The Tampa Bay Times tested 20 kratom products. Here’s what we found.

The Tampa Bay Times had University of Florida scientists test 20 kratom products to better understand their potency and safety.

The researchers analyzed powders, pills, capsules and liquid shots, determining the amount of up to 13 chemical compounds, called alkaloids, in each one. Kratom’s best-studied ingredient, mitragynine, was the most abundant alkaloid in the majority of products. Mitragynine has opioid-like qualities and affects product strength.

Speciociliatine was the second-most abundant alkaloid in 15 of the products. University of Florida scientists think it has more pain-relieving effects than mitragynine and could play a role in determining a product’s safety. None of the products listed the amount of speciociliatine on their packaging.

The alkaloid mitraciliatine also interacts with opioid receptors. And the alkaloids paynantheine and speciogynine interact with serotonin receptors, which researchers think could contribute to the plant’s mood-boosting effects.

The Times bought the products from online vendors, gas stations, smoke shops and other businesses around the region. Below are the key testing results for each product.

They are ordered most potent to least, by product type, based on mitragynine levels. The Times also tested one product containing a large amount of 7-hydroxymitragynine, another kratom alkaloid that is more potent than mitragynine.

Read Part I of Deadly Dose: Hundreds died using kratom in Florida. It was touted as safe.

The Times tested two highly concentrated tablet products, which are far more powerful than kratom leaf powders.

1. 7ΩHMZ

Product type: Tablets, 3 per packet

Where purchased: Whyodious Botanicals website

Cost: $29.99

Mitragynine amount: 0.40 milligrams per tablet

Speciociliatine amount: Below the lower limit of quantification

Paynantheine amount: Below the lower limit of quantification

Speciogynine amount: Below the lower limit of quantification

Mitraciliatine amount: Below the lower limit of quantification

7-hydroxymitragynine amount: 15.27 milligrams per tablet

Summary: This product had what researchers consider to be extreme levels of 7-hydroxymitragynine. It came with three tablets. The suggested serving was half a tablet.

The pills were so strong that Abhisheak Sharma, a University of Florida scientist who studies kratom, likened them to “legal morphine.” He said he believed they shouldn’t be sold to consumers.

To create the potent product, Sharma suspects that the company used a chemical reaction to convert mitragynine into 7-hydroxymitragynine.

This product’s label had no alkaloid levels to inform consumers about strength. The package told customers to consult their doctor before using the product, but included no warning about potential interactions with medications or other substances.

The package the product was sent in came with a printed-out sheet showing testing results for mitragynine, 7-hydroxymitragynine, heavy metals and bacteria. A section of the report showing who ordered the results was blacked out.

A representative for 7ΩHMZ hung up on a reporter when reached by phone. The company did not respond to multiple interview requests sent by text and email.

2. KTAB by Phoria

Product type: Tablets, 5 per container

Where purchased: Phoria website

Cost: $29.95

Mitragynine amount: 58.92 milligrams per tablet

Speciociliatine amount: 0.73 milligrams per tablet

Paynantheine amount: 5.95 milligrams per tablet

Speciogynine amount: 0.73 milligrams per tablet

Mitraciliatine amount: 0.73 milligrams per tablet

7-hydroxymitragynine amount: Below the lower limit of quantification

Summary: This product came with five tablets and each accounted for one serving.

Sharma said he believed the product should not be sold to consumers.

The product’s label advertised “pain relief + mood enhancement.” Federal law prohibits kratom companies from making medical claims on packaging or in advertising because the substance is not an approved drug.

The label told consumers to contact their doctor before using the product. It also said people with health conditions or who are taking medications shouldn’t consume the kratom pills.

Phoria did not respond to requests for an interview.

The Times tested three power-packed liquid shots. Scientists are increasingly concerned about these types of products.

