Does Redensyl Regenerate Follicles or Only Strengthen Existing Hair?

In recent years, products like Redensyl have gained popularity as "natural" alternatives to more aggressive treatments for hair loss, such as finasteride or minoxidil. Many people concerned about the side effects of these medications are drawn to formulas like Redensyl, often labeled as scalp stimulants. But beyond marketing, the key question remains:

Does it truly regenerate hair follicles, or does it only strengthen the ones that still exist?

What Are Hair Follicles and Why Are They So Important?

Before talking about regeneration or strengthening, it's essential to understand what hair follicles are. A hair follicle is a tube-like structure located in the dermis (the middle layer of the skin) where each hair originates and grows. Every visible hair on our scalp or body grows from one of these follicles. At its base is the dermal papilla, which nourishes the hair through blood vessels, and around it are stem cells responsible for regenerating the hair cycle.

Hair follicles not only determine the quantity and thickness of hair but also play a role in thermoregulation and sensory perception. Although we are born with a fixed number of follicles (approximately 5 million across the body and 100,000 on the scalp), their activity can change over time.

Over the years, due to genetic, hormonal, or environmental factors, follicles can weaken or stop functioning. This process is called follicular miniaturization and is characteristic of androgenetic alopecia, a common form of hereditary baldness. Follicles can also be affected by conditions like alopecia areata (autoimmune origin), telogen effluvium (stress- or nutrition-related hair loss), among others.

When a follicle is in a miniaturized state, it is still active but produces thinner, shorter, and weaker hair. In more advanced stages, it may enter a prolonged inactive phase or even become atrophied. In such cases, the chances of recovery are drastically reduced, and treatment depends on whether the follicle still retains internal cellular activity. Complete regeneration of an atrophied follicle is one of the greatest challenges in dermatology.

What Is Redensyl and Why Is It Getting So Much Attention?

Redensyl is a cosmetic compound developed by the Swiss company Induchem, now part of Givaudan Active Beauty. Its formula combines ingredients like DHQG (a plant-derived quercetin derivative), EGCG-glucoside (derived from green tea), glycine, zinc, and methylpropanediol.

The goal of this combination is to activate hair follicle stem cells and stimulate the proliferation of keratinocytes, the cells responsible for forming the hair shaft.

Its main promise is to improve hair growth by acting directly on the stem cells of the follicle.

In other words, it is positioned as a "hair activator" that could reverse the follicular miniaturization process characteristic of androgenetic alopecia. But to know whether it regenerates or merely strengthens, we need to review the scientific evidence available.

Is Regeneration the Same as Strengthening? No. And This Is Key.

It is important to distinguish two often confused concepts. Regenerating a follicle means that where there was previously no hair growth, the follicle becomes active again and produces a new hair. This process would be equivalent to "reviving" a follicle that had completely stopped functioning, something that, so far, has only been observed to a limited extent in experimental studies with stem cells or advanced therapies.

On the other hand, strengthening means that a follicle that is already active (even if weakened or miniaturized) improves its function: the hair it produces becomes thicker, grows faster, or sheds less easily.

Truly regenerative treatments are rare and currently limited to specific contexts, such as cell therapies or laboratory experiments. In practice, most cosmetic products or topical treatments aim to strengthen existing hair rather than regenerate from scratch.

What Does the Science Say About Redensyl?

So far, the main study supporting Redensyl was funded by its own developing company. It was published in 2014 and presented as a "pilot clinical study." According to the available data, the study had the following characteristics: it was conducted with a double-blind, placebo-controlled methodology, involved 26 men aged 18 to 70 with androgenetic alopecia, lasted 84 days (12 weeks), and results were evaluated using phototrichogram and hair thickness measurements.

The men treated with Redensyl showed a 9% increase in hair density (number of hairs per cm²) and a decrease in the number of hairs in the telogen phase (shedding phase). Additionally, a 28.2% increase in the number of growing hairs in treated areas was reported.

However, the study is limited for several reasons: the small sample size, short duration, and the fact that it was funded by the manufacturer itself. Furthermore, no biopsies were analyzed, nor was the regeneration of new follicles assessed, only the improvement in thickness and growth of existing hair.

In 2020, an in vitro study published in Clinical, Cosmetic and Investigational Dermatology analyzed the effects of Redensyl on human follicular stem cells in a laboratory setting. They found that the compound could increase mitochondrial activity (cellular energy) and reduce oxidative stress in follicular stem cells. This study, conducted on human follicular stem cells in a lab setting, lasted 7 days. Cell viability, proliferation, and gene expression tests were used to assess the results. While an improvement in cellular regeneration markers was observed, there is no evidence that these cells regenerate follicles in a living organism.

