Educational guide

Do Popular Skincare Ingredients Like Niacinamide and Retinol Actually Work?

Introduction Niacinamide (Vitamin B3) Retinol and retinoids Other popular ingredients Synergistic combinations and formulation considerations Evidence gaps and areas for future research Conclusion References Further reading Explore the science behind today’s m

Written by Peptide Therapy Guide Editorial TeamPublished September 6, 2026

For education only

This guide cannot diagnose a condition or recommend a personal treatment plan. Discuss medical questions with a qualified professional.

Explore the science behind today’s most popular skincare actives, from niacinamide to retinoids, and discover what truly works, what remains unproven, and how evidence-based choices are shaping the future of skin health.

Introduction

Cosmeceutical ingredients now drive one of dermatology’s fastest-growing markets, as consumers and clinicians seek topical solutions that promise firmer, clearer skin. This rapid expansion, largely fueled by social media trends and accessible over-the-counter formulas, has outpaced rigorous scientific research, with many active ingredients entering medicine cabinets before trials verify their benefits or risks.

This article reviews the evidence on niacinamide (NAM), retinol, vitamin C, hyaluronic acid, peptides, and sunscreens, examining their benefits, safety, and research gaps.

Niacinamide (Vitamin B3)

Niacinamide (NAM), the water-soluble amide of vitamin B3, serves as a precursor for nicotinamide adenine dinucleotide (NAD⁺) synthesis. Both oral and topical niacinamide can increase intracellular NAD⁺ levels in skin cells, supporting cellular energy metabolism and DNA repair.

Topically applied niacinamide enhances epidermal NAD⁺ concentrations, which in turn support DNA repair and strengthen antioxidant defenses by increasing the availability of NADPH, a cofactor for the regeneration of reduced glutathione and other antioxidants.

In addition to modulating keratinocyte lipid output by stimulating the synthesis of ceramides, cholesterol, and free fatty acids to improve skin barrier function, niacinamide also inhibits the transfer of melanosomes from melanocytes to keratinocytes, thereby reducing hyperpigmentation.2

In reconstructed epidermis and human studies, 2-5% NAM upregulates ceramide, free fatty acid (FFA), and cholesterol production while increasing involucrin and filaggrin activity, all of which tighten the stratum corneum and improve hydration. A split-face study demonstrated that a 5% NAM moisturizer reduced hyperpigmented area more than a 2% formula, thus confirming dose-responsive lightening through slower melanosome transfer.2

The anti-inflammatory effects of NAM are attributed to its inhibition of nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) and mitogen-activated protein kinase (MAPK) signaling, which reduces the expression of interleukin-6 (IL-6), IL-8, and prostaglandin E₂ (PGE₂). A 0.25% N-methylnicotinamide (N-MNA) gel has been shown to improve rosacea symptoms within four weeks, with NAM suppressing Cutibacterium acnes (C. acnes)-triggered cytokines relevant to acne. Randomized trials have similarly reported smoother texture, fewer wrinkles, and greater elasticity after twelve weeks of 5% NAM use.2

NAM is well-tolerated when used at a concentration of 5% in leave-on products, with adverse systemic effects only reported following high oral doses. The favorable safety profile of NAM justifies the routine inclusion of 2-5% concentrations in moisturizers, sunscreens, and serums for barrier support, pigment evening, anti-inflammatory care, and long-term skin resilience.2

Retinol and retinoids

Retinoids are in the vitamin A family and include retinol and retinaldehyde, as well as synthetic analogues like tretinoin (all-trans-retinoic acid), adapalene, tazarotene, and isotretinoin.

Retinoids share a conjugated backbone yet differ in their receptor affinity. For example, tretinoin activates all retinoic acid receptor (RAR) subtypes, whereas adapalene favors RAR-β/γ, producing fewer irritant reactions.

