As it turns out, a dime-sized drop of serum is all it takes to cover your entire face, neck, and chest. The best way to make sure the serum goes on evenly on your skin, as dermatologist Dr. Corey L. Hartman tells Byrdie, is to dot the serum across the areas that need application. “Dot a few times across the forehead, once on the nose and chin, and a few times on each cheek,” says Hartman. After that, gently massage the product into the skin until it is fully absorbed.

Echoing this sentiment, dermatologist Dr. Lauren Abramowitz notes that the type of product you use on the skin is more important than how much of it is delivered into the skin. Abramowitz tells Well + Good, “A pea size amount of any type of skin is usually the gold standard for a retinol or an eye serum, whereas if you’re using a cream for the face and neck you would more than likely use a quarter size.”

The rule of thumb is to patch-test first and apply sparingly if your serum is formulated with strong active ingredients like niacinamide or retinol. After dropping a thin amount of serum on your fingertips, apply the formula to your cheeks, chin, forehead, and your neck. Then, gently press the formula into your skin with sweeping motions and tap at your skin until the serum properly settles into the skin. Once you’re done, wait for five minutes before layering moisturizer.