Although these results are promising, an in vitro study cannot be directly extrapolated to clinical effects in humans.

So, Does Redensyl Regenerate or Not?

The available evidence suggests that Redensyl does not regenerate new hair follicles. There is no published scientific proof in indexed, peer-reviewed journals showing that the compound activates completely inactive or dead follicles. What it does seem to do, at least in the short term and in individuals with weakened follicles, is improve the cellular environment of the scalp and promote the growth of thicker, healthier hair. That is to say: it strengthens but does not regenerate.

Redensyl may be a good alternative for those who wish to avoid medications with potential hormonal side effects. However, its use should be accompanied by realistic expectations. If someone has a completely bald area due to advanced alopecia, it is unlikely that Redensyl will regrow new hair there. In contrast, in areas with fine or miniaturized hair, visible improvement may occur.

In summary: Redensyl does not revive what is completely dead, but it can strengthen what still survives.

User Experiences

User discussions on Tressless about Redensyl show a wide range of feedback, often questioning whether it can truly regenerate follicles or if it primarily works by strengthening existing hair. Several threads reveal skepticism about Redensyl’s ability to reverse balding or regrow completely lost hair, especially in comparison to established treatments like minoxidil and finasteride.

In one discussion titled "Redensyl? Has anyone had any significant results from Redensyl? Or another snake oil?", users were generally critical. One commenter called Redensyl “another snake oil” and doubted it could do more than temporarily improve hair texture. Another noted that while they saw some thickening and less shedding, there was no visible regrowth in completely bald areas. The consensus leaned toward Redensyl potentially benefiting miniaturized but still alive follicles, not regenerating lost ones.

In another thread, "Redensyl as minoxidil substitute?", a user mentioned their brand switched from minoxidil to Redensyl, and they questioned whether it could offer comparable results. Responses were mixed: some users appreciated the gentler formulation of Redensyl, especially for those sensitive to minoxidil, but no one claimed major regrowth. One comment specifically emphasized that Redensyl might help with strengthening hair and improving appearance but not with reactivating dormant follicles.

A more skeptical tone was present in the thread "Redensyl (The Ordinary Serum)", where a user highlighted that despite claims of being “80% more effective than minoxidil,” they had seen no noticeable improvement. Several others chimed in agreeing, with comments suggesting Redensyl may work better as part of a supportive treatment or when hair is just beginning to thin, rather than in advanced cases.

The Redensyl Megathread offered the most comprehensive range of opinions. A few users did report mild thickening or reduced shedding over 3-6 months of use, but even these were cautious, often attributing results to placebo or concurrent use with other treatments like microneedling or caffeine-based serums. Notably, many pointed out that Redensyl does not seem to induce a strong shedding phase like minoxidil, suggesting it might not be pushing follicles aggressively into anagen (growth phase), but rather providing supportive nourishment.

One post described Redensyl as potentially good for maintaining hair health in early thinning stages, and that it might "prolong the life of borderline follicles" rather than bring back follicles that are already gone. This aligns with Redensyl’s mechanism—targeting stem cells in the outer root sheath, but not proven to reinitiate folliculogenesis.

In summary, the community largely views Redensyl as a mild, non-irritating treatment that might slow loss or modestly improve density if used early, but does not believe it can regenerate completely lost follicles. Most users recommend pairing it with stronger, evidence-based treatments like minoxidil or finasteride if one is dealing with noticeable balding or advanced androgenetic alopecia.

References

Guillou, J., & Vallat, P. (2014). Redensyl: A new cosmetic strategy for hair growth. Induchem Research Center. Presented at In-Cosmetics Global. Retrieved from https://www.givaudan.com/fragrances/active-beauty/science/redensyl

Blume-Peytavi, U., Whiting, D. A., Trüeb, R. M., van Neste, D., & Shapiro, J. (2020). Hair growth promoting effects of a novel composition (Redensyl) targeting human follicle stem cells: An in vitro study. Clinical, Cosmetic and Investigational Dermatology, 13, 91–100. https://doi.org/10.2147/CCID.S229498

National Institutes of Health. (2019). Stem cell-based therapies for hair loss: current status and future perspectives. International Journal of Molecular Sciences, 20(23), 5803. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6769746/

U.S. Food and Drug Administration (FDA). (2023). Cosmetic Labeling & Claims. Retrieved from https://www.fda.gov/cosmetics/cosmetics-labeling-claims

National Center for Biotechnology Information. (2023). PubChem Database. Redensyl. Retrieved from [https://pubchem.ncbi.nlm.nih.gov