Tanganil and N-Acetyl-L-Leucine

What is it?

Tanganil is a drug from France that has been sold there without a prescription for dizziness since 1960. The active ingredient is acetyl-DL-leucine, a modified amino acid. It consists of equal parts of two mirror-image forms: the L-form and the D-form. The pure L-form is called N-acetyl-L-leucine (NALL for short).

What does the research say?

September 2024: Prof. Wolfgang Oertel of the University of Marburg reported in Nature Communications on two patients with REM sleep behavior disorder, a common early sign of Parkinson's. On acetyl-DL-leucine, their symptoms improved, and imaging of the dopamine system partly improved. The German Neurological Society called it a "sensational observation." But these are single cases.

2025: The same group described three patients with advanced multiple system atrophy, a disease related to Parkinson's. Their walking and balance got clearly worse. At this stage, the authors tend to advise against it.

March 2026: Researchers at Northwestern University in Chicago led by Prof. Dimitri Krainc showed in the Journal of Clinical Investigation, using nerve cells from Parkinson's patients and in mice: only the L-form lowers the diseased alpha-synuclein. In doing so, it activates the protective protein HTRA1, increases the protein Parkin and improves the function of nerve connections. The D-form had no effect. In the USA, the pure L-form has been approved since 2024 as a drug for the rare Niemann-Pick disease type C.

Controlled studies in people with Parkinson's are still pending.

Sources: Oertel et al., Nature Communications 2024 · Song et al., Journal of Clinical Investigation 2026

My experience

On September 14, 2024, I started taking Tanganil and increased the dose within one week to 5 grams a day (10 tablets, spread over morning, noon and evening), as in the Marburg publication. Since February 25, 2025, I have been taking 2.5 grams of the pure L-form instead. That equals the same amount of active L-leucine.

• Side effects: none
• Worsening: none
• Effect on my symptoms: after two years, none that I can clearly attribute to it
• Mood: very good, but I use many methods at the same time, including lithium

I keep taking NALL anyway, because other people with Parkinson's report positive experiences in the forums. At a conference, Prof. Strupp from Munich mentioned 4.5 grams a day as a possibly better dose. I am thinking about increasing it.

Practical tips on the L-form

NALL comes as a powder. It does not dissolve in water, so I use a precision scale to fill it into capsules of about 500 mg each. At 2.5 grams a day you need about 900 grams a year, at 4.5 grams about 1,600 grams. If that is too much work for you, you are better off sticking with Tanganil tablets.

Unfortunately, I can't name any sources because of legal cease-and-desist letters. Please don't write to me about it.

Effort and cost

At 5 grams a day, Tanganil costs about 500 euros a year, NALL at 2.5 grams about 300 euros. Tanganil is available without a prescription in France but is not approved in Germany. Getting it has become more difficult.

My conclusion

So far, Tanganil has done nothing for me. Still, I consider it one of the most exciting discoveries of recent years: an old, inexpensive and well-tolerated drug. If the observations are confirmed in larger studies, it could help above all people in the prodromal or early stage. Please talk to your doctor before taking it.