Neither. Stretch marks are basically mild scars. No amount of moisturizing will get rid of them, because scars have nothing to do with skin moisture.
Two things: Hydroxycitric Acid, and Tretinoin (a Vitamin A derivative. There is another name for it... maybe Retinol).
Cosmetic products containing either of these agents can lessen the appearance of stretch marks, and if the scars are minimal to begin with, they can disappear entirely. This happens through the action of the agents, which are chemically abrasive. They burn the top most layers of your skin, leaving new skin cells to form. Casual use of these agents can "renew" enough skin to get rid of superficial scars and blemishes.
Be careful when using these products. As stated before; they are chemically abrasive. Ingestion can cause Chron's Disease. They will burn your skin (think of a sunburn), so obviously don't use them on sensitive areas, on more than 10% of your body, or on any open or recent wounds.