After binding cellular carriers, retinoids engage RAR/retinoid X receptor heterodimers that attach to retinoic acid response elements. This leads to the modulation of genes that control keratinocyte proliferation and differentiation, as well as collagen remodeling, which support cell turnover, a compact stratum corneum, thicker epidermis, and renewed dermal matrix.3

Placebo-controlled trials confirm that topical tretinoin 0.05-0.1% significantly smooths wrinkles, lightens mottled pigmentation, and increases collagen production between three and 12 months across diverse phototypes, with benefits persisting beyond one year. Adapalene gel diminishes actinic keratoses and brightens lentigines while maintaining excellent tolerability.

Retinol induces comparable epidermal thickening and collagen synthesis with minimal erythema. Isotretinoin alleviates photodamage and, as a result, is frequently used for the treatment of acne.3

Some limitations associated with retinoids include irritation, burning, and early photosensitivity, which are due to the induction of IL-8 and monocyte chemoattractant protein-1. To overcome these limitations, solid-lipid and polymeric nanoparticle formulations have been developed to protect retinol and tretinoin from photodegradation, localize drug accumulation within the epidermis, and reduce irritation in animal and volunteer studies. The continued development of receptor-selective analogs and nanocarriers will further support the advancement of gentle retinoid therapies for aging skin, acne, and pigmentary disorders.3

Other popular ingredients

Topical vitamin C, which is otherwise known as ascorbic acid, is a potent antioxidant that scavenges ultraviolet (UV)-induced reactive oxygen species (ROS) while simultaneously up-regulating pro-collagen messenger ribonucleic acid (RNA). Randomized control trials have confirmed that daily 10% vitamin C serum reduces wrinkles and improves dermal collagen after 12 weeks, particularly when combined with broad-spectrum sun filters.4

Hyaluronic acid is a high-molecular-weight glycosaminoglycan that binds 1,000-fold its weight in water. Oral or injectable hyaluronic acid increases stratum corneum hydration, restores tight-junction proteins, and reduces the appearance of atrophic skin without inducing significant irritation in eight-week studies.4

Alpha-hydroxy acids (AHAs), such as glycolic and lactic acids, as well as the lipid-soluble beta-hydroxy acid (BHA) salicylic acid, dissolve corneodesmosomes to accelerate desquamation. Concentrations of 2-10% flatten hyperkeratotic plugs, fade lentigines, and stimulate dermal matrix renewal, all of which are ideal for managing acne and photoaged skin.5

Short bioactive peptides, typically six or fewer amino acids in length, mimic growth-factor sequences, signal fibroblasts to generate collagen types I and III, as well as exhibit antimicrobial or anti-inflammatory actions that accelerate wound closure in preclinical and early clinical studies. Sunscreens containing inorganic zinc oxide or organic filters counteract UV-A and UV-B radiation, thereby preventing deoxyribonucleic acid (DNA) mutagenesis, dyspigmentation, and 24% of new facial wrinkles in longitudinal cohorts while lowering melanoma incidence.6,7

Synergistic combinations and formulation considerations

Retinoids remain stable at a pH between five and six, with acidic bases causing degradation and alkaline vehicles preventing their uptake. Since patient response to retinoids is dose-dependent, yet irritation rises with strength, clinicians typically initiate a 0.025% tretinoin or 0.25% retinol treatment, then titrate while adding moisturizers that buffer pH and reinforce the skin barrier.

Maintaining formulation pH between five and six also preserves NAM integrity, which hydrolyzes outside the range. Encapsulation tools, including multilayer liposomes and nanostructured lipid carriers, create reservoirs that protect retinoids from light and support their slow delivery, thereby reducing erythema and dryness.9,10

Synergistic pairing amplifies benefits, as NAM supports ceramide synthesis and reduces inflammation. When combined with retinyl propionate, NAM provides more significant reductions in deep wrinkles than prescription tretinoin at equivalent study periods with superior tolerability.

Peptides, carob flavonoids, and antioxidants, such as Terminalia chebula polyphenols, complement retinol by stimulating collagen production and scavenging radicals, allowing clinicians to reduce retinoid doses without compromising efficacy. Formulators also blend gentler esters like retinyl acetate or retinyl palmitate with small retinol amounts to mimic the results of 0.02% tretinoin while minimizing dermatitis.

