The Role of Orthosilicic Acid (OSA) in Hair Care

Technical Article

The beauty market is looking for the latest solutions to combat universal hair issues, such as breakage, thinning, and dryness. With the increasing awareness of ingredients among consumers, the demand for scientifically proven hair care solutions has increased significantly. The global market for hair growth supplements market is expected to grow at a compound annual growth rate (CAGR) of 15.5% from 2025 to 2030. Among the recently emerging trace elements gaining attention for their benefits to hair health, silicon in its bioavailable form as orthosilicic acid (OSA), has been of particular interest to researchers and product formulators.

Compared to other silicon forms that are difficult for the human body to use efficiently, OSA can be readily absorbed and incorporated into biological structures. It makes OSA useful for both topical and dietary usage. Read on to learn more about OSA in hair health, its chemical properties, mechanisms of action and clinical efficacy.

Chemistry and Bioavailability of Orthosilicic Acid

Orthosilicic acid (H₄SiO₄) has a simple chemical makeup with just one silicon atom attached to four hydroxyls as seen in Fig.1. This type of molecular arrangement endows orthosilicic acid with impressive features, including high water solubility and high bioavailability compared to other silicon compounds. As a neutral molecule at physiological pH, orthosilicic acid has a high permeability through cell membranes.

Comparison with Other Silicon Forms

Compared to other forms of silicon found in cosmetics and foods, the differences in bioavailability are readily apparent. Silicates, colloidal silica, and silicon dioxide, most of which are found in many products, accommodate suboptimal rates of absorption, much of which leaves the body without being metabolised. Studies show that only 5% or less of these non-OSA forms reach bioavailability, compared to OSA, which has absorption rates of 50-70% when formulated correctly.

Stability and Formulation Challenges

The biggest challenge of OSA is its inherent instability. In dense solutions, OSA molecules rapidly polymerise to form silica gel, which drastically reduces bioavailability. This instability presents formulation challenges for product developers who want to incorporate active OSA into their products.

Bioavailability in Dietary and Topical Forms

Choline-stabilised OSA (ch-OSA) has been identified as a highly effective formulation, as the choline addition avoids polymerisation while ensuring bioavailability. Other stabilisation techniques involve proprietary pH buffers and co-factors that ensure OSA remains in its monomeric, bioactive form.

When consumed orally, ch-OSA is absorbed through the small intestine into the bloodstream, where it is transported to various tissues, such as the scalp and hair follicles. In topical applications, delivering bioavailable OSA effectively to deeper skin layers and hair follicles presents a challenge due to the skin’s natural barrier. To overcome this, formulations often incorporate transdermal penetration enhancers such as liposomes, nanoemulsions or phospholipid complexes.

The Biological Role of Silicon in Hair Physiology

As the third most common trace element in the human body, silicon is responsible for the development and maintenance of connective tissue, particularly in collagen-rich and glycosaminoglycan-rich tissues.

Role in Connective Tissue and Keratin Production

Silicon cross-links hair structural proteins and glycosaminoglycans, which increases the total structural strength of hair fibres. Silicon is also involved in keratinisation, which strengthens the protein network that forms the hair shaft. Moreover, adequate silicon concentrations are correlated with greater tensile strength and elasticity in hair fibres.

Contribution to Structural Integrity

In addition to the hair shaft, silicon influences scalp health by supporting collagen production in the dermal layer where hair follicles reside. Studies demonstrate that silicon deficiency is frequently linked to reduced collagen synthesis and skin barrier dysfunction, both of which can negatively affect hair growth and retention.

Role in Follicular Health and Hair Anchorage

The extracellular matrix (ECM), which consists primarily of collagen and elastin fibres, maintains the stability of hair follicles in scalp tissue. Silicon preserves the structural integrity of this matrix, thereby potentially enhancing hair anchorage and avoiding hair loss caused by poor follicular attachment. Notably, studies have indicated that silicon content in hair fibres decreases with age and environmental stress, which may be the cause of age-related hair thinning and decreased hair quality. Therefore, supplementation is more popular among the ageing population.

Mechanisms of Action in Hair Health

OSA affects hair health by several interlinked mechanisms. One of the key mechanisms is the induction of collagen production in the hair follicular microenvironment. The entire mechanism of action of OSA for hair health is depicted in Fig.2

Fig.2 Mechanism of Action in Hair Health

Collagen Support and Glycosaminoglycan Production

Working synergistically with collagen, glycosaminoglycans (GAGs) are an integral component of hair follicle structure. OSA appears to enhance collagen type 1 and GAG production, creating a more robust follicular environment for more aggressive hair growth.

Improvement of Hair Thickness and Elasticity

Most OSA-based treatment patients experience enhanced hair thickness and elasticity. There are several reasons for this, but the most probable one is the optimisation of cross-linking and keratin production, resulting in hair shafts with increased diameter and better mechanical properties.

Scalp Barrier Support and Hydration

The skin barrier of the scalp is preserved through adequate silicon levels. OSA initiates ceramide formation and structuring of the epidermal intercellular lipids and thus guarantees adequate hydration levels and protection against harmful external stimuli for the well-being of the follicles.

Antioxidant and Anti-inflammatory Properties

Silicon compounds possess antioxidant activity that can shield hair follicles from oxidative stress, a primary cause of early follicular ageing and dysfunction. Through the neutralisation of reactive oxygen species, OSA can indirectly maintain follicular stem cell function and prolong the anagen (growth) phase of the hair cycle.

