Thorne Berberine Review: 1,000 mg per Serving, About 600 mg Berberine

Thorne is the brand a lot of people pick when they want a supplement company that doctors trust, and its berberine is one of the most searched berberine products in the United States. So we did what a careful buyer would want done: we read the label, the label history the company filed with the NIH, the studies behind the main ingredient, the certificates Thorne links to, and the federal court dockets. We checked all of it on 28 October 2026.

The headline number on the label is 1,000 mg per serving. The amount of berberine in that serving is lower, and working out by how much takes one detail Thorne does not print.

What the label says

Thorne’s current Berberine, sold at an address that still says berberine-500, lists this per two-capsule serving:

Ingredient	Amount per 2 capsules
Berberine HCl (from Indian barberry root extract)	450 mg
Berberine phytosome (Indena’s Berbevis)	550 mg
Other ingredients	calcium laurate, hypromellose capsule

Directions are “1-2 capsules two times daily with food”, so the label allows between two and four capsules a day. The bottle holds 60 capsules and cost $44 on 28 October 2026, or $39.60 on subscription.

The two rows add up to 1,000 mg. They are not 1,000 mg of berberine.

How much of it is berberine

The phytosome row. A phytosome is berberine bound up with other ingredients to help it dissolve and absorb. Indena, which makes Berbevis, describes its berberine phytosome in a 2021 paper as berberine extract combined “with sunflower lecithin, pea protein … and grape seed extract”, and states that it “is standardized to contain 28-34% of berberine”. In the same paper’s human study, Indena counted a 550 mg dose as “equivalent to 188 mg of berberine”. So Thorne’s 550 mg of phytosome carries roughly 154 to 188 mg of berberine.

The HCl row. Berberine HCl is berberine chloride, a salt. The same paper counts 500 mg of berberine chloride as 452 mg of berberine, about 90% by weight. On that ratio, 450 mg of berberine HCl is about 407 mg of berberine.

Together. Our arithmetic gives roughly 560 to 600 mg of berberine per two-capsule serving, and about 1,100 to 1,200 mg at the label maximum of four capsules. Two cautions. Thorne’s label does not state a total berberine figure, so this rests on Indena’s own standardisation range. And the label does not say whether the 450 mg is pure berberine HCl or an extract containing it, which earlier Thorne labels described as “Berberis Concentrate Berberine HCl 85%”. If it is the extract, the total is lower still.

The formula changed in 2024

The NIH Dietary Supplement Label Database keeps every label version a company files, and it shows the switch. Thorne’s Berberine-500 labels from 2012, 2018, 2019 and 2020, and the Berberine 1000 mg labels from 2023, all list 1 gram of berberine HCl per two capsules, with the same “1-2 capsules two times daily” directions. The first label with 450 mg HCl plus 550 mg Berbevis was entered in January 2024, and the 2025 label repeats it.

So someone who bought Thorne Berberine before 2024 and buys it again today, taking the same number of capsules, is getting about 410 mg of berberine from HCl plus 154-188 mg from the phytosome, where they used to get about 900 mg from HCl alone. Thorne’s case is that the phytosome absorbs much better, which is the next question.

The absorption claim rests on one small study

Thorne’s page says the product “contains berberine phytosome for enhanced absorption”. The human evidence for that is a 2021 crossover study in 12 healthy volunteers. Each took 500 mg of plain berberine chloride and two doses of the phytosome on separate days, and blood berberine was higher after the phytosome, the paper says “around 10 times on molar basis”.

The disclosure line reads: “The authors are Indena’s employees.” The study is honest about what it is, a single-dose measurement in 12 young, healthy people. It shows more berberine in the blood, which is a reasonable thing for a formulation to aim at. It does not show that more berberine in the blood lowers blood sugar or cholesterol by more.

The outcome studies of the phytosome are thinner than the pharmacokinetics:

Study	People	Design	What it found
Rondanelli 2021	12 women with PCOS	One group, before and after, 60 days	Improvements in insulin resistance and other markers; no control group
Di Pierro 2023	130 women with PCOS	Randomised, open-label, no placebo	Better menstrual and ovarian outcomes; metabolic and hormonal profiles “did not significantly differentiate” between groups
Cesarone 2024 and 2025	50 adults with borderline cholesterol (2024)	A “pilot, efficacy supplement registry”, not randomised	Lower cholesterol and glucose against standard management

We found no placebo-controlled trial of berberine phytosome for blood sugar, and no trial of any kind of Thorne’s mixed HCl-plus-phytosome capsule.