1. MIT45 Super K Extra Strong

Product type: Liquid, 1 ounce per bottle

Where purchased: Vapor & Pipes Smoke Shop, 1416 W. Kennedy Blvd., Tampa

Cost: $19.98

Mitragynine amount: 367.44 milligrams per bottle

Speciociliatine amount: 64.89 milligrams per bottle

Paynantheine amount: 76.98 milligrams per bottle

Speciogynine amount: 50.4 milligrams per bottle

Mitraciliatine amount: 9.25 milligrams per bottle

7-hydroxymitragynine amount: 1.76 milligrams per bottle

Summary: This product had the highest amount of mitragynine among the supercharged liquid extracts.

The brand has claimed it is the “strongest kratom shot.” Its label said that extracts can be “much more powerful” than regular kratom powder.

The label said “average reported usage” is one-sixth of the bottle.

This product had nine times as much mitragynine as Sharma believes is safe to consume over an entire day.

Its label had no warning about the possibility for interactions with other substances or medications.

The chief executive officer of MIT45, Ryan Niddel, did not respond to multiple interview requests.

2. K Shot Black

Product type: Liquid, 0.3 ounces per bottle

Where purchased: Peace of Mind Smoke Shop, 1628 Central Ave., St. Petersburg

Cost: $20

Mitragynine amount: 114.25 milligrams per bottle

Speciociliatine amount: 24.18 milligrams per bottle

Paynantheine amount: 23.36 milligrams per bottle

Speciogynine amount: 15.72 milligrams per bottle

Mitraciliatine amount: 4.58 milligrams per bottle

7-hydroxymitragynine amount: Below the lower limit of quantification

Summary: This product’s label had no dosing instructions and no information about its potency.

The small bottle contained almost three times as much mitragynine as Sharma believes is safe to consume in a day.

Christopher McCurdy, who also studies kratom at the University of Florida, said he thinks concentrated extracts shouldn’t be sold to people using kratom for the first time.

Of the products tested by the Times, this product’s label had one of the most comprehensive disclaimers. It warned customers not to combine it with alcohol, large amounts of caffeine or other stimulants, prescription drugs or illicit substances. It also said to “not try if you have a history of mental illness.”

The Times attempted to contact representatives behind the K Shot brand. Reporters could not determine who definitively made the product. A reporter tried multiple phone numbers and sent several interview requests by text and email. None of the messages were returned.

3. O.P.M.S. Gold Liquid

Product type: Liquid, roughly 0.3 ounces per bottle

Where purchased: Sligh Petrol Mart, 403 E. Sligh Ave., Tampa

Cost: $20

Mitragynine amount: 79.88 milligrams per bottle

Speciociliatine amount: 18.33 milligrams per bottle

Paynantheine amount: 15.46 milligrams per bottle

Speciogynine amount: 10.29 milligrams per bottle

Mitraciliatine amount: 3.27 milligrams per bottle

7-hydroxymitragynine amount: Below the lower limit of quantification

Summary: This product’s label had no dosing instructions that would help consumers know how much to take.

The little bottle contained nearly twice as much mitragynine as Sharma believes is safe to consume over an entire day.

The product packaging told consumers to ask their doctor about how to safely use it, but it did not contain an explicit warning about the potential for interactions with other substances or medications. The label said ingesting kratom can be dangerous.

Executives behind the O.P.M.S. brand did not respond to multiple interview requests. The Times also sent repeated messages to the company’s general email and did not receive a response. Several people and companies connected to the O.P.M.S. brand did have their attorneys respond to the Times saying they would not be commenting.

There wasn’t much variation in mitragynine levels among capsules filled with leaf powder. They were much less potent than the highly concentrated pills and liquid shots tested by the Times. But they came in packages that contained dozens, and even hundreds, of capsules without any dosing instructions.

1. O.P.M.S. Silver Green Vein Maeng Da

Product type: Capsules, 120 per bag

Where purchased: Green House Smoke & Vape Shop, 2115 E. Hillsborough Ave., Tampa

Cost: $34.99

Mitragynine amount: 5.15 milligrams per capsule

Speciociliatine amount: 1.86 milligrams per capsule

Paynantheine amount: 1.08 milligrams per capsule

Speciogynine amount: 0.84 milligrams per capsule

Mitraciliatine amount: 0.30 milligrams per capsule

7-hydroxymitragynine amount: 0.04 milligrams per capsule

Total mitragynine per bag: 618 milligrams

Summary: This product had no dosing instructions on its label telling consumers how many capsules to take.

