OS-01 Hair Review: Does It Live Up to the Hype?

Article Summary

Curious about OneSkin’s OS-01 scalp serum that’s all over your feed? It claims to combat hair thinning by targeting cellular senescence, essentially attempting to “rejuvenate” your follicles. In this deep dive, we break down what senescence actually is, how it affects hair loss, and whether the science behind OS-01 holds up. We also compare it to rapamycin (the longevity favorite) and unpack the company’s unpublished trial data. If you’re considering adding OS-01 to your hair routine or want the facts beyond the hype, this one’s for you.

Full Article

OS-01 is a topical scalp serum developed by OneSkin, a biotech company based in San Francisco. Marketed as both an anti-aging skin treatment and a hair regrowth product, OS-01 aims to address hair thinning by targeting cellular senescence in the scalp. The serum has gained attention through social media and interviews with the company’s CEO, Carolina Reis Oliveira. In this article, we will examine what OS-01 is, explore the science of cellular senescence and its role in hair loss, and assess the evidence behind OS-01’s claims as a potential treatment for androgenetic alopecia.

Key Takeaways:

• Branding. OS-01 has positioned itself as a biotech-backed anti-aging and hair regrowth serum from OneSkin, a company known for its focus on longevity science. The branding strongly emphasizes scientific credibility and a “rooted in science” approach.
• Unique Selling Point. OS-01 is a peptide that specifically targets cellular senescence in the scalp, aiming to rejuvenate the hair follicle microenvironment by modulating the senescence-associated secretory phenotype (SASP).
• Clinical Support. OneSkin reports a 6-month third-party clinical study showing improvements in hair density, thickness, and hair cycling when used with daily dermarolling. However, these results have not been published in peer-reviewed journals and rely on company-provided summaries.
• Concerns. Key concerns include the lack of independently published human data, reliance on dermarolling for efficacy, marketing claims that oversimplify complex skin and hair biology, and typical limitations seen in brand-led before-and-after photos.
• Evidence Quality. The OS-01 serum scored 31/100 for evidence quality by our metrics.
• Recommendations. We recommend that OS-01 consider publishing the results of their 6-month pilot study and, ideally, conduct a larger, registered, placebo-controlled clinical trial.

What Is OS-01?

OS-01 for hair is a topical scalp serum developed by OneSkin, a biotech company based in San Francisco, as both an anti-aging skin product and a hair regrowth product. The product is claimed to address hair thinning and loss by targeting the biological process of cellular senescence in the scalp.^[1]OneSkin. (no date). Rooted in Science: The Clinical Evidence Supporting OS-01 Hair. Available at:  … Continue reading

The product is sold in 1.7 fl oz bottles, available in 1-, 3-, or 6-month supplies, and comes with a dermaroller for $69, $207, or $424.

The product contains a number of ingredients, of which you can see the whole list here: 

“Water, Glycerin, 1,2-Hexanediol, Butylene Glycol, Hydroxyacetophenone, Panthenol, Inulin, Helianthus Annuus (Sunflower) Sprout Extract, Cellulose Gum, Alpha-Glucan Oligosaccharide, Tetrasodium Glutamate Diacetate, Propanediol, Morus Nigra Leaf Extract, Arginine, Acetyl Tyrosine, Rehmannia Chinensis Root Extract, Pentylene Glycol, Sodium PCA, Erythritol, Chondrus Crispus, PEG-12 Dimethicone, Oryza Sativa (Rice) Bran Water, Decapeptide-52*, Calcium Pantothenate, Zinc Gluconate, Sodium Benzoate, Niacinamide, Ornithine HCL, Caprylyl Glycol, Polyquaternium-11, Citrulline, Hydrolyzed Soy Protein, Xanthan Gum, Glucosamine HCL, Disodium Succinate, Fisetin, Raspberry Ketone, Sodium Benzoate, Citric Acid, Potassium Sorbate, Arctium Majus Root Extract, Panax Ginseng Root Extract, Biotin. *OS-01 Peptide.”

