The Regimen

Six So-Called “Never Mix” Ingredients That Are Made For Each Other

It’s a common blog title: Ingredients You Should Never Mix. Problem is, many of the combos included on the lists are not only perfectly safe to mix, they beg to be paired up for enhanced benefit and powered-up performance. Where do the myths come from? Old, disproven studies. Rumor. Misinterpretation of data. Personal anecdote. Bad research. Cutting and pasting bad information. Let’s set the record straight.


Glycolic Acid and Retinoids

Glycolic acid is a naturally occurring alpha-hydroxy acid that helps remove dead skin cells and accelerate desquamation of pigment. It also reduces initial melanin formation in melanocytes by inhibiting the melanin-producing enzyme tyrosinase.

Retinoids (vitamin A) decrease the synthesis of enzymes known as matrix metalloproteinases (MMPs), which break down proteins in the skin. At the same time, they increase dermal procollagen and collagen synthesis.

Why they’re a great pair: These two play well together, despite what you may have heard. The keratolytic effect of the glycolic acid enhances the penetration of the vitamin A to optimize results. This synergy makes the combo highly effective in the eliminating acne, reducing scarring, promoting a more even tone, and regenerating youthful texture. Studies confirm that the combination is well-tolerated by skin, and the results are very positive.


Niacinamide + AHAs & BHA

Niacinamide is a vitamin B3 derivative is an anti-oxidant, anti-inflammatory, barrier booster. It increases the biosynthesis of ceramides, raises nourishing fatty acid levels in the skin, blocks melanin from reaching the surface of the skin, and boosts collagen production.

Acids work to remove the upper layers of dead skin cells leaving skin renewed, brightened, and free of cellular debris.

Why these are better together: Far from being in conflict, these two complement each other. By removing the obstructive layer of cellular debris, the acids prep skin for better absorption of ingredients like niacinamide. Studies have shown that skin care formulas containing niacinamide and acids significantly improve texture and tone of skin including reducing wrinkles, increasing elasticity, and promoting more even tone.


Niacinamide and Vitamin C

Niacinamide is a barrier-boosting, skin nourishing ingredient that reduces fine lines, and promotes even tone and smoother texture.

Vitamin C is a potent antioxidant that protects against environmental damage and signs of aging, while naturally brightening skin. 

Why they’re a great pair: Together, they form a radiance-boosting duo specializing in reducing fine lines, promoting even tone, firming, brightening, and restoring a more youthful appearance.

The idea that two have incompatible pH levels that render them less effective together is based on old, faulty research. The proposed acidic conflict would occur only if the two ingredients were exposed to a high-temperature environment for an extended period of time. Never leave in a car or in a bathroom window cell.


Vitamin C + Acids

Antioxidant superhero Vitamin C repairs and protects skin from the harmful effects of UV damage, brightens skin, and boosts collagen production making an excellent ally in fighting signs of aging.

AHAs and BHAs remove cellular debris to aid penetration of actives.

Why they’re a great pair: Acids remove obstructive cellular debris to clear that way for antioxidant vitamin C to penetrate more effectively. AHAs and BHA have the effect of reducing skin pH. Since vitamin C works best at low pH (acidic pH), the presence of an AHA or BHA helps to optimize the performance of vitamin C.


Our Top-Selling Corrective Serum Cocktails


Mixes lactic acid, kojic acid, vitamin A, niacinamide and peptides for exceptional retexturing and rejuvenating results. A Dermascope Magazine Aestheticians’ Choice Award winner.


Rejuv Rx

This peptide-rich firming and lifting serum gets a synergistic boost from niacinamide and lactic acid to increase elasticity, decrease fine lines and wrinkles, and protect against future signs of aging.



This customer favorite is a transformative and nourishing cocktail of glycolic acid, vitamin A, niacinamide, lactic acid, and kojic acid formulated to reduce wrinkles, discoloration, and acne scarring for smoother, brighter, healthier skin. A Dermascope Magazine Aestheticians’ Choice Award winner.


Pure C + E

This potent vitamin C & E serum gets a performance-enhancing boost from lactic acid and niacinamide for daily defense against age-accelerating environmental aggressors.

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