Against the trial dose

The study that made berberine famous for blood sugar, a 2008 pilot in Metabolism, gave berberine at “0.5 g 3 times a day”, 1,500 mg of berberine HCl a day. Our berberine supplements guide covers that trial and the potency problem with US products in detail.

Regimen	Berberine HCl	Berberine phytosome	Berberine, our estimate
2008 trial, per day	1,500 mg	none	about 1,360 mg
Thorne before 2024, 4 capsules	2,000 mg	none	about 1,810 mg
Thorne today, 4 capsules	900 mg	1,100 mg	about 1,120-1,190 mg
Thorne today, 2 capsules	450 mg	550 mg	about 560-600 mg

At the label maximum, today’s Thorne Berberine delivers somewhat less berberine than the trial regimen, with a third of it in a form designed to absorb better. Whether that ends up stronger or weaker in your blood than the trial dose is not known, because nobody has measured this product. At two capsules a day, the low end of the directions, you are well below the trial dose on either reading.

The quality claims check out

This is where Thorne does better than most brands we review.

NSF. NSF’s public list of NSF/ANSI 173 Contents Certified products includes “Thorne® Berberine”, with a recommended daily serving of 4 capsules. That certification means NSF tested that the declared ingredients are present in the declared amounts and that contaminants are within limits. It is worth having, given that 9 of 15 US berberine products failed a potency test in the study our berberine guide describes. It checks the label, though, not what the label means: it confirms 550 mg of phytosome, not how much berberine is inside it.

TGA. Thorne’s quality page links to a Certificate of GMP Compliance from Australia’s Therapeutic Goods Administration, number MI-2023-CE-16495-1, issued to Thorne Research Inc for its two Summerville, South Carolina sites. It records an inspection on 15 to 18 September 2025, was issued on 10 December 2025, and expires on 18 September 2028. Thorne’s page also says the company “has an A rating” from the TGA; the certificate it links to confirms compliance and shows no letter rating, so we could not verify that wording.

The lawsuits

We searched CourtListener’s federal dockets for Thorne HealthTech and Thorne Research on 28 October 2026. None of the cases we found concerns berberine.

The 2023 sale. In August 2023 Thorne HealthTech agreed to be bought by funds affiliated with L Catterton at $10.20 a share, and its 8-K of 16 October 2023 reports the merger completed. Between 19 and 21 September 2023, while the tender offer was open, five shareholders filed suits under the Securities Exchange Act: four in the Southern District of New York (O’Dell, Morgan, Wang, Donatacci) and one in Delaware (Taylor). All five were closed by 30 November 2023.

Patents. ChromaDex sued Thorne Research over nicotinamide riboside patents in 2021; the case ended in January 2024. In April 2026 Thorne Research sued Niagen Bioscience in South Carolina, also over a patent; it was open.

Trademarks. Thorne Research has brought several trademark suits in South Carolina against companies and people reselling its products, in 2023 and 2024.

Individual suits. Moody v. Thorne HealthTech was removed to federal court in New York in August 2024 and is classed as personal injury product liability; Haviland v. Thorne HealthTech in California, filed in September 2024, closed that November. The docket entries we could read do not say which product or claim either case concerns, so we cannot say. Fagnani v. Thorne Research, filed in November 2025, is a disability-access suit.

Who it might suit

If you have decided to take berberine, have talked to your doctor about your medications, and want a product whose label contents are independently checked, Thorne Berberine is a defensible choice, and the NSF listing is more than most berberine brands can show.

Know what you are buying, though. The 1,000 mg on the panel is two ingredients, and roughly 560 to 600 mg of it is berberine. If your goal is to copy the trial regimen, the label maximum of four capsules a day gets you close in milligrams, with the phytosome portion an untested bet on better absorption. At $44 for 60 capsules, four a day is a 15-day bottle.

We do not link to Thorne, and there is no affiliate box on this page. The checks Thorne invites, NSF and TGA, hold up. The one it does not invite, how much berberine is in a serving, is the one worth doing.

The bottom line

Thorne Berberine is NSF Contents Certified and made in a TGA-certified facility, and those claims check out. Since January 2024 each two-capsule serving has been 450 mg of berberine HCl plus 550 mg of Indena’s berberine phytosome, replacing 1 gram of berberine HCl. Using Indena’s own figure that the phytosome is 28 to 34% berberine, a serving holds roughly 560 to 600 mg of berberine. The phytosome’s tenfold absorption claim comes from one 12-person study by its maker’s employees, and no trial has tested this formula. Read it as a well-made product whose label number is bigger than its berberine number.