Several familiar ingredients are present here, including niacinamide, calcium pantothenate, zinc gluconate, raspberry ketone, ginseng, fisetin, and biotin.

• Niacinamide: Research shows that it may help protect hair follicle cells from oxidative stres, reduce the expression of DKK-1 (a protein that promotes hair follicle regression), and prolong the anagen (growth) phase of hair follicles.^[2]Choi, Y-H., Shin, J.Y., Kim, J., Kang, N-G., Lee, S. (2021). Niacinamide down-regulates the expression of DKK-1 and protects cells from oxidative stress in cultured human dermal papilla cells. … Continue reading Clinical studies have demonstrated increased hair fullness and thickness in some participants using niacinamide derivatives, though it is thought that it doesn’t actually increase hair density.^[3]Draelos, Z.D., Jacobson, E.L., Kim, H., Kim, M., Jacobson, M.K. (2005). A pilot study evaluating the efficacy of topically applied niacin derivatives for treatment of female pattern alopecia. Journal … Continue reading
• Calcium Pantothenate: This ingredient is commonly found in hair care products and supplements. Some studies suggest it may help improve hair thickness and reduce hair loss, especially when combined with zinc. For example, a clinical trial in women found that co-administration of zinc sulfate and calcium pantothenate alone was less pronounced, and more research is needed.^[4]Siavash, M., Tavakoli, F., Mokhtari, F. (2017). Comparing the effects of zinc sulfate, calcium pantothenate, their combination and minoxidil solution regimens on controlling hair loss in women: a … Continue reading
• Raspberry Ketone: This has been studied in small human trials and animal models. Topical application promoted hair growth in about 50% of humans with alopecia, possibly by increasing dermal IGF-1 production through sensory neuron activation.^[5]Harada, N., Okajima, K., Narimatsu, N., Kurihara, H., Nakagata, N. (2008). Effect of topical application of raspberry ketone on dermal production of insulin-like growth factor-I in mice and on hair … Continue reading However, the evidence base remains limited, and larger studies are necessary to confirm these effects.
• Fisetin: Fisetin is a polyphenol that has shown promise in preclinical studies. It may promote hair growth by increasing telomerase reverse transcriptase (TERT) expression, activating hair follicle stem cells, and facilitating the transition from a resting to a growth phase.^[6]Kubo, C., Ogawa, M., Uehara, N., Katakura, Y. (2020). Fisetin promotes hair growth by augmenting TERT expression. Frontiers in Cell and Developmental Biology. 8(566617). Available at … Continue reading Animal studies suggest that fisetin may induce hair growth; however, human data are currently lacking.
• Biotin: This ingredient is widely marketed for hair health, but strong evidence for its effectiveness in preventing hair loss or promoting hair growth in people without a deficiency is lacking. Biotin supplementation can help restore hair growth in cases of true biotin deficiency, but such deficiencies are rare. Most studies do not support its use for hair loss in otherwise healthy individuals, though it remains a popular ingredient.^[7]Yelich, A., Jenkins, H., Holt, S., Miller, R. (2024). Biotin for Hair Loss: Teasing Out the Evidence. Journal of Clinical and Aesthetic Dermatology. 17(8). 56-61. Available at: … Continue reading

However, the one we will be focusing on in this article is Decapeptide-52, also known as the OS-01 Peptide.

There has been a lot of hype on social media about this product, including a particularly interesting YouTube video featuring Dave Asprey, who talks with Carolina Reis Oliveira, the CEO and Co-founder of OneSkin.^[8]Asprey. D. (2025). Hair Growth Expert: Scientists Discover a Secret Peptide that Reverses Balding | Caroline Oliveria. YouTube. Available at: https://www.youtube.com/watch?v=FSY1x40N2ys Accessed: … Continue reading Carolina holds degrees in stem cell biology and tissue engineering, as well as a doctorate in immunology, which bodes well for the scientific integrity of the product.

