September 21, 2026

Why Some Skincare Routines Are Moving Toward One-Step Formulas

Multi-step skincare routines are harder to maintain consistently over time. Learn what the research says about routine complexity, habit formation, and adherence, and how formulators approach building a single product...

What to know

Research on treatment adherence across dermatology consistently links more complex, multi-step regimens to lower consistency of use over time.
A 2024 study on facial skincare routine adherence found that following recommended steps, not just frequency of use, was associated with better skin outcomes.
Habit-formation research suggests routines built around fewer decisions are more likely to become automatic and stick long-term.
Combining a serum and moisturizer into one formula introduces its own formulation trade-offs, particularly around balancing active-ingredient concentration with barrier-support ingredients and ingredient stability.

A common assumption in skincare is that more steps mean more benefit. Dermatology research on treatment adherence tells a more complicated story: routines that ask for more steps are followed less consistently, and consistency is often what determines whether any given ingredient has a chance to work at all. That's part of why some brands, Darkfin Labs among them, have moved toward combining functions into fewer products rather than adding more.

The Adherence Problem in Skincare Routines

Adherence research in dermatology, most of it focused on prescription treatment regimens, offers a useful proxy for skincare habits more broadly. A 2024 review on treatment adherence across common dermatological conditions found that patients are more likely to follow once-daily regimens than those requiring multiple applications, and that "elaborate treatment protocols frequently confuse patients and dampen their motivation, resulting in suboptimal adherence."¹

The same review pointed to psoriasis as an example: topical treatments, which require frequent application and multiple steps, showed adherence rates as low as 30 to 50%, while less frequent treatment options showed meaningfully higher compliance. The review also noted that consolidating multiple products or steps into fewer ones tends to reduce treatment burden and improve consistency of use.

What the Research Shows About Routine Complexity

A separate 2024 study specifically examining facial skincare routine adherence in the general population found that how consistently people followed recommended steps, not just how often they cleansed or moisturized, was tied to outcomes such as improved hydration and skin microbiome diversity.² The study also found gender differences in which steps were followed most consistently, suggesting that adherence isn't uniform even within a single recommended routine, let alone across more elaborate ones.

Why Habits, Not Willpower, Determine Whether a Routine Sticks

Adherence research and habit-formation research point to a similar underlying mechanism: routines that require fewer ongoing decisions are more likely to become automatic. A 2024 systematic review and meta-analysis of health behavior habit formation, covering 20 studies and more than 2,600 participants across behaviors like physical activity, diet, and flossing, found that the median time to form a habit ranged from roughly 59 to 66 days, with individual variability spanning anywhere from about 4 to 335 days.³

The same review found that morning practices and self-selected habits tended to show greater habit strength than routines imposed with more steps or more variability.

Applied to skincare, this suggests that a routine's long-term success depends less on how many active ingredients it includes and more on how easily it becomes something a person does without having to think about it each time. A single daily step is mechanically simpler to turn into an automatic habit than a multi-product sequence that has to be assembled the same way every morning and night.

How Formulators Approach Combining a Serum and Moisturizer

Reducing the number of steps in a routine doesn't remove the underlying formulation work; it just moves it earlier, into the product itself.

Balancing Active Delivery With Barrier Support

A standalone serum is generally optimized to deliver active ingredients efficiently, while a standalone moisturizer is optimized to reduce water loss and support the skin barrier. Combining both into one formula means neither function can be maximized in isolation; the active-ingredient concentration and the occlusive, humectant, and emollient content both need to be balanced within a single product rather than optimized separately.

Stability Considerations When Combining Ingredient Categories

Peptides in particular are sensitive to their formulation environment. Research on cosmetic peptide stability has found that peptides typically have a narrow optimal pH range for maximal stability and minimal degradation, and that in high-water formulations like serums and lotions, peptide bonds face ongoing hydrolysis pressure from the surrounding water itself.⁵

A widely cited 2007 study on formulating a cosmetic anti-aging peptide tested both an emulsion and a gel base, using rheology and in vitro release testing to evaluate which formulation approach preserved the peptide's stability more effectively, illustrating that the choice of formulation base itself, not just the active ingredient, affects how well a peptide holds up over a product's shelf life.⁵

Combining a peptide complex with a heavier moisturizing base adds another layer of complexity, since emulsifiers, preservatives, and other moisturizing ingredients can interact with peptide chains and affect their stability. Building a stable, single-step formula that houses both an active peptide complex and a heavier moisturizing base is a more involved formulation problem than keeping the two separate, which is part of why not every combined product on the market handles this balance the same way.

What a Combined Formula Looks Like in Practice

Darkfin Labs' Longevity Protocol reflects this consolidation approach directly. Instead of a separate treatment serum and moisturizer, the product combines its L-01™ peptide complex and niacinamide with a squalane-and-propanediol moisture base into a single daily application, reducing what would otherwise be a two-step routine into one.

Application instructions describe applying the product once in the morning and once at night, followed by SPF during the day, rather than layering a separate serum underneath a separate moisturizer. From a habit-formation standpoint, that single step is also a simpler behavior to repeat consistently than a multi-product sequence.

Final Words

Adherence and habit-formation research both point in the same direction: a routine's real-world effectiveness depends as much on how consistently it gets followed as on which ingredients it contains, and fewer required steps generally make consistent follow-through easier.

Reducing the number of steps is one way formulators are responding to that finding, though it shifts the complexity into the formulation itself, particularly around ingredient stability, rather than eliminating it, which is worth keeping in mind when comparing a combined product against a traditional two-step routine.