Tanning lotion and SPF serve completely different purposes when it comes to sun exposure. Tanning lotion is designed to help you achieve a golden glow by accelerating the production of melanin in your skin. SPF, on the other hand, is meant to protect your skin from harmful UV rays that can cause skin damage and increase your risk of skin cancer. If you want to tan safely, it's important to use both products correctly. When tanning outdoors, always apply SPF first and then apply your tanning lotion.