However, in the first ~15 seconds of the above video, Carolina makes some interesting statements:

1. “The scalp of the skin basically has a similar structure of the skin in your face…”
2. “Your hair follicles are basically embedded in the epidermal layer…”
3. “…a lot of the things that we see happening in the skin of our face also happen in our scalp”

Now let’s break down what is wrong with these statements:

• “The scalp of the skin basically has a similar structure of the skin in your face…”

This statement is partially accurate. While the scalp and facial skin share the same basic layers (epidermis, dermis, etc.), there are significant structural and functional differences:

• When measuring total skin thickness in both men and women, scalp skin was found to be among the thickest.^[9]Oitulu, P., Tekecik, M., Taflioglu, T., Kilinc, F., Ince, B. (2022). Measurement of Epidermis, Dermis, and Total Skin Thicknesses from Six Different Face Regions. Selcuk Medical Journal. 38(4). … Continue reading
• The scalp contains a much higher density of hair follicles and sebaceous glands than facial skin.^[10]Gao, J., Liu, C., Zhang, S., Teacher, M.P., Bouabbache, S., Pouradier, F., Pangard. (2018). Revisiting, in vivo, the hair greasing process by the Sebuprint method. Skin Research and Technology. … Continue reading 
• The scalp is more prone to certain inflammatory and microbiome-related disorders due to its unique structure and physiology.^[11]Xu, Z., Wang, Z., Yuan, C., Liu, X., Yang, F., Wang, T., Wang, J., Manabe, K., Qin, O., Wang, X., Zhang, Y., Zhang, M. (2016). Dandruff is associated with the conjoined interactions between host and … Continue reading 

So, while the basic structure is similar, the differences are clinically and biologically significant.

• “Your hair follicles are basically embedded in the epidermal layer…”

This is factually incorrect. Hair follicles are not embedded in the epidermal layer; they are skin appendages that extend deep into the dermis, with the bulb even reaching the hypodermis (subcutaneous tissue).^[12]Oh, J.W., Kloepper, J., Langan, E.A., Kim, Y., Yeo, J., Kim, M.J., Hsi, T.C., Rose, C., Yoon, G.S., Lee, S.J., Seykora, J., Kim, J.C., Sung, Y.K., Kim, M., Paus, R., Plikus, M.V. (2016). A guide to … Continue reading 

• “…a lot of the things that we see happening in the skin of our face also happen in our scalp”

This is generally true, but it oversimplifies the differences. Many skin conditions (like psoriasis, eczema, and seborrheic dermatitis) can occur on both the scalp and face. However, the scalp’s unique anatomy, thicker skin, increased hair follicles, more sebaceous glands, and its coverage by hair, means it is prone to specific issues (like dandruff and increased oiliness) that are less common or present differently on facial skin. So, while there is overlap, the statement ignores important distinctions in disease prevalence and presentation.

These statements reinforce what we have been discussing in other articles – that you cannot blindly trust what people say. We should always adopt a scientific approach to the information we read online and attempt to find the scientific basis for their claims. 

With this in mind, we will explore the science of the product, examine what senescence is, and explore the data that suggests OS-01 can enhance hair growth.

What is Senescence and How is It Involved in Hair Cycling and Loss?

Before we get into how OS-01 works, it is essential to understand what senescence is, when it can be beneficial for hair growth, and when it can be detrimental.

Cellular senescence can be thought of as a “pause button for cells”. When cells are stressed or damaged due to factors such as DNA damage, aging, or excessive environmental stress, they cease to divide permanently. But instead of dying like in programmed cell death (apoptosis) they stay active, sending out signals to their neighboring cells, and beyond. 

