Caffeine is recognized as potent radio-sensitizers, an effect first discovered in the 1970's, and since documented in over 70 published studies. Here are some of the high-level findings of major studies, and you can learn more here and here. As always, follow your doctor’s guidance and talk with your medical team about everything you are doing.

When combined with radiation, caffeine results in reduced survival of cancer cells compared to radiation alone  [Seo et al., 2006]. Caffeine works by inhibiting the repair of DNA double-strand breaks in radiated cancer cells [Iliakis & Nüsse 1983; Park & Cleaver 1979]. In addition, the rate of apoptosis (programmed cell death) following radiation is significantly increased when combined with caffeine [Higuchi et al., 2000].

A human study documenting the benefit of caffeine was conducted in Japan. In this trial, 17 patients with various high-grade soft tissue sarcomas were treated with chemotherapy (doxorubicin and cisplatin), caffeine and radiation therapy. The effectiveness rate of caffeine-potentiated radiochemotherapy was 71%; and 12 patients have remained free of disease over a 3-year mean follow-up period [Tsuchiya et al., 2000]. These responses are significantly better than reported for conventional therapy of this type of cancer (without the addition of caffeine).

Caffeine may also help protect against skin reactions (and hair loss) during radiation. Animals pretreated with caffeine suffered only partial hair loss with slight reddening of the skin compared to controls treated with radiation alone [Hebbar et al., 2002]. A human study confirms this finding—135 patients with gynecologic cancers were interviewed regarding daily caffeine consumption during their radiation treatments. The researchers found a decrease in late radiation toxicity associated increased caffeine intake [Stelzer et al., 1994].

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