RESIST C15 Super Booster

The internal air restrictor, as you noticed, is now packaged separately to reduce the likelihood of the bottle leaking during transit. There are two ways to insert it into your C15, and both are easy! Option #1: Remove the cap from your C15, insert the dropper (do not remove the air restrictor from the glass stem) and screw the dropper cap closed. The cap will appear to tilt unevenly, but keep screwing it down and the internal air restrictor will snap into place. All done! Option #2: Remove the cap from your C15, and then pull the air restrictor off of the glass stem of the dropper. Push the pointed end of the air restrictor into the open C15 bottle, applying pressure until it snaps into place. Once the air restrictor is secure, it will not come loose or fall out—and now your C15 is ready for use!

Absolutely—a great deal of thought went into the packaging for this product! Because RESIST C15 is a water-light liquid, a bottle and dropper-tip applicator were the only way to go for measuring the perfect amount per use while ensuring the product wasn’t messy to dispense. To protect the potency of the formula, tinted glass prevents UV exposure and an internal restrictor (when you pull the dropper out, airflow into the bottle is drastically reduced). In rigorous testing, these packaging safeguards were more than adequate to preserve the effectiveness of the RESIST C15 Super Booster! For maximum potency, we advise using C15 Super Booster within three months of opening.

The C15 Trial Size is 3.5ml, and should last you 20-25 days of usage.

This should be fine for those who are already using such products. If you’re new to using an AHA or BHA exfoliant, we suggest separating application of the exfoliant and C15 Super Booster; for example using one in the morning and the other at night.

RESIST C15 Super Booster is a specialized treatment product designed to supercharge the benefits all of our serums provide. It was created for those who want to boost the efficacy of their anti-aging skincare routine, as it works multiple ways to make skin look and act younger. If you're happy with the results from your serum alone, you probably don't need to add this; however, you may want to experiment with it, as you may be surprised by the additional improvements! RESIST C15 Super Booster contains more than double the amount of vitamin C as our other serums, though all of our serums treat skin to a proven combination of anti-aging ingredients. The 15% concentration of stabilized vitamin C in RESIST C15 is an excellent amount to lighten stubborn brown spots, help fade red marks from acne, and significantly improve sun-damaged skin.

No. The formula was designed to complement the ingredients in our serums and moisturizers.

No, you should never mix any skincare product with a sunscreen because it will dilute the sunscreen making it less effective. For best results, mix RESIST C15 Super Booster with your serum each morning (or apply alone) and follow with your daytime moisturizer with sunscreen. In any daytime skincare routine, sunscreen should always be the last product applied.

Yes! Not only is the texture water-light, the vitamin C plus other antioxidants and repairing ingredients work to reduce the inflammation and redness from acne, as well as encourage healing of red marks from past breakouts.

Maybe. The concern is the amount of vitamin C, which can be too potent for some cases of rosacea. We suggest sampling this product to see how your skin responds. Generally speaking, though, vitamin C's anti-inflammatory action on skin can be helpful for rosacea.

Yes, of course. Although once or twice-daily application is recommended, you will absolutely still see benefits from RESIST C15 Super Booster if it's applied less often. As with any skincare product, you need to pay attention to how your skin responds and adjust usage (or products) accordingly.

Research has shown that the amount of vitamin C the RESIST C15 Super Booster contains can significantly improve brown spots and other sun-induced discolorations. Ideally, you'd want to combine RESIST C15 Super Booster with one of our skin-lightening products with hydroquinone or niacinamide, but if your skin cannot tolerate those ingredients the vitamin C in Super Booster may be the solution!

All of our serums contain a blend of anti-aging ingredients whose results are supported by published research, so which serum you choose comes down to skin type and personal preference, rather than one being better than the other. It is also perfectly fine to use more than one serum; for example, you could apply RESIST Ultra-Light Super Antioxidant Concentrate in the morning mixed with RESIST C15 Super Booster, then at night apply Resist Intensive Wrinkle-Repair Serum. Resist C15 Super Booster works with any of our serums or, if preferred, you may apply this treatment as the serum step in your morning and evening skincare routine.

C15 Super Booster should have a clear to a light yellowish tone. Although judging color can be somewhat subjective, the issue with destabilization of high amounts of vitamin C (ascorbic acid) comes into play once this vitamin begins to discolor significantly, i.e. turning a deep yellow/orange or deep brown shade. This is a sign the vitamin C has become less active which can occur over time, hence our recommendation to use this serum within three months of opening. A minor color variation is normal for products that don't contain artificial colorants to maintain a consistent shade, so between batches there can be a subtle difference in shade due to the natural color of the raw materials used to make the product. This does not mean the product is ineffective or less effective than if it were colorless.

No. The work to stabilize a formula (along with extensive testing) is done during the development process. Once this stage is complete and the product passes all testing, there are no special precautions for storing your products, save for keeping them out of long-term storage in very hot* or very cold environments. Despite the fact that the consistent cool temps of your refrigerator keeps your lettuce crisp, it’s actually detrimental to the stability of your carefully calibrated C15 Super Booster. To get the most from this treatment, keep it at room temperature and secure the dropper cap tightly after each use. *A steamy bathroom such as can occur during a shower does not get hot enough to affect this product’s stability.