been reported in cosmetic use. In safety assessments, caffeine showed low irritation and sensitization potential [6].

Conclusion

Caffeine has documented biological actions on the skin like lipolysis and antioxidant activity. Its effect on under-eye puffiness has been studied, but clinical evidence remains limited and results vary. Studies on cellulite reduction show small but measurable improvements in some individuals, though effects are formulation-dependent and often modest. Caffeine is generally safe for topical use and continues to be widely used in formulations targeting transient puffiness, localized fat, and oxidative stress.

References

1. Amnuaikit, T., Maneenuan, D., & Boonme, P. (2011). Evaluation of caffeine gels on physicochemical characteristics and in vivo efficacy in reducing puffy eyes. Journal of Applied Pharmaceutical Science, 1(2), 56–59.
   https://www.japsonline.com/admin/php/uploads/20_pdf.pdf

2. Elias, M. L., Israeli, A. F., & Madan, R. (2023). Caffeine in skincare: Its role in skin cancer, sun protection, and cosmetics. Indian Journal of Dermatology, 68(5), 546–550.
   https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10718232/

3. Byun, S.-Y., Kwon, S.-H., Heo, S.-H., Shim, J.-S., Du, M.-H., & Na, J.-I. (2015). Efficacy of slimming cream containing 3.5% water-soluble caffeine and xanthenes for the treatment of cellulite: Clinical study and literature review. Annals of Dermatology, 27(3), 243–249.
   https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4466275/

4. Dupont, E., Journet, M., Oula, M.-L., Gomez, J., Léveillé, C., Loing, E., & Bilodeau, D. (2014). An integral topical gel for cellulite reduction: Results from a double-blind, randomized, placebo-controlled evaluation of efficacy. Clinical, Cosmetic and Investigational Dermatology, 7, 73–88.
   https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3933246

5. Herman, A. (2013). Caffeine's mechanisms of action and its cosmetic use. Skin Pharmacology and Physiology, 26(1), 8–14.
   https://pubmed.ncbi.nlm.nih.gov/23075568/

6. Cherian, P. A., Bergfeld, W. F., Belsito, D. V., Hill, R. A., Klaassen, C. D., Liebler, D. C., Marks, J. G. Jr., Shank, R. C., Slaga, T. J., Snyder, P. W., Fiume, M., & Heldreth, B. (2024). Safety Assessment of Methylxanthines as Used in Cosmetics. International Journal of Toxicology, 43(4_suppl), 42S–77S.
   https://journals.sagepub.com/doi/10.1177/10915818241260282