Nail Supplements: When, How, and Why?

Abstract

Background

The number of supplements for nail health is continuously increasing, and consumers are no longer familial with them, which can create confusion, as they do not always understand what they are consuming, and some will seek advice from their dermatologist, who must have as clear and a precise answer.

Summary

Biotin, collagen peptides, solubilized keratin MSM, and choline-stabilized orthosilicic acid have been shown to improve the clinical appearance of nails, strength, and brittleness. There is a lack of regulation from the health authorities concerning dietary supplements. Manufacturers are not required to carry out efficacy and safety studies before marketing.

Key Messages

Dermatologists must be aware of the ingredients available on the market, their possible benefits but also their risks. It is important to specify to patients that our recommendations are as solid as the available evidence. In this article, we will discuss about the supplements available for nails, their mechanisms of action, and possible side effects.

Introduction

Nail supplements are becoming increasingly popular. These products promise stronger, more beautiful nails that grow faster. However, many consumers ignore what they are consuming and have no knowledge of the specificities of the products they are swallowing [1]. Evidence of efficacy is scarce for many supplements. Moreover, the use of certain supplements can lead to side effects. Dermatologists should be able to answer to this growing demand and support their patients [2].

From a regulatory point of view, nail supplements are recognized as foods and not as drugs by the health authorities. This distinction means that manufacturers do not need to prove efficiency, safety, or quality.

Brittle nails are the main indication of prescription/advise of supplements. The dermatologist must therefore distinguish between idiopathic brittle nails and a secondary condition that is a part of a well-defined pathology, such as lichen, psoriasis, etc., requiring specific and adapted medical treatments [3].

This article reviews the main data available on the efficiency and safety of nail supplements. Only molecules that have been the subject of published scientific studies will be detailed. Evidence of efficacy is scarce for most supplements, and some provide well-documented side effects. Many of these studies have significant methodological limitations.

Nail Supplements

Different formulations and delivery vehicles can be used. These include tablets, capsules, liquids, powders, sustained-release tablets, jelly beans, and others [1]. While some studies have evaluated short-term safety, many lack information on long-term safety. Moreover, the optimal duration of supplementation is not indicated by the laboratories. This is a cause for concern, as even supplements with few side effects in short-term studies can cause long-term harm.

One should also consider certain patient populations. Little research has been conducted to ensure safety in pregnant or breastfeeding women. Similar concerns apply to children, the elderly, and people with liver or kidney failure. Another major concern is the proliferation of multi-ingredient supplements, where it is important in addition to evidence of efficacy to ensure that these ingredients can be safely combined.

The main reason to use supplements is brittle nails, which are a frequent reason for consultation, affecting up to 20% of the population, particularly women over 50 years. Brittle nails are characterized by splitting, peeling, and crumbling, becoming soft and losing elasticity [3].

The main clinical presentations are onychoschizia and onychorrhexis. Two main forms are distinguished: (i) a primary idiopathic form and (ii) a form secondary to various etiologies such as inflammatory onychopathy, infections, systemic diseases, and general affections. Optimal management requires a treatment of the etiology whenever possible [3].

Nail growth depends on several factors, which include nutrition, hormonal changes (thyroid, etc.), pregnancy, genetic predisposition, medication (methotrexate, azathioprine), and environmental factors (ambient outside temperature) [4]. Nutrition also plays an important role, and certain deficiencies have a significant impact on nail growth and quality. In the case of deficiencies, mainly in iron and zinc, nails are weakened, striated, soft, and brittle, with slowed growth [5].

Iron supplementation (plus vitamin C) can be highly effective when ferritin levels are below 10 ng/mL. However, a few studies correlate iron deficiency with brittle nails [6, 7]. Nail fragility may be caused by primary or secondary zinc deficiency. A prolonged treatment with zinc at a dose of 20 to 30 mg/day appears to be effective in improving nail fragility in cases of deficiency [7].

In a randomized trial, a formulation containing amino acids (L-cystine, L-arginine, glutamic acid), vitamins (C, E, B6, and biotin), and minerals (zinc, iron, and copper) proved to be well tolerated and effective in strengthening and smoothing nails in onychoschizia subjects after 3 months of treatment [8]. No data on the dosage of each component were provided in the article.

Below, the main dietary supplements that have been studied for nail growth and/or brittle nails are discussed. Main nail supplements are summarized in Table 1.

Table 1.

Main nail supplements

Component	Natural source	Recommended dose/day	Toxicity/side effects	Interaction	Cautions
Biotin	Egg yolks, nuts, cereals, and milk	2.5–30 mg	NR	NO	Interfere with certain laboratory tests
					Troponin (falsely low troponin value, leading to possible missed diagnosis of heart attack)
					TSH and antithyroid antibodies
Collagen peptides	Bone broth, offal or chicken feet, dairy products, meat fish	2.5–10 g	NR/diarrhea, abdominal fullness, heartburn, and headache	NO	Not recommended in pregnant and breastfeeding women
			Anaphylaxisa
Solubilized keratin	Foods that promote keratin production: eggs onion, salmon, carrots, sunflower seeds, sweet potatoes	500 mg	NR	NO	NR
Choline-stabilized orthosilicic acid	Cereal/whole grain-based products	10 mg	NR	NO	NR
MSM	Horsetail, cow’s milk, beets, cabbage, tomatoes, beer, µ	1–3 g	NR	NO	NR

NR, not reported; NO, not observed.