Key features of these cells include:^[14]Nakanishi, M. (2025). Cellular senescence as a source of chronic microinflammation that promotes the aging process. Proceedings of the Japan Academy, Ser.B, Physical and Biological Sciences. 101(4). … Continue reading 

• A permanent stop in cell division: They’re kept in check by guardian pathways (p54/p2 and p16/Rb) that make sure they never divide again.
• Shape changes: They get bigger, flatter, and may look like “fried eggs” under the microscope.
• Special markers: Scientists detect them using a blue stain (called senescence-associated β-galactosidase (SA-β-gal)) that shows they have more lysosomes – cell “recycling bins”. 
• Secretory profile: They secrete a cocktail of chemicals, cytokines, growth factors, and enzymes, known as the senescence-associated secretory phenotype (SASP). This cocktail affects the surrounding tissue, sometimes beneficially, sometimes harmfully.

In recent years, senescence has become a trendy buzzword in the beauty and longevity industries, often used to market products as anti-aging breakthroughs. While genuine scientific research shows that senescent cells play a real role in aging and tissue decline, many companies oversimplify or exaggerate this science to promote creams, serums, or supplements with vague claims of “targeting senescence”. In reality, effectively targeting senescent cells is complex and context-dependent, and not every product touted as a senescence solution is supported by robust clinical evidence. As a result, the term is sometimes misappropriated more as a marketing hook than a rigorously validated mechanism.

Furthermore, while senescence was once thought of as a detrimental mechanism, it can actually be beneficial for both overall health and hair health.

Helpful Senescence: Encouraging Hair Growth

As mentioned above, some senescent cells can actually benefit hair growth:^[15]Wang, X., Ramos, R., Phan, A.Q., Yamaga, K., Flesher, J.L., Jiang, S., et al. (2023). Signalling by senescent melanocytes hyperactivates hair growth. Nature. 618(7966). 808-817. Available at: … Continue reading 

• Osteopontin signal: Senescent pigment cells (melanocytes) in skin moles produce a molecule called osteopontin. This acts like a motivational speaker for nearby hair cells by binding to CD44 receptors, waking them up.
• Stem cell activation: This process prompts hair follicles to exit their resting phase and re-enter growth mode, much like flipping the switch from winter to spring. 
• Proven boost: Injecting osteopontin or turning up its production in lab animals triggered hair growth; blocking it canceled the effect.

Harmful Senescence: Fueling Hair Loss

Recent studies show that accumulation of senescent cells can play a role in both androgenic alopecia (AGA) and age-related hair thinning.

As we age, more cells in the hair follicle’s support structures, like dermal papilla cells (DPCs) and hair follicle stem cells (HFSCs), become senescent.^[16]Shin, W., Rosin, N.L., Sparks, H., Sinha, S., Rahmani, W., Sharma, N., Workentine, M., Abbasi, S., Labit, E., Stratton, J.A., Biernaskie, J. (2020). Dysfunction of Hair Follicle Mesenchymal … Continue reading These cells lose their ability to renew themselves and support healthy hair growth, resulting in weaker follicles that gradually shrink over time. This process, known as hair follicle miniaturization, is why aging hair tends to become thinner and sparser.

Age-related hair thinning features a gradual loss of follicle stem/progenitor cell function, increased senescent cell burden, and mitochondrial dysfunction.^[17]Shin, W., Rosin, N.L., Sparks, H., Sinha, S., Rahmani, W., Sharma, N., Workentine, M., Abbasi, S., Labit, E., Stratton, J.A., Biernaskie, J. (2020). Dysfunction of Hair Follicle Mesenchymal … Continue reading This leads to both HFSC and DPC dysfunction.

Preclinical studies (studies done in cells or animals) have shown that antioxidants, senolytics, and interventions that reduce DPC/HFSC senescence or SASP can delay or ameliorate hair loss.^[18]Deng, Y., Wang, M., He, Y., Liu, F., Chen, L., Xiong, X. (2023). Cellular senescence: Ageing and Androgenetic Alopecia. Dermatology. 239(4). 533-541. Available at: https://doi.org/10.1159/000530681 However, clinical translation remains limited. Furthermore, some evidence suggests that senescence may be a consequence, rather than a sole cause, of follicle dysfunction, meaning that treating just the senescence aspect alone may not be beneficial for hair regrowth.^[19]Mirmirani, P., Karnik, P. (2010). Comparative Gene Expression Profiling of Senescent and Androgenetic Alopecia Using Microarray Analysis. Aging Hair. 67-76. Available at: … Continue reading

How Does the OS-01 Peptide Work?

