Home / Mullein Leaf Extract

Ingredient guide · Updated November 2026

Mullein Leaf Extract 10:1: What the Ratio Means and What the Research Says

Mullein is the first ingredient on the Breathiterol label and the most searched herb in its category. This guide covers the plant, what a 10:1 extract is, what the peer-reviewed research and the European monograph actually say about mullein benefits and safety, what has not been studied, and how the extract is used in a once-daily spray.

Verbascum thapsus10:1 leaf extract2022 peer-reviewed reviewEMA monograph

Check Current Pricing Read the Full Review

Published November 4, 2026 · Facts from the product label and the official order page

The front label of Breathiterol, which lists mullein leaf extract 10:1 first

The plant

Mullein (Verbascum thapsus): The Plant Behind the Extract

Common mullein, Verbascum thapsus, is a tall biennial with soft grey-green leaves and a yellow flower spike. The 2022 review in Phytotherapy Research describes it as native to northern Africa, western and central Asia and Europe, now naturalised across the Americas and Australia. Two parts are used: the leaves, which go into teas, tinctures and the leaf extract found in sprays such as Breathiterol, and the flowers, which are the subject of the European Medicines Agency's herbal monograph and of the traditional flower oil.

Leaf

The part named on the Breathiterol label: "Mullein (Verbascum thapsus) (leaf) Extract 10:1". Leaves are the usual basis of mullein tea and of dried-leaf products.

Flower

The part the EMA monograph covers (Verbasci flos), from V. thapsus, V. densiflorum and V. phlomoides. Flower preparations are a separate tradition from leaf preparations.

What is in it

The 2022 review lists flavonoids, iridoid, phenylethanoid and phenylpropanoid glycosides, saponins, vitamin C and minerals among the plant's constituents, and singles out coumarin and hesperidin.

The number on the label

What "Mullein Leaf Extract 10:1" Means

A 10:1 ratio is a statement about concentration, not about strength. It means that ten parts of dried leaf were used to make one part of finished extract: 10 kg of leaf becomes roughly 1 kg of extract. The ratio tells you how much raw plant stands behind each milligram; it does not tell you which constituents were kept, which solvent was used or how the extract compares with a cup of tea. Breathiterol's label gives the ratio but, like most supplement labels, not the solvent or a marker compound.

What the ratio does say

How concentrated the extract is relative to the dried leaf. A 10:1 extract is ten times more concentrated by weight than the leaf it came from.

What it does not say

How much mullein is in the finished product. In Breathiterol the extract is the first of three botanicals in a 154 mg blend; the blend total is printed, the share of each botanical is not.

The research

Mullein Benefits: What the Published Research Says, and How Strong It Is

Two documents carry most of the weight. Neither is a study of a spray, and neither tested Breathiterol.

The 2022 review (Phytotherapy Research)

A peer-reviewed review of Verbascum thapsus that catalogs its constituents and the activities reported for them in experimental studies, including antioxidant, antimicrobial and anti-inflammatory effects observed in the laboratory. It describes the plant's traditional use in the respiratory, throat and skin areas as an astringent and calming agent. The review draws on "experimental studies" and "emerging literature"; it does not report clinical trials in people. Read the abstract on PubMed.

The EMA herbal monograph (mullein flower)

The European Medicines Agency's Committee on Herbal Medicinal Products accepts mullein flower preparations on the basis of traditional use: at least 30 years of documented use, 15 of them in the EU, for throat comfort during the cold season, in adults and adolescents over 12. The monograph states that there is insufficient evidence from clinical trials and that no side effects had been reported at the time of assessment. Read the EMA summary.

The honest summary: mullein has a long traditional record and a growing body of laboratory work on its constituents, and no clinical trial of a leaf extract in a spray. Anyone who tells you otherwise is ahead of the evidence.

What is not known

What the Research Does Not Show About Mullein Leaf Extract

No published trial has tested a mullein leaf extract delivered as an oral spray.
The EMA monograph covers the flower, not the leaf, and rests on tradition rather than trials.
The laboratory activities in the 2022 review were measured on extracts and isolated compounds, at concentrations that do not translate directly into a 0.60 mL serving.
No study has compared a 10:1 leaf extract with tea, tincture or dried leaf in people.

Mullein in a spray

Mullein Leaf Extract in Breathiterol

Breathiterol lists mullein leaf extract 10:1 first in its 154 mg Proprietary Blend, ahead of ginger root extract and organic lemon extract, which by labeling convention means it is the largest of the three by weight. The serving is 4 sprays (0.60 mL) once a day, and a 60 mL bottle holds 100 servings. The full panel, with the other two botanicals and the spray base, is on the Breathiterol ingredients page; packs and prices are in the buying guide.

See Breathiterol Pricing

Sources

Sources for This Mullein Guide

Verbascum thapsus L. (common mullein): a review. Phytotherapy Research, 2022;36(4):1507-1522. PubMed 35088467
European Medicines Agency, Committee on Herbal Medicinal Products: Verbasci flos (mullein flower), EU herbal monograph and public summary, revised 2018, addendum 2025. ema.europa.eu
The Breathiterol label, reproduced on the reviews page

FAQ

Mullein Leaf Extract: Frequently Asked Questions

What is mullein good for?

Traditionally, throat and respiratory comfort: the European Medicines Agency accepts mullein flower preparations on the basis of at least 30 years of such use, and the 2022 review describes the same traditional role for the plant. Those are statements about tradition, not clinical proof.

Does mullein work?

Laboratory studies report antioxidant, antimicrobial and anti-inflammatory activity for mullein extracts and their constituents, and the EMA records long traditional use. No clinical trial of a mullein leaf extract in people has been published, so the question is open.

Is mullein safe?

The EMA monograph notes that no side effects had been reported for mullein flower at the time of its assessment and limits traditional use to adults and adolescents over 12. Supplement labels, Breathiterol's included, ask pregnant or nursing mothers, anyone under 18 and anyone with a known medical condition to consult a physician first.

What does 10:1 mean on a mullein extract?

Ten parts of dried leaf were used to make one part of extract. It is a concentration ratio, not a measure of potency, and it does not state the solvent or the constituents retained.

Mullein leaf or mullein flower: which is in Breathiterol?

The leaf. The label reads "Mullein (Verbascum thapsus) (leaf) Extract 10:1". The EMA monograph covers the flower, a separate preparation.

How much mullein is in Breathiterol?

The label prints a 154 mg Proprietary Blend per 4-spray serving with mullein leaf extract listed first, which by labeling convention makes it the largest of the three botanicals by weight; the exact milligrams of mullein are not stated.