^aHydrolyzed fish collagen; µ: the MSN contents of these products remain relatively low.

Biotin

Biotin is a water-soluble vitamin that is also labeled as vitamin B7, coenzyme R, and vitamin H. It is involved via five carboxylase enzymes (propionyl-CoA carboxylase, pyruvate carboxylase, methylcrotonyl-CoA carboxylase, and two forms of acetyl-CoA carboxylase) in the metabolism of fatty acids, amino acids, and glucose [9]. Deficiency is rarely described [10].

In an open study reported by Floersheim et al. [11], the effects of biotin supplementation on brittle nails were evaluated. A daily oral dose of 2.5 mg biotin was administered to 71 patients with idiopathic brittle nails. Of the 45 patients in whom efficacy was assessed, 41 (91%) demonstrated a marked improvement in nail firmness and hardness over an average treatment duration of 5.5 ± 2.3 months.

Even lower doses of biotin have been shown to increase nail growth. In a comparative study by Fanian et al. [12], 60 healthy female volunteers received a multivitamin/mineral formula (fat- and water-soluble vitamins, magnesium, zinc, copper), as well as 45 μg of biotin. After 90 days of supplementation, subjects in the supplement group had significantly higher growth than subjects in the placebo group (5.23 mm vs. 5.15 mm, p < 0.001). Although this result cannot be directly linked to biotin alone, as there were other components in the formula, the results of this study suggest that biotin may be effective in increasing nail growth.

Further evidence of biotin’s ability to reduce nail brittleness was seen in a study by Hochman et al. [13]. They found that in a group of 35 subjects with brittle nails, 22 showed clinical improvement. The safety and toxicity of biotin have been well studied [14]. Biotin toxicity has not been reported at doses up to 200 mg orally and 20 mg intravenously [15].

However, it is important to note that smoking and being pregnant increase biotin metabolism, so this group of individuals may need to increase the dose [16]. In addition, exogenous biotin intake may interfere with certain laboratory tests, including troponin (falsely low troponin value, leading to possible missed diagnosis of heart attack), TSH, and antithyroid antibodies [17, 18].

It is important to note that biotin absorption is maximal in about 1 h (but shifted to 3 h if taken with a meal) and its renal half-life elimination is about 15 h (from 8 to 19 h depending on the patient). With a patient taking a 10 mg dose of biotin, interference with thyroid tests persists for around 24 h; for a 30-mg dose, it persists for 48 h, but this varies according to the clinical situation and the molecule dosed.

One solution to avoid misinterpretation of blood tests is to suspend biotin intake. Note that for high doses (100 mg × 3/day), 4 days are needed for T3L, T4L, and TSH assays, and 7 days for R-STSH or troponin assays. Moreover, biotin accumulates in patients with renal failure [19].

Other solutions are possible: a streptavidin solid phase can be used to neutralize biotin prior to assay. Finally, it is also possible to use another assay technique that does not use the biotin-streptavidin system [20].

Although widely prescribed for brittle nails, there is no solid evidence that biotin alone can have a clinically significant effect on nail growth. Biotin is a safe, nontoxic oral supplement that is not contraindicated with other medications. Patients must be warned that exogenous biotin may alter the results of some biological tests.

Collagen Peptides

Collagen is one of the most abundant proteins in the human body, found in connective tissues such as bone, skin, tendons, ligaments, and cartilage. Hexsel et al. [21] in an open-label, single-center trial showed that daily supplementation with oral bioactive collagen peptides is effective in improving the appearance of brittle nails and improving growth rate. The bioactive collagen peptides used in this study were derived from the breakdown of type I collagen of porcine origin and used at a dose of 2.5 g for 24 weeks (daily oral dose). The study included 25 women aged between 26 and 50 with symptoms of brittle nails. In a study of 25 participants, 24 of them showed that, after 12 weeks of peptide treatment, the rate of nail growth increased significantly. At 24 weeks, the rate increased by 12%, and 4 weeks after the end of treatment, the growth rate increased by 15%. Overall, 80% of participants were satisfied with the results in terms of nail growth and improved appearance. Moreover, 75% of participants felt that their nails had become stronger as a result of the treatment, and 71% noticed an increase in nail growth. This study has several biases (lack of blinding, external factors such as participant behavior). Studies with a more rigorous and robust methodology, involving a larger cohort of patients and a longer treatment period, are still needed.

No adverse events were reported in this trial. Some rare adverse events have been associated with collagen supplementation (diarrhea, abdominal fullness, heartburn, and headache). There is limited evidence on the use of collagen peptides in pregnant and breastfeeding women [22].

Solubilized Keratin

Solubilized keratin has become popular in the cosmetics industry since a few years. It is a patented form of highly bioavailable keratin that has been shown to improve the appearance and strength of nails [23].