According to OneSkin, OS-01 for hair targets senescent cells in the hair follicle to improve hair regrowth. One study frequently referenced on their website was conducted using human skin models.^[20]Zonari, A., Brace, L.E., Al-Katib, K., Porto, W.F., Foyt, D., Guiang, M., Cruz, E.A.O., Marshall, B., Gentz, M., Guimaraes, G.R., Franco, O.L., Oliveira, C.R., Boroni, M., Carvalho, J.L. (2023). … Continue reading In this study, OS-01 (referred to as pep14) was identified and characterized for its senomorphic activity. As a senomorphic, the OS-01 peptide reduces the burden of cellular senescence by suppressing the harmful secretions associated with the senescence-associated secretory phenotype (SASP) and by preventing pre-senescent cells from progressing to full senescence. Importantly, it does not kill or eliminate existing senescent cells.

OneSkin also seems to have conducted a laboratory study using outer root sheath keratinocytes (ORSKs).^[21]OneSkin. (no date). Discover the science behind every claim. Available at: https://www.oneskin.co/pages/claims?_ab=0&_fd=0&_sc=1 Accessed: June 2025

Interestingly, we had some difficulty determining the source of this information. It’s present on their shop page for OS-01 HAIR, but they cite 6 studies that don’t contain any information about this study. We then went to their Claims section and found the information below – again, however, there was no reference. 

We went to read some of the blogs where this information was also stated; the citation, however, led us back to the Claims section. The only conclusion we can draw is that OneSkin conducted an internal study that has not yet been published. Therefore, we should take all results with a pinch of salt.

OneSkin treated the cells with corticotropin-releasing hormone (CRH) (to induce senescence) alone or in combination with OS-01. According to the website, after 72 hours, cells treated with OS-01 + CRH showed significantly lower CDKN1A (p21) levels compared to those treated with CRH alone. 

Unfortunately, they don’t have any further data or information about this, so we can only go with what is written here.

Can OS-01 Benefit Patients with Androgenetic Alopecia?

OneSkin has also conducted a 6-month independent third-party clinical study in which 30 participants (23 women and 7 men) applied OS-01 HAIR twice daily and dermarolled their scalps once daily.^[22]OneSkin. (no date). Discover the science behind every claim. Available at: https://www.oneskin.co/pages/claims?_ab=0&_fd=0&_sc=1 Accessed: June 2025 Again, this data is unpublished in any peer-reviewed journal and so we are just having to go from what is on the site.

The overall results showed:

