Doctor’s Best is an American dietary supplement brand recognised for its science-oriented vitamins, minerals, specialty nutrients, and other nutritional products. Founded in 1990 by a physician, the company was established with the concept of developing supplements based on nutritional research rather than traditional wellness marketing alone. Today, Doctor’s Best is headquartered in Tustin, California, operates as part of Xiamen Kingdomway Group, and distributes a broad portfolio of supplements internationally.1

The brand positions itself around research-backed formulations, branded ingredients, and transparent ingredient sourcing, while remaining under the ownership of Chinese nutritional-ingredients company Xiamen Kingdomway Group.

Doctor’s Best describes itself as a science-based nutrition company that emphasises research, branded ingredients, quality control, and clinical evidence in product development.2

Foundation

Doctor’s Best was established in 1990 by a physician with the goal of creating nutritional supplements rooted in scientific research. The company cites this founding principle as the central idea guiding the brand for over three decades.3 Some corporate materials identify the founders as Ken Halvorsrude and James Braly, physicians who worked with Hollywood clients.

The original philosophy was distinctive for the supplement market at the time, following a pathway of research leading to ingredient selection, formulation, and finally the nutritional product, rather than creating items based solely on popular wellness trends.

Growth as a specialty supplement brand

Over subsequent decades, Doctor’s Best developed a portfolio spanning vitamins, minerals, joint-health supplements, cardiovascular nutrition, digestive health products, antioxidants, herbal ingredients, sports nutrition, specialty nutrients, and healthy-ageing products. The company became particularly recognisable among consumers seeking individual nutrients and specialty formulations rather than only conventional multivitamins.

Its High Absorption Magnesium products gained significant prominence; in a 2021 announcement, Doctor’s Best described High Absorption Magnesium as its top-selling product.4

Although Doctor’s Best originated as an American supplement company, its ownership structure eventually became international.

North Castle Partners

Prior to its current ownership, Doctor’s Best was backed by North Castle Partners, a private-equity firm specialising in consumer businesses associated with healthy and active lifestyles. In June 2016, North Castle announced the sale of Doctor’s Best to Xiamen Kingdomway Group Co., though financial terms were not disclosed.5

Kingdomway

The acquisition marked a significant transition. Xiamen Kingdomway Group, headquartered in Xiamen, China, is a publicly listed company involved in pharmaceutical raw materials, nutritional ingredients, and dietary supplement businesses. Kingdomway’s corporate history records its acquisition of Doctor’s Best Holdings in January 2015, followed by additional ownership consolidation.

Current corporate information lists Doctor’s Best among Kingdomway’s group brands, with recent reports stating that Kingdomway holds 96.11% of Doctor’s Best Inc.12 Consequently, while Doctor’s Best remains a US-based brand, it is currently under Chinese corporate ownership.

As of 2026, Doctor’s Best is a controlled subsidiary of Kingdomway USA and Xiamen Kingdomway Group. Doctor’s Best describes Kingdomway USA as the US subsidiary holding company of Xiamen Kingdomway Group, which is publicly listed on the Shenzhen Stock Exchange.

With headquarters in Tustin, California, the brand operates under a structure where a Chinese parent company oversees a US corporate subsidiary that manages the Doctor’s Best brand, with products manufactured through US cGMP-certified facilities. The company states that its products are manufactured and rigorously tested at Current Good Manufacturing Practice (cGMP)-certified facilities in the United States.6

The defining feature of Doctor’s Best is its emphasis on “science-based nutrition.” The company utilises published scientific literature and clinical findings when determining product compositions, emphasising collaboration with nutritional scientists and the use of branded ingredients with supporting research.7

Science

Doctor’s Best reviews published research and clinical findings during product development.8

Ingredient quality

The company emphasises sourcing high-quality raw materials and working with specialised manufacturers.9

Branded ingredients

Rather than listing generic nutrient names, many Doctor’s Best products highlight specific ingredient forms or branded raw materials, which forms a key part of the brand’s identity.

Transparency

Doctor’s Best aims to disclose information regarding manufacturing processes and material sourcing.10

Doctor’s Best marketing is built on the premise that a supplement should have a scientific rationale behind its ingredients and formulation. For example, formulations may specify a particular chemical form or branded raw material rather than treating a nutrient as a single interchangeable commodity. The company website states that products are supported by research and that branded ingredients are clinically studied.

