If there’s one skincare product that can make 2019 the year to take charge of your anti-aging regime, it’s retinol. Retinol combats every sign of aging—fine lines and wrinkles, dark spots and skin dulled by slow cell turnover. That’s not all. The vitamin A derivative treats acne and shrinks the appearance of pores by reducing the signs of hormonal imbalance. While it’s exfoliating, retinol also helps unclog pores and shrink the oil glands. And it works all these wonders better than any other anti-aging product on the market.

Retinol can be purchased over the counter or prescribed by a doctor. The main difference between the OTC and prescription formula is the concentration of ingredients, which affects how well the retinol converts into retinoic acid once it hits your skin. Retinoic acid improves the way cells form and mature.

Incorporating the right formulation of retinoids into your routine can brighten and tone skin and also work to reduce sun damage, redness, pigmentation and acne. However, the ingredient can be drying, and retinol causes increased skin sensitivity to the sun. Increased sensitivity can be expected whether you choose a prescription route or an over-the-counter formula. That makes using a broad-spectrum sunscreen every day as part of your routine an absolute necessity or you risk causing severe redness and damage to your skin.

Dermatologists recommend that you build up your skin’s tolerance before using it daily. They say starting off slow is important. Use your product of choice twice a week, and then work your way up to applying retinol more frequently.

Prescription retinol is more intense than OTC formulas and it can cause skin to become red and flaky. The intensity of prescription retinol means this formula will produce faster results than over-the-counter products. A more gentle, over-the-counter product can give you the same results as a prescription but will take longer to produce those benefits.

The gentleness of an OTC formula will allow you to use the product as part of your daily routine. Prescription retinols aren’t used every day, and they are much more expensive than store bought products if your insurance doesn’t cover it.

Results should be expected within 10 to 14 days and using retinol over a period of 6 to 8 weeks will produce more dramatic results. Applying more than a pea-sized amount isn’t necessary and won’t speed up your results. If you decide to go the route of picking a store-bought retinol-based product, you should choose one that works over time with other ingredients to get the best results.

Experts agree that some women should steer clear of using retinol. Anyone who is pregnant, nursing, or has liver or kidney problems should not use the ingredient. They strongly recommend that any woman who has these or any other concerns should consult her doctor before trying out retinol.

Read more for tips on finding the right retinol product for you: Is Retinol the Answer to All of Your Complexion Concerns?