Thorne supplements: who owns the brand, where it's made and what NSF Certified for Sport means

Who owns Thorne and where it’s made

Thorne started in the Seattle area in 1984. It later moved to northern Idaho, then shifted most operations to Summerville, South Carolina, in 2017–2018. The owner has changed twice in recent years:

• until 2023 it was a listed company, Thorne HealthTech;
• in 2023 the investment firm L Catterton took it private for about $680 million;
• on 1 October 2026 Procter & Gamble completed its $3.9 billion purchase, adding Thorne to its Personal Health Care segment.

Thorne makes its products at its own plant in Summerville. The company reports two in-house labs and four rounds of testing: raw materials, in-process checks, finished product and stability. It also says it avoids magnesium stearate and keeps a list of more than 60 substances it won’t use.

Thorne and NSF Certified for Sport

Thorne is best known for sport certification. The company says more than 20 of its products are NSF Certified for Sport. The NSF programme tests products lot by lot for 280 substances banned in sport and makes unannounced inspections of production sites.

Two certificates are easy to confuse:

• an NSF-certified facility – the factory is audited, but products aren’t screened for banned substances;
• NSF Certified for Sport – a mark on a specific product that has been screened.

Thorne also reports an “A” rating from Australia’s Therapeutic Goods Administration (TGA) and an audit by the Global Retailer and Manufacturer Alliance (GRMA).

Popular Thorne products and their forms

Thorne’s magnesium is bisglycinate with citric acid and monk fruit extract as a sweetener. See our magnesium glycinate guide for more on the form, and the creatine guide for training supplements.

Recall: Captomer, 2014

In June 2014 the FDA warned consumers not to buy Captomer or Captomer-250. They contained DMSA, a chelating agent (used to remove heavy metals). DMSA is approved as a prescription drug for lead poisoning in children, and the FDA has approved no over-the-counter chelation products. The company had received adverse event reports, and Thorne agreed to recall the products.

Thorne strengths and weak points

If you’re drug-tested, Thorne gives you plenty of choice: more than 20 NSF Certified for Sport products. Its own plant and a well-documented testing process count in its favour too. If you dislike swallowing capsules, the powders help, such as magnesium bisglycinate.

Weigh these before you buy:

• reviews place Thorne among the pricier brands;
• not every product has independent certification;
• some multivitamins need 3–6 capsules a day, which is a lot to keep up;
• the company cites clinical research on its formulas, but according to Healthline doesn’t say whether it is published.

Who should take care

Sport certification doesn’t make a supplement necessary: discuss it with your team doctor or GP. With kidney disease, take magnesium only on medical advice. If you’re pregnant or breastfeeding, agree any multivitamin with your midwife or GP. For dose limits, see our guides to vitamin D and zinc.

How to choose Thorne on iHerb

1. Decide whether you need sport certification; if not, compare the same form from other brands.
2. Find the product and check for the NSF Certified for Sport mark on that specific item.
3. Look it up in the NSF database by name and format.
4. Work out the cost per daily dose, as shown in our label guide.
5. Check that it ships to the UK or your EU country.