Category	Details
Hair Density	86.67% showed 39.62% avg increase after 6 months
Hair Density	70% showed 9.97% avg increase after 3 months
Hair Density	Double-blind, 30 participants, twice daily + dermarolling
Hair Density (Men)	85.71% men showed 34.86% avg increase after 6 months (7 men)
Hair Thickness	83.33% showed 42.58% avg increase after 6 months
Hair Thickness	Significant increase between 3 and 6 months
Hair Thickness (Men)	100% men showed 36.68% avg increase after 6 months; 85.71% men 28.42% after 3 months
Hair Cycle	73.33% showed 42.39% avg increase in anagen hairs after 6 months
Hair Cycle	Significant increase between 3 and 6 months
Hair Cycle (Men)	85.71% men showed 20.19% avg increase at 3 months, 35.42% at 6 months
Scalp Microbiome	Supported scalp microbiome: increased M. globosa, improved ratio, better bacterial diversity
Consumer Perception (Clinical) – 3 Months	80% saw hair improvement, 76.67% healthier hair, 70% faster growth, 73.33% fuller hair, 70% nourished scalp
Consumer Perception (Clinical) – 6 Months	70% faster growth, 76.67% healthier hair, 73.33% less shedding, 83.33% nourished hair, 70% thicker, 73.33% stronger, 70% better texture
Consumer Perception (Brand-led) – Immediate	89.47% could style hair, 85% lightweight
Consumer Perception (Brand-led) – 2 Months	80.95% more hydrated scalp
Consumer Perception (Brand-led) – 3 Months	81.82% new hair growth, 72.73% denser hair
Sensitive Skin	Dermatologically tested on 55 volunteers; no reactions
Lab Data – Senescence	OS-01 peptide reduces cellular senescence (lab data)
Lab Data – Senescence (Stress-induced)	Significant reduction in CRH-induced senescence (*p<0.05)
Lab Data – Inflammation	Significant reduction in IL-6 inflammation marker (*p<0.05)

We see some issues immediately jumping out about the clinical trial OneSkin has conducted:

• OneSkin do not explicitly mention whether the participants have any type of hair loss.
• The study included no placebo or treatment group – this means we can’t find out if hair cycle seasonality played any part in the participants’ hair growth.
• The treatment was combined with microneedling. Microneedling has been shown to potentially improve terminal hair counts by itself (we covered one here) so how can we separate out the effects of the peptide vs. the microneedling?
• In a similar vein, the product itself contains a number of other ingredients (with varying evidence showing improvement on hair regrowth) – so how can we separate out the effects of these compared to the peptide?
• While OneSkin do tell us how the hair counts were done, there was no disclosure of how terminal hairs were defined and starting hair zone parameters for the participants. For example in the niostem study, the researchers clearly outlined how they categorized terminal/vellus hair density (vellus (< 40 μm) and terminal (> 40 μm) hairs). A number of other studies however also don’t define terminal hairs (one that comes to mind is the CBD oil study) – so while it does happen, it is not good practice.
• Certain phrasings appear to be potentially misleading:
  • From the Claims section: “After 6 months, 83.33% of participants experienced a 42.58% average increase in hair thickness (sum of hair widths). (****p < 0.0001)”. The statistic refers only to the subset (83.33%) of participants who experienced an increase, not the entire study population. This means that 16.67% of participants did not experience an increase, but their results are not included in the average, potentially inflating the reported effect. The phrasing also raises the question of whether participants with no improvement or negative outcomes were excluded from the calculation. If so, and if those excluded participants had poor or negative results, the true average increase would be lower than reported.
    • This is not the only claim that does this and so we have to wonder what is happening with the other participants?
  • From the Claims section: “Participants saw a significant increase in hair thickness (sum of hair widths) between 3 and 6 months (**p < 0.01)”. Because we don’t have any graphs or data for this, we have to wonder…do we have a Niostem problem all over again? Niostem published their clinical data in February 2025 and claimed that “Terminal hair density improved significantly over time…” but this is not compared to the baseline – it’s compared to the three month time point, where there was actually a decrease in terminal hair density from the baseline. You can read our article about this here. Unfortunately we do not have any further information from OneSkin so we can’t know exactly what is happening.

You can read or watch some of our content that talk about these subjects here:

Deceptive But Legal: 3 Ways Marketers Cheat Hair Loss Studies

The Hair Loss Industry Is Broken | Evidence Quality Masterclass

Understanding Evidence Quality | How Hair Loss Companies Cheat Clinical Trials

Oneskin also has some before-and-after photos on their website, allowing us to see the progress people have experienced. However, they do fall for the usual pitfalls that we have mentioned in other articles, including different lighting, angles, and manipulating the hair so that it appears different in the before-and-after images (see below).

According to OneSkin, several positive results have been observed in their clinical trial; however, like many of these companies, the information has only been published on their website, and we have no way of verifying the data.