Glycerin- or ceramide-rich vehicles, nightly application, and daily broad-spectrum sunscreens complete a regimen that maximizes efficacy, controls irritation, and improves long-term patient adherence over time.9,10

Evidence gaps and areas for future research

Most cosmetic products rely on small, open-label studies, with placebo-controlled, randomized controlled trials (RCTs) remaining scarce, especially for retinol esters, retinaldehyde, and new nano-carriers. Thus, multicenter RCTs powered to detect clinically meaningful differences in wrinkle depth, dyspigmentation, and barrier integrity are crucial.10

Irritation thresholds, pigment responses, and optimal dosing vary with age, phototype, and baseline barrier status. As a result, current guidance to ‘start low and titrate’ is empirical, rather than evidence-driven.

Stratified trials that pre-define cohorts by skin type, genetic polymorphisms such as retinoic acid receptor variants, or microbiome profiles are needed to clarify who benefits most from the treatment. These trials could also determine which patients may be at a greater risk of experiencing dermatitis or post-inflammatory hyperpigmentation.10

Long-term safety data are similarly limited, as only tretinoin has a two-year controlled study confirming sustained benefits without serious adverse events. Other retinoids and emerging nanoformulations lack data on chronic exposure, including the potential for these formulations to cause cumulative irritation, barrier alteration, or disrupted systemic absorption. Extended safety registries and real-world pharmacovigilance, coupled with in vitro and in silico toxicokinetic modeling, are urgently needed before these innovations can be confidently recommended for lifelong photoaging prevention.10

Conclusions

Evolving dermatologic research now offers accurate yet varied support for NAM, retinoids, vitamin C, hyaluronic acid, hydroxy acids, peptides, and broad-spectrum sunscreens. However, efficacy and tolerability remain dependent upon formulation, concentration, and individual biology.

Ultimately, an evidence-based and goal-oriented regimen maximizes therapeutic benefits, minimizes adverse reactions, and fosters patient confidence in modern cosmeceutical care for diverse age groups and backgrounds.

References

Crous, C., Pretorius, J., & Petzer, A. (2024). Overview of popular cosmeceuticals in dermatology. Skin Health and Disease, 4(2), ski2-340. DOI: 10.1002/ski2.340, https://academic.oup.com/skinhd/article/4/2/ski2.340/7736686
Boo, Y. C. (2021). Mechanistic basis and clinical evidence for the applications of nicotinamide (niacinamide) to control skin aging and pigmentation. Antioxidants, 10(8), 1315. DOI: 10.3390/antiox10081315, https://www.mdpi.com/2076-3921/10/8/1315
Mukherjee, S., Date, A., Patravale, V., Korting, H. C., Roeder, A., & Weindl, G. (2006). Retinoids in the treatment of skin aging: an overview of clinical efficacy and safety. Clinical interventions in aging, 1(4), 327-348. DOI: 10.2147/ciia.2006.1.4.327, https://pubmed.ncbi.nlm.nih.gov/18046911/
Boo, Y. C. (2022). Ascorbic acid (vitamin C) as a cosmeceutical to increase dermal collagen for skin antiaging purposes: emerging combination therapies. Antioxidants, 11(9), 1663. DOI: 10.3390/antiox11091663, https://www.mdpi.com/2076-3921/11/9/1663
Moghimipour, E. (2012). Hydroxy acids, the most widely used anti-aging agents. Jundishapur journal of natural pharmaceutical products, 7(1), 9. https://pmc.ncbi.nlm.nih.gov/articles/PMC3941867/
Md Fadilah, N.I., Shahabudin, N.A., Mohd Razif, R.A., Sanyal, A., Ghosh, A., Baharin, K.I., Ahmad, H., Maarof, M., Motta, A. and Fauzi, M.B., 2024. Discovery of bioactive peptides as therapeutic agents for skin wound repair. Journal of Tissue Engineering, 15, 20417314241280359. DOI: 10.1177/20417314241280359, https://journals.sagepub.com/doi/10.1177/20417314241280359
Gabros, S., Nessel, T. A., & Zito, P. M. (2023). Sunscreens and photoprotection. In StatPearls [Internet]. StatPearls Publishing. https://www.ncbi.nlm.nih.gov/books/NBK537164/
Milosheska, D., & Roškar, R. (2022). Use of retinoids in topical antiaging treatments: a focused review of clinical evidence for conventional and nanoformulations. Advances in therapy, 39(12), 5351-5375. DOI: 10.1007/s12325-022-02319-7, https://link.springer.com/article/10.1007/s12325-022-02319-7
Handler, M., Adams-Woodford, A., Ayres, P., Giancola, G., & Diaz, I. (2022). Facial Aging Improvement Case Study Using a Novel Combination of Retinol, Niacinamide, and Terminalia Chebula. Journal of drugs in dermatology: JDD, 21(7), 784-788. DOI: 10.36849/JDD.6621, https://jddonline.com/articles/facial-aging-improvement-case-study-using-a-novel-combination-of-retinol-niacinamide-and-terminalia-chebula-S1545961622P0784X/
Milosheska, D., & Roškar, R. (2022). Use of retinoids in topical antiaging treatments: a focused review of clinical evidence for conventional and nanoformulations. Advances in therapy, 39(12), 5351-5375. DOI: 10.1007/s12325-022-02319-7, https://link.springer.com/article/10.1007/s12325-022-02319-7

