Kratom colours and strain names: what the label can and can't tell you

Browse a kratom shelf and the first thing you meet is a name rather than a number: Red Bali, Green Maeng Da, White Thai. It reads like a wine list. It's fair to ask what those names are actually naming, because a colour on a pack is a lovely thing to have and a poor stand-in for a lab report.

Red, green and white are sorting categories: they began as descriptions of leaf veins and stems, and are now often used for the colour of the finished powder. Bali, Thai, Borneo and Malay are place names. Maeng Da is a trade name that sellers use as a grade or brand label. What researchers have measured is that the alkaloids in kratom leaf shift with leaf age, season, place, cultivar and what's done to the leaf after picking. In one survey-plus-lab study, a vendor's red, green and white products showed no significant difference in the alkaloids measured on their lab certificates, even though users of that vendor reported different effects by colour. So the useful move is to read a colour as a description and compare the things a page can actually show.

What the names are pointing at

• Red, green and white. University of Florida researchers note that kratom strain classes are "most commonly based on the color of the powdered product rather than the actual leaf vein color". The older idea is the veins and stems of the leaf: the EU Drugs Agency's profile (an archived copy dated 1 January 2026) says the veins of kratom leaves "are either greenish-white or red", and adds that the former is reputed to be more potent (EUDA kratom drug profile). Note the word "reputed". A 2026 study of eight Thai kratom accessions (plant lines) found that vein colour can vary on a single tree, from pale green on young leaves to bright red on mature ones (Ransden et al., 2026, Frontiers in Plant Science).
• Bali, Thai, Borneo, Malay, Sumatra. These suggest where the leaf came from. A label on its own can't confirm it.
• Maeng Da. The WHO's 2021 pre-review report lists it among the trade names for kratom sold online (WHO ECDD pre-review, advance copy). Azarius's Maeng Da category page (read 14 October 2026) calls it "a branding convention" for leaf "bred or graded for higher alkaloid content", which leaves open whether it means a selected cultivar or a grade.
• Yellow or gold. Zamnesia's kratom category page (read 14 October 2026) describes its yellow Maeng Da powder as "a blend of White and Red strains".

What has actually been measured

It helps to separate two questions. What makes kratom alkaloids vary? And does the colour label track any of it?

• What changes the alkaloids: Season and place; What the studies found: Across two sets of Thai leaf samples (745 in all), mitragynine ranged from about 0.3% to about 4.9% of dry leaf weight, depending mostly on season and place (Sengnon et al., 2023, Plants). Another Thai survey found 7.5 to 26.6 mg per gram of dry leaf across regions, linked to light, humidity and soil (Leksungnoen et al., 2022); Worth knowing: Field studies in Thailand; they describe leaf, not retail products
• What changes the alkaloids: Leaf age; What the studies found: Young leaves had a different alkaloid mix from mature ones in eight Thai accessions (Ransden et al., 2026); Worth knowing: Leaf age mattered more than which tree it came from
• What changes the alkaloids: Cultivar; What the studies found: Cultivars ranged from undetectable to high mitragynine in one US lab study (Laforest et al., 2023, Journal of Natural Products); Worth knowing: One lab study
• What changes the alkaloids: Wilting and drying after picking; What the studies found: Wilting the leaf for a time before drying raised mitragynine by 14 to 65% in one cultivar and 3 to 8% in another; hot drying made powder reddish-brown, cool drying kept it green (Zhang et al., 2025, Frontiers in Plant Science); Worth knowing: Controlled experiment on two cultivars at the University of Florida; wilting was tested, fermentation was not
• What changes the alkaloids: Vein colour of the leaf; What the studies found: Red-vein and green-vein leaves showed no difference in alkaloid production in the Thai samples above (Sengnon 2023). Mature leaves in eight accessions with visibly different vein colours had largely similar alkaloid profiles (Ransden 2026); Worth knowing: Different alkaloids were measured in each study
• What changes the alkaloids: Colour on the label; What the studies found: See below; Worth knowing: One vendor, one survey

The Florida team drew a pointed conclusion: powder colour "does not necessarily correlate with alkaloid composition, but rather serves as an indicator of the postharvest environment". Same-coloured powders, they found, could still differ in alkaloids, depending on whether the leaf had been wilted first.

Now the study closest to your shopping basket. A survey received 644 responses from current kratom users, mostly customers of one US vendor, about the red, green and white products they used. Respondents reported different effects for the different colours, in a pattern matching how vendors describe them, although only 6 of the 39 effects asked about differed significantly between colours. The researchers were also given the vendor's certificates of analysis from an independent laboratory, covering six products (white, red and green Maeng Da, green Bali, white Thai and red Bali) across three batches. Mitragynine (about 1.4 to 1.6%) and total alkaloids (about 2.2 to 2.4%) showed no significant difference between the products. The authors suggest expectation and marketing may play a part, but note that a real effect from compounds they didn't measure remains possible, and that a blinded experiment would be needed to tell (Huisman et al., 2023, International Journal of Environmental Research and Public Health). Limits: one vendor, mostly US respondents, self-reported effects, and four individual alkaloids plus the total.