The product packaging directed consumers to ask their doctor about how to safely use it, but it did not contain an explicit warning about the potential for interactions with other substances or medications. The label said ingesting kratom can be dangerous.

This product type was found at the scenes of two kratom-only overdoses in Florida.

Executives behind the O.P.M.S. brand did not respond to multiple interview requests. The Times also sent repeated messages to the company’s general email and did not receive a response. Several people and companies connected to the O.P.M.S. brand did have their attorneys respond to the Times saying they would not be commenting.

2. Pure Infinity Botanicals Premium Trainwreck

Product type: Capsules, 100 per bag

Where purchased: Cosmic Fish Smoke Shop & Kava Bar, 5944 34th St. N., St. Petersburg

Cost: $19.99

Mitragynine amount: 4.41 milligrams per capsule

Speciociliatine amount: 1.46 milligrams per capsule

Paynantheine amount: 0.90 milligrams per capsule

Speciogynine amount: 0.65 milligrams per capsule

Mitraciliatine amount: 0.25 milligrams per capsule

7-hydroxymitragynine amount: Below the lower limit of quantification

Total mitragynine per bag: 441 milligrams

Summary: This product’s label had no dosing instructions informing consumers how many capsules to take.

It also had no information about potency or warnings about the potential for interactions with other substances or medications.

Owner Josh Sutherland and vice president of sales Abram Jacobson said the product purchased by the Times must have had “old packaging that was still floating around.” They said the new labels would include QR codes to lab tests and would show mitragynine levels on their products. They also said the product’s new labels would include disclaimers such as telling consumers to talk to their doctor before using the product.

They said they would send examples of the brand’s new packaging but the Times did not receive any from the company.

3. Whole Herbs Red Vein Bali

Product type: Capsules, 250 per bottle

Where purchased: South Tampa Smoke Shop, 3902 Henderson Blvd. Suite 100, Tampa

Cost: $40

Mitragynine amount: 4.20 milligrams per capsule

Speciociliatine amount: 1.36 milligrams per capsule

Paynantheine amount: 0.87 milligrams per capsule

Speciogynine amount: 0.65 milligrams per capsule

Mitraciliatine amount: 0.21 milligrams per capsule

7-hydroxymitragynine amount: Below the lower limit of quantification

Total mitragynine per bottle: 1,050 milligrams

Summary: This product’s package included no dosing instructions for how many capsules consumers should take.

The product label directed consumers to ask their doctor about how to safely use it, but it did not contain an explicit warning about the potential for interactions with other substances or medications. The packaging said ingesting kratom can be dangerous.

This product type was found at the scene of a kratom-only overdose in Florida.

The Times attempted to contact representatives of the Whole Herbs brand. The phone number and email listed on the product’s bottle didn’t work. The brand’s online retailer said it was separate from the brand. The Times sent an interview request through an online form on the brand’s website but did not receive a response.

The Times tested 12 powders. They were far less potent than the concentrated pills and liquid shots, but they often came in packages that included large amounts of mitragynine. The average amount of mitragynine in the products was 8.7 milligrams per gram.

1. Remarkable Herbs Maeng Da Kratom Green Vein

Product type: Powder, roughly 227 grams per bag

Where purchased: Smoke Shop Zone, 4430 W. Kennedy Blvd., Tampa

Cost: $27.99

Mitragynine amount: 11.69 milligrams per gram

Speciociliatine amount: 3.25 milligrams per gram

Paynantheine amount: 2.38 milligrams per gram

Speciogynine amount: 1.78 milligrams per gram

Mitraciliatine amount: 0.60 milligrams per gram

7-hydroxymitragynine amount: Below the lower limit of quantification

Mitragynine per bag: 2,651.25 milligrams

Summary: This product had no dosing information telling consumers how much to take. It had the highest amount of mitragynine per gram among the powders tested by the Times.

