Will vitamin d leave a bad taste in your mouth?

Yes. For instance, sulbutiamine is a synthetic form of thiamine (B1). It is very bitter tasting. After having ingested the vitamin, however, the taste in your mouth should subside within a few minutes. Drink some water. If taking any vitamin, you may wish to place the vitamin in a capsule so that it does not come in direct contact with your tongue. Capsules may be found at better health food stores across the nation.