St John's Wort (Hypericum perforatum): A Botanical Guide

A herbaceous perennial with bright yellow, five-petalled flowers. Not a shrub in the ornamental sense. Not the ornamental Hypericum grown in gardens for its berries, either — the genus runs to hundreds of species, and only Hypericum perforatum is the one used in the European herbal tradition.

Family

Hypericaceae (older references place it in Clusiaceae / Guttiferae)

Common names

St John's Wort, perforate St John's-wort, common St John's-wort

Part used

Aerial parts — the flowering tops, leaves and upper stems, cut while the plant is in flower

Native range

Europe, North Africa and western Asia

Naturalised range

Temperate regions worldwide, including North and South America, southern Africa, Australia and New Zealand, where it is often treated as an invasive weed

Typical habitat

Open, disturbed, well-drained ground — roadside verges, meadows, field margins, waste ground, old quarries

Height

Roughly 30–90 cm

Why "perforatum"

The tiny translucent dots across the leaf are not holes. They are pale oil glands set in the leaf tissue, and they gave the species its Latin epithet. Darker glands sit along the margins of the petals and sepals; those hold hypericin, a deep red pigment. Crush a fresh flower bud between finger and thumb and it can stain them reddish-purple.

The name

The plant comes into full flower around midsummer in northern Europe, close to St John's Day on 24 June, and the common name is generally linked to that timing. "Wort" is the old English word for a plant. Nothing more elaborate than that.

Wild-harvested or cultivated?

Both. It grows abundantly in the wild across Europe and is easy to gather. But hypericin content in wild stands varies considerably with the season, the site and the stage of flowering at cutting. Material destined for standardised extracts is therefore generally grown as a field crop, harvested at a controlled point in flowering, then dried and assayed — a consistent starting material is what allows an extract to be standardised to a stated marker level at all. Ours is a standardised extract, produced to a declared hypericin specification.

Our St John's Wort Capsules contain one ingredient plus the capsule shell. No filler, no bulking agent, no flow agent, no flavouring.

Active ingredient

900mg St John's Wort extract (aerial parts) per capsule

Extract ratio

10:1

Standardisation

0.3% hypericin

Capsule shell

Cellulose (vegetarian capsule shell)

Other ingredients

None

Allergens

Free from gluten, soy and dairy. No artificial additives or sweeteners

Suitable for

Vegans and vegetarians. Non-GMO

Capsules per bottle

60

Bottle duration

30 days at the label serving of 2 capsules daily

Format

Capsules only — we do not sell St John's Wort as drops, tincture, tea or oil

What "10:1" actually means, arithmetically

An extract ratio describes how much dried plant material went in relative to how much extract came out. Ten parts of dried herb processed to yield one part of finished extract: ten kilograms of dried aerial parts for every kilogram of extract powder.

900mg of a 10:1 extract is derived from roughly 9 grams of dried aerial parts. The two-capsule serving: about 18 grams.

Applied to our capsule:

• 900mg of a 10:1 extract is derived from approximately 9,000mg — that is 9 grams — of dried aerial parts.
• The label serving of 2 capsules provides 1,800mg of extract, derived from approximately 18 grams of dried aerial parts.

Two caveats. An extract ratio is a manufacturing description, not a measure of strength — extraction is selective, so an extract is not simply "concentrated herb". And ratios are quoted as a nominal figure; a real batch sits within a range around it.

What "standardised to 0.3% hypericin" means, arithmetically

Standardisation means the extract is assayed and adjusted so a named marker compound is present at a stated level. Here the marker is hypericin, one of the plant's characteristic naturally occurring constituents.

• 0.3% of 900mg = 2.7mg of hypericin per capsule.
• At 2 capsules daily, that is 5.4mg of hypericin per day.

A note on hyperforin

This bears on safety, so we are being explicit. St John's Wort contains a second well-studied constituent, hyperforin, and hyperforin is the constituent most closely associated with the enzyme-induction interactions described further down this page. The EMA herbal monograph on Hypericum perforatum L., herba draws a line between preparations delivering 1mg or less of hyperforin per day used for no longer than two weeks — for which it states no clinically relevant interactions are to be expected — and preparations above that threshold, for which it lists extensive contraindications.

Our extract is standardised to hypericin. Hyperforin is not standardised and no hyperforin content is declared on our label. So we do not claim the low-hyperforin exemption, and you should assume the full set of interaction cautions on this page applies to this product.

Serving

2 capsules daily

With food?

Preferably with a meal, and with water

Timing

The label does not specify a time of day. Most people find it simplest to attach it to whichever meal is most consistent in their week

Maximum

Do not exceed the recommended amount

Drops or liquid

Not applicable — this product is capsules only

Storage

Cool, dry place out of direct sunlight. Replace the cap firmly. Keep out of the sight and reach of children

Swallow the capsules whole with water. Do not exceed the stated serving on the assumption that more is somehow better — St John's Wort has a documented overdose picture, and the product label carries the relevant cautions.

Food supplements are not a substitute for a varied and balanced diet or a healthy lifestyle.

Read the information supplied with the product before the first capsule. With this botanical the question that matters is not how to take it. It is whether you should be taking it at all.

One format only: a two-piece cellulose capsule holding the dry extract powder. No drops, tincture, tea or infused oil in the range, so there is no liquid dosing to get wrong.

Swallowed whole with water, a capsule has essentially no taste. The cellulose shell is neutral and dissolves after swallowing, so the extract inside is not released in the mouth.

Open one and the powder is typically dark greenish-brown to olive, with a dry, hay-like, faintly bitter herbal smell — recognisably a dried-plant extract rather than anything floral. Hypericin is a strongly coloured red pigment, and concentrated St John's Wort material can stain fabric and worktops. We would not recommend opening the capsules or sprinkling the contents onto food: the extract is unpleasantly bitter on its own, the serving becomes harder to measure, and you lose the point of the capsule.

No flavourings, sweeteners or coatings. Nothing has been added to mask the taste because, taken as intended, there is no taste to mask.