Alkaloid found in coffee, tea, and kola nuts. Caffeine is the chief stimulant in beverages such as coffee and tea. It’s often included in skincare products with claims that it will reduce cellulite or puffy eyes. Unfortunately, research into caffeine’s effects in this regard are mixed.
Caffeine and its constituents are thought to convey antioxidant benefits when consumed orally. Studies have looked at oral consumption of caffeine-containing beverages followed by exposure to UVB light (the kind that causes sunburn and skin tumors) and found that, compared with those who drank decaffeinated beverages, the drinks with caffeine conveyed a protective benefit. [1,2,3]
Applied to skin, caffeine may have anti-inflammatory properties.  It can penetrate skin’s barrier and has a constricting effect, which can help reduce redness but also may be irritating. Caffeine is not a slam dunk for reducing facial redness; in fact, may worsen the problem, but it’s worth experimenting with if you’re curious.
Caffeine’s popularity in products related to cellulite is due to its distant relationship to aminophylline (a pharmaceutical once thought to reduce cellulite), which is a modified form of theophylline, and caffeine contains theophylline.  There is no substantiated research proving theophylline can affect cellulite, but researchers have disproved aminophyilline’s claimed impact on cellulite.
Research on caffeine’s effect on cellulite when applied topically is mixed, and the more recent studies were performed on mice, not on humans with cellulite. Although caffeine may play a role in reducing the size or number of fat cells, the appearance of cellulite results from a combination of fat and changes in skin’s structure, the latter of which caffeine cannot impact. [6, 7]
When it comes to puffy eyes, there is no research indicating caffeine can have any benefit when applied topically. However, caffeine does have potential as an antioxidant, so it isn’t a wasted ingredient in skincare products. [8, 9]
- Kerzendorfer C, O’Driscoll M. UVB and caffeine: inhibiting the DNA damage response to protect against the adverse effects of UVB. J Invest Dermatol.. 2009;129(7):161-3.
- Conney A, Kramata P, Lou Y, Lu Y. Effect of caffeine on UVB-induced carcinogenesis, apoptosis, and the elimination of UVB-induced patches of p53 mutant epidermal cells in SKH-1 mice. Photochem Photobiol.. 2008;84(2):330-8.
- Lu Y, Lou Y, Liao J, Xie J, Peng Q, Yang C, Conney A. Administration of green tea or caffeine enhances the disappearance of UVB-induced patches of mutant p53 positive epidermal cells in SKH-1 mice. Carcinogenesis.. 2005;26(8):1465-72.
- Yazheng L, Kitts D. Activation of antioxidant response element (ARE)-dependent genes by roasted coffee extracts. Food Funct. 2012;3(9):950-4.
- Ribeiro J, Sebastião A, de Mendonca A. Adenosine receptors in the nervous system: pathophysiological implications. Prog Neurobiol. 2002;68(6):377-92.
- Velasco M, Tano C, Machado-Santelli G, Consiglieri V, Kaneko T, Baby R. Effects of caffeine and siloxanetriol alginate caffeine, as anticellulite agents, on fatty tissue: histological evaluation. J Cosmet Dermatol.. 2008;7(1):23-9.
- Herman A, Herman A. Caffeine’s mechanisms of action and its cosmetic use.. Skin Pharmacol Physiol.. 2013;26(1):8-14.
- Shimoda H, Seki E, Michio A. Inhibitory effect of green coffee bean extract on fat accumulation and body weight gain in mice. BMC Complement Altern Med. 2006;6(9):17.
- Kobayashi-Hattori K, Mogi A, Matsumoto Y, Takita T. Effect of caffeine on the body fat and lipid metabolism.