What is Reindeer lichen?

Reindeer lichen is a pale, branching ground lichen of northern heaths and open pine forest. It is not a plant. It is a fungus and an alga living together as one body.

In Scandinavia it is called reinlav in Norwegian and jeagil in Sami. It was gathered mainly as winter pasture for reindeer. In hard years people washed it, treated it and baked it into bread.

Today it shows up as a foraged food, a craft material and the odd supplement. Long traditional use is not proof that it works, and it is not proof that it is safe. Human evidence for any health claim is essentially absent.

How does Reindeer lichen work?

No one has shown that reindeer lichen does anything useful in the human body.

The lichen makes bitter acids that guard it against grazing and microbes. In test tubes, these acids slow some bacteria and fungi. Whether that happens in a person is not established.

It is also rich in lichenan, a fibre-like sugar chain. In theory that could soothe the gut or feed gut bacteria. The idea has not been tested in people.

Processing changes the picture. Soaking in ash water or weak soda strips out much of the bitter acid. Whatever those acids might do is likely cut by that step.

Reindeer digest lichen well, with help from their gut microbes. Humans do not. Animal findings here say little about you.

What forms does Reindeer lichen come in?

Reindeer lichen turns up in a few plain forms.

Dried whole lichen is the most common. Foragers soak and rinse it, dry it again, then grind it to a flour.

You may also meet it as a boiled tea, as a powder in capsules, or as a liquid extract. Quality and content vary a lot between sellers.

Dyed lichen is sold for wreaths, floristry and model railways. This craft material is treated with dyes and preservatives. Never eat it or brew it.

Where it comes from:

Sami and other northern peoples knew reindeer lichen first as reindeer winter feed. Herders tracked lichen heaths season by season, because the herds depended on them.

In famine years people prepared it for themselves. Records from Norway, Sweden and Finland describe soaking it in ash water or weak soda. It was then dried, ground and mixed into bread with grain flour.

Folk use also covered coughs, chest trouble and loose bowels. A bitter boiled brew was the usual form. Poultices on wounds and sores are also recorded.

These accounts describe what people did. They did not measure whether anyone got better.

What does Reindeer lichen help with?

• Cough and chest congestion: Nordic folk practice used a boiled lichen brew for coughs and chest complaints. The thick, slimy liquid was thought to coat a sore throat. No human trial supports this. Any comfort is most likely the warm drink itself.
• Diarrhoea and upset stomach: Tradition used the bitter decoction for loose bowels. The fibre-like sugars may bulk stool, as other soluble fibres do. This has not been tested in people with diarrhoea. Raw or poorly washed lichen can make stomach upset worse.
• Wounds and skin sores: Mashed lichen was laid on wounds and sores in some northern households. In test tubes, lichen acids slow the growth of some bacteria. There is no human evidence that it helps wounds heal. Applying unsterile plant matter to a broken skin surface can cause infection.
• Famine or survival food: This is the use with the strongest historical record. Soaked, treated and ground lichen stretched scarce grain through bad winters. It is a source of carbohydrate, not a balanced food. It is very low in protein and vitamins.
• Source of dietary fibre: Lichenan acts much like other soluble fibres in the lab. Whether it benefits human digestion or cholesterol has not been studied. Oats, barley and psyllium have real human evidence for fibre effects. Reindeer lichen does not.

Which foods are rich in Reindeer lichen?

Reindeer lichen is not an ingredient in everyday foods. It appears only as foraged lichen flour or in a few novelty Nordic products. Reindeer meat is the usual way lichen compounds, and lichen-borne caesium, reach the human diet.

What are the side effects of Reindeer lichen?

• Strong bitter taste and nausea
• Stomach cramps and wind
• Diarrhoea or constipation from the fibre
• Mouth and throat irritation from unwashed lichen
• Itchy skin rash in people who handle lichens often
• Liver injury linked to usnic acid in concentrated lichen supplements
• Taking in caesium-137 or heavy metals from lichen picked in polluted or fallout areas

Good to know:

Most reported problems are mild gut upset from raw or badly washed lichen.

The serious risk is liver harm, and it is tied to concentrated supplements that contain usnic acid. Cases are rare but some have been severe. Food-style use of washed lichen has no such case record, but it has not been studied either.

How much Reindeer lichen should you take?

• Recommended daily: No established dose exists for reindeer lichen, so this page gives none. Dried lichen is handled as a food, not a medicine, and labels rarely carry an amount. Capsule and extract products differ widely in strength. Several have been found not to match their labels. In tradition it was a flour extender in bread, not something taken by the spoonful. If you are weighing up a lichen supplement, ask a pharmacist or doctor first.
• Best time of day: Time of day does not matter. Nothing in the lichen is known to act on sleep or alertness. If you eat it as food, meal times are the practical choice.
• With or without food: Treat it as a food and take it with meals. The bitter acids can irritate an empty stomach. Soaking and rinsing before use lowers that bitterness.
• Time to effect: There is no reliable effect to time. No human trial has shown a health benefit, so it may do nothing at all. Fibre effects on bowel habit, if they happen, would show in a day or two. Any throat comfort from a warm brew lasts only while you drink it.
• How long to take it: No safe length of use has been set. Traditional food use was seasonal and short, tied to hard winters. Long daily use has never been studied in people. Lichens also collect caesium-137 and metals over years of growth. That is a further reason not to make it a daily habit.