Can I Take Green Tea Extract (EGCG) With Tretinoin?

Is there a known interaction between EGCG and topical tretinoin?

The Renova label's drug interactions section does not name green tea extract or EGCG. It says that concomitant topical medications, medicated or abrasive soaps, cosmetics with a strong drying effect, high-alcohol products, astringents, and other products that may irritate the skin should be used with caution because they may increase irritation [1].

The label not naming EGCG does not show that the combination is harmless. It means the label gives no EGCG-specific instruction [1].

What does the tretinoin label warn about?

The Renova label says topical use may cause severe local erythema, pruritus, burning, stinging, and peeling at the application site, and that tretinoin is a dermal irritant [1]. In its vehicle-controlled studies, almost all patients reported one or more local reactions such as peeling, dry skin, burning, stinging, erythema, and pruritus [1]. It says larger amounts than recommended have not been shown to work faster or better and may cause marked redness, peeling, or discomfort. If irritation is severe enough, the label says patients should be directed to use less medication, apply it less often, stop temporarily, or stop altogether [1].

Photosensitivity is the other label warning. The label says exposure to sunlight, including sunlamps, should be avoided or minimized, and that patients should use sunscreen with a minimum SPF of 15 and protective clothing. It says people with sunburn should not use the product until fully recovered [1].

On absorption, the label reports less than 2% absorption of tretinoin from the older 0.05% cream after single and repeated daily application in healthy men. It adds that no percutaneous absorption study was done in human volunteers with the 0.02% cream [1].

Do green tea supplements add a different concern?

Supplements taken by mouth are a separate question from a topical product. Case reports have described hepatotoxicity associated with supplements containing Chinese green tea [2]. Those reports concern the supplements themselves, not a study of green tea with tretinoin.

In laboratory work, green tea extract strongly inhibited CYP2C9, CYP2D6 and CYP3A4 activity in human liver microsomes, and in rats one week of green tea extract altered midazolam pharmacokinetics, with opposite effects in the liver and the small intestine [3]. That work did not test tretinoin, so it does not show whether green tea extract interacts with topical tretinoin.

What about a green tea serum used with tretinoin?

EGCG has been studied for acne by itself. In an 8-week randomized split-face trial, EGCG improved acne and was well tolerated [4]. That trial tested EGCG alone, not EGCG plus tretinoin.

For a topical green tea product used alongside tretinoin, the relevant label statement is the one about other topical products that may irritate the skin and may increase irritation with Renova [1].

Bottom line

The Renova label's practical warnings are skin irritation and photosensitivity, with sunscreen of SPF 15 or higher and protective clothing advised [1]. It does not name EGCG as an interaction [1]. The liver-injury case reports concern green tea supplements taken by mouth [2].