German drug maker Bayer AG says it won't raise its offer for Schiff Nutrition, refusing to engage in a bidding war with British consumer goods company Reckitt Benckiser Group PLC.

Shares of vitamin and nutritional supplement seller Schiff Nutrition International Inc. dropped 5 percent in premarket trading on Tuesday.

The English company on Friday said that it was starting a tender offer to buy Schiff for $1.4 billion, or $42 per share.

Bayer had offered to pay $1.2 billion, or $34 per share, for Schiff on Oct. 30.

Schiff's products include Tiger's Milk nutrition bars, Omega 3 supplement MegaRed, and Airborne immune system health supplements. Its portfolio includes brands in three of the largest health supplement segments joint care, cardiovascular health and immune support.

Shares of Schiff, which is based in Salt Lake City, fell $2.23 to $41.90 before the market open. Its stock had gained 90 percent since just before the initial offer from Bayer.

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Bayer won't raise offer for Schiff Nutrition