However, evidence for an ingredient does not equate to proof that every finished product produces a clinically meaningful health outcome. A compound may have scientific literature supporting it without every specific health claim being independently demonstrated in large randomised clinical trials. This distinction is relevant when assessing any supplement brand.

Doctor’s Best maintains a broad portfolio across several categories.

Vitamins

Products include Vitamin C, Vitamin D, Vitamin K, B vitamins, multivitamins, and specialty vitamin formulations.14

Minerals

This is one of the brand’s strongest categories, featuring magnesium, zinc, iron, calcium, selenium, copper, and other mineral formulations. The brand has particularly strong recognition for its magnesium products.

Joint and connective tissue

Products contain ingredients such as glucosamine, MSM, chondroitin, boswellia, collagen-related ingredients, and hyaluronic acid.

Heart and metabolic health

Offerings have included CoQ10, omega-3 products, berberine, cholesterol-support ingredients, and antioxidants.

Digestive health

The portfolio includes digestive enzymes, probiotics, fibre products, and plant-derived digestive ingredients.

Antioxidants

Examples include alpha-lipoic acid, NAC, quercetin, resveratrol, and CoQ10.

Healthy ageing

Doctor’s Best has expanded into ingredients associated with longevity and cellular metabolism, including NMN. In 2026, the company announced the relaunch of several NMN products following an FDA New Dietary Ingredient (NDI) letter received by its parent company, Kingdomway.2

A representative product is Doctor’s Best Quercetin Bromelain. The formulation lists 500 mg of quercetin and 250 mg of bromelain per two-capsule serving. Marketed for immune, joint, circulatory, and digestive support, it is described as non-GMO, gluten-free, soy-free, and vegan.9

This illustrates the brand’s typical approach: specifying the ingredient, dose, and form, alongside an explanation of the intended nutritional role.

Doctor’s Best places substantial emphasis on manufacturing standards, stating that products are manufactured at cGMP-certified facilities in the United States and undergo rigorous testing.6 The company also works with manufacturers globally to source ingredients and produce finished products.10

This creates a distinction between ingredient origin and finished-product manufacturing. An ingredient may originate from a supplier outside the United States, while the finished product is manufactured in a US cGMP-certified facility. Therefore, “Made in the USA” claims do not necessarily indicate that every raw material originates domestically.

Doctor’s Best products commonly carry claims such as non-GMO, gluten-free, soy-free, vegan, vegetarian, and cGMP manufacturing. However, these characteristics vary by product. For instance, while Quercetin Bromelain is explicitly labelled non-GMO, gluten-free, soy-free, and vegan,9 consumers should evaluate individual product labels rather than assuming identical certifications across the entire range.

Doctor’s Best has historically maintained a strong presence in online supplement retail. Products are sold through Amazon, iHerb, Walmart, Sprouts, specialty health retailers, and other online and brick-and-mortar outlets. A 2021 expansion brought selected products to thousands of Walmart stores alongside a larger selection on Walmart.com.4

Doctor’s Best is a global supplement brand. Kingdomway states that products are distributed in more than 120 countries, with a portfolio exceeding 240 products in corporate descriptions. Doctor’s Best materials more conservatively cite more than 200 products.11 The discrepancy likely reflects different counting methods or catalogue updates, but the brand remains highly visible in international online supplement markets.

In June 2024, Doctor’s Best acquired the Viactiv brand, known primarily for calcium and magnesium soft chews.13 The acquisition was described as part of a growth strategy to expand retail distribution and convenient nutritional formats. This move diversified the brand’s offerings beyond its traditional reputation for capsules and technically formulated supplements into consumer-friendly chewable formats.6

NMN (nicotinamide mononucleotide) is a compound involved in NAD-related biological pathways. In January 2026, Doctor’s Best announced that Xiamen Kingdomway Group had received an FDA New Dietary Ingredient (NDI) letter concerning its NMN supplements. The company subsequently relaunched three formulations: NMN + CoQ10 (150 mg), NMN+ (200 mg), and NMN Delayed Release (400 mg).2

An NDI letter should not be interpreted as FDA approval of NMN as a drug or as proof of specific anti-aging benefits, as dietary supplements are regulated differently from pharmaceuticals.

Doctor’s Best operates in the dietary supplement industry, not the pharmaceutical sector. In the United States, supplements are regulated under a different framework than prescription medicines and generally do not require pharmaceutical-style efficacy demonstrations before marketing.