Helpful context for this guide

Source-derived material selected through this article’s indexed topics.

Related questions

01What is nisin?

Some bacterial species produce antimicrobial peptides known as bacteriocins that have been used in the food industry as preservatives. For example, nisin, which is produced by Lactococcus lactis, has broad-spectrum bactericidal activity and has been used as a food preservative throughout the world. Nisin is effective in controlling Gram-positive bacteria such as Clostridioides difficile. In combination with other compounds like ethylene diamine tetra-acetic acid and cinnamaldehyde, nisin has been effective in controlling enterotoxigenic Gram-negative bacteria such as Escherichia coli. Previous studies have used chicken and mouse models to demonstrate the in vivo efficacy of nisin on the microbiome, whereas nisin efficacy has been proven in ex vivo experiments on the human microbiome. To date, no studies have assessed the in vivo effects of nisin in large mammals.

Source: www.news-medical.net ↗

02What was done in this study?

In the study, published in Scientific Reports, the researchers built on their earlier discovery of the peptide called AC253. This compound was tested in mice with AD. It was found to block the attachment of beta-amyloid to a brain cell receptor called the amylin receptor, and thus inhibit its toxic effects, as shown by an improvement in spatial memory. However, it is difficult to administer this compound because it doesn’t cross the blood-brain barrier in large amounts, and is quickly broken down in the blood. The dosage must therefore be massively increased, pushing up the amounts required for efficacy and increasing the difficulty of administration, besides enhancing the chances of an immune reaction. One way out is to convert the formulation into a pill rather than an injectable form. The complex structure of AC253 makes this difficult as well. Instead, the team devised an ingenious solution. They cleaved the compound into smaller amylin peptides, or chains of 12-14 amino acids, and tested each for its anti-amyloid activity in old mice which showed signs of AD. In this way, they found two short peptides that had the same effects as the larger compound. In particular, the researchers identified a segment that was common to both peptides, namely, SQELHRLQTY.

Source: www.news-medical.net ↗

03A peptide identified in a fungus found in northern European pine forests possesses as much power as penicillin as well as vancomycin, according to an international team of researchers.

