You've started using a new skincare routine. Now what? Here's when you can expect results.

The short answer is that you’ll start to see results from your new skincare routine in about a month. Why a month? Because your skin effectively replaces itself every 28 days. That’s the time it takes for a fresh skin cell to mature, die, and then slough off. So, theoretically, 28 days allows for an entirely new batch of skin cells (that have all been treated by your skincare routine) to appear on the surface of your skin.

However, that doesn’t mean you should ditch your skincare routine if you don’t see results in four weeks. Many dermatologists recommend waiting three months to gauge the efficacy of your skincare routine.

Some products work faster than others. For example, moisturizers and exfoliating scrubs work instantly. Products meant to treat fine lines or hyperpigmentation (like Perfect “C” Treatment Serum) take longer to work because they require several cycles of skin cell turnover for maximum results. Products that contain peptides (like Super Cream) may take up to four months to yield results since they affect skin at a genetic level.

On the other hand, there are few signs that a product is not working that you may notice right away. If a skincare product stings your face or leaves it red, something is wrong. There’s no need to keep applying it for 28 days to see if it works!

However, it may not be the new product itself that is irritating your skin. Another step in your routine – like over-exfoliating – may be sensitizing your skin, causing a reaction with the new product. If you eliminate the sensitizing step or product, you may be able to better tolerate the new product.

Then again, an allergy may develop closer to the 28-day mark. Skin allergies usually appear as red or scaly patches, but on rare occasions, they can even present as blistering rashes and facial swelling. If you experience an allergic reaction, discontinue the use of the product immediately.

Skincare is all about discovery and experimentation. Some skincare enthusiasts find it helpful to use a journal to track their skincare routine and results. But don’t go overboard! It’s best to test out only one new product every two to four weeks.