Consequently, “clinically studied ingredient” does not mean “FDA-approved treatment,” and “science-based” does not equate to FDA approval. Doctor’s Best positions its products as nutritional supplements, not medical treatments, and includes standard warnings to consult a physician where appropriate.13

Doctor’s Best is generally perceived as more technical and science-oriented than mass-market vitamin brands focused on general wellness. Its strengths appeal to consumers prioritising exact ingredient forms, dosage, branded raw materials, scientific literature, and specialty nutrients over generic multivitamins. Wide online availability also makes the brand accessible internationally.

Doctor’s Best occupies a space between mainstream consumer supplements and highly technical specialty supplements, effectively positioning itself as scientifically informed supplementation for everyday consumers.

• Scientific positioning: Consistent identity built around nutritional research and scientific literature.3
• Specialty nutrient selection: Useful for consumers seeking specific compounds rather than generic multivitamins.
• Ingredient transparency: Many products clearly identify active ingredient forms and quantities.
• International distribution: Significant e-commerce and global availability.11
• Established history: Operating since 1990, providing longer tenure than many newer startups.
• Manufacturing standards: Finished products manufactured and tested at US cGMP-certified facilities.6

The “science-based” designation does not guarantee that every product or claim is equally well supported. Evidence quality depends on the specific ingredient, chemical form, dose, population studied, clinical endpoint, and whether research was conducted on the finished product or merely the ingredient. Evaluating Doctor’s Best on a product-by-product basis provides a more accurate assessment than relying solely on brand reputation.

A common misconception is that Doctor’s Best is currently an independent American company. While the brand originated in the US and remains headquartered there, Xiamen Kingdomway Group is the controlling parent with a 96.11% ownership stake.12 Thus, while it retains American origins, US headquarters, and US finished-product manufacturing, it is not currently US-owned.

• 1990: Doctor’s Best founded by a physician in the United States.1
• 1990s–2000s: Development of science-oriented specialty nutritional supplement portfolio.
• 2015: Kingdomway begins acquiring Doctor’s Best Holdings.
• 2016: Kingdomway acquires Doctor’s Best from North Castle Partners; ownership transition becomes public.5
• 2021: Expansion of US retail distribution, including Walmart.4
• 2024: Acquisition of Viactiv brand, expanding into chewable supplements.6
• 2026: Relaunch of NMN portfolio following FDA NDI letter received by parent company.2

Doctor’s Best is distinct from Nature’s Bounty, Solgar, or Puritan’s Pride. In 2021, Nestlé Health Science acquired core brands of The Bountiful Company, but Doctor’s Best was not among them. It remains part of the Kingdomway corporate group.

Doctor’s Best is characterised as a long-established, science-oriented, specialty nutritional supplement brand with significant international presence. Key differentiators include over 30 years of history, physician-founded origins, research-oriented branding, a strong specialty-nutrient portfolio, emphasis on branded ingredients, US finished-product manufacturing claims, global distribution, and Chinese corporate ownership through Kingdomway.

It differs significantly from generic supermarket vitamin brands. However, consumers should distinguish the brand’s “science-based” positioning from pharmaceutical-level clinical proof for every health claim. As a legitimate, established brand founded in 1990, its strongest identity lies in minerals, specialty nutrients, antioxidants, joint-health products, and technically formulated supplements. Comprehensive evaluation should consider quality-control systems, third-party testing, ingredient suppliers, manufacturing practices, recalls, and specific product evidence beyond brand reputation alone.

1. About us – Original Copy – Doctor’s Best
2. Doctor’s Best Celebrates FDA Decision on NMN Supplements, Relaunches P
3. Science – Doctor’s Best
4. Doctor’s Best Products Hit The Shelves Of Walmart Stores Nationwide
5. North Castle Partners Sells Doctor’s Best, Inc.
6. Doctor’s Best Inc. Acquires Viactiv® Brand – Doctor’s Best
7. About Us – Doctor’s Best
8. Doctor’s Best Celebrates FDA Decision on NMN Supplements, Relaunches P
9. Doctor’s Best Quercetin Bromelain, 180 Veggie Caps
10. Doctor’s Best Inc. Acquires Viactiv® Brand
11. Global Blueberry Lutein Gummies Market Outlook and Growth Opportunities 2026
12. Who Owns Doctor’s Best Brand? A Look at its Chinese Parent Company
13. Guardion Health Sciences Announces Entry into Definitive Agreement to Sell its Well-Known Viactiv® Brand and Business to Doctor’s Best Inc. | Nasdaq
14. Vitamin C :: Directions for Me