Reporting in the October 13 issue of Nature, a team from Denmark-based biotech company Novozymes, and researchers from Georgetown University Medical Center and the David Geffen School of Medicine at UCLA, say they have isolated "plectasin," the first defensin ever found in fungi. The research was performed at Novozymes laboratories in Denmark. Defensins are peptides, miniature protein molecules that are produced by a wide range of animals to protect themselves against infection. Humans have defensins in their white blood cells and in their skin, for example, but it is believed that this new fungal defensin, plectasin, is more potent and targets certain bacteria more specifically. Indeed, when plectasin was tested in the laboratory and in animals, it proved to be highly effective against the bacteria Streptococcus pneumoniae, and Streptococcus pyogenes, including strains that are now resistant to conventional antibiotics. These bacteria are responsible for such diseases as meningitis, community-acquired pneumonia, strep throat, life-threatening sepsis, and flesh destroying skin infections. The discovery of plectasin has implications for the development of defensins as a treatment against many common, and deadly, infections, and may initiate a new era of antibiotic discovery and development, said study co-author Michael Zasloff, M.D., Ph.D., Professor in the Departments of Surgery and Pediatrics at Georgetown University Medical Center. Zasloff says that the field of antibiotic development has not changed much since 1929 when Alexander Fleming realized that the fungal "bread mold" Penicillium, which had landed by chance in a Petri dish produced a substance that eliminated colonies of staphylococcal bacteria. "Most antibiotics used by humans are produced by fungi and certain soil bacteria," he said. "Using our existing tools of discovery, we have failed to uncover any new classes of antibiotics from these sources over the past decade. However, by utilizing a new genetic approach that allowed the team to discover plectasin, we now know that a whole class of antibiotics has been overlooked." "This finding (plectasin), and the existence of about 200,000 additional species of fungi, opens up a vast universe to explore for novel peptide antibiotics," said co-author Robert Lehrer, M.D., Distinguished Professor of Medicine at the David Geffen School of Medicine at UCLA. Plectasin, if proven safe and effective in humans, could be on the market by 2012, said Lehrer. Zasloff and Lehrer are known internationally as experts in antimicrobial peptides - the class of antibiotics that plectasin falls within - and in this study they collaborated with Novozymes, a Danish biotech company that led the research. Zasloff and Lehrer are the only two scientists from U.S. universities on the team of 20 researchers who co-authored the research paper. All life forms have to defend themselves against microbial invaders - bacteria, fungi, viruses - and to do this, they produce antimicrobial defensin peptides. In humans, defensins are made by specific white blood cells and immune cells that later engulf foreign invaders, and by the skin and mucous membranes, in order to kill microbes before they invade protective barriers. Researchers believe that fungi have a similar system of defense, especially since these plant-like organisms live off rotting matter, said Zasloff. "They must compete with other organisms, like bacteria and viruses, which also want to consume the same meal. In addition, they need to defend themselves from being eaten by the microbes which surround them." But he said no one had been able to find defensins in fungi using traditional research techniques, which involved growing fungi in liquid cultures and then testing the culture to see if it contained any antibiotic molecule. The research team instead used the latest genetic science to search for the defensins they thought fungi must have. Selecting the Pseudoplectania nigrella species of fungus may have been serendipitous, Lehrer said, but the Novozymes team used state-of-the-art biotechnology to intercept ,and interpret its genetic messages and exhibited tremendous skill in producing plectasin efficiently, economically, and in large amounts." "I started working on antimicrobial peptides over three decades ago, said Lehrer, and my laboratory first described human defensins in 1985. So, the discovery of plectasin makes me feel like a grandfather." Further examination revealed that this defensin, plectasin, resembles defensins found in spiders, scorpions, dragonflies and mussels - thus suggesting that the defensins found in insects, molluscs and fungi arose from a common ancestral gene, the researchers say. Based on this information, the scientists now believe that defensins appeared in living things more than a billion years ago. The investigators then turned to the National Center for Antimicrobials and Infection Control, the Danish equivalent of the U.S. Centers for Disease Control, to test plectasin in the laboratory for antimicrobial activity against a broad spectrum of bacteria. It showed potent activity against several species of Gram-positive bacteria, and was especially active against S. pneumoniae (the leading cause of pneumonia), including all known clinical strains and those that are now resistant to conventional antibiotics. "That is important because increasing bacterial resistance to conventional antibiotics threatens the future of many antibiotics in current use," Zasloff said. "In mouse studies, plectasin showed extremely low toxicity, and was as effective as vancomycin and penicillin in curing the animals of experimental peritonitis (inflammation of the lining of the abdominal cavity, which can be deadly) and pneumonia caused by S. pneumoniae, the researchers report. "Although the precise mechanism by which plectasin exerts its antimicrobial activity is still under investigation, it may work by a mechanism that is very different from traditional antibiotics, Zasloff said. "As a group, defensins exhibit activity against many types of bacteria, fungi, protozoa, and even viruses. It is entirely possible that fungal defensins will be discovered that could be developed against all of these human pathogens," Zasloff added.