The product label directed consumers to ask their doctor about how to safely use it, but it did not contain an explicit warning about the potential for interactions with other substances or medications. The packaging said ingesting kratom can be dangerous.

This product type was found at the scenes of two kratom-only overdoses in Florida.

The Times attempted to contact representatives of the Remarkable Herbs brand. The phone number and email listed on the product’s bag didn’t work. The Times sent an interview request through an online form on the brand’s website but did not receive a response.

2. Choice Botanicals Maeng Da Kratom Green Strain

Product type: Powder, 60 grams per container

Where purchased: Choice Botanicals website

Cost: $24.99

Mitragynine amount: 11.35 milligrams per gram

Speciociliatine amount: 3.51 milligrams per gram

Paynantheine amount: 2.08 milligrams per gram

Speciogynine amount: 1.57 milligrams per gram

Mitraciliatine amount: 0.63 milligrams per gram

7-hydroxymitragynine amount: 0.12 milligrams per gram

Total mitragynine per container: 681 milligrams

Summary: This product contained more mitragynine per gram than the average level among the powders. Its label had no dosing instructions explaining how much consumers should take. It also had no information about potency.

The package included a QR code linking to testing results on alkaloid content from 2021. The label did not warn about potential interactions with other substances or medications.

This product type was found at the scene of a kratom-only overdose in Florida.

The Times called the phone number listed on the Choice Botanicals website and was directed to send emails to a representative, who did not respond. Choice Botanicals founder Billy Cosgrove first hung up on a reporter when reached by phone. Cosgrove then sent a text apologizing and said he couldn’t talk at the time. He then directed the Times to the company’s attorney, who did not respond to an interview request.

3. The Kratom Distro Premium Kratom Powder White Horned Maeng Da

Product type: Powder, total weight not listed on bag

Where purchased: The Kratom Distro website

Cost: $39.99

Mitragynine amount: 10.79 milligrams per gram

Speciociliatine amount: 3.23 milligrams per gram

Paynantheine amount: 2.13 milligrams per gram

Speciogynine amount: 1.64 milligrams per gram

Mitraciliatine amount: 0.62 milligrams per gram

7-hydroxymitragynine amount: Below the lower limit of quantification

Summary: This product contained more mitragynine per gram than the average level among the powders. Its label had no information about potency. It suggested 1 gram as a serving, but did not identify how many grams were in the package.

The label did not warn about potential interactions with other substances or medications.

The Times ordered one product from The Kratom Distro. But the company sent two bags of kratom powder labeled “old batch” and “new batch” without further explanation. These test results pertain to the “old batch.”

This product type was found at the scene of a kratom-only overdose in Florida.

A representative for The Kratom Distro hung up on a reporter, then did not respond to follow-up requests for comment via text and email.

4. Plastic packet with “Trainwreck” written on it from The Kratom Distro

Product type: Powder, total weight not listed on packet

Where purchased: The Kratom Distro included the packet as a complimentary product

Cost: Free

Mitragynine amount: 10.42 milligrams per gram

Speciociliatine amount: 3.03 milligrams per gram

Paynantheine amount: 2.07 milligrams per gram

Speciogynine amount: 1.59 milligrams per gram

Mitraciliatine amount: 0.55 milligrams per gram

7-hydroxymitragynine amount: 0.09 milligrams per gram

Summary: This product had no label at all other than “Trainwreck” written on it. It contained more mitragynine per gram than the average level among the powders.

The Times ordered one product from The Kratom Distro, but the company included two complimentary powders.

They came in plastic pouches with nothing written on them except Trainwreck and what appeared to be “G16.” The Times tested the Trainwreck product.

A representative for The Kratom Distro hung up on a reporter, then did not respond to follow-up requests for comment via text and email.