That survey, people's own accounts and shop descriptions are what exists on whether red, green or white kratom feels different. No blinded or controlled trial has compared colours in people, so it isn't established that the label is the reason for any difference. That's a gap, not a verdict: it doesn't say the experiences people describe aren't real.

One older lab study did report differences. It found different alkaloid profiles in purified extracts of five named strains (Red Thai, Red Malay, Red Bali, White Borneo and Green Malay), with more compounds detected in Red Bali (Boffa et al., 2018, Natural Product Communications). These were extracts, not products from a shop.

What shops and others say

Supplier statements below are as published on the pages, read on 14 October 2026; we haven't tested any product.

Azarius's red kratom page (it shows "Last updated: April 2026") says the colour "refers to the veins and stems of the leaf at harvest, which correlate with different alkaloid ratios", and that "soil, region, drying method, and the grower all matter as much as vein colour". Zamnesia's kratom category page (no date shown) says the alkaloid balance "shifts with the harvest and the drying method", and gives that as the reason "the vein colour on the label tells you more than the brand name does". Both are supplier descriptions, quoted as written.

Health and drug-information sources are more careful. Jellinek, a Dutch addiction-care organisation (page version January 2022), says the three main kinds are split by the colour of stem and veins, and that the difference is not always entirely clear and depends on location, age and the conditions the tree grew in. For red, it attributes the effects it lists to what users report (Jellinek). DRUGSinfo, run by the Trimbos Institute, says there are various kinds sold, such as Maeng Da, red and Bali, that they are often powders made from particular leaf parts or dried or treated in a particular way, that it is hard to know what is really in the powder, and that effects can differ even when the name is the same (DRUGSinfo, undated).

Reading a product page when the colour is the headline

Treat the colour as a descriptor: it may tell you something about how the seller sorts leaf. Then look for what can be checked. Here's a translation table for common label words.

• The page says: "Red", "green", "white"; What it probably is: A seller's sorting category: leaf vein or powder colour; What to look for instead: Whether the page says how the colour was decided and, above all, the alkaloid figures
• The page says: "Maeng Da", "Premium", "Super"; What it probably is: A trade name used as a grade or brand label; What to look for instead: A stated mitragynine content per gram or per unit
• The page says: "Bali", "Thai", "Borneo"; What it probably is: A place-style name; origin isn't checkable from the label; What to look for instead: Harvest date or year, country of origin, how it was dried
• The page says: "80 mg", "extract"; What it probably is: A figure whose unit may be leaf, extract or mitragynine; What to look for instead: The declared unit; our guide to kratom formats walks through it
• The page says: "Lab tested"; What it probably is: A claim; What to look for instead: A batch number matching your pack, the lab, the date, the method, and mitragynine and 7-hydroxymitragynine reported separately

Two things sit above colour. The first is whether a product is leaf or an extract, or has added 7-hydroxymitragynine, because that changes the product far more than any vein colour (the formats guide covers that). The second is the batch certificate. The same leaf material can end up with different alkaloid levels depending on when and how it was picked and dried, so a colour name can't stand in for a measurement of the batch in your hand.

Legal and safety footing

Colour doesn't change either. In the Netherlands, as read on 8 October 2026: kratom isn't on the Opium Act lists. In a June 2025 ruling (College van Beroep voor het bedrijfsleven, case 24/93) on an import of kratom leaf powder, the court held that kratom is not excluded from food law as a narcotic; the authorities' position that kratom is an unauthorised novel food was not contested on appeal (ECLI:NL:CBB:2025:340). We found no ruling on retail smartshop sales, capsules, extracts or gummies. A 31 March 2026 draft decision amending Opium Act lists I and IA exists, and we couldn't confirm that it's unrelated to kratom. Rules differ if you order from, or travel to, another country. Laws change; check the current rules. This isn't legal advice.

On the health side, regular use can lead to dependence and withdrawal in some people, and the products vary a lot in content; our kratom guide goes through the evidence. For medicines, a 2023 clinical study in 12 healthy adults found that a low-dose kratom tea raised exposure to the sedative midazolam 1.39-fold, a modest measured rise, so it's worth showing a pharmacist the actual label if you take anything regularly (Tanna et al., 2023, Clinical Pharmacology and Therapeutics; more in our supplement and drug interactions guide).

So what does a colour tell you?

Not much about alkaloids, on the evidence so far. A fair amount about how a seller sorts and names the leaf. A page that also gives the unit, the alkaloid figures and a batch certificate gives you something checkable, and next to that the colour is a bit like the colour of the coffee bag.

Written by Smart Supplements with AI assistance from the sources linked in the text. It has not been reviewed by a clinician.

Last updated: 14 October 2026

This article is for informational purposes only and is not intended as medical advice. Always consult a healthcare professional before starting any new supplement, especially if you take prescription medication.