Source: www.news-medical.net ↗

04What was this study about?

It has been noted in around 20 percent of the world population suffers from some form of pain or the other. In many individuals, pain may be relieved initially with pain medications, but soon tolerance develops, and there is a decrease in the efficacy of pain relievers. One of the main symptoms of IBS seen commonly in many sufferers is chronic abdominal pain. Professor Lewis said, "All pains are complex, but gut pain is particularly challenging to treat and affects around 20 percent of the world's population. Current drugs are failing to produce effective pain relief in many patients before side effects limit the dose that can be administered." Professor Brierley echoed this statement saying, "Internal organs have a complex network of sensory nerves that have a wide array of voltage-gated ion channels and receptors to detect stimuli... The hypersensitivity of these nerves in disease often contributes to the development of pain."

Source: www.news-medical.net ↗

05What are functional peptides?

Conventional pharmacological studies on spices have traditionally focused on secondary metabolites like polyphenols, alkaloids, and terpenes. More recently, food science research has also examined spice proteins and their enzymatic hydrolysates, using proteomic methods such as liquid chromatography–tandem mass spectrometry (LC-MS/MS) to identify short bioactive peptide sequences released from larger precursor proteins.6 Once released during food processing, fermentation, or gastrointestinal digestion, these functional peptides can act as metabolic regulators, antimicrobials, or antioxidants.1 Functional peptides refer to specific protein fragments that, once released from their parent proteins, exert biological activities.1,2 In the context of foods, these activities are most often demonstrated using in vitro biochemical or cell-based assays, and their physiological relevance depends on bioavailability and dose.2 Unlike intact proteins, which can have the potential to be allergenic or difficult to absorb due to their complex tertiary structures, functional peptides may exhibit improved bioaccessibility, and some small peptides can cross the intestinal epithelial barrier via peptide transport systems. However, absorption efficiency varies substantially by peptide sequence and digestive conditions.6 Nutriomics and mechanistic investigations have established that the bioactivity of a peptide is dictated by its physicochemical properties, particularly its amino acid composition, molecular weight, and net charge. For example, the presence of hydrophobic amino acids like proline, leucine, and valine often correlates with high antioxidant and enzyme-inhibitory activity.2,3 Smaller peptides, typically those less than three kilodaltons (kDa) in size, exhibit greater stability against proteolytic degradation in the gastrointestinal tract.3 Moreover, cationic peptides are particularly effective as antimicrobial agents through their electrostatic interactions with bacterial membranes.3

Source: www.news-medical.net ↗

comparison

Comparisons

Side-by-side pages for commonly compared peptides and research compounds.

Source: peptideuniv.com

Research context

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Longevity, Performance & Obesity Research

A research peptide formulation developed to investigate metabolic regulation, mitochondrial function, and nutrient-sensing pathways.

Source: mypeptidematch.com ↗

About the author

Peptide Therapy Guide Editorial Team

Editorial team for Peptide Therapy Guide.

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Introduction

Niacinamide (Vitamin B3)

Retinol and retinoids

Other popular ingredients

Synergistic combinations and formulation considerations

Evidence gaps and areas for future research

Conclusions

References

Further Reading

Related questions

Comparisons

Longevity, Performance & Obesity Research

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