Let’s break down the biological plausibility of OS-01 HAIR, based on the mechanism OneSkin claims it has and current scientific understanding:

• Targeting Cellular Senescence

There is solid evidence that senescent cells accumulate in the hair follicle microenvironment with age and stress, disrupting the stem cell niche and impairing normal cycling. Studies show that hair follicle cells lose inductive capacity partly due to senescence and SASP-driven inflammation.^[23]Pappalardo, A., Kim, J.Y., Abaci, H.E., Christiano, A.M. (2024). Restoration of hair follicle inductive properties by depletion of senescent cells. Aging Cell. 24(1). E14353. Available at: … Continue reading So, reducing senescence or its effects could, in theory, rejuvenate follicle activity.

• OS-01 Peptide Mechanism

As mentioned above, OS-01 has been shown to reduce markers of cellular senescence in skin cells in vitro (and has been claimed to do the same in ORSKs). While these are promising cell culture results, translating that to sustained, clinically meaningful effects in human follicles in vivo is the critical step. 

• Delivery and Context

Topical peptides face challenges: skin penetration, stability, and reaching target cells in viable concentrations.^[24]Pintea, A., Manea, A., Pintea, C., Vlad, R.A., Birsan, M., Antonoaea, P., Redai, E.M., Ciurba, A. (2025). Peptides: Emerging Candidates for the Prevention and Treatment of Skin Senescence: A Review. … Continue reading Dermarolling (used in the clinical study) does enhance delivery through microchannels, aligning with other evidence that microneedling can improve topical drug uptake for hair growth.^[25]Zhang, S., Qiu, Y., Gao, Y. (2014). Enhanced delivery of hydrophilic peptides in vitro by transdermal microneedle pretreatment. Acta Pharmaceutica Sinica B. 4(1). 100-104. Available at: … Continue reading 

• Supporting Evidence

The company’s small clinical trial shows statistically significant improvements in hair density, thickness, and anagen hairs, aligning with the proposed mechanism. However, the studies are short-term, small, and unpublished in peer-reviewed journals. Larger, independent trials would strengthen credibility.

How Does OS-01 Compare to Rapamycin?

Rapamycin is a well-studied compound that has garnered significant attention in aging research due to its ability to slow cellular senescence, promote autophagy, and extend lifespan in multiple animal models. Rapamycin’s unique mechanism, which targets the mechanistic target of rapamycin (mTOR pathway), a central regulator of cell growth and aging, makes it a gold standard for interventions aimed at reducing age-related cellular dysfunction and tissue decline. So, let’s see how OS-01 stands up to it.

Both OS-01 and rapamycin aim to mitigate cellular senescence but use distinct mechanisms and applications.

Aspect	OS-01	Rapamycin
Primary target	Senescence-associated secretory phenotype (SASP).	mTOR pathway.
Senotherapeutic Class	Senomorphic (modulates SASP, prevents progression of pre-senescent cells).	Dual senomorphic/senolytic- inhibits mTOR and promotes autophagy (a process where a cell breaks down and recycles its own components).
Key Action	Reduces SASP markers, including IL-6, CXCL1, and CXCL8, in skin cells.	Inhibits mTORC1, enhances autophagy, and clears senescent cells.[26]Selvarani, R., Mohammed, S., Richardson, A. (2020). Effect of rapamycin on aging and age-related diseases – past and future. GeroScience. 43(3). 1135-1158. Available at: … Continue reading
Delivery	Topical serum applied with dermarolling for enhanced penetration.	Systemic (oral/injected) or localized formulations.

Efficacy in Hair and Senescence

OS-01

• Lab Studies: Reduced CRH-induced senescence in outer root sheath keratinocytes (ORSKs) by lowering p21 levels.
• Clinical Claims: In a 6-month trial (30 participants), reported 39.6% average hair density and 42.6% thickness improvement with dermarolling.
• Limitations: Small sample size, unpublished peer-reviewed data, and reliance on self-reported metrics.