Delivery Methods for OSA in Hair Care Products

The effectiveness of OSA relies heavily on how it is delivered. Topical applications and oral supplements both have special benefits, but they need different formulations and have different effectiveness levels, as explained in Table 1

Table 1. Key Characteristics of OSA Delivery Systems in Hair Care Products

Delivery FormTypeKey Details
Topical ApplicationsShampoos and ConditionersStabilized OSA (0.5-3%) with humectants, strengthens hair fibers and hydrates the scalp.
 Serums and Scalp TreatmentsUp to 5% stabilized OSA; leave-in formulas; deeper follicle penetration for targeted repair.
 Products with Penetration EnhancersLiposomes, nanoemulsions and phospholipid carriers enhance delivery to follicles.
Oral SupplementsCholine-Stabilized OSA (ch-OSA)Highly bioavailable; absorbed through the GI tract; improves hair strength, reduces breakage.
 Formulas with Synergistic NutrientsCombined with biotin, zinc and vitamin C. Supports keratin production, collagen synthesis, and scalp health.

Clinical Evidence and Effectiveness

Scientific literature concerning the effects of OSA on hair health consists of both clinical trials and in vitro studies, with generally positive results on different parameters of hair growth and quality.

In Vitro and Laboratory Research

In vitro tests repeatedly show silicon exposure to induce keratin synthesis in hair follicle cells and increase cross-linking among structural proteins. These cellular effects are expressed as quantifiable strengthening and breaking resistance of hair fibre.

Hair Strength and Breakage Reduction

Human clinical trials of oral and topical OSA supplementation have shown a number of positive outcomes. In a double-blind, placebo-controlled trial involving 48 women with fine hair, daily supplementation with 10 mg of ch-OSA for 9 months increased hair thickness by about 12.8% over the placebo. Break load parameters (breakage resistance) increased by a mean of 13.7%.

Improvement in Thickness and Shine

Many trials comparing topical OSA application showed significant hair shine and smoothness improvements after 8 weeks of treatment, with objective measurements supporting subjective results. Comparative studies have indicated that although other trace minerals like copper and zinc are also useful for hair health, silicon has a better outcome for enhancing mechanical properties and structure strength. Nevertheless, the best results come from formulations that synergistically combine these nutrients.

Dosage and Treatment Duration

The persistence of visible effects depends on the delivery system. Surface changes in topical treatments take 2-4 weeks, and structural changes due to oral supplementation take 3-6 months of regular use, similar to the natural cycle of hair growth.

Formulation and Stability Considerations

Formulating effective OSA formulations introduces significant technological hurdles because the compound is inherently unstable when exposed to aqueous matrices. Exposed, OSA polymerises quickly to inactive silica, especially with concentrations above 100 ppm.

Stability in Aqueous Solutions and Emulsions

For water-based products such as shampoos and conditioners, OSA stability is ensured by pH adjustment (preferably 5.5-7.0) and inclusion of some stabilizers such as choline or some organic acids.

Compatibility with Common Cosmetic Ingredients

OSA has inconsistent compatibility with many typical cosmetic ingredients. Multivalent cations at high concentrations, some preservative systems, and strong chelating agents can significantly enhance the polymerisation of OSA. Thus, stability tests should be done carefully by formulators to confirm product performance for the anticipated shelf life.

Encapsulation and Delivery Systems

Advanced drug delivery systems offer promising prospects to enhance the stability and efficacy of OSA. Methods like microencapsulation, liposomal drug delivery systems and silica nanoparticles with OSA have all proven to increase stability properties and sustain or enhance bioavailability. Such technologies can offer the capability to achieve greater functional concentrations of OSA compared to standard formulations.

Safety and Regulatory Aspects

Large toxicological studies demonstrate that OSA has an excellent safety profile when administered within guidelines. Acute toxicity tests demonstrate very high LD50 values, placing OSA as “practically non-toxic.” Chronic exposure tests have discovered no evidence of cumulative toxicity, sensitisation, or carcinogenicity.

Regulatory Status in Cosmetic and Nutraceutical Applications

Regulatory status varies somewhat in international markets. Stabilised OSA is authorised in the European Union as a food supplement under Regulation (EC) No 1170/2009 with some provisions for claims for hair, skin and nail health. The US FDA classifies OSA as a Generally Recognised as Safe (GRAS) nutritional supplement, and some stabilised forms have FDA clearance for specific cosmetic uses.

Labeling Considerations and Allowed Claims

For cosmetics, labelling laws commonly include OSA or orthosilicic acid in ingredient statements, but stabilised forms may appear under trade names or as “silicon complex” in certain nations. Allowed claims differ by country but generally include claims for hair strength, thickness, and appearance without breaching the line into a drug claim. The language used in these claims should not cross into therapeutic territory. For example, claims should avoid suggesting that the product can cure hair loss or any scalp conditions, as this would require regulatory approval as a drug rather than a cosmetic.

Long-term Use and Tolerability

Long-term safety trials demonstrate excellent tolerability with both topical and oral OSA when used as directed. Recommended standard dosages (5-10 mg silicon daily from oral supplements) remain far below the estimated safe upper intake level of 700-1,500 mg/day set by such regulatory agencies.

Market Potential and Future Outlook!

Orthosilicic acid has a special place in the contemporary hair care market, with science-backed benefits of structural strength and appearance. Cumulative evidence demonstrates its efficacy when well-formulated for stability and bioavailability. Driven by a commitment to holistic wellness, consumers are choosing products that feature active ingredients with scientifically proven benefits. OSA is well-positioned to capitalize on this trend. The scientific evidence supporting OSA continues to grow, with both laboratory studies and clinical trials confirming its efficacy across multiple parameters of hair health and appearance. This evidence-based approach positions OSA as a legitimate functional ingredient rather than merely a marketing claim.

NICHEM offers TresTle ® based on OSA – a unique solution for hair loss. It connects the weak links by cementing action on the surface of the hair strand at a molecular level. It uniformly aligns the cuticle & strengthens the hair strand to prevent breakage.

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