In a randomized, double-blind, placebo-controlled trial, Beer et al. [23] compared nail strength between two groups of women aged from 40 to 71, randomized between two arms to either two capsules of solubilized keratin (500 mg) plus vitamins and minerals (vitamin B3, B5, B6, B8, zinc, and copper) (n = 25) or two placebo capsules of maltodextrin (n = 25) daily for 90 days. Patients receiving solubilized keratin showed slight to moderate improvement in nail quality after 90 days of treatment, compared to the placebo group, which showed no improvement at all.

No toxicity of solubilized keratin was observed. Throughout the trial, no adverse effects were reported [23]. Further clinical trials are required to validate these results.

Choline-Stabilized Orthosilicic Acid

Silica is one of the most abundant trace elements in the body and is a component of nails [24]. Silica has been associated with the improvement of nail fragility [25].

Choline-stabilized orthosilicic acid has a high bioavailability compared to other forms of silicon supplements [25]. It is easily absorbed by the small intestine due to its small size and neutral charge [26]. It has been shown to increase the synthesis of type 1 collagen. In addition, it improves the cross-linking of glycosaminoglycan in the dermis and the structure of keratin in hair and nails [27].

Barel et al. [25] studied the effects of choline-stabilized orthosilicic acid on skin, hair, and nails in a randomized, double-blind, placebo-controlled study involving 48 women receiving (n = 24), 10 mg choline-stabilized orthosilicic acid for 20 weeks, or placebo (n = 24). The degree of nail brittleness was measured on a four-point Visual Analog Scale (VAS): “0” means no nail brittleness, “1” mild, “2” moderate, and “3” severe at baseline and at 20 weeks post-supplementation. VAS scores for nail brittleness in the orthosilicic acid group were significantly lower at 20 weeks than at baseline. There was no significant difference in VAS scores in the placebo group at 20 weeks compared with baseline [25]. No adverse events were reported with the 10 mg dose of choline-stabilized orthosilicic acid over the study period [25].

Evidence for the value of choline-stabilized orthosilicic acid is weak, and long-term safety data are lacking. Further studies are needed to further validate the value of choline-stabilized orthosilicic acid.

Methylsulfonylmethane

Methylsulfonylmethane (MSM) is a naturally occurring sulfur compound used for its anti-inflammatory and antioxidant properties, as well as for arthritis and muscle pain. Recently, it has become a well-known dietary supplement for improving nail quality, by maintaining normal keratin levels in the nails, the main constituent of the nail plate. The sulfur contained in MSM strengthens the disulfide bridges of keratin. In a 16-week double-blind study by Muizzuddin and Benjamin [28] involving 63 women, the effects of two doses of MSM on nail quality were evaluated (1 g or 3 g of MSM per day). For both dosages, there was a statistically significant improvement in nail appearance, according to the experts. The majority of patients reported that MSM supplementation made their nails stronger and healthier [28]. MSM is a nontoxic supplement that is generally well tolerated [29].

The evidence supporting the use of this nail supplement is weak. Thus, more clinical trials are needed. It is important to be aware that many supplements marketed as nail supplements contain high levels of micronutrients. Some contain high levels of vitamins A, B6, B12, E, and selenium, all of which have been associated with a higher risk of cancer in various groups. Selenium and vitamin A supplementation may on the contrary be responsible for nail dystrophy.

Conclusion

A rapid expansion of the nail supplement market is partly attributed to the public’s infatuation with nail health and beauty. Dermatologists must not forget the proper use of dietary supplements. Fragile nails are the main reason for using dietary supplements. All patients want healthy nails: strong, smooth, pink, and free of bumps. Prior to any prescription, it is important to identify the precise cause(s) and then to find the appropriate supplement, if available. There are several nail health supplements on the market. There is little or even no evidence for the efficacy of some substances, and very little data on their safety.

Many consumers are unaware of the potential problems associated with their use, since manufacturers do not need to provide evidence of safety, efficacy, or even quality before sale. Consumers should approach all supplements with caution.

Biotin is known for its positive impact on brittle nails. However, studies lack robustness. A multivitamin formula containing biotin and minerals (magnesium, zinc, copper) has demonstrated a positive impact on nail growth. Ingesting bioactive collagen peptides, solubilized keratin, and MSM has shown improvements in brittle nails, however, with weak evidence requiring more research to validate these results. In order to optimize the contribution of food supplements, it is essential to take a personalized approach to nutritional diagnosis and the choice of supplement. This would explain why certain individuals may respond to nail supplements, for instance, while others may not. More standardized, randomized, double-blind, placebo-controlled studies are strongly needed.

Conflict of Interest Statement

The authors have no conflicts of interest to declare.

Funding Sources

This study was not supported by any sponsor or funder.

Author Contributions

For both Dr. Ines Zaraa and Prof. Bertrand Richert: substantial contributions to the conception or design of the work; drafting the work and reviewing it critically for important intellectual content; and final approval of the version to be published.

Funding Statement

This study was not supported by any sponsor or funder.