Synergy of supplements, part 6 – L-DOPA, 5-HTP and EGCG


Knowledge about biochemistry, also in the brain, is increasingly available. As a result, many people seek help in supplements to improve their mental state. In the search for happiness, we want to increase the levels of serotonin and dopamine, which put our brains on positive vibrations. The simplest way seems to be to provide direct precursors to these neurotransmitters, which are easily available in stores with supplements.

Neurotransmitters supplementation

Opinions on the supplementation of direct precursors are mixed, and it is particularly discouraged to take them in constant supplementation, which could potentially cause negative consequences. Ad hoc admission, however, often works quite well, although of course it is best to choose supplements for specific indications. We will not focus here, however, on the analysis of indications and contraindications, and on improving the effectiveness of 5-HTP and L-DOPA supplements in aspects of mood improvement, when someone will decide on supplementation. In this, green tea extract can help us! More specifically, polyphenols contained in it, with EGCG at the forefront.

At the beginning, let's get acquainted with the specificity of each substance

Specification of substances

5-HTP (5-hydroxytryptophan) - a derivative of the amino acid tryptophan, which then converts to serotonin. The 5-HTP half-life is quite short because it is about 2 hours, which severely limits its therapeutic use. 5-HTP has numerous interactions with drugs, mainly anti-depressants, which is the most common reason for abandoning supplementation.

5-HTP - chemical formula
5-HTP - chemical formula

L-DOPA (3,4-dihydroxyphenylalanine) - an element on the pathway of conversion of tyrosine to dopamine. Used in supplementation to raise the level of this neurotransmitter, but also to increase the level of testosterone. In medicine, it is used as part of the Parkinson's disease treatment. It is usually obtained from natural sources, mainly from Mucuna Pruriens ( Velvet Bean).

Levodopa - chemical structure
Levodopa - chemical structure

EGCG (Galusan epigallocatechin) - the main flavonoid contained in green tea, next to epigallocatechin , gallate epicatechin and epicatechin . EGCG is a combination of gallic acid with epigallocatechin . After oral administration, part of EGCG is broken down into these two components by intestinal bacteria4. It has a strong antioxidant effect, it is also a popular addition to complex fat burners.

EGCG (epigallocatechin gallate) chemical formula
EGCG (epigallocatechin gallate) chemical formula

What connects these 3 substances?

Well, 5-HTP and L-DOPA are converted to major neurotransmitters with the same enzyme - aromatic L-amino acid decarboxylase (AAAD), often also called L-DOPA decarboxylase (DDC). And the AAAD activity in turn is irreversibly blocked by EGCG23. Therefore, one could wonder why EGCG should be used, since it inhibits the conversion of precursors to the desired neurotransmitters? Well, EGCG has a very limited ability to cross the blood-brain barrier4, thus inhibiting this conversion only in peripheral tissues. It causes that smaller amounts of precursors are converted in the bloodstream, and larger ones reach the brain, only to be transformed into happy molecules. This is important because the serotonin and dopamine produced in the peripheral tissues are not able to cross the barrier and enter the brain.

L-DOPA, EGCG and 5-HTP synergy

In medicine, L-DOPA is often used with the pharmacological inhibitor of AAAD - carbidopa , which significantly increases the effectiveness of the treatment. Carbidopa was also tested as a 5-HTP companion, with a 5-HTP half-life in this procedure doubling and AUC increasing more than 15-fold at the same dose1. The green tea extract seems to be an attractive, non-prescription alternative.

In supplements, we usually see green tea extracts that are standardized at 50% EGCG. The rest of the mass contains in some amounts other flavonoids, including ECG ( epigallocatechin ). This compound similarly to EGCG inhibits AAAD2 activity, so the effect is even more effective.

If we talk about synergy, it is worth mentioning that the AAAD enzyme is dependent on vitamin B6, and more specifically the active form of P5P, so it is worth to take care of its proper level, so that the synthesis of neurotransmitters goes without complications.

L-DOPA, EGCG and 5-HTP synergy - summarization

In conclusion, adding green tea extract to the supplement with L-DOPA or 5-HTP seems to be a great solution when the goal is to improve the well-being. It allows to significantly increase the effectiveness of supplementation, enriching it simultaneously with a package of health-promoting properties, of which green tea is known.

Tags: 5-htp, egcg, l-dopa, synergy


  1. Avatar

    Hi David
    Thanks for this article.
    I have been experimenting with this combination for some time and am happy to find this info.
    The problem is so much info out there and I can’t seem to find any references to specific dosages including schedules of the combinations,
    I know it varies, but what would have you found to be a good dose
    (I have 250 mg 98% Ldopa from Mucuna Pruriens)
    green tea- which has variable EGCG standardized percentages of polyphenols

    The most important thing I haven’t found specifically is how much polyphenols are needed/ per ?mg dose of Ldopa AFTER you do the math and get down to the actual numbers!
    AND, does the 5htp get taken at the same time ?
    or can 5htp be taken at night and Ldopa/Green tea during the day?
    Id love to hear if you have found any specific info
    Thanks again

  2. Avatar

    Hi David –

    Do you take L-Dopa, 5-htp, and ecgc at the same time? Or should it only be l-dopa or 5-htp?

  3. Avatar

    so itmentions the use of p5p with the AAAD enzyme etc. does the addition of p5p help with the amount able to cross the bbb? and if so, and was taking 500mg of each before bed to be happy and relieve a bit of pain/rls and get some happy sleep would you have any recommendations?

    • David

      Potentially It could. Nonetheless, 500mg is a very high dose indeed. Try to start from lower dosages as an addition to stack provided above. Should do the trick!

  4. Avatar

    Where are the scientific references ?

  5. Avatar

    Hi David I’m taking DOPA anf 5HTP but I can not tolerate caffeine from Green Tea so any other suggestion instead of Green Tea? Thanks

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