Rapamycin

• Preclinical Evidence: Reduces senescence in cardiac progenitor cells and hair follicles by suppressing mTOR and promoting autophagy.
• Hair Growth: Extends the anagen phase and increases follicle size and density in animal models.^[27]Suzuki, T., Cheret, J., Scala, F.D., Akhundlu, A., Gherardini, J., Demetrius, D.L., O’Sullivan, J.D.B., Epstein, G.K., Bauman, A.J., Demetriades, C., Paus, R. (2023). mTORC1 activity negatively … Continue reading 
• Human Data: Limited direct hair studies, but show systemic anti-aging benefits (e.g., improved vascular function, cognitive decline reversal).

Safety and Practical Considerations

Factor	OS-01	Rapamycin
Side Effects	Minimal (skin dryness and irritation).[28]Zonari, A., Brace, L.E., Harder, N.H.O., Harker, C., Oliveira, C.R., Boroni, M., Carvalho, J.L. (2024). Double-blind, vehicle-controlled clinical investigation of peptide OS-01 for skin rejuvenation. … Continue reading	Immunosuppression and metabolic disruptions.
Application	Twice daily topical use and dermarolling.	Requires systemic dosing or specialized delivery.
Evidence Strength	Early-stage, company-led studies.	Robust preclinical and some clinical data.

Key Differences

• Approach: OS-01 focuses on localized SASP modulation, while rapamycin systemically targets mTOR to influence multiple aging pathways.
• Accessibility: OS-01 is available as a consumer product, whereas rapamycin is primarily used off-label or in research settings.
• Scope: Rapamycin has broader anti-aging applications beyond hair (e.g., cardiovascular, cognitive), while OS-01 targets scalp senescence and hair metrics.

In summary, OS-01 may offer a targeted, low-risk option for hair senescence; however, the data is preliminary and unpublished. Rapamycin, however, offers systemic or targeted action to provide broader anti-aging benefits but may have higher complexity and a more severe risk profile.

Is OS-01 Safe?

As mentioned above, in the clinical trial in which OS-01 was used for skin aging, skin dryness and irritation was observed in two participants. 

Beyond this, OneSkin mentioned that the peptide has been tested in in vitro toxicity and irritation tests, genotoxicity testing, and a repeated insult patch test (RIPT), and its effect on cancer cells has also been evaluated, with no negative effects observed.^[29]OneSkin. (no date). How Do We Know the OS-01 Peptide is Safe? Available at: https://www.oneskin.co/blogs/reference-lab/how-os-01-peptide-safety Accessed: June 2025,^[30]Zonari, A., Brace, L.E., Alencar-Silva, T., Porto, W.F., Foyt, D., Guiang, M., Cruz, E.A.O., Franco, O.L., Oliveira, C.R., Boroni, M., Carvalho, J.L. (2022). In vitro and in vivo toxicity assessment … Continue reading

However, it is worth noting that there have been no long-term human studies to evaluate any other potential effects.

Is OS-01 for Me?

OS-01 for hair may be worth a try for you:

• You want to add another product to your routine (it can be used alongside topical minoxidil, etc.)
• You do not suffer from inflammatory scalp conditions, which might mean you can’t use a dermaroller.
• Are happy using a dermaroller every day to facilitate penetration of the peptide into the scalp.

Final Thoughts

While OS-01 shows promise as an innovative approach to addressing hair thinning through targeting cellular senescence, the current evidence is still early and largely company-reported. Laboratory and small-scale clinical data suggest that it may help improve hair density and thickness, particularly when combined with dermarolling; however, these results need to be confirmed by larger, independent studies. There is no definitive proof yet that OS-01 can effectively reverse androgenic alopecia in the long term. If you are interested in trying OS-01, it may be reasonable to use it in conjunction with established treatments like minoxidil; however, it’s best to manage expectations and continue to follow emerging research as more data becomes available.