Skincare ingredients are a lot like fashion. They are susceptible to trends and fads, but the classics are always in style. And just as a well-tailored blazer is a staple in every wardrobe, a good vitamin C serum is an essential in every skincare routine.

Vitamin C is an ingredient we’ve all heard of, and most self-described skincare junkies are already using some form of vitamin C in their routine. This popular antioxidant has been proven to help boost collagen production, brighten the skin and help with overall anti-aging.

However, this seemingly simple ingredient is much more complicated than you might think. Vitamin C is notoriously difficult to formulate and can easily cause sensitivity and breakouts if not used properly.

The most common form of vitamin C is L-ascorbic acid. It is a particularly fragile ingredient and can become inactive if exposed to light, oxygen or excessive heat. Leave your beloved vitamin C serum in the car on a hot sunny day and you might as well throw it away.

Fortunately, there are some newer, more stable forms of vitamin C on the market that offer similar benefits to the ultra-potent, yet ultra-sensitive L-ascorbic acid.

Our Guide to Vitamin C breaks down the best vitamin C serums on the block and how to incorporate them into your routine:

One of the newer, more stable forms of vitamin C on the market is Sodium Ascorbyl Phosphate, which can be found in Agent Nateur’s holi(c) duo.

Sodium Ascorbyl Phosphate (SAP) is made by combining potent ascorbic acid with a salt to make a more stable, water-soluble molecule. When applied to the skin, our body converts SAP into pure vitamin C. This conversion process makes SAP more gentle than applying pure ascorbic acid directly to the skin.

Luckily, you don’t have to compromise results for less irritation. Studies show that SAP has similar wrinkle-smoothing and elasticity-boosting effects to L-ascorbic acid. An additional benefit of SAP is that is can be beneficial for acne because of its soothing properties.

If you’re new to the world of vitamin C and want to start incorporating this anti-aging antioxidant into your routine, Agent Nateur’s holi(c) is a great choice. This unique dry powder formula won’t oxidize, ensuring that you receive all of its regenerative benefits.

Mix a dash of holi(c) with your favorite lightweight hydrating serum for a gentle dose of antioxidants. Top off with SPF for total protection.

Magnesium Ascorbyl Phosphate (MAP) is a water-soluble form of vitamin C made by combining ascorbic acid with magnesium salt to improve its stability in water-based formulas. The benefit of MAP is that it is stable in the presence of light, so it won’t oxidize (go bad) as quickly!

Another bonus point for MAP is that is lipophilic, meaning it penetrates more effectively into the deeper layers of the skin. This enhanced penetration makes MAP a more hydrating form of vitamin C.

For dry skin types, we love Valmont’s Prime B Cellular. This serum provides all of the essential elements for revitalized skin and is a great choice to fight the first signs of skin aging.

For experienced vitamin C users, IS Clinical’s Super Serum Advance+ is one of the most advanced pure L-ascorbic acid serums on the market.

Super Serum Advance+ combines a 15% concentration of a next generation stable L-ascorbic acid with a bioidentical Copper Tripeptide growth factor for added anti-aging benefits. Super Serum Advance+ also contains powerful botanical antioxidants and safe skin brighteners such as arbutin and mushroom extract, making this an excellent choice for those with hyperpigmentation.