5. Golden Monk Green Maeng Da

Product type: Powder, 250 grams per bag

Where purchased: Golden Monk website

Cost: $39.99

Mitragynine amount: 10.11 milligrams per gram

Speciociliatine amount: 2.73 milligrams per gram

Paynantheine amount: 2.08 milligrams per gram

Speciogynine amount: 1.51 milligrams per gram

Mitraciliatine amount: 0.43 milligrams per gram

7-hydroxymitragynine amount: Below the lower limit of quantification

Total mitragynine per bag: 2,527.5 milligrams

Summary: This product contained more mitragynine per gram than the average level among the powders. Its label included a suggested serving of 1 gram and told consumers not to take more than 4 grams in a 24-hour period.

The packaging said consumers should consult their doctor before using the product, but it did not include an explicit warning about the potential for interactions with other substances or medications. The label said ingesting kratom may be harmful.

This product type was found at the scenes of two kratom-only overdoses in Florida.

The Times called and emailed Ryan Niddel, the chief executive officer for MIT45, which last year acquired the Golden Monk brand. Niddel did not respond to requests for comment. The Times also reached out to the company via the contact email on its website but did not get a response.

6. Plastic bag with “Red” written on it from Bula Kafe

Product type: Powder, total weight not listed on bag

Where purchased: Bula Kafe, 2500 5th Ave N., St. Petersburg

Cost: $9.30

Mitragynine amount: 8.97 milligrams per gram

Speciociliatine amount: 2.19 milligrams per gram

Paynantheine amount: 1.76 milligrams per gram

Speciogynine amount: 1.32 milligrams per gram

Mitraciliatine amount: 0.43 milligrams per gram

7-hydroxymitragynine amount: Below the lower limit of quantification

Summary: This product had no label at all other than “Red” written on it. It contained more mitragynine per gram than the average level among the powders.

This product type was found at the scene of a kratom-only overdose in Florida.

Ross Kashtan, the owner of Bula, said he believes “regular kratom is impossible to overdose on.”

“I get up every morning and I know that my business saves lives,” he said.

7. Unlabeled plastic bag from The Funky Farmacy

Product type: Powder, total weight not listed on bag

Where purchased: The Funky Farmacy, 4260 Park Blvd., Pinellas Park

Cost: $6

Mitragynine amount: 8.22 milligrams per gram

Speciociliatine amount: 2.26 milligrams per gram

Paynantheine amount: 1.79 milligrams per gram

Speciogynine amount: 1.29 milligrams per gram

Mitraciliatine amount: 0.41 milligrams per gram

7-hydroxymitragynine amount: Below the lower limit of quantification

Summary: This product had no label at all. It contained less mitragynine per gram than the average level among the powders.

Funky Farmacy owner Tristan O’Connell said the company recently made changes to include labels on its bags.

8. Sea Kratom White Maeng Da

Product type: Powder, 500 grams per bag

Where purchased: Johnny’s Smoke Shop & Kava Bar, 5402 Park Blvd., Pinellas Park

Cost: $55

Mitragynine amount: 7.97 milligrams per gram

Speciociliatine amount: 2.80 milligrams per gram

Paynantheine amount: 1.62 milligrams per gram

Speciogynine amount: 1.11 milligrams per gram

Mitraciliatine amount: 0.50 milligrams per gram

7-hydroxymitragynine amount: Below the lower limit of quantification

Total mitragynine per bag: 3,985 milligrams

Summary: This product contained less mitragynine per gram than the average level among the powders. Its label had no information about its potency. Its packaging included a “suggested use” of 2 to 4 grams per serving but said the dosage should be “regarded as loose approximations.”

The label told consumers to talk to their doctor about how to use the product safely, but it did not include a warning about possible interactions with other substances or medications.

The Times sent multiple interview requests to Sea Kratom through an apparent company email but received no response.

