Natrol Mood Positive 5-HTP Review

Mood Positive 5-HTP

Mood Positive 5-HTP is a mood-aid by Natrol which contains just two active ingredients: Theanine and 5-HTP…


Mood Positive 5-HTP is a mood-aid by Natrol which contains just two active ingredients: Theanine and 5-HTP…[Skip to the Bottom Line]


Neurotransmission is the process by which neurons (brain cells) send each other electrical or (as in the case of serotonin) chemical signals. During neurotransmission, neurotransmitters (like serotonin) are sent from one neuron to the next through a junction called a synapse. Some of the neurotransmitters are absorbed into the next neuron, but some remain in the space between the neurons, called the synaptic space. The molecules that remain in the synaptic space are then either reabsorbed (through the process of reuptake) or destroyed. There are three theoretical ways to treat depression through increasing the neurotransmission of serotonin.

The first way, the most commonly prescribed treatment for depression, is with compounds called selective serotonin reuptake inhibitors (SSRIs). SSRIs, as the name implies, are compounds which inhibit the reuptake of serotonin from the synaptic space (as described above). The result is that more serotonin is available to be absorbed by the next neuron.

The second way is with compounds called monoamine oxidase inhibitors (MAOIs). The term “monoamine” refers to a group of neurotransmitters including adrenaline, noradrenaline, dopamine, and serotonin. “Monoamine oxidase” refers to a group of enzymes whose main function is to destroy (oxidize) monoamines that are leftover in the synaptic space during neurotransmission. The result is that more monoamines remain available for absorption by the next neuron. Because monoamine oxidase inhibitors are not just specific to serotonin, they are generally not the first choice for doctors when treating depression, but are used in certain cases to modulate several neurotransmitters.

The third way, which is also the least proven and therefore least commonly prescribed way of treating depression, has to do with the formation of serotonin in the first place. Serotonin is created through a process of chemical conversions starting with the amino acid Tryptophan, so it is theorized that supplementing with the precursors (either Tryptophan or 5-HTP) can increase serotonin, as alluded to in a 1989 study published in the “Journal of Affective Disorders” in which researchers found lower levels of tryptophan in depressed subjects compared to non-depressed subjects. However, because of rate-limiting factors, Tryptophan is relatively ineffective at increasing serotonin when supplemented, which brings us to 5-HTP.


While 5-HTP has been demonstrated to effective increase serotonin, it has produced lackluster results when studied as a potential treatment for depression. The theoretical mechanism of action by which 5-HTP could be used to treat depression is there, but other treatments (such as SSRIs) have simply proven to be more effective. Since 5-HTP is not clinically proven, there is no clinically proven dose but the supplement industry standard is 50 or 100mg. Mood Positive contains 50mg of 5-HTP.


Theanine is an amino acid found primarily in green tea, and is alleged to counteract the jitteriness generally associated with caffeine (also in green tea) consumption. Animal studies have shown a decrease in markers of stress when theanine is consumed, as well decreased corticosterone (a hormone which regulates the stress response) levels, indicating reduced corticosterone is likely the mechanism of action by which theanine reduces stress/anxiety. In humans, doses of 200mg have been effective at reducing perceived stress, but more studies are needed to determine the degree of efficacy at different doses. Anecdotal reports have described theanine as being capable of inducing a state of “calm alertness”, because while Theanine does appear to have anxiolytic potential, it does not cause drowsiness. Mood Positive contains 50 mg which has never been studied. At this dose, it is not as likely users would report an obvious effect, but there may be some benefit over time.


Mood Positive contains a very simple blend of 5-HTP (50mg) and L-Theanine (50mg). While both of these compounds have some preliminary support, neither is objectively effective for treating depression. 5-HTP has been anecdotally reported by many to reduce symptoms of depression, while Theanine has been reported to reduce symptoms of anxiety and stress (although generally at closer to 200mg). However, given the lack of conclusive evidence, there are better options for treating depression than Mood Positive. At about 20 cents per dose (lowest price found), the product is expensive consider the same formula could be easily reconstructed for half that.

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  2. Shaw, K., J. Turner, and C. Del Mar. “Tryptophan and 5-hydroxytryptophan for depression.” Cochrane Database Syst Rev 1 (2002).
  3. Neumeister, Alexander. “Tryptophan depletion, serotonin, and depression: where do we stand?.” Psychopharmacology bulletin 37.4 (2002): 99-115.
  4. Lacasse, Jeffrey R., and Jonathan Leo. “Serotonin and depression: A disconnect between the advertisements and the scientific literature.” PLoS Medicine 2.12 (2005): e392.
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  6. Kimura, Kenta, et al. “L-Theanine reduces psychological and physiological stress responses.” Biological psychology 74.1 (2007): 39-45.
  7. Takeda, Atsushi, et al. “Unique induction of CA1 LTP components after intake of theanine, an amino acid in tea leaves and its effect on stress response.”Cellular and molecular neurobiology 32.1 (2012): 41-48.
  8. Tamano, Haruna, et al. “Preventive Effect of Theanine Intake on Stress-induced Impairments of Hippocamapal Long-term Potentiation and Recognition Memory.” Brain research bulletin (2013).

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