9. Sembuh Kratom Red Bali

Product type: Powder, 30 grams per bag

Where purchased: Mobil, 6201 34th St. N., Pinellas Park

Cost: $9.99

Mitragynine amount: 7.63 milligrams per gram

Speciociliatine amount: 1.93 milligrams per gram

Paynantheine amount: 1.61 milligrams per gram

Speciogynine amount: 1.18 milligrams per gram

Mitraciliatine amount: 0.35 milligrams per gram

7-hydroxymitragynine amount: Below the lower limit of quantification

Total mitragynine per bag: 228.9 milligrams

Summary: This product contained less mitragynine per gram than the average level among the powders. Its label had no information about potency. It suggested that consumers take up to 2 grams every four hours, or as needed.

The packaging warned consumers to not mix the product with alcohol or medications. It also said that “prolonged use or exceeding the recommended use may be habit forming.”

The Times contacted the company via Facebook and email with an interview request but received no response.

10. Majestic Kratom Hulu White

Product type: Powder, 125 grams per bag

Where purchased: Pipe Dreamz Smoke Shop, 4215 4th St. N., St. Petersburg

Cost: $20

Mitragynine amount: 6.82 milligrams per gram

Speciociliatine amount: 2.41 milligrams per gram

Paynantheine amount: 3.33 milligrams per gram

Speciogynine amount: 1.99 milligrams per gram

Mitraciliatine amount: 0.90 milligrams per gram

7-hydroxymitragynine amount: 0.08 milligrams per gram

Total mitragynine per bag: 852.5 milligrams

Summary: This product contained less mitragynine per gram than the average level among the powders. Its label had no dosing instructions telling consumers how much to take. It also had no information about potency.

The label did not have a warning about possible interactions with other substances or medications.

The Times contacted the Pipe Dreamz Smoke Shop and a manager provided an email for the owner of the store and the Majestic Kratom brand. No one responded to an email seeking an interview.

11. Lipht Kratom Premium Maeng Da

Product type: Powder, 50 grams per container

Where purchased: Vapes ATL website

Cost: $10.95

Mitragynine amount: 5.27 milligrams per gram

Speciociliatine amount: 1.75 milligrams per gram

Paynantheine amount: 4.53 milligrams per gram

Speciogynine amount: 3.51 milligrams per gram

Mitraciliatine amount: 1.34 milligrams per gram

7-hydroxymitragynine amount: Below the lower limit of quantification

Total mitragynine per container: 263.5 milligrams

Summary: This product contained less mitragynine per gram than the average level among the powders. Its label had no potency information. It suggested that consumers take 2 grams every four hours, or as needed.

The label said customers should check with their doctor before taking supplements. It warned that “prolonged use or exceeding the recommended dosage may be habit forming.”

The label had no warning about possible interactions with other substances or medications.

This product type was found at the scene of a kratom-only overdose in Florida.

Lipht Kratom representatives did not respond to multiple interview requests sent to a company email and through a form on its website.

12. Herbal RVA Royal Bentuangie

Product type: Powder, 100 grams per bag

Where purchased: Herbal RVA website

Cost: $10.80

Mitragynine amount: 4.72 milligrams per gram

Speciociliatine amount: 1.47 milligrams per gram

Paynantheine amount: 1.05 milligrams per gram

Speciogynine amount: 0.85 milligrams per gram

Mitraciliatine amount: 0.26 milligrams per gram

7-hydroxymitragynine amount: Below the lower limit of quantification

Total mitragynine per bag: 472 milligrams

Summary: This product contained less mitragynine per gram than the average level among the powders. Its label had no information about potency. The packaging had a “suggested use” of 3 grams and said to not take more than two servings over 24 hours.

The label had no warning about potential interactions with other substances or medications.

A representative for Herbal RVA told the Times this product is one of the brand’s weakest offerings. He also pointed to alkaloid testing results for the product available online.

Times staff writers Helen Freund, Hannah Critchfield, Kirby Wilson and Langston Taylor contributed to this report.

Former Times staff writer Eli Murray contributed reporting before joining another news organization.

This article was produced as a project with the USC Annenberg Center for Health Journalism’s 2023 National Fellowship.